Merge remote-tracking branch 'origin/eigensolvers-dev' into arpack-dev

Verify that `ofstream` is open

.github/actions/sanitize/mfem/action.yml

@@ -25,7 +25,7 @@ runs:
   steps:
     - uses: ./.github/actions/sanitize/config
 
-    - uses: actions/cache@v4
+    - uses: actions/cache@v5
       if: ${{env.DEBUG == 'true'}}
       id: debug
       with:

.github/actions/sanitize/restore/action.yml

@@ -36,7 +36,7 @@ runs:
   steps:
     - uses: ./.github/actions/sanitize/config
 
-    - uses: actions/cache@v4
+    - uses: actions/cache@v5
       if: ${{env.DEBUG == 'true' && inputs.cache-skip != 'true'}}
       id: debug
       with:

.github/actions/sanitize/setup/action.yml

@@ -23,7 +23,7 @@ inputs:
 runs:
   using: 'composite'
   steps:
-    - uses: actions/cache/restore@v4  # Cache for LLVM libcxx
+    - uses: actions/cache/restore@v5  # Cache for LLVM libcxx
       with:
         path: ${{env.LLVM_DIR}}
         fail-on-cache-miss: true
@@ -32,14 +32,14 @@ runs:
     - uses: ./.github/actions/sanitize/mpi
       if: ${{inputs.par == 'true'}}
 
-    - uses: actions/cache/restore@v4  # Cache for Hypre
+    - uses: actions/cache/restore@v5  # Cache for Hypre
       if: ${{inputs.par == 'true'}}
       with:
         path: ${{env.HYPRE_DIR}}
         fail-on-cache-miss: true
         key: ${{runner.os}}-ompi-build-${{env.HYPRE_DIR}}-int32-fp64-v2.5
 
-    - uses: actions/cache/restore@v4  # Cache for Metis
+    - uses: actions/cache/restore@v5  # Cache for Metis
       if: ${{inputs.par == 'true'}}
       with:
         path: ${{env.METIS_DIR}}
@@ -51,13 +51,13 @@ runs:
       run: ln -s -f ${{env.HYPRE_DIR}} hypre && ln -s -f ${{env.METIS_DIR}} metis-4.0
       shell: bash
 
-    - uses: actions/cache/restore@v4  # Cache for LSAN suppression file
+    - uses: actions/cache/restore@v5  # Cache for LSAN suppression file
       with:
         path: ${{env.LSAN_DIR}}
         fail-on-cache-miss: true
         key: build-lsan-suppression-file
 
-    - uses: actions/checkout@v4  # Checkout the repository
+    - uses: actions/checkout@v6  # Checkout the repository
       with:
         path: mfem
         # ref: ${{env.BRANCH}}

.github/workflows/build-container.yml

@@ -43,7 +43,7 @@ jobs:
           remove-docker-images: 'true'
 
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # It's easier to reference named variables than indexes of the matrix
       - name: Set Environment

.github/workflows/builds-and-tests.yml

@@ -153,7 +153,7 @@ jobs:
       # /home/runner/work/mfem/mfem/mfem
       # Note: Done now to access "install-hypre" and "install-metis" actions.
       - name: checkout mfem
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           path: ${{ env.MFEM_TOP_DIR }}
           # Fetch the complete history for codecov to access commits ID
@@ -225,7 +225,7 @@ jobs:
       - name: cache hypre
         id: hypre-cache
         if: matrix.mpi == 'par'
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ env.HYPRE_TOP_DIR }}
           key: ${{ runner.os }}-ompi-build-${{ env.HYPRE_TOP_DIR }}-${{ matrix.hypre-target }}-${{ matrix.precision }}-v2.5
@@ -255,7 +255,7 @@ jobs:
       - name: cache metis
         id: metis-cache
         if: matrix.mpi == 'par' && matrix.os != 'windows-latest'
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ env.METIS_TOP_DIR }}
           key: ${{ runner.os }}-build-${{ env.METIS_TOP_DIR }}-v2.5
@@ -270,7 +270,7 @@ jobs:
       - name: cache vcpkg (Windows)
         id: vcpkg-cache
         if: matrix.os == 'windows-latest'
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: vcpkg_cache
           key: ${{ runner.os }}-${{ matrix.mpi }}-vcpkg-v1
@@ -295,7 +295,8 @@ jobs:
           export HOMEBREW_NO_INSTALL_CLEANUP=1
           brew update
           brew install enzyme
-          ENZYME_LLVM=$(brew info enzyme | sed -n 's/^Required:.*\(llvm[^ ]*\).*/\1/p')
+          ENZYME_LLVM=$(brew info enzyme | sed -n 's/^Required.*:.*\(llvm[^ ]*\).*/\1/p')
+          echo "ENZYME_LLVM=$ENZYME_LLVM"
           LLVM_PREFIX=$(brew --prefix $ENZYME_LLVM)
           echo "LLVM_PREFIX=$LLVM_PREFIX" >> $GITHUB_ENV
           echo "OMPI_CC=$LLVM_PREFIX/bin/clang" >> $GITHUB_ENV

.github/workflows/codeql-analysis.yml

@@ -40,11 +40,11 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       # Initializes the CodeQL tools for scanning.
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v2
+        uses: github/codeql-action/init@v4
         with:
           languages: ${{ matrix.language }}
           # If you wish to specify custom queries, you can do so here or in a config file.
@@ -57,7 +57,7 @@ jobs:
       # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
       # If this step fails, then you should remove it and run the build manually (see below)
       - name: Autobuild
-        uses: github/codeql-action/autobuild@v2
+        uses: github/codeql-action/autobuild@v4
 
       # ℹ️ Command-line programs to run using the OS shell.
       # 📚 See https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idstepsrun
@@ -70,4 +70,4 @@ jobs:
       #   ./location_of_script_within_repo/buildscript.sh
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v2
+        uses: github/codeql-action/analyze@v4

.github/workflows/mfem-analysis.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
       - name: checkout MFEM
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           path: mfem
 
@@ -50,7 +50,7 @@ jobs:
 
       - name: Cache Hypre Install
         id: hypre-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ env.HYPRE_TOP_DIR }}
           key: ${{ runner.os }}-ompi-build-${{ env.HYPRE_TOP_DIR }}-v2.5
@@ -65,7 +65,7 @@ jobs:
 
       - name: Cache Metis Install
         id: metis-cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{ env.METIS_TOP_DIR }}
           key: ${{ runner.os }}-build-${{ env.METIS_TOP_DIR }}-v2.5

.github/workflows/repo-check.yml

@@ -38,7 +38,7 @@ jobs:
        github.event.pull_request.head.repo.full_name != github.repository)
     steps:
       - name: checkout mfem
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: copyright check
         id: copyright
@@ -93,7 +93,7 @@ jobs:
        github.event.pull_request.head.repo.full_name != github.repository)
     steps:
       - name: checkout mfem
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: get astyle
         run: |
@@ -110,7 +110,7 @@ jobs:
        github.event.pull_request.head.repo.full_name != github.repository)
     steps:
       - name: checkout mfem
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: get doxygen and graphviz
         run: |
@@ -135,7 +135,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: checkout mfem
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
 

.github/workflows/sanitize-build-hypre.yml

@@ -17,11 +17,11 @@ jobs:
     runs-on: ubuntu-latest
     name: 2.19.0
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/config
       - name: Cache
         id: cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{env.HYPRE_DIR}}
           key: ${{runner.os}}-ompi-build-${{env.HYPRE_DIR}}-int32-fp64-v2.5

.github/workflows/sanitize-build-libcxx.yml

@@ -27,13 +27,13 @@ jobs:
             llvm_use_sanitizer: "Undefined"
     name: ${{matrix.sanitizer}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/config
         with:
           NO_FLAGS: true
       - name: Cache
         id: cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{env.LLVM_DIR}}
           key: build-libcxx-${{env.LLVM_VER}}-${{matrix.sanitizer}}

.github/workflows/sanitize-build-lsan.yml

@@ -17,11 +17,11 @@ jobs:
     runs-on: ubuntu-latest
     name: lsan.supp
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/config
       - name: Cache
         id: cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{env.LSAN_DIR}}
           key: build-lsan-suppression-file

.github/workflows/sanitize-build-metis.yml

@@ -17,11 +17,11 @@ jobs:
     runs-on: ubuntu-latest
     name: 4.0.3
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/config
       - name: Cache
         id: cache
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: ${{env.METIS_DIR}}
           key: ${{runner.os}}-build-${{env.METIS_DIR}}-v2.5

.github/workflows/sanitize-tests.yml

@@ -28,7 +28,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/mfem
         with:
           par: ${{inputs.par}}
@@ -40,7 +40,7 @@ jobs:
     env:
       ex: ${{inputs.par && 'ex1p' || 'ex1'}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/restore
         id: restore
         with:
@@ -58,7 +58,7 @@ jobs:
     env:
       exclude: ${{inputs.par && '-E "_ser"' || ''}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/restore
         id: restore
         with:
@@ -82,7 +82,7 @@ jobs:
     env:
       exclude: ${{inputs.par && '-E "_ser"' || ''}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/restore
         id: restore
         with:
@@ -107,7 +107,7 @@ jobs:
       run: ${{inputs.par && '-R "_cpu_np"' || ''}}
       exclude: ${{inputs.par && '"unit_tests|debug"' || '"^unit_tests$|debug"'}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/restore
         id: restore
         with:
@@ -131,7 +131,7 @@ jobs:
     env:
       unit_tests: ${{inputs.par && 'punit_tests' || 'unit_tests'}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/restore
         id: restore
         with:
@@ -165,7 +165,7 @@ jobs:
       unit_tests: ${{inputs.par && 'punit_tests' || 'unit_tests'}}
       np: ${{inputs.par && '_np=2' || ''}}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - uses: ./.github/actions/sanitize/restore
         id: restore
         with:

.gitignore

@@ -369,6 +369,7 @@ miniapps/shifted/lsf_integral
 miniapps/tools/display-basis
 miniapps/tools/load-dc
 miniapps/tools/convert-dc
+miniapps/tools/compare-dc
 miniapps/tools/gridfunction-bounds
 miniapps/tools/lor-transfer
 miniapps/tools/plor-transfer
@@ -442,6 +443,10 @@ miniapps/diag-smoothers/mg-abs-l1-jacobi
 miniapps/contact/contact
 miniapps/contact/ParaView
 
+miniapps/plasma/pic/electrostatic-*
+!miniapps/plasma/pic/electrostatic-*.cpp
+miniapps/plasma/pic/*.csv
+
 # Unit test binary and outputs
 tests/unit/output_meshes
 tests/unit/unit_tests

CHANGELOG

@@ -8,6 +8,22 @@
                                https://mfem.org
 
 
+Version 4.10 (development)
+==========================
+
+Discretization improvements
+---------------------------
+- Replaced legacy simplex quadrature rules with symmetric positive-weight
+  rules for triangles (orders 0-25) and tetrahedra (orders 0-20). These
+  rules guarantee all-positive weights and interior quadrature points,
+  improving numerical stability. Higher orders fall back to Grundmann-Moller.
+  Triangle rules: Witherden & Vincent, Comput. Math. Appl. 69(10):1232-1241,
+  2015.
+  Tet rules (d=1-13): Witherden & Vincent (ibid).
+  Tet rules (d=14-20): Chuluunbaatar et al., Comput. Math. Appl. 124:89-97,
+  2022.
+
+
 Version 4.9.1 (development)
 ===========================
 
@@ -17,11 +33,19 @@ Discretization improvements
   Vector and VectorFE, also NURBS versions. Optionally different types of
   projections can be selected, default behaviour has not changed.
 
+- Added methods to estimate function extremum using piecewise linear bounds +
+  recursive subdivision.
+
 Meshing improvements
 --------------------
 - Improved support for 1D NURBS meshes with variable order, including using
   the patches construct for 1D NURBS meshes.
 
+New and updated examples and miniapps
+-------------------------------------
+- Electromagnetics/lorentz miniapp has been updated to leverage the ParticleSet
+  capability.
+
 
 Version 4.9, released on Dec 11, 2025
 =====================================
@@ -106,6 +130,23 @@ Linear and nonlinear solvers
   Filtering (AMGF), providing robust preconditioning for linear systems arising
   in constrained optimization problems such as frictionless contact.
 
+  Added 'GetResiduals' and 'GetFinalAbsResidualNorm' to 'HyprePCG',
+  'HypreGMRES', and 'HypreFGMRES' to get 'r' and '|r|_p'. Note that the latter
+  computes '|r|_p' from 'r' instead of returning a cached value like the
+  relative 'GetFinalResidualNorm'. These require Hypre >= 2.15.0.
+
+  Changed the default solver parameters for 'HyprePCG' to 'tol=1e-6' and
+  'max_iter=1000'. This matches the default parameters in Hypre 3.0.
+
+  Added various helper functions for querying/modifying Hypre solvers:
+  'HypreSmoother::GetType', 'HypreSmoother::GetSOROptions',
+  'HypreSmoother::GetPolyOptions', 'HypreSmoother::GetWindowParameters',
+  'HypreSmoother::IsOperatorSymmetric', 'HyprePCG::GetTol',
+  'HyprePCG::GetAbsTol', 'HyprePCG::GetMaxIter', 'HyprePCG::SetUseTwoNorm',
+  'HypreGMRES::GetTol', 'HypreGMRES::GetAbsTol', 'HypreGMRES::GetMaxIter',
+  'HypreGMRES::GetKDim', 'HypreFGMRES::GetTol', 'HypreFGMRES::GetMaxIter',
+  'HypreFGMRES::GetKDim', and 'HypreBoomerAMG::GetMaxIter'.
+
 GPU computing
 -------------
 - Added the 'gpu', 'raja-gpu', and 'ceed-gpu' backend aliases/shortcuts which

CMakeLists.txt

@@ -652,6 +652,8 @@ foreach(TPL IN LISTS MFEM_TPLS)
   endif()
 endforeach(TPL)
 
+# reverse to remove the first instance of entries in TPL_LIBRARIES
+# so later duplicates are kept (for dependency ordering)
 list(REVERSE TPL_LIBRARIES)
 list(REMOVE_DUPLICATES TPL_LIBRARIES)
 list(REVERSE TPL_LIBRARIES)
@@ -1015,5 +1017,7 @@ install(DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/data
 # Create 'config.mk' from 'config.mk.in' for the build and install locations and
 # define install rules for 'config.mk' and 'test.mk'
 #-------------------------------------------------------------------------------
-
+if (MFEM_USE_CUDA OR MFEM_USE_HIP)
+  option(MFEM_EXPORT_GPU_CONFIG "Export config.mk for GPU-enabled downstream packages" ON)
+endif()
 mfem_export_mk_files()

config/cmake/MFEMConfig.cmake.in

@@ -109,6 +109,10 @@ if (MFEM_USE_RAJA)
    find_dependency(RAJA)
 endif()
 
+if (MFEM_USE_UMPIRE)
+   find_dependency(umpire)
+endif()
+
 if (NOT TARGET mfem)
   include(${CMAKE_CURRENT_LIST_DIR}/MFEMTargets.cmake)
 endif (NOT TARGET mfem)

config/cmake/modules/FindUMPIRE.cmake

@@ -14,12 +14,12 @@
 #   - UMPIRE_LIBRARIES
 #   - UMPIRE_INCLUDE_DIRS
 
-if (NOT umpire_DIR AND UMPIRE_DIR)
-  set(umpire_DIR ${UMPIRE_DIR}/lib/cmake/umpire)
+if (NOT umpire_ROOT AND UMPIRE_DIR)
+  set(umpire_ROOT ${UMPIRE_DIR})
 endif()
 message(STATUS "Looking for UMPIRE ...")
 message(STATUS "   in UMPIRE_DIR = ${UMPIRE_DIR}")
-message(STATUS "      umpire_DIR = ${umpire_DIR}")
+message(STATUS "      umpire_ROOT = ${umpire_ROOT}")
 find_package(umpire CONFIG)
 set(UMPIRE_FOUND ${umpire_FOUND})
 set(UMPIRE_LIBRARIES "umpire")

config/cmake/modules/MfemCmakeUtilities.cmake

@@ -701,7 +701,6 @@ endfunction(mfem_find_library)
 # Extract compile and link options needed by the given target.
 #
 function(mfem_get_target_options Target CompileOptsVar LinkOptsVar)
-
   if (NOT TARGET ${Target})
     return()
   endif()
@@ -799,7 +798,12 @@ function(mfem_get_target_options Target CompileOptsVar LinkOptsVar)
           # message(STATUS "Lib = ${Lib}")
           # Filter-out generator expressions
           if (NOT ("${Lib}" MATCHES "^\\$"))
-            list(APPEND LinkOpts "${Lib}")
+            if(NOT ("${Lib}" STREQUAL "dl"))
+              list(APPEND LinkOpts "${Lib}")
+            else()
+              # for some reason libdl doesn't include the "-l"
+              list(APPEND LinkOpts "-ldl")
+            endif()
           endif()
         else()
           mfem_get_target_options(${Lib} COpts LOpts)
@@ -888,9 +892,18 @@ function(mfem_export_mk_files)
       set(${var} NO)
     endif()
   endforeach()
-  # TODO: Add support for MFEM_USE_CUDA=YES
-  set(MFEM_CXX ${CMAKE_CXX_COMPILER})
-  set(MFEM_HOST_CXX ${MFEM_CXX})
+  if (MFEM_USE_CUDA AND MFEM_EXPORT_GPU_CONFIG)
+    set(MFEM_CXX ${CMAKE_CUDA_COMPILER})
+    if(MFEM_CUDA_COMPILER_IS_NVCC)
+      set(MFEM_HOST_CXX ${CMAKE_CUDA_HOST_COMPILER})
+    else()
+      set(MFEM_HOST_CXX ${CMAKE_CXX_COMPILER})
+    endif()
+  else()
+    # mfem doesn't use enable_language(HIP)
+    set(MFEM_CXX ${CMAKE_CXX_COMPILER})
+    set(MFEM_HOST_CXX ${CMAKE_CXX_COMPILER})
+  endif()
   set(MFEM_CPPFLAGS "")
   get_target_property(cxx_std mfem CXX_STANDARD)
   # For now, we ignore the setting of the CXX_EXTENSIONS property. If this
@@ -900,6 +913,50 @@ function(mfem_export_mk_files)
   string(STRIP
          "${cxx_std_flag} ${CMAKE_CXX_FLAGS_${BUILD_TYPE}} ${CMAKE_CXX_FLAGS}"
          MFEM_CXXFLAGS)
+  if(MFEM_EXPORT_GPU_CONFIG)
+    if (MFEM_USE_CUDA)
+      set(MFEM_CXXFLAGS "${MFEM_CXXFLAGS} ${CMAKE_CUDA_FLAGS}")
+      if (MFEM_CUDA_COMPILER_IS_NVCC)
+        set(MFEM_CXXFLAGS "-x=cu ${MFEM_CXXFLAGS} -ccbin ${CMAKE_CXX_COMPILER} --forward-unknown-to-host-compiler")
+        # The following intentionally hides CUDA deprecation warnings
+        foreach(ENTRY IN LISTS CUDAToolkit_INCLUDE_DIRS)
+          set(MFEM_CXXFLAGS "${MFEM_CXXFLAGS} -isystem ${ENTRY}")
+        endforeach()
+        if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.18.0)
+          # architecture flags not part of CMAKE_CUDA_FLAGS
+          if ("all" STREQUAL "${CMAKE_CUDA_ARCHITECTURES}"
+              OR "native" STREQUAL "${CMAKE_CUDA_ARCHITECTURES}"
+              OR "all-major" STREQUAL "${CMAKE_CUDA_ARCHITECTURES}")
+            set(MFEM_CXXFLAGS "${MFEM_CXXFLAGS} -arch=${CMAKE_CUDA_ARCHITECTURES}")
+          else()
+            foreach (ENTRY IN LISTS CMAKE_CUDA_ARCHITECTURES)
+              set(MFEM_CXXFLAGS
+                "${MFEM_CXXFLAGS} -gencode arch=compute_${ENTRY},code=sm_${ENTRY}")
+            endforeach()
+          endif()
+        endif()
+      else()
+        set(MFEM_CXXFLAGS "${MFEM_CXXFLAGS} -xcuda --cuda-path=${CUDAToolkit_LIBRARY_ROOT}")
+        if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.18.0)
+          # architecture flags not part of CMAKE_CUDA_FLAGS
+          if ("all" STREQUAL "${CMAKE_CUDA_ARCHITECTURES}"
+              OR "native" STREQUAL "${CMAKE_CUDA_ARCHITECTURES}"
+              OR "all-major" STREQUAL "${CMAKE_CUDA_ARCHITECTURES}")
+            # TODO: not supported
+          else()
+            foreach(ENTRY IN LISTS CMAKE_CUDA_ARCHITECTURES)
+              set(MFEM_CXXFLAGS "-cuda-gpu-arch=sm_${ENTRY} ${MFEM_CXXFLAGS}")
+            endforeach()
+          endif()
+        endif()
+      endif()
+    elseif (MFEM_USE_HIP)
+      set(MFEM_CXXFLAGS "${MFEM_CXXFLAGS} -xhip")
+      foreach(ENTRY IN LISTS CMAKE_HIP_ARCHITECTURES)
+        set(MFEM_CXXFLAGS "--offload-arch=${ENTRY} ${MFEM_CXXFLAGS}")
+      endforeach()
+    endif()
+  endif()
   set(MFEM_TPLFLAGS "")
   foreach(dir ${TPL_INCLUDE_DIRS})
     set(MFEM_TPLFLAGS "${MFEM_TPLFLAGS} -I${dir}")
@@ -930,6 +987,9 @@ function(mfem_export_mk_files)
     set(MFEM_SHARED NO)
     set(MFEM_STATIC YES)
   endif()
+  if (MFEM_USE_CUDA)
+    set(MFEM_EXT_LIBS "${MFEM_EXT_LIBS} -lcudart")
+  endif()
   set(MFEM_BUILD_TAG "${CMAKE_SYSTEM}")
   set(MFEM_PREFIX "${CMAKE_INSTALL_PREFIX}")
   # For the next 4 variables, these are the values for the build-tree version of
@@ -938,8 +998,15 @@ function(mfem_export_mk_files)
   set(MFEM_LIB_DIR "${PROJECT_BINARY_DIR}")
   set(MFEM_TEST_MK "${PROJECT_SOURCE_DIR}/config/test.mk")
   set(MFEM_CONFIG_EXTRA "MFEM_BUILD_DIR ?= ${PROJECT_BINARY_DIR}")
-  # TODO: CUDA/HIP support:
-  set(MFEM_XLINKER "${CMAKE_CXX_LINKER_WRAPPER_FLAG}")
+  if (MFEM_USE_CUDA AND MFEM_EXPORT_GPU_CONFIG)
+    if (MFEM_CUDA_COMPILER_IS_NVCC)
+      set(MFEM_XLINKER "-Xlinker=")
+    else()
+      set(MFEM_XLINKER "${CMAKE_CUDA_LINKER_WRAPPER_FLAG}")
+    endif()
+  else()
+    set(MFEM_XLINKER "${CMAKE_CXX_LINKER_WRAPPER_FLAG}")
+  endif()
   set(MFEM_MPIEXEC ${MPIEXEC})
   if (NOT MFEM_MPIEXEC)
     set(MFEM_MPIEXEC "mpirun")
@@ -987,16 +1054,21 @@ function(mfem_export_mk_files)
     # handle interfaces (e.g., SCOREC::apf)
     if ("${lib}" MATCHES "SCOREC::.*" OR "${lib}" MATCHES "Ginkgo::.*" OR "${lib}" MATCHES "ParMoonolith::.*")
     elseif (TARGET "${lib}")
-      mfem_get_target_options(${lib} CompileOpts LinkOpts)
+      mfem_get_target_options(${lib} CompileOpts2 LinkOpts2)
+      # remove generator expressions
+      string(GENEX_STRIP "${CompileOpts2}" CompileOpts)
+      string(GENEX_STRIP "${LinkOpts2}" LinkOpts)
       # Removing duplicates may lead to issues:
       # list(REMOVE_DUPLICATES CompileOpts)
       # list(REMOVE_DUPLICATES LinkOpts)
-      string(REPLACE ";" " " COpts "${CompileOpts}")
-      string(REPLACE ";" " " LOpts "${LinkOpts}")
-      # message(STATUS "${lib}[COpts]: '${COpts}'")
-      # message(STATUS "${lib}[LOpts]: '${LOpts}'")
-      set(MFEM_TPLFLAGS "${MFEM_TPLFLAGS} ${COpts}")
-      set(MFEM_EXT_LIBS "${MFEM_EXT_LIBS} ${LOpts}")
+      # message(WARNING "${lib}[LinkOpts]: ${LinkOpts}")      
+      # message(WARNING "${lib}[CompileOpts]: ${CompileOpts}")
+      foreach(LOpt IN LISTS LinkOpts)
+        set(MFEM_EXT_LIBS "${MFEM_EXT_LIBS} ${LOpt}")
+      endforeach()
+      foreach(COpt IN LISTS CompileOpts)
+        set(MFEM_TPLFLAGS "${MFEM_TPLFLAGS} ${COpt}")
+      endforeach()
       # message(FATAL_ERROR "***** interface lib found ... exiting *****")
       # handle static and shared libs
     elseif ("${suffix}" STREQUAL "${CMAKE_SHARED_LIBRARY_SUFFIX}")
@@ -1004,7 +1076,7 @@ function(mfem_export_mk_files)
       get_filename_component(fullLibName ${lib} NAME_WE)
       string(REGEX REPLACE "^lib" "" libname ${fullLibName})
       set(MFEM_EXT_LIBS
-          "${MFEM_EXT_LIBS} ${shared_link_flag}${dir} -L${dir} -l${libname}")
+        "${MFEM_EXT_LIBS} ${shared_link_flag}${dir} -L${dir} -l${libname}")
     else()
       set(MFEM_EXT_LIBS "${MFEM_EXT_LIBS} ${lib}")
     endif()
@@ -1013,7 +1085,7 @@ function(mfem_export_mk_files)
   # Create the build-tree version of 'config.mk'
   configure_file(
     "${PROJECT_SOURCE_DIR}/config/config.mk.in"
-    "${PROJECT_BINARY_DIR}/config/config.mk")
+    "${PROJECT_BINARY_DIR}/config/config.mk" @ONLY)
   # Copy 'test.mk' from the source-tree to the build-tree
   configure_file(
     "${PROJECT_SOURCE_DIR}/config/test.mk"
@@ -1031,7 +1103,7 @@ function(mfem_export_mk_files)
   # Create the install-tree version of 'config.mk'
   configure_file(
     "${PROJECT_SOURCE_DIR}/config/config.mk.in"
-    "${PROJECT_BINARY_DIR}/config/config-install.mk")
+    "${PROJECT_BINARY_DIR}/config/config-install.mk" @ONLY)
 
   # Install rules for 'config.mk' and 'test.mk'
   install(FILES ${PROJECT_SOURCE_DIR}/config/test.mk

config/config.hpp.in

@@ -97,6 +97,9 @@
 // Enable MFEM functionality based on the SuiteSparse library.
 // #define MFEM_USE_SUITESPARSE
 
+// Enable MFEM functionality based on the ARPACK library.
+// #define MFEM_USE_ARPACK
+
 // Enable MFEM functionality based on the SuperLU_DIST library.
 // #define MFEM_USE_SUPERLU
 // #define MFEM_USE_SUPERLU5

config/config.mk.in

@@ -32,6 +32,7 @@ MFEM_USE_MEMALLOC      = @MFEM_USE_MEMALLOC@
 MFEM_TIMER_TYPE        = @MFEM_TIMER_TYPE@
 MFEM_USE_SUNDIALS      = @MFEM_USE_SUNDIALS@
 MFEM_USE_SUITESPARSE   = @MFEM_USE_SUITESPARSE@
+MFEM_USE_ARPACK        = @MFEM_USE_ARPACK@
 MFEM_USE_SUPERLU       = @MFEM_USE_SUPERLU@
 MFEM_USE_SUPERLU5      = @MFEM_USE_SUPERLU5@
 MFEM_USE_MUMPS         = @MFEM_USE_MUMPS@

config/defaults.mk

@@ -18,6 +18,7 @@
 # Some choices below are based on the OS type:
 NOTMAC := $(subst Darwin,,$(shell uname -s))
 
+ASTYLE_BIN = astyle
 ETAGS_BIN = $(shell command -v etags 2> /dev/null)
 EGREP_BIN = $(shell command -v egrep 2> /dev/null)
 
@@ -177,6 +178,7 @@ MFEM_USE_ALGOIM        = NO
 MFEM_USE_UMPIRE        = NO
 MFEM_USE_SIMD          = NO
 MFEM_USE_ADIOS2        = NO
+MFEM_USE_ARPACK        = NO
 MFEM_USE_MKL_CPARDISO  = NO
 MFEM_USE_MKL_PARDISO   = NO
 MFEM_USE_MOONOLITH     = NO
@@ -426,6 +428,14 @@ NETCDF_LIB = $(XLINKER)-rpath,$(NETCDF_DIR)/lib -L$(NETCDF_DIR)/lib\
  $(XLINKER)-rpath,$(HDF5_DIR)/lib -L$(HDF5_DIR)/lib\
  -lnetcdf -lhdf5_hl -lhdf5 $(ZLIB_LIB)
 
+# ARPACK library configuration
+ARPACK_DIR = @MFEM_DIR@/../ARPACK
+ifeq ($(MFEM_USE_MPI),YES)
+ARPACK_LIB = -L$(ARPACK_DIR) -lparpack -larpack
+else
+ARPACK_LIB = -L$(ARPACK_DIR) -larpack
+endif
+
 # PETSc library configuration (version greater or equal to 3.8 or the dev branch)
 PETSC_ARCH := arch-linux2-c-debug
 PETSC_DIR  := $(MFEM_DIR)/../petsc/$(PETSC_ARCH)

examples/CMakeLists.txt

@@ -49,6 +49,13 @@ list(APPEND ALL_EXE_SRCS
   ex41.cpp
   )
 
+if (MFEM_USE_ARPACK)
+list(APPEND ALL_EXE_SRCS
+  ex11.pp
+  ex13.pp
+)
+endif()
+
 if (MFEM_USE_MPI)
   list(APPEND ALL_EXE_SRCS
     ex0p.cpp

examples/ex11.cpp

@@ -0,0 +1,298 @@
+//                       MFEM Example 11 - Serial Version
+//
+// Compile with: make ex11
+//
+// Sample runs:  ex11 -m ../data/square-disc.mesh
+//               ex11 -m ../data/star.mesh
+//               ex11 -m ../data/star-mixed.mesh
+//               ex11 -m ../data/periodic-annulus-sector.msh
+//               ex11 -m ../data/square-disc-p2.vtk -o 2
+//               ex11 -m ../data/square-disc-p3.mesh -o 3
+//               ex11 -m ../data/square-disc-nurbs.mesh -o -1
+//               ex11 -m ../data/disc-nurbs.mesh -o -1 -n 20
+//               ex11 -m ../data/star-surf.mesh
+//               ex11 -m ../data/square-disc-surf.mesh
+//               ex11 -m ../data/inline-segment.mesh
+//               ex11 -m ../data/inline-quad.mesh
+//               ex11 -m ../data/inline-tri.mesh
+//               ex11 -m ../data/amr-quad.mesh
+//               ex11 -m ../data/amr-hex.mesh
+//               ex11 -m ../data/mobius-strip.mesh -n 8
+//
+// Description:  This example code demonstrates the use of MFEM to solve the
+//               eigenvalue problem -Delta u = lambda u with homogeneous
+//               Dirichlet boundary conditions.
+//
+//               We compute a number of the lowest eigenmodes by discretizing
+//               the Laplacian and Mass operators using a FE space of the
+//               specified order, or an isoparametric/isogeometric space if
+//               order < 1 (quadratic for quadratic curvilinear mesh, NURBS for
+//               NURBS mesh, etc.)
+//
+//               The example highlights the use of the ARPACK eigenvalue solver
+//               (regular inverse mode). Reusing a single GLVis visualization
+//               window for multiple eigenfunctions is also illustrated.
+//
+//               We recommend viewing Example 1 before viewing this example.
+
+#include "mfem.hpp"
+#include <fstream>
+#include <iostream>
+
+using namespace std;
+using namespace mfem;
+
+#ifdef MFEM_USE_ARPACK
+
+int main(int argc, char *argv[])
+{
+   // 1. Parse command-line options.
+   const char *mesh_file = "../data/star.mesh";
+   int ser_ref_levels = 3;
+   int order = 1;
+   int nev = 5;
+   double dbc_eig = 1e3;
+   bool visualization = 1;
+   bool arp_solver = true;
+
+   OptionsParser args(argc, argv);
+   args.AddOption(&mesh_file, "-m", "--mesh",
+                  "Mesh file to use.");
+   args.AddOption(&ser_ref_levels, "-rs", "--refine-serial",
+                  "Number of times to refine the mesh uniformly in serial.");
+   args.AddOption(&order, "-o", "--order",
+                  "Finite element order (polynomial degree) or -1 for"
+                  " isoparametric space.");
+   args.AddOption(&nev, "-n", "--num-eigs",
+                  "Number of desired eigenmodes.");
+   args.AddOption(&dbc_eig, "-d", "--dbc-eig",
+                  "Eigenvalues associated with Dirichlet BC "
+                  "(should be larger than the maximum desired eigenvalue).");
+   args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
+                  "--no-visualization",
+                  "Enable or disable GLVis visualization.");
+   args.Parse();
+   if (!args.Good())
+   {
+      args.PrintUsage(cout);
+      return 1;
+   }
+   args.PrintOptions(cout);
+
+   // 2. Read the (serial) mesh from the given mesh file on all processors. We
+   //    can handle triangular, quadrilateral, tetrahedral, hexahedral, surface
+   //    and volume meshes with the same code.
+   Mesh *mesh;
+   ifstream imesh(mesh_file);
+   if (!imesh)
+   {
+      cerr << "\nCan not open mesh file: " << mesh_file << '\n' << endl;
+      return 2;
+   }
+   mesh = new Mesh(imesh, 1, 1);
+   imesh.close();
+   int dim = mesh->Dimension();
+
+   // 3. Refine the serial mesh on all processors to increase the resolution. In
+   //    this example we do 'ref_levels' of uniform refinement (2 by default, or
+   //    specified on the command line with -rs).
+   for (int lev = 0; lev < ser_ref_levels; lev++)
+   {
+      mesh->UniformRefinement();
+   }
+
+   // 4. Define a finite element space on the mesh. Here we
+   //    use continuous Lagrange finite elements of the specified order. If
+   //    order < 1, we instead use an isoparametric/isogeometric space.
+   FiniteElementCollection *fec;
+   if (order > 0)
+   {
+      fec = new H1_FECollection(order, dim);
+   }
+   else if (mesh->GetNodes())
+   {
+      fec = mesh->GetNodes()->OwnFEC();
+   }
+   else
+   {
+      fec = new H1_FECollection(order = 1, dim);
+   }
+   FiniteElementSpace *fespace = new FiniteElementSpace(mesh, fec);
+   int size = fespace->GetVSize();
+
+   cout << "Number of unknowns: " << size << endl;
+
+   // 5. Set up the parallel bilinear forms a(.,.) and m(.,.) on the finite
+   //    element space. The first corresponds to the Laplacian operator -Delta,
+   //    while the second is a simple mass matrix needed on the right hand side
+   //    of the generalized eigenvalue problem below. The boundary conditions
+   //    are implemented by elimination with special values on the diagonal to
+   //    shift the Dirichlet eigenvalues out of the computational range. After
+   //    serial and parallel assembly we extract the corresponding parallel
+   //    matrices A and M.
+   ConstantCoefficient one(1.0);
+   Array<int> ess_bdr;
+   if (mesh->bdr_attributes.Size())
+   {
+      ess_bdr.SetSize(mesh->bdr_attributes.Max());
+      ess_bdr = 1;
+   }
+
+   BilinearForm *a = new BilinearForm(fespace);
+   a->AddDomainIntegrator(new DiffusionIntegrator(one));
+   if (mesh->bdr_attributes.Size() == 0)
+   {
+      // Add a mass term if the mesh has no boundary, e.g. periodic mesh or
+      // closed surface.
+      a->AddDomainIntegrator(new MassIntegrator(one));
+   }
+   a->Assemble();
+   if (mesh->bdr_attributes.Size() != 0)
+   {
+      a->EliminateEssentialBCDiag(ess_bdr, dbc_eig);
+   }
+   a->Finalize();
+
+   BilinearForm *m = new BilinearForm(fespace);
+   m->AddDomainIntegrator(new MassIntegrator(one));
+   m->Assemble();
+   if (mesh->bdr_attributes.Size() != 0)
+   {
+      // shift the eigenvalue corresponding to eliminated dofs to a large value
+      m->EliminateEssentialBCDiag(ess_bdr, 1.0);
+   }
+   m->Finalize();
+
+   Solver       * solver = NULL;
+
+#ifndef MFEM_USE_SUITESPARSE
+   // 6. Define a simple symmetric Gauss-Seidel preconditioner and use it to
+   //    solve the system A X = B with PCG.
+   cout << "Building CGSolver" << endl;
+   GSSmoother M(m->SpMat());
+   CGSolver * cg_solver = new CGSolver;
+   cg_solver->SetPreconditioner(M);
+   cg_solver->SetRelTol(1.0e-12);
+   solver = cg_solver;
+#else
+   // 7. If MFEM was compiled with SuiteSparse, use UMFPACK to solve the system.
+   cout << "Building UMFPackSolver" << endl;
+   UMFPackSolver * umf_solver = new UMFPackSolver;
+   umf_solver->Control[UMFPACK_ORDERING] = UMFPACK_ORDERING_METIS;
+   solver = umf_solver;
+#endif
+   solver->SetOperator(m->SpMat());
+
+   // 7. Define and configure the ARPACK eigensolver
+   SymGenEigensolver * eig_solver = NULL;
+
+   if (arp_solver)
+   {
+      // ArPackSymGen * arpack = new ArPackSymGen();
+      ArPackSAUPD * arpack = new ArPackSAUPD();
+      arpack->SetMode(2);
+      arpack->SetNumModes(nev);
+      arpack->SetMaxIter(400);
+      arpack->SetTol(1e-8);
+      arpack->SetPrintLevel(2);
+      arpack->SetSolver(*solver);
+
+      eig_solver = arpack;
+   }
+
+   eig_solver->SetOperators(*a, *m);
+
+   // 8. Compute the eigenmodes and extract the array of eigenvalues. Define a
+   //    parallel grid function to represent each of the eigenmodes returned by
+   //    the solver.
+   Array<double> eigenvalues;
+   eig_solver->Solve();
+   eig_solver->GetEigenvalues(eigenvalues);
+
+   cout << endl;
+   std::ios::fmtflags old_fmt = cout.flags();
+   cout.setf(std::ios::scientific);
+   std::streamsize old_prec = cout.precision(14);
+   for (int i=0; i<nev; i++)
+   {
+      cout << "Eigenvalue lambda   " << eigenvalues[i] << endl;
+   }
+   cout.precision(old_prec);
+   cout.flags(old_fmt);
+   cout << endl;
+
+   GridFunction x(fespace);
+
+   // 9. Save the refined mesh and the modes in parallel. This output can be
+   //    viewed later using GLVis: "glvis -np <np> -m mesh -g mode".
+   {
+      ostringstream mesh_name, mode_name;
+      mesh_name << "ex11.mesh";
+
+      ofstream mesh_ofs(mesh_name.str().c_str());
+      mesh_ofs.precision(8);
+      mesh->Print(mesh_ofs);
+
+      for (int i=0; i<nev; i++)
+      {
+         // convert eigenvector from Vector to GridFunction
+         x = eig_solver->GetEigenvector(i);
+
+         mode_name << "mode_" << setfill('0') << setw(2) << i;
+
+         ofstream mode_ofs(mode_name.str().c_str());
+         mode_ofs.precision(8);
+         x.Save(mode_ofs);
+         mode_name.str("");
+      }
+   }
+
+   // 10. Send the solution by socket to a GLVis server.
+   if (visualization)
+   {
+      char vishost[] = "localhost";
+      int  visport   = 19916;
+      socketstream mode_sock(vishost, visport);
+      mode_sock.precision(8);
+
+      for (int i=0; i<nev; i++)
+      {
+         cout << "Eigenmode " << i+1 << '/' << nev
+              << ", Lambda = " << eigenvalues[i] << endl;
+
+         // convert eigenvector from Vector to GridFunction
+         x = eig_solver->GetEigenvector(i);
+
+         mode_sock << "solution\n" << *mesh << x << flush
+                   << "window_title 'Eigenmode " << i+1 << '/' << nev
+                   << ", Lambda = " << eigenvalues[i] << "'" << endl;
+
+         char c;
+         cout << "press (q)uit or (c)ontinue --> " << flush;
+         cin >> c;
+
+         if (c != 'c')
+         {
+            break;
+         }
+      }
+      mode_sock.close();
+   }
+
+   // 11. Free the used memory.
+   delete eig_solver;
+   delete solver;
+   delete m;
+   delete a;
+
+   delete fespace;
+   if (order > 0)
+   {
+      delete fec;
+   }
+   delete mesh;
+
+   return 0;
+}
+
+#endif // MFEM_USE_ARPACK

examples/ex11p.cpp

@@ -72,6 +72,8 @@ int main(int argc, char *argv[])
    int seed = 75;
    bool slu_solver  = false;
    bool sp_solver = false;
+   bool lob_solver = true;
+   bool arp_solver = false;
    bool cpardiso_solver = false;
    bool visualization = 1;
 
@@ -97,6 +99,10 @@ int main(int argc, char *argv[])
    args.AddOption(&sp_solver, "-sp", "--strumpack", "-no-sp",
                   "--no-strumpack", "Use the STRUMPACK Solver.");
 #endif
+#ifdef MFEM_USE_ARPACK
+   args.AddOption(&arp_solver, "-arp", "--arpack", "-no-arp",
+                  "--no-arpack", "Use the Parallel ARPACK Solver.");
+#endif
 #ifdef MFEM_USE_MKL_CPARDISO
    args.AddOption(&cpardiso_solver, "-cpardiso", "--cpardiso", "-no-cpardiso",
                   "--no-cpardiso", "Use the MKL CPardiso Solver.");
@@ -113,6 +119,11 @@ int main(int argc, char *argv[])
               << "         Defaulting to SuperLU." << endl;
       sp_solver = false;
    }
+   if (arp_solver)
+   {
+      lob_solver = false;
+   }
+
    // The command line options are also passed to the STRUMPACK
    // solver. So do not exit if some options are not recognized.
    if (!sp_solver)
@@ -243,70 +254,119 @@ int main(int argc, char *argv[])
    // 8. Define and configure the LOBPCG eigensolver and the BoomerAMG
    //    preconditioner for A to be used within the solver. Set the matrices
    //    which define the generalized eigenproblem A x = lambda M x.
+   Solver * solver = NULL;
    Solver * precond = NULL;
    if (!slu_solver && !sp_solver && !cpardiso_solver)
    {
       HypreBoomerAMG * amg = new HypreBoomerAMG(*A);
       amg->SetPrintLevel(0);
       precond = amg;
-   }
-   else
-   {
-#ifdef MFEM_USE_SUPERLU
-      if (slu_solver)
+
+      if (arp_solver)
+      {
+         HyprePCG * pcg = new HyprePCG(*A);
+         pcg->SetTol(1e-12);
+         pcg->SetPreconditioner(*amg);
+         solver = pcg;
+      }
+   }
+#ifdef MFEM_USE_SUPERLU
+   else if (slu_solver)
+   {
+      SuperLUSolver * superlu = new SuperLUSolver(MPI_COMM_WORLD);
+      superlu->SetPrintStatistics(false);
+      superlu->SetSymmetricPattern(true);
+      superlu->SetColumnPermutation(superlu::PARMETIS);
+      superlu->SetOperator(*Arow);
+
+      if (arp_solver)
+      {
+         solver = superlu;
+      }
+      else
       {
-         SuperLUSolver * superlu = new SuperLUSolver(MPI_COMM_WORLD);
-         superlu->SetPrintStatistics(false);
-         superlu->SetSymmetricPattern(true);
-         superlu->SetColumnPermutation(superlu::PARMETIS);
-         superlu->SetOperator(*Arow);
          precond = superlu;
       }
+   }
 #endif
 #ifdef MFEM_USE_STRUMPACK
-      if (sp_solver)
+   else if (sp_solver)
+   {
+      STRUMPACKSolver * strumpack = new STRUMPACKSolver(argc, argv,
+                                                        MPI_COMM_WORLD);
+      strumpack->SetPrintFactorStatistics(true);
+      strumpack->SetPrintSolveStatistics(false);
+      strumpack->SetKrylovSolver(strumpack::KrylovSolver::DIRECT);
+      strumpack->SetReorderingStrategy(strumpack::ReorderingStrategy::METIS);
+      strumpack->SetMatching(strumpack::MatchingJob::NONE);
+      strumpack->SetCompression(strumpack::CompressionType::NONE);
+      strumpack->SetOperator(*Arow);
+      strumpack->SetFromCommandLine();
+      if (arp_solver)
+      {
+         solver = strumpack;
+      }
+      else
       {
-         STRUMPACKSolver * strumpack = new STRUMPACKSolver(MPI_COMM_WORLD, argc, argv);
-         strumpack->SetPrintFactorStatistics(true);
-         strumpack->SetPrintSolveStatistics(false);
-         strumpack->SetKrylovSolver(strumpack::KrylovSolver::DIRECT);
-         strumpack->SetReorderingStrategy(strumpack::ReorderingStrategy::METIS);
-         strumpack->SetMatching(strumpack::MatchingJob::NONE);
-         strumpack->SetCompression(strumpack::CompressionType::NONE);
-         strumpack->SetOperator(*Arow);
-         strumpack->SetFromCommandLine();
          precond = strumpack;
       }
+   }
 #endif
 #ifdef MFEM_USE_MKL_CPARDISO
-      if (cpardiso_solver)
+   else if (cpardiso_solver)
+   {
+      auto cpardiso = new CPardisoSolver(A->GetComm());
+      cpardiso->SetMatrixType(CPardisoSolver::MatType::REAL_STRUCTURE_SYMMETRIC);
+      cpardiso->SetPrintLevel(1);
+      cpardiso->SetOperator(*A);
+      if (arp_solver)
+      {
+         solver = cpardiso;
+      }
+      else
       {
-         auto cpardiso = new CPardisoSolver(A->GetComm());
-         cpardiso->SetMatrixType(CPardisoSolver::MatType::REAL_STRUCTURE_SYMMETRIC);
-         cpardiso->SetPrintLevel(1);
-         cpardiso->SetOperator(*A);
          precond = cpardiso;
       }
-#endif
    }
+#endif
 
-   HypreLOBPCG * lobpcg = new HypreLOBPCG(MPI_COMM_WORLD);
-   lobpcg->SetNumModes(nev);
-   lobpcg->SetRandomSeed(seed);
-   lobpcg->SetPreconditioner(*precond);
-   lobpcg->SetMaxIter(200);
-   lobpcg->SetTol(1e-8);
-   lobpcg->SetPrecondUsageMode(1);
-   lobpcg->SetPrintLevel(1);
-   lobpcg->SetMassMatrix(*M);
-   lobpcg->SetOperator(*A);
+   SymGenEigensolver * eig_solver = NULL;
+
+   if (lob_solver)
+   {
+      HypreLOBPCG * lobpcg = new HypreLOBPCG(MPI_COMM_WORLD);
+      lobpcg->SetNumModes(nev);
+      lobpcg->SetRandomSeed(seed);
+      lobpcg->SetPreconditioner(*precond);
+      lobpcg->SetMaxIter(200);
+      lobpcg->SetTol(1e-8);
+      lobpcg->SetPrecondUsageMode(1);
+      lobpcg->SetPrintLevel(1);
+
+      eig_solver = lobpcg;
+   }
+#ifdef MFEM_USE_ARPACK
+   else if (arp_solver)
+   {
+      ArPackPSAUPD * arpack = new ArPackPSAUPD(MPI_COMM_WORLD);
+      arpack->SetNumModes(nev);
+      arpack->SetMaxIter(400);
+      arpack->SetTol(1e-8);
+      arpack->SetMode(3);
+      arpack->SetPrintLevel(2);
+      arpack->SetSolver(*solver);
+
+      eig_solver = arpack;
+   }
+#endif
+   eig_solver->SetOperators(*A, *M);
 
    // 9. Compute the eigenmodes and extract the array of eigenvalues. Define a
    //    parallel grid function to represent each of the eigenmodes returned by
    //    the solver.
    Array<real_t> eigenvalues;
-   lobpcg->Solve();
-   lobpcg->GetEigenvalues(eigenvalues);
+   eig_solver->Solve();
+   eig_solver->GetEigenvalues(eigenvalues);
    ParGridFunction x(fespace);
 
    // 10. Save the refined mesh and the modes in parallel. This output can be
@@ -321,8 +381,8 @@ int main(int argc, char *argv[])
 
       for (int i=0; i<nev; i++)
       {
-         // convert eigenvector from HypreParVector to ParGridFunction
-         x = lobpcg->GetEigenvector(i);
+         // convert eigenvector from Vector to ParGridFunction
+         x.Distribute(eig_solver->GetEigenvector(i));
 
          mode_name << "mode_" << setfill('0') << setw(2) << i << "."
                    << setfill('0') << setw(6) << myid;
@@ -350,8 +410,8 @@ int main(int argc, char *argv[])
                  << ", Lambda = " << eigenvalues[i] << endl;
          }
 
-         // convert eigenvector from HypreParVector to ParGridFunction
-         x = lobpcg->GetEigenvector(i);
+         // convert eigenvector from Vector to ParGridFunction
+         x.Distribute(eig_solver->GetEigenvector(i));
 
          mode_sock << "parallel " << num_procs << " " << myid << "\n"
                    << "solution\n" << *pmesh << x << flush
@@ -375,7 +435,8 @@ int main(int argc, char *argv[])
    }
 
    // 12. Free the used memory.
-   delete lobpcg;
+   delete eig_solver;
+   delete solver;
    delete precond;
    delete M;
    delete A;

examples/ex11p_arpack.cpp

@@ -0,0 +1,381 @@
+//                       MFEM Example 11 - Parallel Version
+//
+// Compile with: make ex11p
+//
+// Sample runs:  mpirun -np 4 ex11p -m ../data/square-disc.mesh
+//               mpirun -np 4 ex11p -m ../data/star.mesh
+//               mpirun -np 4 ex11p -m ../data/escher.mesh
+//               mpirun -np 4 ex11p -m ../data/fichera.mesh
+//               mpirun -np 4 ex11p -m ../data/square-disc-p2.vtk -o 2
+//               mpirun -np 4 ex11p -m ../data/square-disc-p3.mesh -o 3
+//               mpirun -np 4 ex11p -m ../data/square-disc-nurbs.mesh -o -1
+//               mpirun -np 4 ex11p -m ../data/disc-nurbs.mesh -o -1 -n 20
+//               mpirun -np 4 ex11p -m ../data/pipe-nurbs.mesh -o -1
+//               mpirun -np 4 ex11p -m ../data/ball-nurbs.mesh -o 2
+//               mpirun -np 4 ex11p -m ../data/star-surf.mesh
+//               mpirun -np 4 ex11p -m ../data/square-disc-surf.mesh
+//               mpirun -np 4 ex11p -m ../data/inline-segment.mesh
+//               mpirun -np 4 ex11p -m ../data/amr-quad.mesh
+//               mpirun -np 4 ex11p -m ../data/amr-hex.mesh
+//               mpirun -np 4 ex11p -m ../data/mobius-strip.mesh -n 8
+//               mpirun -np 4 ex11p -m ../data/klein-bottle.mesh -n 10
+//
+// Description:  This example code demonstrates the use of MFEM to solve the
+//               eigenvalue problem -Delta u = lambda u with homogeneous
+//               Dirichlet boundary conditions.
+//
+//               We compute a number of the lowest eigenmodes by discretizing
+//               the Laplacian and Mass operators using a FE space of the
+//               specified order, or an isoparametric/isogeometric space if
+//               order < 1 (quadratic for quadratic curvilinear mesh, NURBS for
+//               NURBS mesh, etc.)
+//
+//               The example highlights the use of the LOBPCG and ARPACK
+//               eigenvalue solvers together with the BoomerAMG preconditioner
+//               in HYPRE, as well as optionally the SuperLU parallel direct
+//               solver. Reusing a single GLVis visualization window for
+//               multiple eigenfunctions is also illustrated.
+//
+//               We recommend viewing Example 1 before viewing this example.
+
+#include "mfem.hpp"
+#include <fstream>
+#include <iostream>
+
+using namespace std;
+using namespace mfem;
+
+int main(int argc, char *argv[])
+{
+   // 1. Initialize MPI.
+   int num_procs, myid;
+   MPI_Init(&argc, &argv);
+   MPI_Comm_size(MPI_COMM_WORLD, &num_procs);
+   MPI_Comm_rank(MPI_COMM_WORLD, &myid);
+
+   // 2. Parse command-line options.
+   const char *mesh_file = "../data/star.mesh";
+   int ser_ref_levels = 2;
+   int par_ref_levels = 1;
+   int order = 1;
+   int nev = 5;
+   bool slu_solver = false;
+   bool use_arpack = false;
+   bool visualization = 1;
+
+   OptionsParser args(argc, argv);
+   args.AddOption(&mesh_file, "-m", "--mesh",
+                  "Mesh file to use.");
+   args.AddOption(&ser_ref_levels, "-rs", "--refine-serial",
+                  "Number of times to refine the mesh uniformly in serial.");
+   args.AddOption(&par_ref_levels, "-rp", "--refine-parallel",
+                  "Number of times to refine the mesh uniformly in parallel.");
+   args.AddOption(&order, "-o", "--order",
+                  "Finite element order (polynomial degree) or -1 for"
+                  " isoparametric space.");
+   args.AddOption(&nev, "-n", "--num-eigs",
+                  "Number of desired eigenmodes.");
+#ifdef MFEM_USE_SUPERLU
+   args.AddOption(&slu_solver, "-slu", "--superlu", "-no-slu",
+                  "--no-superlu", "Use the SuperLU Solver.");
+#endif
+#ifdef MFEM_USE_ARPACK
+   args.AddOption(&use_arpack, "-arpack", "--use-arpack", "-no-arpack",
+                  "--no-arpack",
+                  "Enable or disable the use of ARPACK.");
+#endif
+   args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
+                  "--no-visualization",
+                  "Enable or disable GLVis visualization.");
+   args.Parse();
+   if (!args.Good())
+   {
+      if (myid == 0)
+      {
+         args.PrintUsage(cout);
+      }
+      MPI_Finalize();
+      return 1;
+   }
+   if (myid == 0)
+   {
+      args.PrintOptions(cout);
+   }
+
+   // 3. Read the (serial) mesh from the given mesh file on all processors. We
+   //    can handle triangular, quadrilateral, tetrahedral, hexahedral, surface
+   //    and volume meshes with the same code.
+   Mesh *mesh;
+   ifstream imesh(mesh_file);
+   if (!imesh)
+   {
+      if (myid == 0)
+      {
+         cerr << "\nCan not open mesh file: " << mesh_file << '\n' << endl;
+      }
+      MPI_Finalize();
+      return 2;
+   }
+   mesh = new Mesh(imesh, 1, 1);
+   imesh.close();
+   int dim = mesh->Dimension();
+
+   // 4. Refine the serial mesh on all processors to increase the resolution. In
+   //    this example we do 'ref_levels' of uniform refinement (2 by default, or
+   //    specified on the command line with -rs).
+   for (int lev = 0; lev < ser_ref_levels; lev++)
+   {
+      mesh->UniformRefinement();
+   }
+
+   // 5. Define a parallel mesh by a partitioning of the serial mesh. Refine
+   //    this mesh further in parallel to increase the resolution (1 time by
+   //    default, or specified on the command line with -rp). Once the parallel
+   //    mesh is defined, the serial mesh can be deleted.
+   ParMesh *pmesh = new ParMesh(MPI_COMM_WORLD, *mesh);
+   delete mesh;
+   for (int lev = 0; lev < par_ref_levels; lev++)
+   {
+      pmesh->UniformRefinement();
+   }
+
+   // 6. Define a parallel finite element space on the parallel mesh. Here we
+   //    use continuous Lagrange finite elements of the specified order. If
+   //    order < 1, we instead use an isoparametric/isogeometric space.
+   FiniteElementCollection *fec;
+   if (order > 0)
+   {
+      fec = new H1_FECollection(order, dim);
+   }
+   else if (pmesh->GetNodes())
+   {
+      fec = pmesh->GetNodes()->OwnFEC();
+   }
+   else
+   {
+      fec = new H1_FECollection(order = 1, dim);
+   }
+   ParFiniteElementSpace *fespace = new ParFiniteElementSpace(pmesh, fec);
+   HYPRE_Int size = fespace->GlobalTrueVSize();
+   if (myid == 0)
+   {
+      cout << "Number of unknowns: " << size << endl;
+   }
+
+   // 7. Set up the parallel bilinear forms a(.,.) and m(.,.) on the finite
+   //    element space. The first corresponds to the Laplacian operator -Delta,
+   //    while the second is a simple mass matrix needed on the right hand side
+   //    of the generalized eigenvalue problem below. The boundary conditions
+   //    are implemented by elimination with special values on the diagonal to
+   //    shift the Dirichlet eigenvalues out of the computational range. After
+   //    serial and parallel assembly we extract the corresponding parallel
+   //    matrices A and M.
+   ConstantCoefficient one(1.0);
+   Array<int> ess_bdr;
+   if (pmesh->bdr_attributes.Size())
+   {
+      ess_bdr.SetSize(pmesh->bdr_attributes.Max());
+      ess_bdr = 1;
+   }
+
+   ParBilinearForm *a = new ParBilinearForm(fespace);
+   a->AddDomainIntegrator(new DiffusionIntegrator(one));
+   if (pmesh->bdr_attributes.Size() == 0)
+   {
+      // Add a mass term if the mesh has no boundary, e.g. periodic mesh or
+      // closed surface.
+      a->AddDomainIntegrator(new MassIntegrator(one));
+   }
+   a->Assemble();
+   a->EliminateEssentialBCDiag(ess_bdr, 1.0);
+   a->Finalize();
+
+   ParBilinearForm *m = new ParBilinearForm(fespace);
+   m->AddDomainIntegrator(new MassIntegrator(one));
+   m->Assemble();
+   // shift the eigenvalue corresponding to eliminated dofs to a large value
+   m->EliminateEssentialBCDiag(ess_bdr, numeric_limits<double>::min());
+   m->Finalize();
+
+   HypreParMatrix *A = a->ParallelAssemble();
+   HypreParMatrix *M = m->ParallelAssemble();
+
+#ifdef MFEM_USE_SUPERLU
+   Operator * Arow = NULL;
+   if (slu_solver)
+   {
+      Arow = new SuperLURowLocMatrix(*A);
+   }
+#endif
+
+   delete a;
+   delete m;
+
+   // 8. Define and configure the LOBPCG eigensolver and the BoomerAMG
+   //    preconditioner for A to be used within the solver. Set the matrices
+   //    which define the generalized eigenproblem A x = lambda M x.
+   Eigensolver * esolver = NULL;
+   Solver      *  solver = NULL;
+   Solver      * precond = NULL;
+
+   if (!slu_solver)
+   {
+      HypreBoomerAMG * amg = new HypreBoomerAMG(*A);
+      amg->SetPrintLevel(0);
+      precond = amg;
+
+#ifdef MFEM_USE_ARPACK
+      if ( use_arpack )
+      {
+         HyprePCG * pcg = new HyprePCG(*A);
+         pcg->SetTol(1e-12);
+         pcg->SetMaxIter(200);
+         pcg->SetPreconditioner(*amg);
+         pcg->SetPrintLevel(0);
+
+         solver = pcg;
+      }
+#endif
+   }
+#ifdef MFEM_USE_SUPERLU
+   else
+   {
+      SuperLUSolver * superlu = new SuperLUSolver(MPI_COMM_WORLD);
+      superlu->SetPrintStatistics(false);
+      superlu->SetSymmetricPattern(true);
+      superlu->SetColumnPermutation(superlu::PARMETIS);
+      superlu->SetOperator(*Arow);
+
+      solver  = use_arpack?superlu:NULL;
+      precond = use_arpack?NULL:superlu;
+   }
+#endif
+
+   if ( use_arpack )
+   {
+      ParArPackSym * arpack = new ParArPackSym(MPI_COMM_WORLD);
+      arpack->SetMode(3);
+      arpack->SetPrintLevel(2);
+      arpack->SetSolver(*solver);
+
+      esolver = arpack;
+   }
+   else
+   {
+      HypreLOBPCG * lobpcg = new HypreLOBPCG(MPI_COMM_WORLD);
+      lobpcg->SetPreconditioner(*precond);
+      lobpcg->SetPrecondUsageMode(1);
+      lobpcg->SetPrintLevel(1);
+
+      esolver = lobpcg;
+   }
+
+   esolver->SetNumModes(nev);
+   esolver->SetMaxIter(100);
+   esolver->SetTol(1e-8);
+
+   esolver->SetMassMatrix(*M);
+   esolver->SetOperator(*A);
+
+   // 9. Compute the eigenmodes and extract the array of eigenvalues. Define a
+   //    parallel grid function to represent each of the eigenmodes returned by
+   //    the solver.
+   Array<double> eigenvalues;
+   esolver->Solve();
+   esolver->GetEigenvalues(eigenvalues);
+
+   if ( myid == 0 && use_arpack )
+   {
+      cout << endl;
+      for (int i=0; i<eigenvalues.Size(); i++)
+      {
+         cout << "Eigenvalue lambda " << eigenvalues[i] << endl;
+      }
+      cout << endl;
+   }
+
+   ParGridFunction x(fespace);
+
+   // 10. Save the refined mesh and the modes in parallel. This output can be
+   //     viewed later using GLVis: "glvis -np <np> -m mesh -g mode".
+   {
+      ostringstream mesh_name, mode_name;
+      mesh_name << "mesh." << setfill('0') << setw(6) << myid;
+
+      ofstream mesh_ofs(mesh_name.str().c_str());
+      mesh_ofs.precision(8);
+      pmesh->Print(mesh_ofs);
+
+      for (int i=0; i<nev; i++)
+      {
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x.Distribute(esolver->GetEigenvector(i));
+
+         mode_name << "mode_" << setfill('0') << setw(2) << i << "."
+                   << setfill('0') << setw(6) << myid;
+
+         ofstream mode_ofs(mode_name.str().c_str());
+         mode_ofs.precision(8);
+         x.Save(mode_ofs);
+         mode_name.str("");
+      }
+   }
+
+   // 11. Send the solution by socket to a GLVis server.
+   if (visualization)
+   {
+      char vishost[] = "localhost";
+      int  visport   = 19916;
+      socketstream mode_sock(vishost, visport);
+      mode_sock.precision(8);
+
+      for (int i=0; i<nev; i++)
+      {
+         if ( myid == 0 )
+         {
+            cout << "Eigenmode " << i+1 << '/' << nev
+                 << ", Lambda = " << eigenvalues[i] << endl;
+         }
+
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x.Distribute(esolver->GetEigenvector(i));
+
+         mode_sock << "parallel " << num_procs << " " << myid << "\n"
+                   << "solution\n" << *pmesh << x << flush
+                   << "window_title 'Eigenmode " << i+1 << '/' << nev
+                   << ", Lambda = " << eigenvalues[i] << "'" << endl;
+
+         char c;
+         if (myid == 0)
+         {
+            cout << "press (q)uit or (c)ontinue --> " << flush;
+            cin >> c;
+         }
+         MPI_Bcast(&c, 1, MPI_CHAR, 0, MPI_COMM_WORLD);
+
+         if (c != 'c')
+         {
+            break;
+         }
+      }
+      mode_sock.close();
+   }
+
+   // 12. Free the used memory.
+   delete esolver;
+   delete solver;
+   delete precond;
+   delete M;
+   delete A;
+
+   delete fespace;
+   if (order > 0)
+   {
+      delete fec;
+   }
+   delete pmesh;
+
+   MPI_Finalize();
+
+   return 0;
+}

examples/ex12p.cpp

@@ -5,9 +5,9 @@
 // Sample runs:
 //    mpirun -np 4 ex12p -m ../data/beam-tri.mesh
 //    mpirun -np 4 ex12p -m ../data/beam-quad.mesh
-//    mpirun -np 4 ex12p -m ../data/beam-tet.mesh -s 462 -n 10 -o 2 -elast
+//    mpirun -np 4 ex12p -m ../data/beam-tet.mesh -s 464 -n 10 -o 2 -elast
 //    mpirun -np 4 ex12p -m ../data/beam-hex.mesh -s 3878
-//    mpirun -np 4 ex12p -m ../data/beam-wedge.mesh -s 81
+//    mpirun -np 4 ex12p -m ../data/beam-wedge.mesh -s 82
 //    mpirun -np 4 ex12p -m ../data/beam-tri.mesh -s 3877 -o 2 -sys
 //    mpirun -np 4 ex12p -m ../data/beam-quad.mesh -s 4544 -n 6 -o 3 -elast
 //    mpirun -np 4 ex12p -m ../data/beam-quad-nurbs.mesh
@@ -276,8 +276,8 @@ int main(int argc, char *argv[])
 
       for (int i=0; i<nev; i++)
       {
-         // convert eigenvector from HypreParVector to ParGridFunction
-         x = lobpcg->GetEigenvector(i);
+         // convert eigenvector from Vector to ParGridFunction
+         x.Distribute(lobpcg->GetEigenvector(i));
 
          mode_name << "mode_" << setfill('0') << setw(2) << i << "."
                    << setfill('0') << setw(6) << myid;
@@ -303,7 +303,7 @@ int main(int argc, char *argv[])
       pmesh->Print(adios2output);
       for (int i=0; i<nev; i++)
       {
-         x = lobpcg->GetEigenvector(i);
+         x.Distribute(lobpcg->GetEigenvector(i));
          // x is a temporary that must be saved immediately
          x.Save(adios2output, "mode_" + std::to_string(i));
       }
@@ -326,8 +326,8 @@ int main(int argc, char *argv[])
                  << ", Lambda = " << eigenvalues[i] << endl;
          }
 
-         // convert eigenvector from HypreParVector to ParGridFunction
-         x = lobpcg->GetEigenvector(i);
+         // convert eigenvector from Vector to ParGridFunction
+         x.Distribute(lobpcg->GetEigenvector(i));
 
          mode_sock << "parallel " << num_procs << " " << myid << "\n"
                    << "solution\n" << *pmesh << x << flush

examples/ex13.cpp

@@ -0,0 +1,282 @@
+//                       MFEM Example 13
+//
+// Compile with: make ex3p
+//
+// Sample runs:  ex13 -m ../data/star.mesh -s 5
+//               ex13 -m ../data/square-disc.mesh -o 2 -n 4 // minres fails to conv.
+//               ex13 -m ../data/beam-hex.mesh
+//               ex13 -m ../data/square-disc.mesh -rs 1 -s 26
+//               ex13 -m ../data/square-disc-nurbs.mesh -rs 3 -s 26
+//               ex13 -m ../data/amr-quad.mesh -o 2 // minres fails to conv.
+//               ex13 -m ../data/mobius-strip.mesh -n 8
+//
+// Description:  This example code solves a simple 3D electromagnetic
+//               eigenmode problem corresponding to the second order
+//               Maxwell equation curl curl E = lambda E with boundary
+//               condition E x n = 0. We discretize with Nedelec finite
+//               elements.
+//
+//               The example demonstrates the use of H(curl) finite element
+//               spaces with the curl-curl and the (vector finite element) mass
+//               bilinear form, as well as the use of the ARPACK eigenmode
+//               solver for symmetric matrices using the shift-invert mode.
+//
+
+#include "mfem.hpp"
+#include <fstream>
+#include <iostream>
+
+using namespace std;
+using namespace mfem;
+
+#ifdef MFEM_USE_ARPACK
+
+int main(int argc, char *argv[])
+{
+   // 1. Parse command-line options.
+   const char *mesh_file = "../data/beam-tet.mesh";
+   int order = 1;
+   int nev = 5;
+   int sr = 2;
+   double sigma = 11.0;
+   bool visualization = 1;
+   bool arp_solver = true;
+
+   OptionsParser args(argc, argv);
+   args.AddOption(&mesh_file, "-m", "--mesh",
+                  "Mesh file to use.");
+   args.AddOption(&order, "-o", "--order",
+                  "Finite element order (polynomial degree).");
+   args.AddOption(&nev, "-n", "--num-eigs",
+                  "Number of desired eigenmodes.");
+   args.AddOption(&sr, "-rs", "--refine-serial",
+                  "Number of times to refine the mesh uniformly in serial.");
+   args.AddOption(&sigma, "-s", "--shift",
+                  "Average of the desired eigenvalue range.");
+   args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
+                  "--no-visualization",
+                  "Enable or disable GLVis visualization.");
+   args.Parse();
+   if (!args.Good())
+   {
+      args.PrintUsage(cout);
+      return 1;
+   }
+   args.PrintOptions(cout);
+
+   // 2. Read the mesh from the given mesh file.  We can handle triangular,
+   //    quadrilateral, tetrahedral, hexahedral, surface and volume meshes
+   //    with the same code.
+   Mesh *mesh;
+   ifstream imesh(mesh_file);
+   if (!imesh)
+   {
+      cerr << "\nCan not open mesh file: " << mesh_file << '\n' << endl;
+      return 2;
+   }
+   mesh = new Mesh(imesh, 1, 1);
+   imesh.close();
+   int dim = mesh->Dimension();
+
+   // 3. Refine the mesh to increase the resolution. In this example we do
+   //    'ref_levels' of uniform refinement.
+   {
+      int ref_levels = sr;
+      for (int l = 0; l < ref_levels; l++)
+      {
+         mesh->UniformRefinement();
+      }
+   }
+
+   // 4. Define a finite element space on the mesh. Here we use the lowest
+   //    order Nedelec finite elements, but we can easily switch
+   //    to higher-order spaces by changing the value of p.
+   FiniteElementCollection *fec = new ND_FECollection(order, dim);
+   FiniteElementSpace *fespace = new FiniteElementSpace(mesh, fec);
+   int size = fespace->GetVSize();
+
+   cout << "Number of unknowns: " << size << endl;
+   cout << "Number of boundary attributes: " << mesh->bdr_attributes.Max()
+        << endl;
+
+   // 5. Set up the parallel bilinear form corresponding to the EM diffusion
+   //    operator curl muinv curl - sigma I, by adding the curl-curl and the
+   //    mass domain integrators and finally imposing homogeneous Dirichlet
+   //    boundary conditions. The boundary conditions are implemented by
+   //    marking all the boundary attributes from the mesh as essential
+   //    (Dirichlet). After serial and parallel assembly we extract the
+   //    parallel matrices A and M.
+   Coefficient *muinv    = new ConstantCoefficient(1.0);
+   Coefficient *negSigma = new ConstantCoefficient(-sigma);
+
+   BilinearForm *a = new BilinearForm(fespace);
+   a->AddDomainIntegrator(new CurlCurlIntegrator(*muinv));
+   a->AddDomainIntegrator(new VectorFEMassIntegrator(*negSigma));
+   a->Assemble();
+   Array<int> ess_bdr(mesh->bdr_attributes.Max());
+   ess_bdr = 1;
+   a->EliminateEssentialBC(ess_bdr);
+   a->Finalize();
+
+   BilinearForm *m = new BilinearForm(fespace);
+   m->AddDomainIntegrator(new VectorFEMassIntegrator());
+   m->Assemble();
+   m->EliminateEssentialBCDiag(ess_bdr, sqrt(numeric_limits<double>::min()));
+   m->Finalize();
+
+   // 6. Define a parallel grid function to approximate each of the
+   // eigenmodes returned by the solver.  Use this as a template to
+   // create a special multi-vector object needed by the eigensolver
+   // which is then initialized with random values.
+   GridFunction x(fespace);
+   x = 0.0;
+
+   // 7. Define and configure the GMRES
+   //    solver to be used within the eigensolver.
+   Solver    * solver = NULL;
+   if ( false )
+   {
+      GMRESSolver *  gmres = new GMRESSolver();
+
+      gmres->SetOperator(*a);
+      gmres->SetRelTol(1e-8);
+      gmres->SetMaxIter(1000);
+      gmres->SetPrintLevel(0);
+      solver = gmres;
+   }
+   else
+   {
+#ifndef MFEM_USE_SUITESPARSE
+      cout << "Building MINRESSolver" << endl;
+      MINRESSolver * minres = new MINRESSolver();
+
+      minres->SetRelTol(1e-12);
+      minres->SetMaxIter(1000);
+      minres->SetPrintLevel(0);
+      solver = minres;
+#else
+      // 7. If MFEM was compiled with SuiteSparse, use UMFPACK to solve the system.
+      cout << "Building UMFPackSolver" << endl;
+      UMFPackSolver * umf_solver = new UMFPackSolver;
+      umf_solver->Control[UMFPACK_ORDERING] = UMFPACK_ORDERING_METIS;
+      solver = umf_solver;
+#endif
+   }
+   solver->SetOperator(a->SpMat());
+
+   // 7. Define and configure the ARPACK eigensolver
+   SymGenEigensolver * eig_solver = NULL;
+   if (arp_solver)
+   {
+      ArPackSAUPD * arpack = new ArPackSAUPD();
+
+      arpack->SetNumModes(nev);
+      arpack->SetMaxIter(400);
+      arpack->SetTol(1e-8);
+      arpack->SetShift(sigma);
+      arpack->SetMode(3);
+      arpack->SetPrintLevel(2);
+      arpack->SetSolver(*solver);
+
+      eig_solver = arpack;
+   }
+
+   eig_solver->SetOperators(*a, *m);
+
+   // Obtain the eigenvalues and eigenvectors
+   Array<double> eigenvalues(nev);
+   eigenvalues = -1.0;
+
+   // arpack->Solve(eigenvalues, *eigenvectors);
+   eig_solver->Solve();
+
+   eig_solver->GetEigenvalues(eigenvalues);
+
+   cout << endl;
+   std::ios::fmtflags old_fmt = cout.flags();
+   cout.setf(std::ios::scientific);
+   std::streamsize old_prec = cout.precision(14);
+   for (int i=0; i<min(nev,eigenvalues.Size()); i++)
+   {
+      cout << "Eigenvalue lambda   " << eigenvalues[i] << endl;
+   }
+   cout.precision(old_prec);
+   cout.flags(old_fmt);
+   cout << endl;
+
+   VisItDataCollection visit_dc("Example13", mesh);
+   GridFunction ** mode = new GridFunction*[min(nev,eigenvalues.Size())];
+   for (int i=0; i<min(nev,eigenvalues.Size()); i++)
+   {
+      mode[i] = new GridFunction(fespace);
+      *mode[i] = eig_solver->GetEigenvector(i);
+
+      ostringstream modeName;
+      modeName << "mode_" << setfill('0') << setw(2) << i;
+      visit_dc.RegisterField(modeName.str().c_str(),mode[i]);
+   }
+   visit_dc.Save();
+
+   // 8. Save the refined mesh and the modes. This output can
+   //    be viewed later using GLVis: "glvis -m mesh -g mode".
+   {
+      ofstream mesh_ofs("refined.mesh");
+      mesh_ofs.precision(8);
+      mesh->Print(mesh_ofs);
+
+      for (int i=0; i<min(nev,eigenvalues.Size()); i++)
+      {
+         x = eig_solver->GetEigenvector(i);
+
+         ostringstream modeName;
+         modeName << "mode_" << setfill('0') << setw(2) << i;
+
+         ofstream mode_ofs(modeName.str().c_str());
+         mode_ofs.precision(8);
+         x.Save(mode_ofs);
+         modeName.str("");
+      }
+   }
+
+   // 9. Send the solution by socket to a GLVis server.
+   if (visualization)
+   {
+      char vishost[] = "localhost";
+      int  visport   = 19916;
+      socketstream mode_sock(vishost, visport);
+      mode_sock.precision(8);
+
+      for (int i=0; i<min(nev,eigenvalues.Size()); i++)
+      {
+         x = eig_solver->GetEigenvector(i);
+
+         mode_sock << "solution\n" << *mesh << x << flush;
+
+         char c;
+         cout << "press (q)uit or (c)ontinue --> " << flush;
+         cin >> c;
+
+         if (c != 'c')
+         {
+            break;
+         }
+      }
+      mode_sock.close();
+   }
+
+   // 10. Free the used memory.
+   delete a;
+   delete m;
+   delete negSigma;
+   delete muinv;
+   delete eig_solver;
+   delete solver;
+   // delete X;
+   delete fespace;
+   delete fec;
+   delete mesh;
+
+   return 0;
+}
+
+#endif // MFEM_USE_ARPACK

examples/ex13p.cpp

@@ -215,8 +215,8 @@ int main(int argc, char *argv[])
 
       for (int i=0; i<nev; i++)
       {
-         // convert eigenvector from HypreParVector to ParGridFunction
-         x = ame->GetEigenvector(i);
+         // convert eigenvector from Vector to ParGridFunction
+         x.Distribute(ame->GetEigenvector(i));
 
          mode_name << "mode_" << setfill('0') << setw(2) << i << "."
                    << setfill('0') << setw(6) << myid;
@@ -244,8 +244,8 @@ int main(int argc, char *argv[])
                  << ", Lambda = " << eigenvalues[i] << endl;
          }
 
-         // convert eigenvector from HypreParVector to ParGridFunction
-         x = ame->GetEigenvector(i);
+         // convert eigenvector from Vector to ParGridFunction
+         x.Distribute(ame->GetEigenvector(i));
 
          mode_sock << "parallel " << num_procs << " " << myid << "\n"
                    << "solution\n" << *pmesh << x << flush

examples/ex22p.cpp

@@ -302,15 +302,21 @@ int main(int argc, char *argv[])
       char vishost[] = "localhost";
       int  visport   = 19916;
       socketstream sol_sock_r(vishost, visport);
-      socketstream sol_sock_i(vishost, visport);
       sol_sock_r << "parallel " << num_procs << " " << myid << "\n";
-      sol_sock_i << "parallel " << num_procs << " " << myid << "\n";
       sol_sock_r.precision(8);
-      sol_sock_i.precision(8);
       sol_sock_r << "solution\n" << *pmesh << u_exact->real()
                  << "window_title 'Exact: Real Part'" << flush;
+      // Make sure all ranks have sent their real solution before initiating
+      // another set of GLVis connections (one from each rank):
+      MPI_Barrier(pmesh->GetComm());
+      socketstream sol_sock_i(vishost, visport);
+      sol_sock_i << "parallel " << num_procs << " " << myid << "\n";
+      sol_sock_i.precision(8);
       sol_sock_i << "solution\n" << *pmesh << u_exact->imag()
                  << "window_title 'Exact: Imaginary Part'" << flush;
+      // Make sure all ranks have sent their imaginary solution before initiating
+      // another set of GLVis connections (one from each rank):
+      MPI_Barrier(pmesh->GetComm());
    }
 
    // 11. Set up the parallel sesquilinear form a(.,.) on the finite element
@@ -534,15 +540,21 @@ int main(int argc, char *argv[])
       char vishost[] = "localhost";
       int  visport   = 19916;
       socketstream sol_sock_r(vishost, visport);
-      socketstream sol_sock_i(vishost, visport);
       sol_sock_r << "parallel " << num_procs << " " << myid << "\n";
-      sol_sock_i << "parallel " << num_procs << " " << myid << "\n";
       sol_sock_r.precision(8);
-      sol_sock_i.precision(8);
       sol_sock_r << "solution\n" << *pmesh << u.real()
                  << "window_title 'Solution: Real Part'" << flush;
+      // Make sure all ranks have sent their real solution before initiating
+      // another set of GLVis connections (one from each rank):
+      MPI_Barrier(pmesh->GetComm());
+      socketstream sol_sock_i(vishost, visport);
+      sol_sock_i << "parallel " << num_procs << " " << myid << "\n";
+      sol_sock_i.precision(8);
       sol_sock_i << "solution\n" << *pmesh << u.imag()
                  << "window_title 'Solution: Imaginary Part'" << flush;
+      // Make sure all ranks have sent their imaginary solution before initiating
+      // another set of GLVis connections (one from each rank):
+      MPI_Barrier(pmesh->GetComm());
    }
    if (visualization && exact_sol)
    {
@@ -551,15 +563,21 @@ int main(int argc, char *argv[])
       char vishost[] = "localhost";
       int  visport   = 19916;
       socketstream sol_sock_r(vishost, visport);
-      socketstream sol_sock_i(vishost, visport);
       sol_sock_r << "parallel " << num_procs << " " << myid << "\n";
-      sol_sock_i << "parallel " << num_procs << " " << myid << "\n";
       sol_sock_r.precision(8);
-      sol_sock_i.precision(8);
       sol_sock_r << "solution\n" << *pmesh << u_exact->real()
                  << "window_title 'Error: Real Part'" << flush;
+      // Make sure all ranks have sent their real solution before initiating
+      // another set of GLVis connections (one from each rank):
+      MPI_Barrier(pmesh->GetComm());
+      socketstream sol_sock_i(vishost, visport);
+      sol_sock_i << "parallel " << num_procs << " " << myid << "\n";
+      sol_sock_i.precision(8);
       sol_sock_i << "solution\n" << *pmesh << u_exact->imag()
                  << "window_title 'Error: Imaginary Part'" << flush;
+      // Make sure all ranks have sent their imaginary solution before initiating
+      // another set of GLVis connections (one from each rank):
+      MPI_Barrier(pmesh->GetComm());
    }
    if (visualization)
    {

examples/ex32p.cpp

@@ -228,7 +228,7 @@ int main(int argc, char *argv[])
       for (int i=0; i<nev; i++)
       {
          // convert eigenvector from HypreParVector to ParGridFunction
-         x = ame->GetEigenvector(i);
+         x.Distribute(ame->GetEigenvector(i));
          curl.Mult(x, dx);
 
          mode_name << "mode_" << setfill('0') << setw(2) << i << "."
@@ -295,7 +295,7 @@ int main(int argc, char *argv[])
             }
 
             // convert eigenvector from HypreParVector to ParGridFunction
-            x = ame->GetEigenvector(i);
+            x.Distribute(ame->GetEigenvector(i));
             curl.Mult(x, dx);
 
             {
@@ -469,7 +469,7 @@ int main(int argc, char *argv[])
             }
 
             // convert eigenvector from HypreParVector to ParGridFunction
-            x = ame->GetEigenvector(i);
+            x.Distribute(ame->GetEigenvector(i));
             curl.Mult(x, dx);
 
             {
@@ -599,7 +599,7 @@ int main(int argc, char *argv[])
             }
 
             // convert eigenvector from HypreParVector to ParGridFunction
-            x = ame->GetEigenvector(i);
+            x.Distribute(ame->GetEigenvector(i));
             curl.Mult(x, dx);
 
             mode_sock << "parallel " << num_procs << " " << myid << "\n"

examples/ex35p.cpp

@@ -658,7 +658,7 @@ void ScalarWaveGuide(int mode, ParGridFunction &x)
    lobpcg.SetOperator(*A);
    lobpcg.Solve();
 
-   x = lobpcg.GetEigenvector(mode);
+   x.Distribute(lobpcg.GetEigenvector(mode));
 
    delete A;
    delete M;
@@ -714,7 +714,7 @@ void VectorWaveGuide(int mode, ParGridFunction &x)
    ame.SetOperator(*A);
    ame.Solve();
 
-   x = ame.GetEigenvector(mode);
+   x.Distribute(ame.GetEigenvector(mode));
 
    delete A;
    delete M;
@@ -780,7 +780,7 @@ void PseudoScalarWaveGuide(int mode, ParGridFunction &x_l2)
    lobpcg.SetOperator(*A);
    lobpcg.Solve();
 
-   x = lobpcg.GetEigenvector(mode);
+   x.Distribute(lobpcg.GetEigenvector(mode));
 
    x_l2.ProjectCoefficient(xCoef);
 

examples/ex37.cpp

@@ -5,8 +5,8 @@
 // Sample runs:
 //     ex37 -alpha 10
 //     ex37 -alpha 10 -pv
-//     ex37 -lambda 0.1 -mu 0.1
-//     ex37 -o 2 -alpha 5.0 -mi 50 -vf 0.4 -ntol 1e-5
+//     ex37 -lambda 0.1 -mu 0.1 -growth 1
+//     ex37 -o 2 -alpha 10.0 -mi 50 -vf 0.4 -ntol 1e-5 -growth 1.5
 //     ex37 -r 6 -o 1 -alpha 25.0 -epsilon 0.02 -mi 50 -ntol 1e-5
 //
 // Description: This example code demonstrates the use of MFEM to solve a
@@ -55,53 +55,6 @@
 using namespace std;
 using namespace mfem;
 
-/**
- * @brief Bregman projection of ρ = sigmoid(ψ) onto the subspace
- *        ∫_Ω ρ dx = θ vol(Ω) as follows:
- *
- *        1. Compute the root of the R → R function
- *            f(c) = ∫_Ω sigmoid(ψ + c) dx - θ vol(Ω)
- *        2. Set ψ ← ψ + c.
- *
- * @param psi a GridFunction to be updated
- * @param target_volume θ vol(Ω)
- * @param tol Newton iteration tolerance
- * @param max_its Newton maximum iteration number
- * @return real_t Final volume, ∫_Ω sigmoid(ψ)
- */
-real_t proj(GridFunction &psi, real_t target_volume, real_t tol=1e-12,
-            int max_its=10)
-{
-   MappedGridFunctionCoefficient sigmoid_psi(&psi, sigmoid);
-   MappedGridFunctionCoefficient der_sigmoid_psi(&psi, der_sigmoid);
-
-   LinearForm int_sigmoid_psi(psi.FESpace());
-   int_sigmoid_psi.AddDomainIntegrator(new DomainLFIntegrator(sigmoid_psi));
-   LinearForm int_der_sigmoid_psi(psi.FESpace());
-   int_der_sigmoid_psi.AddDomainIntegrator(new DomainLFIntegrator(
-                                              der_sigmoid_psi));
-   bool done = false;
-   for (int k=0; k<max_its; k++) // Newton iteration
-   {
-      int_sigmoid_psi.Assemble(); // Recompute f(c) with updated ψ
-      const real_t f = int_sigmoid_psi.Sum() - target_volume;
-
-      int_der_sigmoid_psi.Assemble(); // Recompute df(c) with updated ψ
-      const real_t df = int_der_sigmoid_psi.Sum();
-
-      const real_t dc = -f/df;
-      psi += dc;
-      if (abs(dc) < tol) { done = true; break; }
-   }
-   if (!done)
-   {
-      mfem_warning("Projection reached maximum iteration without converging. "
-                   "Result may not be accurate.");
-   }
-   int_sigmoid_psi.Assemble();
-   return int_sigmoid_psi.Sum();
-}
-
 /*
  * ---------------------------------------------------------------
  *                      ALGORITHM PREAMBLE
@@ -180,10 +133,11 @@ int main(int argc, char *argv[])
    int ref_levels = 5;
    int order = 2;
    real_t alpha = 1.0;
+   real_t growth = 2;
    real_t epsilon = 0.01;
    real_t vol_fraction = 0.5;
    int max_it = 1e3;
-   real_t itol = 1e-1;
+   real_t itol = 1e-2;
    real_t ntol = 1e-4;
    real_t rho_min = 1e-6;
    real_t lambda = 1.0;
@@ -198,6 +152,8 @@ int main(int argc, char *argv[])
                   "Order (degree) of the finite elements.");
    args.AddOption(&alpha, "-alpha", "--alpha-step-length",
                   "Step length for gradient descent.");
+   args.AddOption(&growth, "-growth", "--alpha-growth-rate",
+                  "Growth rate of step length for gradient descent.");
    args.AddOption(&epsilon, "-epsilon", "--epsilon-thickness",
                   "Length scale for ρ.");
    args.AddOption(&max_it, "-mi", "--max-it",
@@ -332,6 +288,7 @@ int main(int argc, char *argv[])
    }
    FilterSolver->SetEssentialBoundary(ess_bdr_filter);
    FilterSolver->SetupFEM();
+   FilterSolver->AssembleDiffusionBilinear();
 
    BilinearForm mass(&control_fes);
    mass.AddDomainIntegrator(new InverseIntegrator(new MassIntegrator(one)));
@@ -385,7 +342,7 @@ int main(int argc, char *argv[])
    // 11. Iterate:
    for (int k = 1; k <= max_it; k++)
    {
-      if (k > 1) { alpha *= ((real_t) k) / ((real_t) k-1); }
+      if (k > 1) { alpha = std::pow((real_t) k,growth); }
 
       mfem::out << "\nStep = " << k << std::endl;
 
@@ -422,7 +379,9 @@ int main(int argc, char *argv[])
 
       // Step 5 - Update design variable ψ ← proj(ψ - αG)
       psi.Add(-alpha, grad);
-      const real_t material_volume = proj(psi, target_volume);
+      GridFunction alpha_grad(grad);
+      alpha_grad *= alpha;
+      const real_t material_volume = proj(psi, alpha_grad, target_volume);
 
       // Compute ||ρ - ρ_old|| in control fes.
       real_t norm_increment = zerogf.ComputeL1Error(succ_diff_rho);

examples/ex37.hpp

@@ -137,7 +137,7 @@ public:
         exponent(exponent_), rho_min(rho_min_)
    {
       MFEM_ASSERT(rho_min_ >= 0.0, "rho_min must be >= 0");
-      MFEM_ASSERT(rho_min_ < 1.0,  "rho_min must be > 1");
+      MFEM_ASSERT(rho_min_ < 1.0,  "rho_min must be < 1");
       MFEM_ASSERT(u, "displacement field is not set");
       MFEM_ASSERT(rho_filter, "density field is not set");
    }
@@ -231,9 +231,12 @@ private:
    FiniteElementCollection * fec = nullptr;
    FiniteElementSpace * fes = nullptr;
    Array<int> ess_bdr;
+   Array<int> ess_tdof_list;
    Array<int> neumann_bdr;
    GridFunction * u = nullptr;
    LinearForm * b = nullptr;
+   BilinearForm * a = nullptr;
+   OperatorPtr A;
    bool parallel;
 #ifdef MFEM_USE_MPI
    ParMesh * pmesh = nullptr;
@@ -267,6 +270,8 @@ public:
    void ResetFEM();
    void SetupFEM();
 
+   void UpdateEssentialTDofs();
+   void AssembleDiffusionBilinear(bool update_ess_tdofs=true);
    void Solve();
    GridFunction * GetFEMSolution();
    LinearForm * GetLinearForm() {return b;}
@@ -371,6 +376,130 @@ public:
 
 };
 
+/**
+ * @brief Bregman projection of ρ = sigmoid(ψ) onto the subspace
+ *        ∫_Ω ρ dx = θ vol(Ω) as follows:
+ *
+ *        1. Compute the root of the R → R function
+ *            f(c) = ∫_Ω sigmoid(ψ + c) dx - θ vol(Ω)
+ *           using the Illinois method
+ *        2. Set ψ ← ψ + c.
+ *
+ * @param psi a GridFunction to be updated
+ * @param alpha_grad alpha multiplied by gradient
+ * @param target_volume θ vol(Ω)
+ * @param tol Illinois iteration tolerance
+ * @param max_its Illinois maximum iteration number
+ * @return real_t Final volume (∫_Ω sigmoid(ψ) dx)
+ */
+real_t proj(GridFunction &psi, GridFunction &alpha_grad, real_t target_volume,
+            real_t tol = 1e-12, int max_its = 100)
+{
+#ifdef MFEM_USE_MPI
+   FiniteElementSpace *fes = psi.FESpace();
+   ParFiniteElementSpace *pfes = dynamic_cast<ParFiniteElementSpace*>(fes);
+#endif
+   ConstantCoefficient zero_cf(0.0);
+   real_t a = -alpha_grad.ComputeMaxError(zero_cf);
+   real_t b = -a;
+   real_t y = 0.0;
+
+   MappedGridFunctionCoefficient sigmoid_psi(
+   &psi, [&y](const real_t x) { return sigmoid(x + y); });
+   std::unique_ptr<LinearForm> int_sigmoid_psi;
+#ifdef MFEM_USE_MPI
+   ParGridFunction *par_psi = dynamic_cast<ParGridFunction *>(&psi);
+   if (par_psi)
+   {
+      int_sigmoid_psi.reset(new ParLinearForm(par_psi->ParFESpace()));
+   }
+   else
+   {
+      int_sigmoid_psi.reset(new LinearForm(psi.FESpace()));
+   }
+#else
+   int_sigmoid_psi.reset(new LinearForm(psi.FESpace()));
+#endif
+   int_sigmoid_psi->AddDomainIntegrator(new DomainLFIntegrator(sigmoid_psi));
+
+   y = a;
+   int_sigmoid_psi->Assemble();
+   real_t f_a = int_sigmoid_psi->Sum();  // f_a := f(a) + θ vol(Ω)
+
+   y = b;
+   int_sigmoid_psi->Assemble();
+   real_t f_b = int_sigmoid_psi->Sum();  // f_b := f(b) + θ vol(Ω)
+#ifdef MFEM_USE_MPI
+   if (pfes)
+   {
+      MPI_Allreduce(MPI_IN_PLACE, &f_a, 1, MPITypeMap<real_t>::mpi_type,
+                    MPI_SUM, MPI_COMM_WORLD);
+      MPI_Allreduce(MPI_IN_PLACE, &f_b, 1, MPITypeMap<real_t>::mpi_type,
+                    MPI_SUM, MPI_COMM_WORLD);
+   }
+#endif
+   f_a -= target_volume; // f_a := f(a)
+   f_b -= target_volume; // f_b := f(b)
+   real_t c = 0.0;
+   real_t f_c = 0.0;
+   int side = 0;
+
+   bool done = false;
+   for (int k=0; k < max_its; k++)
+   {
+      c = (f_a * b - f_b * a) / (f_a - f_b);
+
+      if (abs(b - a) < tol * abs(b + a)) { done = true; break; }
+
+      y = c;
+      int_sigmoid_psi->Assemble();
+      f_c = int_sigmoid_psi->Sum(); // f_c := f(c) + θ vol(Ω)
+#ifdef MFEM_USE_MPI
+      if (pfes)
+      {
+         MPI_Allreduce(MPI_IN_PLACE, &f_c, 1, MPITypeMap<real_t>::mpi_type,
+                       MPI_SUM, MPI_COMM_WORLD);
+      }
+#endif
+      f_c -= target_volume; // f_c := f(c)
+
+      if (f_c * f_b > 0)
+      {
+         b = c;
+         f_b = f_c;
+         if (side == -1) { f_a /= 2.0; }
+         side = -1;
+      }
+      else if (f_c * f_a > 0)
+      {
+         a = c;
+         f_a = f_c;
+         if (side == 1) { f_b /= 2.0; }
+         side = 1;
+      }
+      else
+      {
+         done = true; break;
+      }
+   }
+   if (!done)
+   {
+      mfem_warning("Projection reached maximum iteration without converging. "
+                   "Result may not be accurate.");
+   }
+   y = 0.0;
+   psi += c;
+   int_sigmoid_psi->Assemble();
+   real_t material_volume = int_sigmoid_psi->Sum();
+#ifdef MFEM_USE_MPI
+   if (pfes)
+   {
+      MPI_Allreduce(MPI_IN_PLACE, &material_volume, 1,
+                    MPITypeMap<real_t>::mpi_type, MPI_SUM, MPI_COMM_WORLD);
+   }
+#endif
+   return material_volume;
+}
 
 // Poisson solver
 
@@ -422,12 +551,8 @@ void DiffusionSolver::SetupFEM()
    }
 }
 
-void DiffusionSolver::Solve()
+void DiffusionSolver::UpdateEssentialTDofs()
 {
-   OperatorPtr A;
-   Vector B, X;
-   Array<int> ess_tdof_list;
-
 #ifdef MFEM_USE_MPI
    if (parallel)
    {
@@ -440,7 +565,39 @@ void DiffusionSolver::Solve()
 #else
    fes->GetEssentialTrueDofs(ess_bdr,ess_tdof_list);
 #endif
-   *u=0.0;
+}
+
+void DiffusionSolver::AssembleDiffusionBilinear(bool update_ess_tdofs)
+{
+   if (update_ess_tdofs)
+   {
+      UpdateEssentialTDofs();
+   }
+#ifdef MFEM_USE_MPI
+   if (parallel)
+   {
+      a = new ParBilinearForm(pfes);
+   }
+   else
+   {
+      a = new BilinearForm(fes);
+   }
+#else
+   a = new BilinearForm(fes);
+#endif
+   a->AddDomainIntegrator(new DiffusionIntegrator(*diffcf));
+   if (masscf)
+   {
+      a->AddDomainIntegrator(new MassIntegrator(*masscf));
+   }
+   a->Assemble();
+   a->FormSystemMatrix(ess_tdof_list, A);
+}
+
+void DiffusionSolver::Solve()
+{
+   Vector B, X;
+
    if (b)
    {
       delete b;
@@ -475,31 +632,33 @@ void DiffusionSolver::Solve()
 
    b->Assemble();
 
-   BilinearForm * a = nullptr;
-
-#ifdef MFEM_USE_MPI
-   if (parallel)
-   {
-      a = new ParBilinearForm(pfes);
-   }
-   else
-   {
-      a = new BilinearForm(fes);
-   }
-#else
-   a = new BilinearForm(fes);
-#endif
-   a->AddDomainIntegrator(new DiffusionIntegrator(*diffcf));
-   if (masscf)
-   {
-      a->AddDomainIntegrator(new MassIntegrator(*masscf));
-   }
-   a->Assemble();
+   *u=0.0;
    if (essbdr_cf)
    {
       u->ProjectBdrCoefficient(*essbdr_cf,ess_bdr);
    }
-   a->FormLinearSystem(ess_tdof_list, *u, *b, A, X, B);
+
+#ifdef MFEM_USE_MPI
+   if (parallel)
+   {
+      X.SetSize(pfes->TrueVSize());
+      B.SetSize(pfes->TrueVSize());
+      dynamic_cast<ParGridFunction*>(u)->ParallelAssemble(X);
+      dynamic_cast<ParLinearForm*>(b)->ParallelAssemble(B);
+      dynamic_cast<ParBilinearForm*>(a)->ParallelEliminateTDofsInRHS(
+         ess_tdof_list, X, B);
+   }
+   else
+   {
+      X.NewDataAndSize(u->GetData(), u->Size());
+      B.NewDataAndSize(b->GetData(), b->Size());
+      a->EliminateVDofsInRHS(ess_tdof_list, X, B);
+   }
+#else
+   X.NewDataAndSize(u->GetData(), u->Size());
+   B.NewDataAndSize(b->GetData(), b->Size());
+   a->EliminateVDofsInRHS(ess_tdof_list, X, B);
+#endif
 
    CGSolver * cg = nullptr;
    Solver * M = nullptr;
@@ -528,7 +687,6 @@ void DiffusionSolver::Solve()
    delete M;
    delete cg;
    a->RecoverFEMSolution(X, *b, *u);
-   delete a;
 }
 
 GridFunction * DiffusionSolver::GetFEMSolution()
@@ -560,6 +718,8 @@ DiffusionSolver::~DiffusionSolver()
 #endif
    delete fec; fec = nullptr;
    delete b;
+   A.Clear();
+   delete a;
 }
 
 

examples/ex37p.cpp

@@ -4,8 +4,8 @@
 //
 // Sample runs:
 //    mpirun -np 4 ex37p -alpha 10 -pv
-//    mpirun -np 4 ex37p -lambda 0.1 -mu 0.1
-//    mpirun -np 4 ex37p -o 2 -alpha 5.0 -mi 50 -vf 0.4 -ntol 1e-5
+//    mpirun -np 4 ex37p -lambda 0.1 -mu 0.1 -growth 1
+//    mpirun -np 4 ex37p -o 2 -alpha 10.0 -mi 50 -vf 0.4 -ntol 1e-5 -growth 1.5
 //    mpirun -np 4 ex37p -r 6 -o 2 -alpha 10.0 -epsilon 0.02 -mi 50 -ntol 1e-5
 //
 // Description: This example code demonstrates the use of MFEM to solve a
@@ -54,61 +54,6 @@
 using namespace std;
 using namespace mfem;
 
-/**
- * @brief Bregman projection of ρ = sigmoid(ψ) onto the subspace
- *        ∫_Ω ρ dx = θ vol(Ω) as follows:
- *
- *        1. Compute the root of the R → R function
- *            f(c) = ∫_Ω sigmoid(ψ + c) dx - θ vol(Ω)
- *        2. Set ψ ← ψ + c.
- *
- * @param psi a GridFunction to be updated
- * @param target_volume θ vol(Ω)
- * @param tol Newton iteration tolerance
- * @param max_its Newton maximum iteration number
- * @return real_t Final volume, ∫_Ω sigmoid(ψ)
- */
-real_t proj(ParGridFunction &psi, real_t target_volume, real_t tol=1e-12,
-            int max_its=10)
-{
-   MappedGridFunctionCoefficient sigmoid_psi(&psi, sigmoid);
-   MappedGridFunctionCoefficient der_sigmoid_psi(&psi, der_sigmoid);
-
-   ParLinearForm int_sigmoid_psi(psi.ParFESpace());
-   int_sigmoid_psi.AddDomainIntegrator(new DomainLFIntegrator(sigmoid_psi));
-   ParLinearForm int_der_sigmoid_psi(psi.ParFESpace());
-   int_der_sigmoid_psi.AddDomainIntegrator(new DomainLFIntegrator(
-                                              der_sigmoid_psi));
-   bool done = false;
-   for (int k=0; k<max_its; k++) // Newton iteration
-   {
-      int_sigmoid_psi.Assemble(); // Recompute f(c) with updated ψ
-      real_t f = int_sigmoid_psi.Sum();
-      MPI_Allreduce(MPI_IN_PLACE, &f, 1, MPITypeMap<real_t>::mpi_type,
-                    MPI_SUM, MPI_COMM_WORLD);
-      f -= target_volume;
-
-      int_der_sigmoid_psi.Assemble(); // Recompute df(c) with updated ψ
-      real_t df = int_der_sigmoid_psi.Sum();
-      MPI_Allreduce(MPI_IN_PLACE, &df, 1, MPITypeMap<real_t>::mpi_type,
-                    MPI_SUM, MPI_COMM_WORLD);
-
-      const real_t dc = -f/df;
-      psi += dc;
-      if (abs(dc) < tol) { done = true; break; }
-   }
-   if (!done)
-   {
-      mfem_warning("Projection reached maximum iteration without converging. "
-                   "Result may not be accurate.");
-   }
-   int_sigmoid_psi.Assemble();
-   real_t material_volume = int_sigmoid_psi.Sum();
-   MPI_Allreduce(MPI_IN_PLACE, &material_volume, 1,
-                 MPITypeMap<real_t>::mpi_type, MPI_SUM, MPI_COMM_WORLD);
-   return material_volume;
-}
-
 /*
  * ---------------------------------------------------------------
  *                      ALGORITHM PREAMBLE
@@ -193,10 +138,11 @@ int main(int argc, char *argv[])
    int ref_levels = 5;
    int order = 2;
    real_t alpha = 1.0;
+   real_t growth = 2;
    real_t epsilon = 0.01;
    real_t vol_fraction = 0.5;
    int max_it = 1e3;
-   real_t itol = 1e-1;
+   real_t itol = 1e-2;
    real_t ntol = 1e-4;
    real_t rho_min = 1e-6;
    real_t lambda = 1.0;
@@ -211,6 +157,8 @@ int main(int argc, char *argv[])
                   "Order (degree) of the finite elements.");
    args.AddOption(&alpha, "-alpha", "--alpha-step-length",
                   "Step length for gradient descent.");
+   args.AddOption(&growth, "-growth", "--alpha-growth-rate",
+                  "Growth rate of step length for gradient descent.");
    args.AddOption(&epsilon, "-epsilon", "--epsilon-thickness",
                   "Length scale for ρ.");
    args.AddOption(&max_it, "-mi", "--max-it",
@@ -359,6 +307,7 @@ int main(int argc, char *argv[])
    }
    FilterSolver->SetEssentialBoundary(ess_bdr_filter);
    FilterSolver->SetupFEM();
+   FilterSolver->AssembleDiffusionBilinear();
 
    ParBilinearForm mass(&control_fes);
    mass.AddDomainIntegrator(new InverseIntegrator(new MassIntegrator(one)));
@@ -412,7 +361,7 @@ int main(int argc, char *argv[])
    // 11. Iterate:
    for (int k = 1; k <= max_it; k++)
    {
-      if (k > 1) { alpha *= ((real_t) k) / ((real_t) k-1); }
+      if (k > 1) { alpha = std::pow((real_t) k,growth); }
 
       if (myid == 0)
       {
@@ -452,7 +401,9 @@ int main(int argc, char *argv[])
 
       // Step 5 - Update design variable ψ ← proj(ψ - αG)
       psi.Add(-alpha, grad);
-      const real_t material_volume = proj(psi, target_volume);
+      ParGridFunction alpha_grad(grad);
+      alpha_grad *= alpha;
+      const real_t material_volume = proj(psi, alpha_grad, target_volume);
 
       // Compute ||ρ - ρ_old|| in control fes.
       real_t norm_increment = zerogf.ComputeL1Error(succ_diff_rho);

examples/ex4.cpp

@@ -9,6 +9,7 @@
 //               ex4 -m ../data/beam-hex.mesh -o 2 -pa
 //               ex4 -m ../data/escher.mesh
 //               ex4 -m ../data/fichera.mesh -o 2 -hb
+//               ex4 -m ../data/fichera.mesh -o 2 -hb -ea
 //               ex4 -m ../data/fichera-q2.vtk
 //               ex4 -m ../data/fichera-q3.mesh -o 2 -sc
 //               ex4 -m ../data/square-disc-nurbs.mesh
@@ -18,6 +19,7 @@
 //               ex4 -m ../data/amr-quad.mesh
 //               ex4 -m ../data/amr-hex.mesh
 //               ex4 -m ../data/amr-hex.mesh -o 2 -hb
+//               ex4 -m ../data/amr-hex.mesh -o 2 -hb -ea
 //               ex4 -m ../data/fichera-amr.mesh -o 2 -sc
 //               ex4 -m ../data/ref-prism.mesh -o 1
 //               ex4 -m ../data/octahedron.mesh -o 1
@@ -25,6 +27,8 @@
 //
 // Device sample runs:
 //               ex4 -m ../data/star.mesh -pa -d cuda
+//               ex4 -m ../data/star.mesh -hb -ea -d cuda
+//               ex4 -m ../data/amr-quad.mesh -hb -ea -d cuda
 //               ex4 -m ../data/star.mesh -pa -d raja-cuda
 //               ex4 -m ../data/star.mesh -pa -d raja-omp
 //               ex4 -m ../data/beam-hex.mesh -pa -d cuda
@@ -193,7 +197,7 @@ int main(int argc, char *argv[])
    cout << "Size of linear system: " << A->Height() << endl;
 
    // 11. Solve the linear system A X = B.
-   if (!pa)
+   if (!pa && (!ea || hybridization))
    {
 #ifndef MFEM_USE_SUITESPARSE
       // Use a simple symmetric Gauss-Seidel preconditioner with PCG.

examples/ex4p.cpp

@@ -9,6 +9,7 @@
 //               mpirun -np 4 ex4p -m ../data/beam-hex.mesh -o 2 -pa
 //               mpirun -np 4 ex4p -m ../data/escher.mesh -o 2 -sc
 //               mpirun -np 4 ex4p -m ../data/fichera.mesh -o 2 -hb
+//               mpirun -np 4 ex4p -m ../data/fichera.mesh -o 2 -hb -ea
 //               mpirun -np 4 ex4p -m ../data/fichera-q2.vtk
 //               mpirun -np 4 ex4p -m ../data/fichera-q3.mesh -o 2 -sc
 //               mpirun -np 4 ex4p -m ../data/square-disc-nurbs.mesh -o 3
@@ -17,14 +18,18 @@
 //               mpirun -np 4 ex4p -m ../data/periodic-cube.mesh -no-bc
 //               mpirun -np 4 ex4p -m ../data/amr-quad.mesh
 //               mpirun -np 3 ex4p -m ../data/amr-quad.mesh -o 2 -hb
+//               mpirun -np 3 ex4p -m ../data/amr-quad.mesh -o 2 -hb -ea
 //               mpirun -np 4 ex4p -m ../data/amr-hex.mesh -o 2 -sc
 //               mpirun -np 4 ex4p -m ../data/amr-hex.mesh -o 2 -hb
+//               mpirun -np 4 ex4p -m ../data/amr-hex.mesh -o 2 -hb -ea
 //               mpirun -np 4 ex4p -m ../data/ref-prism.mesh -o 1
 //               mpirun -np 4 ex4p -m ../data/octahedron.mesh -o 1
 //               mpirun -np 4 ex4p -m ../data/star-surf.mesh -o 3 -hb
 //
 // Device sample runs:
 //               mpirun -np 4 ex4p -m ../data/star.mesh -pa -d cuda
+//               mpirun -np 4 ex4p -m ../data/star.mesh -ea -hb -d cuda
+//               mpirun -np 4 ex4p -m ../data/amr-hex.mesh -ea -hb -d cuda
 //               mpirun -np 4 ex4p -m ../data/star.mesh -pa -d raja-cuda
 //               mpirun -np 4 ex4p -m ../data/star.mesh -pa -d raja-omp
 //               mpirun -np 4 ex4p -m ../data/beam-hex.mesh -pa -d cuda
@@ -230,7 +235,7 @@ int main(int argc, char *argv[])
    pcg->SetMaxIter(2000);
    pcg->SetPrintLevel(1);
    if (hybridization) { prec = new HypreBoomerAMG(*A.As<HypreParMatrix>()); }
-   else if (pa) { prec = new OperatorJacobiSmoother(*a, ess_tdof_list); }
+   else if (pa || ea) { prec = new OperatorJacobiSmoother(*a, ess_tdof_list); }
    else
    {
       ParFiniteElementSpace *prec_fespace =

examples/makefile

@@ -31,6 +31,9 @@ SEQ_DEVICE_EXAMPLES = ex1 ex3 ex4 ex5 ex6 ex9 ex14 ex22 ex24 ex25 ex26 ex34
 PAR_DEVICE_EXAMPLES = ex1p ex2p ex3p ex4p ex5p ex6p ex7p ex9p ex13p ex14p \
    ex22p ex24p ex25p ex26p ex34p ex35p
 
+ifeq ($(MFEM_USE_ARPACK),YES)
+   SEQ_EXAMPLES += ex11 ex13
+endif
 ifeq ($(MFEM_USE_LAPACK),YES)
    SEQ_EXAMPLES += ex38
 endif
@@ -157,6 +160,8 @@ ex37-test-seq: ex37
 	@$(call mfem-test,$<,, Serial example,-mi 3)
 ex37p-test-par: ex37p
 	@$(call mfem-test,$<, $(RUN_MPI), Parallel example,-mi 3)
+ex39-test-seq: ex39
+	@$(call mfem-test,$<,, Serial example,-m ../data/compass.mesh)
 ex41-test-seq: ex41
 	@$(call mfem-test,$<,, Serial example,-tf 1.0)
 ex41p-test-par: ex41p

fem/bilinearform.cpp

@@ -729,7 +729,8 @@ void BilinearForm::Assemble(int skip_zeros)
          tr = mesh -> GetBdrFaceTransformations (i);
          if (tr != NULL)
          {
-            fes -> GetElementVDofs (tr -> Elem1No, vdofs);
+            mfem::DofTransformation doftrans;
+            fes -> GetElementVDofs (tr -> Elem1No, vdofs, doftrans);
             fe1 = fes -> GetFE (tr -> Elem1No);
             // The fe2 object is really a dummy and not used on the boundaries,
             // but we can't dereference a NULL pointer, and we don't want to
@@ -743,6 +744,7 @@ void BilinearForm::Assemble(int skip_zeros)
 
                boundary_face_integs[k] -> AssembleFaceMatrix (*fe1, *fe2, *tr,
                                                               elemmat);
+               doftrans.TransformDual(elemmat);
                mat -> AddSubMatrix (vdofs, vdofs, elemmat, skip_zeros);
             }
          }
@@ -825,14 +827,46 @@ void BilinearForm::FormLinearSystem(const Array<int> &ess_tdof_list, Vector &x,
                                     Vector &b, OperatorHandle &A, Vector &X,
                                     Vector &B, int copy_interior)
 {
+   const SparseMatrix *P = fes->GetConformingProlongation();
+   const SparseMatrix *R = fes->GetConformingRestriction();
    if (ext)
    {
       if (hybridization)
       {
          FormSystemMatrix(ess_tdof_list, A);
-         ConstrainedOperator A_constrained(this, ess_tdof_list);
-         A_constrained.EliminateRHS(x, b);
-         hybridization->ReduceRHS(b, B);
+
+         std::unique_ptr<ConstrainedOperator> A_constrained([&]()
+         {
+            Operator *op;
+            Operator::FormSystemOperator(ess_tdof_list, op);
+            return dynamic_cast<ConstrainedOperator*>(op);
+         }());
+         MFEM_ASSERT(A_constrained != nullptr, "");
+
+         Vector conf_b, conf_x;
+         if (P)
+         {
+            // Nonconforming
+            conf_b.SetSize(P->Width());
+            conf_x.SetSize(P->Width());
+            P->MultTranspose(b, conf_b);
+            R->Mult(x, conf_x);
+         }
+         else
+         {
+            // Conforming
+            conf_b.MakeRef(b, 0, b.Size());
+            conf_x.MakeRef(x, 0, x.Size());
+         }
+
+         A_constrained->EliminateRHS(conf_x, conf_b);
+
+         if (P)
+         {
+            R->MultTranspose(conf_b, b); // store eliminated rhs in b
+         }
+
+         hybridization->ReduceRHS(conf_b, B);
          X.SetSize(B.Size());
          X = 0.0;
       }
@@ -842,7 +876,6 @@ void BilinearForm::FormLinearSystem(const Array<int> &ess_tdof_list, Vector &x,
       }
       return;
    }
-   const SparseMatrix *P = fes->GetConformingProlongation();
    FormSystemMatrix(ess_tdof_list, A);
 
    // Transform the system and perform the elimination in B, based on the
@@ -878,7 +911,6 @@ void BilinearForm::FormLinearSystem(const Array<int> &ess_tdof_list, Vector &x,
       if (hybridization)
       {
          // Reduction to the Lagrange multipliers system
-         const SparseMatrix *R = fes->GetConformingRestriction();
          Vector conf_b(P->Width()), conf_x(P->Width());
          P->MultTranspose(b, conf_b);
          R->Mult(x, conf_x);
@@ -891,7 +923,6 @@ void BilinearForm::FormLinearSystem(const Array<int> &ess_tdof_list, Vector &x,
       else
       {
          // Variational restriction with P
-         const SparseMatrix *R = fes->GetConformingRestriction();
          B.SetSize(P->Width());
          P->MultTranspose(b, B);
          X.SetSize(R->Height());
@@ -1694,6 +1725,7 @@ void MixedBilinearForm::Assemble(int skip_zeros)
          }
       }
 
+      DofTransformation dom_dof_trans, ran_dof_trans;
       for (int i = 0; i < trial_fes -> GetNBE(); i++)
       {
          const int bdr_attr = mesh->GetBdrAttribute(i);
@@ -1702,8 +1734,8 @@ void MixedBilinearForm::Assemble(int skip_zeros)
          ftr = mesh -> GetBdrFaceTransformations (i);
          if (ftr != NULL)
          {
-            trial_fes->GetElementVDofs(ftr->Elem1No, trial_vdofs);
-            test_fes->GetElementVDofs(ftr->Elem1No, test_vdofs);
+            trial_fes->GetElementVDofs(ftr->Elem1No, trial_vdofs, dom_dof_trans);
+            test_fes->GetElementVDofs(ftr->Elem1No, test_vdofs, ran_dof_trans);
             trial_fe1 = trial_fes->GetFE(ftr->Elem1No);
             test_fe1 = test_fes->GetFE(ftr->Elem1No);
             // The test_fe2 object is really a dummy and not used on the
@@ -1719,6 +1751,7 @@ void MixedBilinearForm::Assemble(int skip_zeros)
                boundary_face_integs[k]->AssembleFaceMatrix(*trial_fe1, *test_fe1, *trial_fe2,
                                                            *test_fe2,
                                                            *ftr, elemmat);
+               TransformDual(ran_dof_trans, dom_dof_trans, elemmat);
                mat->AddSubMatrix(test_vdofs, trial_vdofs, elemmat, skip_zeros);
             }
          }

fem/bilininteg.hpp

@@ -2710,7 +2710,7 @@ public:
 
 
 /** Integrator for $(-Q u, \nabla v)$ for Nedelec ($u$) and $H^1$ ($v$) elements.
-    This is equivalent to a weak divergence of the $H(curl$ basis functions. */
+    This is equivalent to a weak divergence of the $H(curl)$ basis functions. */
 class VectorFEWeakDivergenceIntegrator: public BilinearFormIntegrator
 {
 protected:

fem/bounds.cpp

@@ -39,8 +39,8 @@ void PLBound::Setup(const int nb_i, const int ncp_i,
    b_type = b_type_i;
    cp_type = cp_type_i;
    tol = tol_i;
-   lbound.SetSize(nb, ncp);
-   ubound.SetSize(nb, ncp);
+   lbound.SetSize(ncp, nb);
+   ubound.SetSize(ncp, nb);
    nodes.SetSize(nb);
    weights.SetSize(nb);
    control_points.SetSize(ncp);
@@ -125,21 +125,25 @@ void PLBound::Setup(const int nb_i, const int ncp_i,
       {
          if (j == 0)
          {
-            lbound(i, j) = bv(i);
-            ubound(i, j) = bv(i);
+            lbound(j,i) = bv(i);
+            ubound(j,i) = bv(i);
          }
          else if (j == ncp-1)
          {
-            lbound(i, j) = bv(i);
-            ubound(i, j) = bv(i);
+            lbound(j,i) = bv(i);
+            ubound(j,i) = bv(i);
          }
          else
          {
             vals(0)  = bv(i);
             vals(1) =  bmv(i) +  dm*bdmv(i);
             vals(2) =  bpv(i) +  dp*bdpv(i);
-            lbound(i, j) = vals.Min()-tol; // tolerance for good measure
-            ubound(i, j) = vals.Max()+tol; // tolerance for good measure
+            lbound(j,i) = vals.Min()-tol; // tolerance for good measure
+            ubound(j,i) = vals.Max()+tol; // tolerance for good measure
+            if (b_type == 2)
+            {
+               lbound(j,i) = std::max(lbound(j,i),0_r);
+            }
          }
       }
    }
@@ -273,8 +277,7 @@ void PLBound::Get1DBounds(const Vector &coeff, Vector &intmin,
    intmax.SetSize(ncp);
    intmin = 0.0;
    intmax = 0.0;
-   Vector coeffm(nb);
-   coeffm = 0.0;
+   Vector coeffm;
 
    real_t a0 = 0.0;
    real_t a1 = 0.0;
@@ -302,6 +305,8 @@ void PLBound::Get1DBounds(const Vector &coeff, Vector &intmin,
    // compute L2 projection for linear bases: a0 + a1*x
    if (proj)
    {
+      coeffm.SetSize(nb);
+      coeffm = 0.0;
       for (int i = 0; i < nb; i++)
       {
          x = 2.0*nodes_int(i)-1;
@@ -342,8 +347,8 @@ void PLBound::Get1DBounds(const Vector &coeff, Vector &intmin,
       real_t c = coeffm(i);
       for (int j = 0; j < ncp; j++)
       {
-         intmin(j) += min(lbound(i,j)*c, ubound(i,j)*c);
-         intmax(j) += max(lbound(i,j)*c, ubound(i,j)*c);
+         intmin(j) += min(lbound(j,i)*c, ubound(j,i)*c);
+         intmax(j) += max(lbound(j,i)*c, ubound(j,i)*c);
       }
    }
 }
@@ -474,10 +479,10 @@ void PLBound::Get2DBounds(const Vector &coeff, Vector &intmin,
          real_t w1 = intmaxT(id2++);
          for (int k = 0; k < ncp; k++) // kth row
          {
-            vals(0) = w0*lbound(j,k);
-            vals(1) = w0*ubound(j,k);
-            vals(2) = w1*lbound(j,k);
-            vals(3) = w1*ubound(j,k);
+            vals(0) = w0*lbound(k,j);
+            vals(1) = w0*ubound(k,j);
+            vals(2) = w1*lbound(k,j);
+            vals(3) = w1*ubound(k,j);
             intmin(k*ncp+i) += vals.Min();
             intmax(k*ncp+i) += vals.Max();
          }
@@ -553,17 +558,17 @@ void PLBound::Get3DBounds(const Vector &coeff, Vector &intmin,
             for (int i = 0; i < nb; i++)
             {
                x = 2.0*nodes(i)-1; // x-coordinate
-               minBounds(i) -= a0V(j) + a1V(j)*x;
-               maxBounds(i) -= a0V(j) + a1V(j)*x;
+               minNodalVals(i) -= a0V(j) + a1V(j)*x;
+               maxNodalVals(i) -= a0V(j) + a1V(j)*x;
             }
             // Compute Bernstein coefficients
             LUFactors lu(basisMatLU.GetData(), lu_ip.GetData());
-            lu.Solve(nb, 1, minBounds.GetData());
-            lu.Solve(nb, 1, maxBounds.GetData());
+            lu.Solve(nb, 1, minNodalVals.GetData());
+            lu.Solve(nb, 1, maxNodalVals.GetData());
             for (int i = 0; i < nb; i++)
             {
-               intminT(i*ncp2+j) = minBounds(i);
-               intmaxT(i*ncp2+j) = maxBounds(i);
+               intminT(i*ncp2+j) = minNodalVals(i);
+               intmaxT(i*ncp2+j) = maxNodalVals(i);
             }
          }
       }
@@ -617,10 +622,10 @@ void PLBound::Get3DBounds(const Vector &coeff, Vector &intmin,
          real_t w1 = intmaxT(id2++);
          for (int k = 0; k < ncp; k++) // kth slice
          {
-            vals(0) = w0*lbound(j,k);
-            vals(1) = w0*ubound(j,k);
-            vals(2) = w1*lbound(j,k);
-            vals(3) = w1*ubound(j,k);
+            vals(0) = w0*lbound(k,j);
+            vals(1) = w0*ubound(k,j);
+            vals(2) = w1*lbound(k,j);
+            vals(3) = w1*ubound(k,j);
             intmin(k*ncp2+i) += vals.Min();
             intmax(k*ncp2+i) += vals.Max();
          }
@@ -653,7 +658,8 @@ void PLBound::SetupBernsteinBasisMat(DenseMatrix &basisMat,
                                      Vector &nodesBern) const
 {
    const int nbern = nodesBern.Size();
-   L2_SegmentElement el(nbern-1, 2); // we use L2 to leverage lexicographic order
+   L2_SegmentElement el(nbern-1, 2);
+   // we use L2 to leverage lexicographic order
    Array<int> ordering = el.GetLexicographicOrdering();
    basisMat.SetSize(nbern, nbern);
    Vector shape(nbern);
@@ -666,6 +672,39 @@ void PLBound::SetupBernsteinBasisMat(DenseMatrix &basisMat,
    }
 }
 
+DenseMatrix PLBound::GetBoundingMatrix(int dim, bool is_lower) const
+{
+   if (dim > 1)
+   {
+      const int ncpd = static_cast<int>(std::pow(ncp, dim));
+      const int nbd = static_cast<int>(std::pow(nb, dim));
+      DenseMatrix boundND(ncpd, nbd);
+      Vector phimin, phimax, col;
+      Vector coeffs(nbd);
+      coeffs = 0.0;
+      for (int j = 0; j < nbd; j++)
+      {
+         coeffs(j) = 1.0;
+         boundND.GetColumnReference(j, col);
+         GetNDBounds(dim, coeffs, phimin, phimax);
+         col = is_lower ? phimin : phimax;
+         coeffs(j) = 0.0;
+      }
+      return boundND;
+   }
+   return is_lower ? lbound : ubound;
+}
+
+DenseMatrix PLBound::GetLowerBoundMatrix(int dim) const
+{
+   return GetBoundingMatrix(dim, true);
+}
+
+DenseMatrix PLBound::GetUpperBoundMatrix(int dim) const
+{
+   return GetBoundingMatrix(dim, false);
+}
+
 constexpr int PLBound::min_ncp_gl_x[2][11];
 constexpr int PLBound::min_ncp_gll_x[2][11];
 constexpr int PLBound::min_ncp_pos_x[2][11];
@@ -716,4 +755,4 @@ void PLBound::Print(std::ostream &outp) const
    ubound.Print(outp);
 }
 
-}
+}

fem/bounds.hpp

@@ -19,14 +19,18 @@ namespace mfem
 {
 
 /** @name Piecewise linear bounds of bases
-    \brief Piecewise linear bounds of bases can be used to compute bounds on the grid function in each element. The bounds for the bases are constructed based on the following parameters:
+    \brief Piecewise linear bounds of bases can be used to compute bounds on
+    the grid function in each element. The bounds for the bases are constructed
+    based on the following parameters:
 
     (i) @b nb: number of bases/nodes in 1D (i.e. polynomial order+1),
 
-    (ii) @b b_type: bases type, 0 - Lagrange interpolants on Gauss-Legendre nodes, 1 - Lagrange interpolants on Gauss-Lobatto-Legendre nodes, and
+    (ii) @b b_type: bases type, 0 - Lagrange interpolants on Gauss-Legendre
+    nodes, 1 - Lagrange interpolants on Gauss-Lobatto-Legendre nodes, and
     2 - Positive/Bernstein bases on uniformly distributed nodes,
 
-    (iii) @b ncp: number of control points used to construct the piecewise linear bounds
+    (iii) @b ncp: number of control points used to construct the piecewise
+    linear bounds
 
     (iv) @b cp_type: control point distribution. 0 - GL + end-points,
                     1 - Chebyshev.
@@ -35,7 +39,9 @@ namespace mfem
 
     If the user does not specify @b ncp and @b cp_type, the minimum value of
     @b ncp is used that would bound the bases for the @b cp_type. We default
-    to @b cp_type = 0 as it requires fewer number of points to bound the bases. Typically, @b ncp = 2 @b nb is sufficient to get fairly compact bounds, and increasing @b ncp results in tighter bounds.
+    to @b cp_type = 0 as it requires fewer number of points to bound the bases.
+    Typically, @b ncp = 2 @b nb is sufficient to get fairly compact bounds, and
+    increasing @b ncp results in tighter bounds.
 
     Finally, only tensor-product elements are currently supported.
 
@@ -54,7 +60,7 @@ private:
    bool proj = true; // Use linear projection to compute bounds.
    real_t tol = 0.0; // offset bounds to avoid round-off errors
    Vector nodes, weights, control_points;
-   DenseMatrix lbound, ubound; // nb x ncp matrices with bounds of all bases
+   DenseMatrix lbound, ubound; // ncp x nb matrices with bounds of all bases
    // Some auxillary storage for computing the bounds with Bernstein
    DenseMatrix basisMatNodes; // Bernstein bases at equispaced nodes
    DenseMatrix basisMatInt;   // Bernstein bases at GLL nodes
@@ -80,6 +86,9 @@ private:
       {3,5,8,9,11,12,13,13,14,15,16}
    };
 
+   /// Helper function to extract lower or upper bounding matrix
+   DenseMatrix GetBoundingMatrix(int dim, bool is_lower) const;
+
 public:
    // Constructor
    PLBound(const int nb_i, const int ncp_i, const int b_type_i,
@@ -92,40 +101,82 @@ public:
    PLBound(const FiniteElementSpace *fes,
            const int ncp_i = -1, const int cp_type_i = 0);
 
-   // Get minimum number of control points needed to bound the given bases
+   /// Get minimum number of control points needed to bound the given bases
    int GetMinimumPointsForGivenBases(int nb_i, int b_type_i,
                                      int cp_type_i) const;
 
-   // Print information about the bounds
+   /// Print information about the bounds
    void Print(std::ostream &outp = mfem::out) const;
 
-   // Enable (default) or disable linear projection before bounding.
-   // This projection increases the computational cost but results in tighter
-   // bounds.
+   /** @brief Enable (default) or disable linear projection before bounding.
+    *
+    *  @details This projection increases the computational cost but results in
+    *  tighter bounds.
+    */
    void SetProjectionFlagForBounding(bool proj_) { proj = proj_; }
 
-   /// Compute piecewise linear bounds for the lexicographically-ordered
-   /// coefficients in @a coeff in 1D/2D/3D.
+   /** @brief Compute piecewise linear bounds for the lexicographically-ordered
+    *  nodal coefficients in @a coeff in 1D/2D/3D.
+    *
+    *  @param[in] rdim    The spatial dimension of the element (1, 2, or 3).
+    *  @param[in] coeff   The vector of lexicographically-ordered coefficients.
+    *                     Should be of size nb^rdim, where nb is the number of
+    *                     bases/nodes in 1D. These coefficients must correspond
+    *                     to the bases type and number of bases, used in the
+    *                     constructor of PLBound.
+    *
+    *  @param[out] intmin The vector of minimum bound for all control points.
+    *  @param[out] intmax The vector of maximum bound for all control points.
+    *                     Both intmin and intmax are of size ncp^rdim, where
+    *                     ncp is the number of control points in 1D, and are
+    *                     ordered lexicographically.
+    */
    void GetNDBounds(const int rdim, const Vector &coeff,
                     Vector &intmin, Vector &intmax) const;
 
    /// Get number of control points used to compute the bounds.
    int GetNControlPoints() const { return ncp; }
+
+   /// Get 1D control point locations (lexicographic order) in [0,1].
+   const Vector &GetControlPoints() const { return control_points; }
+
+   /** @brief Get lower and upper bounding matrix (ncp^dim x nb^dim)
+    *
+    *  @details The matrices can be used to compute the bounds at control points
+    *           by a simple matrix-vector product with the
+    *           lexicographically-ordered nodal coefficients.
+    *           The resulting output is also lexicographically-ordered.
+    *
+    *  @note These matrices do not account for the linear projection step that
+    *        is optionally done in GetNDBounds before bounding the function.
+    */
+   ///@{
+   DenseMatrix GetLowerBoundMatrix(int dim = 1) const;
+   DenseMatrix GetUpperBoundMatrix(int dim = 1) const;
+   ///@}
+
 private:
-   /// Compute piecewise linear bounds for the lexicographically-ordered
-   /// coefficients in @a coeff in 1D.
+   /** @brief Compute piecewise linear bounds for the lexicographically-ordered
+    *  nodal coefficients in @a coeff in 1D.
+    *  See GetNDBounds for details of the input and output parameters.
+    */
    void Get1DBounds(const Vector &coeff, Vector &intmin, Vector &intmax) const;
 
-   /// Compute piecewise linear bounds for the lexicographically-ordered
-   /// coefficients in @a coeff in 2D.
+   /** @brief Compute piecewise linear bounds for the lexicographically-ordered
+    *  nodal coefficients in @a coeff in 2D.
+    *  See GetNDBounds for details of the input and output parameters.
+    */
    void Get2DBounds(const Vector &coeff, Vector &intmin, Vector &intmax) const;
 
-   /// Compute piecewise linear bounds for the lexicographically-ordered
-   /// coefficients in @a coeff in 3D.
+   /** @brief Compute piecewise linear bounds for the lexicographically-ordered
+    *  nodal coefficients in @a coeff in 3D.
+    *  See GetNDBounds for details of the input and output parameters.
+    */
    void Get3DBounds(const Vector &coeff, Vector &intmin, Vector &intmax) const;
 
-   /// Setup matrix used to compute values at given 1D locations in [0,1]
-   /// for Bernstein bases.
+   /** @brief Setup matrix used to compute values at given 1D locations in [0,1]
+    *  for Bernstein bases.
+    */
    void SetupBernsteinBasisMat(DenseMatrix &basisMat, Vector &nodesBern) const;
 
    void Setup(const int nb_i, const int ncp_i, const int b_type_i,

fem/coefficient.hpp

@@ -52,6 +52,9 @@ public:
    /// Get the time for time dependent coefficients
    real_t GetTime() { return time; }
 
+   /// Returns dimension of the vector.
+   int GetVDim() { return 1; }
+
    /** @brief Evaluate the coefficient in the element described by @a T at the
        point @a ip. */
    /** @note When this method is called, the caller must make sure that the

fem/complex_fem.hpp

@@ -82,6 +82,25 @@ public:
    /// underlying #fes
    int VectorDim() const;
 
+   /// Copy assignment. Only the data of the base class Vector is copied.
+   /** It is assumed that this object and @a rhs use FiniteElementSpace%s that
+       have the same size.
+
+       @note Defining this method overwrites the implicitly defined copy
+       assignment operator. */
+   ComplexGridFunction &operator=(const ComplexGridFunction &rhs)
+   { return operator=((const Vector &)rhs); }
+
+   /// Copy the data from @a v.
+   /** The size of @a v must be equal to double of the size of the associated
+       FiniteElementSpace #fes. */
+   ComplexGridFunction &operator=(const Vector &v)
+   {
+      MFEM_ASSERT(fes && v.Size() == 2*fes->GetVSize(), "");
+      Vector::operator=(v);
+      return *this;
+   }
+
    /// Assign constant values to the ComplexGridFunction data.
    ComplexGridFunction &operator=(const std::complex<real_t> & value)
    { *gfr = value.real(); *gfi = value.imag(); return *this; }

fem/datacollection.cpp

@@ -492,6 +492,8 @@ void VisItDataCollection::SaveRootFile()
                            to_padded_string(cycle, pad_digits_cycle) +
                            ".mfem_root";
    std::ofstream root_file(root_name);
+   MFEM_VERIFY(root_file.is_open(),
+               "Failed to open ofstream " << root_name);
    root_file << GetVisItRootString();
    if (!root_file)
    {
@@ -977,7 +979,10 @@ void ParaViewDataCollection::Save()
    // Save the local part of the mesh and grid functions fields to the local
    // VTU file. Also save coefficient fields.
    {
-      std::ofstream os(vtu_prefix + GenerateVTUFileName("proc", myid));
+      std::string os_str = vtu_prefix + GenerateVTUFileName("proc", myid);
+      std::ofstream os(os_str);
+      MFEM_VERIFY(os.is_open(),
+                  "Failed to open ofstream " << os_str);
       os.precision(precision);
       SaveDataVTU(os, levels_of_detail);
    }
@@ -989,7 +994,10 @@ void ParaViewDataCollection::Save()
                   "QuadratureFunction output is not supported for "
                   "ParaViewDataCollection on domain boundary!");
       const std::string &field_name = qfield.first;
-      std::ofstream os(vtu_prefix + GenerateVTUFileName(field_name, myid));
+      std::string os_str = vtu_prefix + GenerateVTUFileName(field_name, myid);
+      std::ofstream os(os_str);
+      MFEM_VERIFY(os.is_open(),
+                  "Failed to open ofstream " << os_str);
       qfield.second->SaveVTU(os, pv_data_format, GetCompressionLevel(), field_name);
    }
 
@@ -1000,7 +1008,10 @@ void ParaViewDataCollection::Save()
    {
       // Create the main PVTU file
       {
-         std::ofstream pvtu_out(vtu_prefix + GeneratePVTUFileName("data"));
+         std::string os_str = vtu_prefix + GeneratePVTUFileName("data");
+         std::ofstream pvtu_out(os_str);
+         MFEM_VERIFY(pvtu_out.is_open(),
+                     "Failed to open ofstream " << os_str);
          WritePVTUHeader(pvtu_out);
 
          // Grid function fields and coefficient fields
@@ -1055,8 +1066,10 @@ void ParaViewDataCollection::Save()
          const std::string &q_field_name = q_field.first;
          std::string q_fname = GeneratePVTUPath() + "/"
                                + GeneratePVTUFileName(q_field_name);
-
-         std::ofstream pvtu_out(col_path + "/" + q_fname);
+         std::string os_str = col_path + "/" + q_fname;
+         std::ofstream pvtu_out(os_str);
+         MFEM_VERIFY(pvtu_out.is_open(),
+                     "Failed to open ofstream " << os_str);
          WritePVTUHeader(pvtu_out);
          int vec_dim = q_field.second->GetVDim();
          pvtu_out << "<PPointData>\n";

fem/dfem/integrate.hpp

@@ -90,8 +90,8 @@ void map_quadrature_data_to_fields_impl(
    }
    else
    {
-      MFEM_ABORT("quadrature data mapping to field is not implemented for"
-                 " this field descriptor");
+      MFEM_ABORT_KERNEL("quadrature data mapping to field is not implemented"
+                        " for this field descriptor");
    }
 }
 
@@ -169,8 +169,9 @@ void map_quadrature_data_to_fields_tensor_impl_1d(
    }
    else
    {
-      MFEM_ABORT("quadrature data mapping to field is not implemented for"
-                 " this field descriptor with sum factorization on tensor product elements");
+      MFEM_ABORT_KERNEL("quadrature data mapping to field is not implemented"
+                        "for this field descriptor with sum factorization on"
+                        " tensor product elements");
    }
 }
 
@@ -306,8 +307,9 @@ void map_quadrature_data_to_fields_tensor_impl_2d(
    }
    else
    {
-      MFEM_ABORT("quadrature data mapping to field is not implemented for"
-                 " this field descriptor with sum factorization on tensor product elements");
+      MFEM_ABORT_KERNEL("quadrature data mapping to field is not implemented"
+                        " for this field descriptor with sum factorization on"
+                        " tensor product elements");
    }
 }
 
@@ -492,8 +494,9 @@ void map_quadrature_data_to_fields_tensor_impl_3d(
    }
    else
    {
-      MFEM_ABORT("quadrature data mapping to field is not implemented for"
-                 " this field descriptor with sum factorization on tensor product elements");
+      MFEM_ABORT_KERNEL("quadrature data mapping to field is not implemented"
+                        " for this field descriptor with sum factorization on"
+                        " tensor product elements");
    }
 }
 

fem/dgmassinv_kernels.hpp

@@ -387,7 +387,7 @@ void DGMassInverse::DGMassCGIteration(const Vector &b_, Vector &u_) const
 
    static constexpr int NB = Q1D ? Q1D : 1; // block size
 
-   mfem::forall_2D(NE, NB, NB, [=] MFEM_HOST_DEVICE (int e)
+   mfem::forall_2D<NB*NB>(NE, NB, NB, [=] MFEM_HOST_DEVICE (int e)
    {
       // Perform change of basis if needed
       if (CHANGE_BASIS)

fem/estimators.hpp

@@ -320,8 +320,8 @@ public:
     error estimation procedure where the flux averaging is replaced by a global
     L2 projection (requiring a mass matrix solve).
 
-    The required BilinearFormIntegrator must implement the methods
-    ComputeElementFlux() and ComputeFluxEnergy().
+    The required BilinearFormIntegrator must implement the method
+    ComputeElementFlux().
 
     Implemented for the parallel case only.
  */
@@ -357,8 +357,8 @@ protected:
 
 public:
    /** @brief Construct a new L2ZienkiewiczZhuEstimator object.
-       @param integ    This BilinearFormIntegrator must implement the methods
-                       ComputeElementFlux() and ComputeFluxEnergy().
+       @param integ    This BilinearFormIntegrator must implement the method
+                       ComputeElementFlux().
        @param sol      The solution field whose error is to be estimated.
        @param flux_fes The L2ZienkiewiczZhuEstimator assumes ownership of this
                        FiniteElementSpace and will call its Update() method when
@@ -382,8 +382,8 @@ public:
    { }
 
    /** @brief Construct a new L2ZienkiewiczZhuEstimator object.
-       @param integ    This BilinearFormIntegrator must implement the methods
-                       ComputeElementFlux() and ComputeFluxEnergy().
+       @param integ    This BilinearFormIntegrator must implement the method
+                       ComputeElementFlux().
        @param sol      The solution field whose error is to be estimated.
        @param flux_fes The L2ZienkiewiczZhuEstimator does NOT assume ownership
                        of this FiniteElementSpace; will call its Update() method

fem/fe/face_map_utils.hpp

@@ -69,9 +69,9 @@ inline int ToLexOrdering2D(const int face_id, const int size1d, const int i)
 }
 
 /// @brief Given a face DOF index on a shared face, ordered lexicographically
-/// relative to element the element (where the local face is face_id), and
-/// return the corresponding face DOF index ordered lexicographically relative
-/// to the face itself.
+/// relative to the element (where the local face is face_id), return the
+/// corresponding face DOF index ordered lexicographically relative to the face
+/// itself.
 MFEM_HOST_DEVICE
 inline int PermuteFace2D(const int face_id, const int orientation,
                          const int size1d, const int index)

fem/fe/fe_base.cpp

@@ -231,7 +231,7 @@ void FiniteElement::CalcPhysLaplacian(ElementTransformation &Trans,
    {
       for (int nd = 0; nd < dof; nd++)
       {
-         Laplacian[nd] = hess(nd,0) + hess(nd,4) + hess(nd,5);
+         Laplacian[nd] = hess(nd,0) + hess(nd,3) + hess(nd,5);
       }
    }
    else if (dim == 2)
@@ -268,11 +268,9 @@ void FiniteElement::CalcPhysLinLaplacian(ElementTransformation &Trans,
       scale[0] =   Gij(0,0);
       scale[1] = 2*Gij(0,1);
       scale[2] = 2*Gij(0,2);
-
-      scale[3] = 2*Gij(1,2);
-      scale[4] =   Gij(2,2);
-
-      scale[5] =   Gij(1,1);
+      scale[3] =   Gij(1,1);
+      scale[4] = 2*Gij(1,2);
+      scale[5] =   Gij(2,2);
    }
    else if (dim == 2)
    {
@@ -309,12 +307,12 @@ void  FiniteElement::CalcPhysHessian(ElementTransformation &Trans,
       map[2] = 2;
 
       map[3] = 1;
-      map[4] = 5;
-      map[5] = 3;
+      map[4] = 3;
+      map[5] = 4;
 
       map[6] = 2;
-      map[7] = 3;
-      map[8] = 4;
+      map[7] = 4;
+      map[8] = 5;
    }
    else if (dim == 2)
    {
@@ -382,11 +380,7 @@ const DofToQuad &FiniteElement::GetDofToQuad(const IntegrationRule &ir,
    #pragma omp critical (DofToQuad)
 #endif
    {
-      for (int i = 0; i < dof2quad_array.Size(); i++)
-      {
-         d2q = dof2quad_array[i];
-         if (d2q->IntRule != &ir || d2q->mode != mode) { d2q = nullptr; }
-      }
+      d2q = DofToQuad::SearchArray(dof2quad_array, ir, mode);
       if (!d2q)
       {
 #ifdef MFEM_THREAD_SAFE
@@ -661,58 +655,67 @@ void ScalarFiniteElement::ScalarLocalL2Restriction(
 void NodalFiniteElement::CreateLexicographicFullMap(const IntegrationRule &ir)
 const
 {
+   // Get the FULL version of the map. This call contains omp critical region,
+   // so it is done before the critical region below.
+   auto &d2q = GetDofToQuad(ir, DofToQuad::FULL);
 
 #if defined(MFEM_THREAD_SAFE) && defined(MFEM_USE_OPENMP)
    #pragma omp critical (DofToQuad)
 #endif
    {
-      // Get the FULL version of the map.
-      auto &d2q = GetDofToQuad(ir, DofToQuad::FULL);
-      //Undo the native ordering which is what FiniteElement::GetDofToQuad returns.
-      auto *d2q_new = new DofToQuad(d2q);
-      d2q_new->mode = DofToQuad::LEXICOGRAPHIC_FULL;
-      const int nqpt = ir.GetNPoints();
-
-      const int b_dim = (range_type == VECTOR) ? dim : 1;
-
-      for (int i = 0; i < nqpt; i++)
+      // Do not run if the new Dof2Quad is already present, e.g. added in a
+      // previous call or added by another omp thread.
+      if (DofToQuad::SearchArray(dof2quad_array, ir,
+                                 DofToQuad::LEXICOGRAPHIC_FULL) == nullptr)
       {
-         for (int d = 0; d < b_dim; d++)
+         // Undo the native ordering which is what FiniteElement::GetDofToQuad
+         // returns.
+         auto *d2q_new = new DofToQuad(d2q);
+         d2q_new->mode = DofToQuad::LEXICOGRAPHIC_FULL;
+         const int nqpt = ir.GetNPoints();
+
+         const int b_dim = (range_type == VECTOR) ? dim : 1;
+
+         for (int i = 0; i < nqpt; i++)
          {
-            for (int j = 0; j < dof; j++)
+            for (int d = 0; d < b_dim; d++)
             {
-               const double val = d2q.B[i + nqpt*(d+b_dim*lex_ordering[j])];
-               d2q_new->B[i+nqpt*(d+b_dim*j)] = val;
-               d2q_new->Bt[j+dof*(i+nqpt*d)] = val;
+               for (int j = 0; j < dof; j++)
+               {
+                  const double val = d2q.B[i + nqpt*(d+b_dim*lex_ordering[j])];
+                  d2q_new->B[i+nqpt*(d+b_dim*j)] = val;
+                  d2q_new->Bt[j+dof*(i+nqpt*d)] = val;
+               }
             }
          }
-      }
 
-      const int g_dim = [this]()
-      {
-         switch (deriv_type)
+         const int g_dim = [this]()
          {
-            case GRAD: return dim;
-            case DIV: return 1;
-            case CURL: return cdim;
-            default: return 0;
-         }
-      }();
-
-      for (int i = 0; i < nqpt; i++)
-      {
-         for (int d = 0; d < g_dim; d++)
-         {
-            for (int j = 0; j < dof; j++)
+            switch (deriv_type)
             {
-               const double val = d2q.G[i + nqpt*(d+g_dim*lex_ordering[j])];
-               d2q_new->G[i+nqpt*(d+g_dim*j)] = val;
-               d2q_new->Gt[j+dof*(i+nqpt*d)] = val;
+               case GRAD: return dim;
+               case DIV: return 1;
+               case CURL: return cdim;
+               default: return 0;
+            }
+         }();
+
+         for (int i = 0; i < nqpt; i++)
+         {
+            for (int d = 0; d < g_dim; d++)
+            {
+               for (int j = 0; j < dof; j++)
+               {
+                  const double val = d2q.G[i + nqpt*(d+g_dim*lex_ordering[j])];
+                  d2q_new->G[i+nqpt*(d+g_dim*j)] = val;
+                  d2q_new->Gt[j+dof*(i+nqpt*d)] = val;
+               }
             }
          }
+
+         dof2quad_array.Append(d2q_new);
       }
 
-      dof2quad_array.Append(d2q_new);
    }
 }
 
@@ -724,13 +727,7 @@ const DofToQuad &NodalFiniteElement::GetDofToQuad(const IntegrationRule &ir,
    #pragma omp critical (DofToQuad)
 #endif
    {
-      //Should make this loop a function of FiniteElement
-      for (int i = 0; i < dof2quad_array.Size(); i++)
-      {
-         d2q = dof2quad_array[i];
-         if (d2q->IntRule == &ir && d2q->mode == mode) { break; }
-         d2q = nullptr;
-      }
+      d2q = DofToQuad::SearchArray(dof2quad_array, ir, mode);
    }
    if (d2q) { return *d2q; }
    if (mode != DofToQuad::LEXICOGRAPHIC_FULL)
@@ -1047,9 +1044,50 @@ void VectorFiniteElement::SetDerivMembers()
    switch (map_type)
    {
       case H_DIV:
-         deriv_type = DIV;
-         deriv_range_type = SCALAR;
-         deriv_map_type = INTEGRAL;
+         switch (dim)
+         {
+            case 3: // div: 3D H_DIV -> 3D INTEGRAL
+               deriv_type = DIV;
+               deriv_range_type = SCALAR;
+               deriv_map_type = INTEGRAL;
+               break;
+            case 2: // div: 2D H_DIV -> 2D INTEGRAL
+               deriv_type = DIV;
+               deriv_range_type = SCALAR;
+               deriv_map_type = INTEGRAL;
+               break;
+            default:
+               MFEM_ABORT("Invalid dimension, Dim = " << dim);
+         }
+         break;
+      case H_DIV_R2D:
+         switch (dim)
+         {
+            case 2: // div: 2D H_DIV_R2D -> 2D INTEGRAL
+               deriv_type = DIV;
+               deriv_range_type = SCALAR;
+               deriv_map_type = INTEGRAL;
+               break;
+            case 1: // div: 1D H_DIV_R2D -> 1D INTEGRAL
+               deriv_type = DIV;
+               deriv_range_type = SCALAR;
+               deriv_map_type = INTEGRAL;
+               break;
+            default:
+               MFEM_ABORT("Invalid dimension, Dim = " << dim);
+         }
+         break;
+      case H_DIV_R1D:
+         switch (dim)
+         {
+            case 1: // div: 1D H_DIV_R1D -> 1D INTEGRAL
+               deriv_type = DIV;
+               deriv_range_type = SCALAR;
+               deriv_map_type = INTEGRAL;
+               break;
+            default:
+               MFEM_ABORT("Invalid dimension, Dim = " << dim);
+         }
          break;
       case H_CURL:
          switch (dim)
@@ -1067,13 +1105,49 @@ void VectorFiniteElement::SetDerivMembers()
                break;
             case 1:
                deriv_type = NONE;
-               deriv_range_type = SCALAR;
-               deriv_map_type = INTEGRAL;
+               deriv_range_type = UNKNOWN_RANGE_TYPE;
+               deriv_map_type = UNKNOWN_MAP_TYPE;
                break;
             default:
                MFEM_ABORT("Invalid dimension, Dim = " << dim);
          }
          break;
+      case H_CURL_R2D:
+         switch (dim)
+         {
+            case 2:
+               // curl: 2D H_CURL_R2D -> H_DIV_R2D
+               deriv_type = CURL;
+               deriv_range_type = VECTOR;
+               deriv_map_type = H_DIV_R2D;
+               break;
+            case 1:
+               // curl: 1D H_CURL_R2D -> H_DIV_R2D
+               deriv_type = CURL;
+               deriv_range_type = VECTOR;
+               deriv_map_type = H_DIV_R2D;
+               break;
+            default:
+               MFEM_ABORT("Invalid dimension, Dim = " << dim);
+         }
+         break;
+      case H_CURL_R1D:
+         switch (dim)
+         {
+            case 1:
+               // curl: 1D H_CURL_R1D -> H_DIV_R1D
+               deriv_type = CURL;
+               deriv_range_type = VECTOR;
+               deriv_map_type = H_DIV_R1D;
+               break;
+            case 0:
+               deriv_type = NONE;
+               deriv_range_type = UNKNOWN_RANGE_TYPE;
+               deriv_map_type = UNKNOWN_MAP_TYPE;
+            default:
+               MFEM_ABORT("Invalid dimension, Dim = " << dim);
+         }
+         break;
       default:
          MFEM_ABORT("Invalid MapType = " << map_type);
    }
@@ -2631,15 +2705,7 @@ const DofToQuad &TensorBasisElement::GetTensorDofToQuad(
    #pragma omp critical (DofToQuad)
 #endif
    {
-      for (int i = 0; i < dof2quad_array.Size(); i++)
-      {
-         auto* d2q_ = dof2quad_array[i];
-         if (d2q_->IntRule == &ir && d2q_->mode == mode)
-         {
-            d2q = d2q_;
-            break;
-         }
-      }
+      d2q = DofToQuad::SearchArray(dof2quad_array, ir, mode);
       if (!d2q)
       {
          d2q = new DofToQuad;

fem/fe/fe_base.hpp

@@ -222,6 +222,12 @@ public:
 
    /// Returns absolute value of the maps
    DofToQuad Abs() const;
+
+   /// Auxiliary function for searching DofToQuad arrays.
+   static inline DofToQuad *SearchArray(
+      const Array<DofToQuad*> &dof2quad_array,
+      const IntegrationRule &ir,
+      DofToQuad::Mode mode);
 };
 
 /// Describes the function space on each element
@@ -289,10 +295,20 @@ public:
                           $ u(x) = (1/w) \hat u(\hat x) $ */
       H_DIV,     /**< For vector fields; preserves surface integrals of the
                           normal component $ u(x) = (J/w) \hat u(\hat x) $ */
-      H_CURL     /**< For vector fields; preserves line integrals of the
+      H_CURL,    /**< For vector fields; preserves line integrals of the
                           tangential component
                           $ u(x) = J^{-t} \hat u(\hat x) $ (square J),
                           $ u(x) = J(J^t J)^{-1} \hat u(\hat x) $ (general J) */
+      H_DIV_R2D, /**< For 3-component vector fields in 2D; equivalent to a
+                          direct sum of an H_DIV basis and an INTEGRAL basis */
+      H_CURL_R2D,/**< For 3-component vector fields in 2D; equivalent to a
+                          direct sum of an H_CURL basis and a VALUE basis */
+      H_DIV_R1D, /**< For 3-component vector fields in 1D; equivalent to a
+                          direct sum of a VALUE basis and a pair of INTEGRAL
+                          bases */
+      H_CURL_R1D /**< For 3-component vector fields in 1D; equivalent to a
+                          direct sum of an INTEGRAL basis and a pair of VALUE
+                          bases */
    };
 
    /** @brief Enumeration for DerivType: defines which derivative method
@@ -324,12 +340,28 @@ public:
    int GetDim() const { return dim; }
 
    /** @brief Returns the vector dimension for vector-valued finite elements,
-       which is also the dimension of the interpolation operation. */
+       which is also the dimension of the interpolation operation and the
+       width of the DenseMatrix argument in
+       CalcVShape(const IntegrationPoint &ip, DenseMatrix &shape). */
    int GetRangeDim() const { return vdim; }
 
-   /// Returns the dimension of the curl for vector-valued finite elements.
+   /** @brief Returns the vector dimension, in physical space, for
+       vector-valued finite elements, which is also the width of the
+       DenseMatrix argument in
+       CalcPhysVShape(ElementTransformation &Trans, DenseMatrix &shape). */
+   virtual int GetPhysRangeDim(int /* space_dim */) const { return vdim; }
+
+   /** Returns the dimension of the curl for vector-valued finite elements,
+       which is also the width of the DenseMatrix argument in
+       CalcCurlShape(const IntegrationPoint &ip, DenseMatrix &curl_shape). */
    int GetCurlDim() const { return cdim; }
 
+   /** Returns the dimension, in physical space, of the curl for vector-valued
+       finite elements, which is also the width of the DenseMatrix argument in
+       CalcPhysCurlShape(ElementTransformation &Trans, DenseMatrix &curl_shape).
+   */
+   virtual int GetPhysCurlDim(int /* space_dim */) const { return cdim; }
+
    /// Returns the Geometry::Type of the reference element.
    Geometry::Type GetGeomType() const { return geom_type; }
 
@@ -407,6 +439,7 @@ public:
    /** Each row of the result DenseMatrix @a Hessian contains upper triangular
        part of the Hessian of one shape function.
        The order in 2D is {u_xx, u_xy, u_yy}.
+       The order in 3D is {u_xx, u_xy, u_xz, u_yy, u_yz, u_zz}.
        The size (#dof x (#dim (#dim+1)/2) of @a Hessian must be set in advance.*/
    virtual void CalcHessian(const IntegrationPoint &ip,
                             DenseMatrix &Hessian) const;
@@ -983,6 +1016,8 @@ protected:
 public:
    VectorFiniteElement(int D, Geometry::Type G, int Do, int O, int M,
                        int F = FunctionSpace::Pk);
+
+   int GetPhysRangeDim(int space_dim) const override { return space_dim; }
 };
 
 /// @brief Class for computing 1D special polynomials and their associated basis
@@ -1376,6 +1411,21 @@ public:
 void InvertLinearTrans(ElementTransformation &trans,
                        const IntegrationPoint &pt, Vector &x);
 
+
+// static inline method
+inline DofToQuad *DofToQuad::SearchArray(
+   const Array<DofToQuad*> &dof2quad_array,
+   const IntegrationRule &ir,
+   DofToQuad::Mode mode)
+{
+   for (int i = 0; i < dof2quad_array.Size(); i++)
+   {
+      DofToQuad *d2q = dof2quad_array[i];
+      if (d2q->IntRule == &ir && d2q->mode == mode) { return d2q; }
+   }
+   return nullptr;
+}
+
 } // namespace mfem
 
 #endif

fem/fe/fe_fixed_order.cpp

@@ -60,6 +60,12 @@ void Linear1DFiniteElement::CalcDShape(const IntegrationPoint &ip,
    dshape(1,0) =  1.;
 }
 
+void Linear1DFiniteElement::CalcHessian(const IntegrationPoint &ip,
+                                        DenseMatrix &h) const
+{
+   h = 0.0;
+}
+
 Linear2DFiniteElement::Linear2DFiniteElement()
    : NodalFiniteElement(2, Geometry::TRIANGLE, 3, 1)
 {
@@ -87,6 +93,11 @@ void Linear2DFiniteElement::CalcDShape(const IntegrationPoint &ip,
    dshape(2,0) =  0.; dshape(2,1) =  1.;
 }
 
+void Linear2DFiniteElement::CalcHessian(const IntegrationPoint &ip,
+                                        DenseMatrix &h) const
+{
+   h = 0.0;
+}
 
 BiLinear2DFiniteElement::BiLinear2DFiniteElement()
    : NodalFiniteElement(2, Geometry::SQUARE, 4, 1, FunctionSpace::Qk)
@@ -1256,6 +1267,12 @@ void Linear3DFiniteElement::CalcDShape(const IntegrationPoint &ip,
    }
 }
 
+void Linear3DFiniteElement::CalcHessian(const IntegrationPoint &ip,
+                                        DenseMatrix &h) const
+{
+   h = 0.0;
+}
+
 void Linear3DFiniteElement::GetFaceDofs (int face, int **dofs, int *ndofs)
 const
 {
@@ -1632,6 +1649,37 @@ void TriLinear3DFiniteElement::CalcDShape(const IntegrationPoint &ip,
    dshape(7,2) =   ox *  y;
 }
 
+void TriLinear3DFiniteElement::CalcHessian(const IntegrationPoint &ip,
+                                           DenseMatrix &h) const
+{
+   real_t x = ip.x, y = ip.y, z = ip.z;
+   real_t ox = 1.-x, oy = 1.-y, oz = 1.-z;
+
+   h(0,0) = 0.;   h(0,1) =  oz;   h(0,2) = oy;
+   h(0,3) = 0.;   h(0,4) =  ox;   h(0,5) = 0.;
+
+   h(1,0) = 0.;   h(1,1) = -oz;   h(1,2) = -oy;
+   h(1,3) = 0.;   h(1,4) =  x;    h(1,5) = 0.;
+
+   h(2,0) = 0.;   h(2,1) =  oz;   h(2,2) = -y;
+   h(2,3) = 0.;   h(2,4) =  -x;   h(2,5) = 0.;
+
+   h(3,0) = 0.;   h(3,1) = -oz;   h(3,2) = y;
+   h(3,3) = 0.;   h(3,4) = -ox;   h(3,5) = 0.;
+
+   h(4,0) = 0.;   h(4,1) =  z;    h(4,2) = -oy;
+   h(4,3) = 0.;   h(4,4) = -ox;   h(4,5) = 0.;
+
+   h(5,0) = 0.;   h(5,1) = -z;    h(5,2) = oy;
+   h(5,3) = 0.;   h(5,4) = -x;    h(5,5) = 0.;
+
+   h(6,0) = 0.;   h(6,1) =  z;    h(6,2) = y;
+   h(6,3) = 0.;   h(6,4) =  x;    h(6,5) = 0.;
+
+   h(7,0) = 0.;   h(7,1) = -z;    h(7,2) = -y;
+   h(7,3) = 0.;   h(7,4) = ox;    h(7,5) = 0.;
+}
+
 
 P0SegmentFiniteElement::P0SegmentFiniteElement(int Ord)
    : NodalFiniteElement(1, Geometry::SEGMENT, 1, Ord)   // default Ord = 0

fem/fe/fe_fixed_order.hpp

@@ -50,6 +50,8 @@ public:
        contains the derivative of one shape function */
    void CalcDShape(const IntegrationPoint &ip,
                    DenseMatrix &dshape) const override;
+   void CalcHessian(const IntegrationPoint &ip,
+                    DenseMatrix &h) const override;
 };
 
 /// A 2D linear element on triangle with nodes at the vertices of the triangle
@@ -70,6 +72,8 @@ public:
        so that each row contains the derivatives of one shape function */
    void CalcDShape(const IntegrationPoint &ip,
                    DenseMatrix &dshape) const override;
+   void CalcHessian(const IntegrationPoint &ip,
+                    DenseMatrix &h) const override;
    void ProjectDelta(int vertex, Vector &dofs) const override
    { dofs = 0.0; dofs(vertex) = 1.0; }
 };
@@ -404,6 +408,9 @@ public:
    void CalcDShape(const IntegrationPoint &ip,
                    DenseMatrix &dshape) const override;
 
+   void CalcHessian(const IntegrationPoint &ip,
+                    DenseMatrix &h) const override;
+
    void ProjectDelta(int vertex, Vector &dofs) const override
    { dofs = 0.0; dofs(vertex) = 1.0; }
 
@@ -445,7 +452,8 @@ public:
        so that each row contains the derivatives of one shape function */
    void CalcDShape(const IntegrationPoint &ip,
                    DenseMatrix &dshape) const override;
-
+   void CalcHessian(const IntegrationPoint &ip,
+                    DenseMatrix &h) const override;
    void ProjectDelta(int vertex, Vector &dofs) const override
    { dofs = 0.0; dofs(vertex) = 1.0; }
 };

fem/fe/fe_h1.cpp

@@ -589,7 +589,7 @@ void H1_TriangleElement::CalcHessian(const IntegrationPoint &ip,
    Vector   shape_x(p + 1),   shape_y(p + 1),   shape_l(p + 1);
    Vector  dshape_x(p + 1),  dshape_y(p + 1),  dshape_l(p + 1);
    Vector ddshape_x(p + 1), ddshape_y(p + 1), ddshape_l(p + 1);
-   DenseMatrix ddu(dof, dim);
+   DenseMatrix ddu(dof, (dim*(dim+1))/2);
 #endif
 
    poly1d.CalcBasis(p, ip.x, shape_x, dshape_x, ddshape_x);

fem/fe/fe_nd.cpp

@@ -2531,7 +2531,7 @@ void ND_FuentesPyramidElement::calcCurlBasis(const int p,
 
 ND_R1D_PointElement::ND_R1D_PointElement(int p)
    : VectorFiniteElement(1, Geometry::POINT, 2, p,
-                         H_CURL, FunctionSpace::Pk)
+                         H_CURL_R1D, FunctionSpace::Pk)
 {
    // VectorFiniteElement::SetDerivMembers doesn't support 0D H_CURL elements
    // so we mimic a 1D element and then correct the dimension here.
@@ -2562,7 +2562,7 @@ ND_R1D_SegmentElement::ND_R1D_SegmentElement(const int p,
                                              const int cb_type,
                                              const int ob_type)
    : VectorFiniteElement(1, Geometry::SEGMENT, 3 * p + 2, p,
-                         H_CURL, FunctionSpace::Pk),
+                         H_CURL_R1D, FunctionSpace::Pk),
      dof2tk(dof),
      cbasis1d(poly1d.GetBasis(p, VerifyClosed(cb_type))),
      obasis1d(poly1d.GetBasis(p - 1, VerifyOpen(ob_type)))
@@ -2839,7 +2839,7 @@ ND_R2D_SegmentElement::ND_R2D_SegmentElement(const int p,
                                              const int cb_type,
                                              const int ob_type)
    : VectorFiniteElement(1, Geometry::SEGMENT, 2 * p + 1, p,
-                         H_CURL, FunctionSpace::Pk),
+                         H_CURL_R2D, FunctionSpace::Pk),
      dof2tk(dof),
      cbasis1d(poly1d.GetBasis(p, VerifyClosed(cb_type))),
      obasis1d(poly1d.GetBasis(p - 1, VerifyOpen(ob_type)))
@@ -3023,7 +3023,7 @@ void ND_R2D_SegmentElement::Project(VectorCoefficient &vc,
 ND_R2D_FiniteElement::ND_R2D_FiniteElement(int p, Geometry::Type G, int Do,
                                            const real_t *tk_fe)
    : VectorFiniteElement(2, G, Do, p,
-                         H_CURL, FunctionSpace::Pk),
+                         H_CURL_R2D, FunctionSpace::Pk),
      tk(tk_fe),
      dof_map(dof),
      dof2tk(dof)

fem/fe/fe_nd.hpp

@@ -663,6 +663,9 @@ public:
                          const int cb_type = BasisType::GaussLobatto,
                          const int ob_type = BasisType::GaussLegendre);
 
+   int GetPhysRangeDim(int space_dim) const override { return 2; }
+   int GetPhysCurlDim(int space_dim) const override { return 1; }
+
    void CalcVShape(const IntegrationPoint &ip,
                    DenseMatrix &shape) const override;
 
@@ -705,6 +708,9 @@ private:
                            DenseMatrix &I) const;
 
 public:
+   int GetPhysRangeDim(int space_dim) const override { return 3; }
+   int GetPhysCurlDim(int space_dim) const override { return 3; }
+
    using FiniteElement::CalcVShape;
    using FiniteElement::CalcPhysCurlShape;
 

fem/fe/fe_nurbs.cpp

@@ -445,11 +445,10 @@ void NURBS3DFiniteElement::CalcHessian (const IntegrationPoint &ip,
             d2sum[0] += ( hessian(o,0) = d2sx*sy*sz*weights(o) );
             d2sum[1] += ( hessian(o,1) = dsx*dsy*sz*weights(o) );
             d2sum[2] += ( hessian(o,2) = dsx*sy*dsz*weights(o) );
+            d2sum[3] += ( hessian(o,3) = sx*d2sy*sz*weights(o) );
+            d2sum[4] += ( hessian(o,4) = sx*dsy*dsz*weights(o) );
+            d2sum[5] += ( hessian(o,5) = sx*sy*d2sz*weights(o) );
 
-            d2sum[3] += ( hessian(o,3) = sx*dsy*dsz*weights(o) );
-
-            d2sum[4] += ( hessian(o,4) = sx*sy*d2sz*weights(o) );
-            d2sum[5] += ( hessian(o,5) = sx*d2sy*sz*weights(o) );
          }
       }
    }

fem/fe/fe_rt.cpp

@@ -2006,7 +2006,7 @@ RT_R1D_SegmentElement::RT_R1D_SegmentElement(const int p,
                                              const int cb_type,
                                              const int ob_type)
    : VectorFiniteElement(1, Geometry::SEGMENT, 3 * p + 4, p + 1,
-                         H_DIV, FunctionSpace::Pk),
+                         H_DIV_R1D, FunctionSpace::Pk),
      dof2nk(dof),
      cbasis1d(poly1d.GetBasis(p + 1, VerifyClosed(cb_type))),
      obasis1d(poly1d.GetBasis(p, VerifyOpen(ob_type)))
@@ -2281,7 +2281,7 @@ const real_t RT_R2D_SegmentElement::nk[2] = { 0.,1.};
 RT_R2D_SegmentElement::RT_R2D_SegmentElement(const int p,
                                              const int ob_type)
    : VectorFiniteElement(1, Geometry::SEGMENT, p + 1, p + 1,
-                         H_DIV, FunctionSpace::Pk),
+                         H_DIV_R2D, FunctionSpace::Pk),
      dof2nk(dof),
      obasis1d(poly1d.GetBasis(p, VerifyOpen(ob_type)))
 {
@@ -2392,7 +2392,7 @@ void RT_R2D_SegmentElement::LocalInterpolation(const VectorFiniteElement &cfe,
 RT_R2D_FiniteElement::RT_R2D_FiniteElement(int p, Geometry::Type G, int Do,
                                            const real_t *nk_fe)
    : VectorFiniteElement(2, G, Do, p + 1,
-                         H_DIV, FunctionSpace::Pk),
+                         H_DIV_R2D, FunctionSpace::Pk),
      nk(nk_fe),
      dof_map(dof),
      dof2nk(dof)

fem/fe/fe_rt.hpp

@@ -510,6 +510,9 @@ public:
    RT_R2D_SegmentElement(const int p,
                          const int ob_type = BasisType::GaussLegendre);
 
+   int GetPhysRangeDim(int space_dim) const override { return 2; }
+   int GetPhysCurlDim(int space_dim) const override { return 0; }
+
    void CalcVShape(const IntegrationPoint &ip,
                    DenseMatrix &shape) const override;
 
@@ -547,6 +550,9 @@ private:
                            DenseMatrix &I) const;
 
 public:
+   int GetPhysRangeDim(int space_dim) const override { return 3; }
+   int GetPhysCurlDim(int space_dim) const override { return 0; }
+
    using FiniteElement::CalcVShape;
 
    void CalcVShape(ElementTransformation &Trans,

fem/fespace.cpp

@@ -282,14 +282,7 @@ int FiniteElementSpace::DofToVDof(int dof, int vd, int ndofs_) const
 void FiniteElementSpace::AdjustVDofs(Array<int> &vdofs)
 {
    int n = vdofs.Size(), *vdof = vdofs;
-   for (int i = 0; i < n; i++)
-   {
-      int j;
-      if ((j = vdof[i]) < 0)
-      {
-         vdof[i] = -1-j;
-      }
-   }
+   for (int i = 0; i < n; i++) { vdof[i] = UnsignIndex(vdof[i]); }
 }
 
 void FiniteElementSpace::GetElementVDofs(int i, Array<int> &vdofs,
@@ -483,13 +476,14 @@ void FiniteElementSpace::ReorderElementToDofTable()
    for (int k = 0, dof_counter = 0; k < nnz; k++)
    {
       const int sdof = J[k]; // signed dof
-      const int dof = (sdof < 0) ? -1-sdof : sdof;
+      const int dof = UnsignIndex(sdof);
       int new_dof = dof_marker[dof];
       if (new_dof < 0)
       {
          dof_marker[dof] = new_dof = dof_counter++;
       }
-      J[k] = (sdof < 0) ? -1-new_dof : new_dof; // preserve the sign of sdof
+      // Preserve the sign of sdof
+      J[k] = (sdof < 0) ? FlipIndexSign(new_dof) : new_dof;
    }
 }
 
@@ -547,7 +541,7 @@ void MarkDofs(const Array<int> &dofs, Array<int> &mark_array)
 {
    for (auto d : dofs)
    {
-      mark_array[d >= 0 ? d : -1 - d] = -1;
+      mark_array[UnsignIndex(d)] = -1;
    }
 }
 
@@ -931,7 +925,7 @@ void FiniteElementSpace::AddDependencies(
             if (std::abs(coef) > 1e-12)
             {
                const int mdof = master_dofs[j];
-               if (mdof != sdof && mdof != (-1-sdof))
+               if (mdof != sdof && mdof != FlipIndexSign(sdof))
                {
                   deps.Add(sdof, mdof, coef);
                }
@@ -1024,7 +1018,7 @@ int FiniteElementSpace::GetDegenerateFaceDofs(int index, Array<int> &dofs,
    // FiniteElementSpace::AddDependencies.
 
    Array<int> edof;
-   int order = GetEdgeDofs(-1 - index, edof, variant);
+   int order = GetEdgeDofs(FlipIndexSign(index), edof, variant);
 
    int nv = fec->DofForGeometry(Geometry::POINT);
    int ne = fec->DofForGeometry(Geometry::SEGMENT);
@@ -1516,36 +1510,76 @@ const FaceRestriction *FiniteElementSpace::GetFaceRestriction(
    const bool is_dg_space = IsDGSpace();
    const L2FaceValues m = (is_dg_space && mul==L2FaceValues::DoubleValued) ?
                           L2FaceValues::DoubleValued : L2FaceValues::SingleValued;
-   key_face key = std::make_tuple(is_dg_space, f_ordering, type, m);
+   auto key = std::make_tuple(is_dg_space, f_ordering, type, m);
    auto itr = L2F.find(key);
    if (itr != L2F.end())
    {
-      return itr->second;
+      return itr->second.get();
    }
    else
    {
-      FaceRestriction *res;
+      std::unique_ptr<FaceRestriction> res;
       if (is_dg_space)
       {
          if (Conforming())
          {
-            res = new L2FaceRestriction(*this, f_ordering, type, m);
+            res.reset(new L2FaceRestriction(*this, f_ordering, type, m));
          }
          else
          {
-            res = new NCL2FaceRestriction(*this, f_ordering, type, m);
+            res.reset(new NCL2FaceRestriction(*this, f_ordering, type, m));
          }
       }
       else if (dynamic_cast<const DG_Interface_FECollection*>(fec))
       {
-         res = new L2InterfaceFaceRestriction(*this, f_ordering, type);
+         res.reset(new L2InterfaceFaceRestriction(*this, f_ordering, type));
       }
       else
       {
-         res = new ConformingFaceRestriction(*this, f_ordering, type);
+         res.reset(new ConformingFaceRestriction(*this, f_ordering, type));
       }
-      L2F[key] = res;
-      return res;
+      return L2F.emplace(key, std::move(res)).first->second.get();
+   }
+}
+
+const InterpolationManager &FiniteElementSpace::GetInterpolationManager(
+   ElementDofOrdering f_ordering, FaceType type) const
+{
+   const auto key = make_tuple(f_ordering, type);
+
+   auto it = interpolations.find(key);
+   if (it != interpolations.end())
+   {
+      return *it->second;
+   }
+   else
+   {
+      auto interp = make_unique<InterpolationManager>(*this, f_ordering, type);
+
+      int face_idx = 0;
+      for (int f = 0; f < mesh->GetNumFacesWithGhost(); ++f)
+      {
+         Mesh::FaceInformation face = mesh->GetFaceInformation(f);
+         if (!face.IsOfFaceType(type) || face.IsNonconformingCoarse())
+         {
+            continue;
+         }
+         if (face.IsConforming() || face.IsBoundary())
+         {
+            interp->RegisterFaceConformingInterpolation(face, face_idx);
+         }
+         else
+         {
+            interp->RegisterFaceCoarseToFineInterpolation(face, face_idx);
+         }
+         ++face_idx;
+      }
+
+      // Transform the interpolation matrix map into contiguous memory.
+      interp->LinearizeInterpolatorMapIntoVector();
+      interp->InitializeNCInterpConfig();
+
+      return *interpolations.emplace(key, std::move(interp)).first->second;
    }
 }
 
@@ -1670,8 +1704,8 @@ SparseMatrix *FiniteElementSpace::RefinementMatrix_main(
 
          for (int i = 0; i < fine_ldof; i++)
          {
-            int r = DofToVDof(dofs[i], vd);
-            int m = (r >= 0) ? r : (-1 - r);
+            const int r = DofToVDof(dofs[i], vd);
+            const int m = UnsignIndex(r);
 
             if (!mark[m])
             {
@@ -1732,7 +1766,7 @@ SparseMatrix *FiniteElementSpace::VariableOrderRefinementMatrix(
          for (int i = 0; i < fine_ldof; i++)
          {
             const int r = DofToVDof(dofs[i], vd);
-            int m = (r >= 0) ? r : (-1 - r);
+            const int m = UnsignIndex(r);
 
             if (!mark[m])
             {
@@ -2442,8 +2476,8 @@ SparseMatrix* FiniteElementSpace::DerefinementMatrix(int old_ndofs,
          {
             if (!std::isfinite(lR(i, 0))) { continue; }
 
-            int r = DofToVDof(dofs[i], vd);
-            int m = (r >= 0) ? r : (-1 - r);
+            const int r = DofToVDof(dofs[i], vd);
+            const int m = UnsignIndex(r);
 
             if (is_dg || !mark[m])
             {
@@ -3161,7 +3195,7 @@ void FiniteElementSpace::CalcEdgeFaceVarOrders(
             else
             {
                // degenerate face (i.e., edge-face constraint)
-               slave_orders |= edge_orders[-1 - slave.index];
+               slave_orders |= edge_orders[FlipIndexSign(slave.index)];
             }
          }
 
@@ -3900,6 +3934,16 @@ const FiniteElement *FiniteElementSpace::GetBE(int i) const
    return BE;
 }
 
+const FiniteElement *FiniteElementSpace::GetTypicalBE() const
+{
+   if (mesh->GetNBE() > 0) { return GetBE(0); }
+
+   Geometry::Type geom = mesh->GetTypicalFaceGeometry();
+   const FiniteElement *be = fec->FiniteElementForGeometry(geom);
+   MFEM_VERIFY(be != nullptr, "Could not determine a typical BE!");
+   return be;
+}
+
 const FiniteElement *FiniteElementSpace::GetFaceElement(int i) const
 {
    MFEM_VERIFY(!IsVariableOrder(), "not implemented");
@@ -3930,6 +3974,11 @@ const FiniteElement *FiniteElementSpace::GetFaceElement(int i) const
    return fe;
 }
 
+const FiniteElement *FiniteElementSpace::GetTypicalFaceElement() const
+{
+   return fec->FiniteElementForGeometry(mesh->GetTypicalFaceGeometry());
+}
+
 const FiniteElement *FiniteElementSpace::GetEdgeElement(int i,
                                                         int variant) const
 {
@@ -3969,11 +4018,8 @@ void FiniteElementSpace::Destroy()
       delete E2Q_array[i];
    }
    E2Q_array.SetSize(0);
-   for (auto &x : L2F)
-   {
-      delete x.second;
-   }
    L2F.clear();
+   interpolations.clear();
    for (int i = 0; i < E2IFQ_array.Size(); i++)
    {
       delete E2IFQ_array[i];

fem/fespace.hpp

@@ -13,6 +13,7 @@
 #define MFEM_FESPACE
 
 #include "../config/config.hpp"
+#include "../general/hash_util.hpp"
 #include "../linalg/ordering.hpp"
 #include "../linalg/sparsemat.hpp"
 #include "../mesh/mesh.hpp"
@@ -320,18 +321,11 @@ protected:
    mutable OperatorHandle L2E_nat, L2E_lex;
    /// The face restriction operators, see GetFaceRestriction().
    using key_face = std::tuple<bool, ElementDofOrdering, FaceType, L2FaceValues>;
-   struct key_hash
-   {
-      std::size_t operator()(const key_face& k) const
-      {
-         return std::get<0>(k)
-                + 2 * (int)std::get<1>(k)
-                + 4 * (int)std::get<2>(k)
-                + 8 * (int)std::get<3>(k);
-      }
-   };
-   using map_L2F = std::unordered_map<const key_face,FaceRestriction*,key_hash>;
-   mutable map_L2F L2F;
+   mutable std::unordered_map<key_face,std::unique_ptr<FaceRestriction>,
+           TupleHasher> L2F;
+
+   mutable std::unordered_map<std::tuple<ElementDofOrdering,FaceType>,
+           std::unique_ptr<InterpolationManager>, TupleHasher> interpolations;
 
    mutable Array<QuadratureInterpolator*> E2Q_array;
    mutable Array<FaceQuadratureInterpolator*> E2IFQ_array;
@@ -751,6 +745,9 @@ public:
       ElementDofOrdering f_ordering, FaceType,
       L2FaceValues mul = L2FaceValues::DoubleValued) const;
 
+   const InterpolationManager &GetInterpolationManager(
+      ElementDofOrdering f_ordering, FaceType type) const;
+
    /** @brief Return a QuadratureInterpolator that interpolates E-vectors to
        quadrature point values and/or derivatives (Q-vectors). */
    /** An E-vector represents the element-wise discontinuous version of the FE
@@ -842,7 +839,7 @@ public:
        Note: For vector-valued elements, the results pads up the range dimension
        to the spatial dimension. E.g., consider a stack of 5 vector-valued
        elements each representing 2D vectors, living in a 3 dimensional space.
-       Then this fucntion would give 15, not 10.
+       Then this function would give 15, not 10.
        */
    int GetVectorDim() const;
 
@@ -1153,7 +1150,7 @@ public:
 
    /// Helper to return the DOF associated with a sign encoded DOF
    static inline int DecodeDof(int dof)
-   { return (dof >= 0) ? dof : (-1 - dof); }
+   { return UnsignIndex(dof); }
 
    /// Helper to determine the DOF and sign of a sign encoded DOF
    static inline int DecodeDof(int dof, real_t& sign)
@@ -1326,12 +1323,24 @@ public:
         associated with i'th boundary face in the mesh object. */
    const FiniteElement *GetBE(int i) const;
 
+   /// @brief Return a "typical" boundary element.
+   ///
+   /// This can be used in situations where the local mesh partition may be
+   /// empty.
+   const FiniteElement *GetTypicalBE() const;
+
    /** @brief Returns pointer to the FiniteElement in the FiniteElementCollection
         associated with i'th face in the mesh object.  Faces in this case refer
         to the MESHDIM-1 primitive so in 2D they are segments and in 1D they are
         points.*/
    const FiniteElement *GetFaceElement(int i) const;
 
+   /// @brief Return a "typical" face element.
+   ///
+   /// This can be used in situations where the local mesh partition may be
+   /// empty.
+   const FiniteElement *GetTypicalFaceElement() const;
+
    /** @brief Returns pointer to the FiniteElement in the FiniteElementCollection
         associated with i'th edge in the mesh object. */
    const FiniteElement *GetEdgeElement(int i, int variant = 0) const;

fem/gridfunc.cpp

@@ -30,6 +30,7 @@
 #include <cmath>
 #include <iostream>
 #include <algorithm>
+#include <queue>
 
 namespace mfem
 {
@@ -344,27 +345,6 @@ void GridFunction::ComputeFlux(BilinearFormIntegrator &blfi,
    }
 }
 
-int GridFunction::VectorDim() const
-{
-   const FiniteElement *fe = fes->GetTypicalFE();
-   if (!fe || fe->GetRangeType() == FiniteElement::SCALAR)
-   {
-      return fes->GetVDim();
-   }
-   return fes->GetVDim()*std::max(fes->GetMesh()->SpaceDimension(),
-                                  fe->GetRangeDim());
-}
-
-int GridFunction::CurlDim() const
-{
-   const FiniteElement *fe = fes->GetTypicalFE();
-   if (!fe || fe->GetRangeType() == FiniteElement::SCALAR)
-   {
-      return 2 * fes->GetMesh()->SpaceDimension() - 3;
-   }
-   return fes->GetVDim()*fe->GetCurlDim();
-}
-
 void GridFunction::GetTrueDofs(Vector &tv) const
 {
    const SparseMatrix *R = fes->GetRestrictionMatrix();
@@ -2049,6 +2029,18 @@ void GridFunction::AccumulateAndCountBdrValues(
    Coefficient *coeff[], VectorCoefficient *vcoeff, const Array<int> &attr,
    Array<int> &values_counter)
 {
+   if (vcoeff)
+   {
+      MFEM_VERIFY(fes->GetVDim() == vcoeff->GetVDim(),
+                  "vcoeff vdim != fes VDim");
+      MFEM_VERIFY(fes->GetTypicalBE()->GetMapType() == FiniteElement::VALUE &&
+                  fes->GetTypicalBE()->GetRangeType() ==
+                  FiniteElement::SCALAR,
+                  "Can only call ProjectBdrCoefficient on scalar value-type "
+                  "boundary elements. "
+                  "Did you intended to call ProjectBdrCoefficientNormal or "
+                  "ProjectBdrCoefficientTangent for vector finite elements?");
+   }
    Array<int> vdofs;
    Vector vc;
 
@@ -2201,6 +2193,9 @@ void GridFunction::AccumulateAndCountBdrTangentValues(
    VectorCoefficient &vcoeff, const Array<int> &bdr_attr,
    Array<int> &values_counter)
 {
+   MFEM_VERIFY(fes->GetTypicalBE()->GetPhysRangeDim(
+                  fes->GetMesh()->SpaceDimension()) == vcoeff.GetVDim(),
+               "vcoeff vdim != PhysRangeDim");
    const FiniteElement *fe;
    ElementTransformation *T;
    Array<int> dofs;
@@ -2354,6 +2349,9 @@ void GridFunction::ProjectDeltaCoefficient(DeltaCoefficient &delta_coeff,
 
 void GridFunction::ProjectCoefficient(Coefficient &coeff, ProjectType type)
 {
+   MFEM_VERIFY(
+      VectorDim() == 1,
+      "Cannot project scalar Coefficient onto vector GridFunction");
    DeltaCoefficient *delta_c = dynamic_cast<DeltaCoefficient *>(&coeff);
    DofTransformation doftrans;
    Array<int> vdofs;
@@ -2629,6 +2627,7 @@ void GridFunction::ProjectCoefficient(
 void GridFunction::ProjectCoefficient(VectorCoefficient &vcoeff,
                                       ProjectType type)
 {
+   MFEM_VERIFY(VectorDim() == vcoeff.GetVDim(), "vcoeff vdim != VectorDim()");
    Array<int> vdofs;
    Vector vals;
    DofTransformation doftrans;
@@ -2944,6 +2943,7 @@ void GridFunction::ProjectCoefficientElementL2(VectorCoefficient &vcoeff)
 void GridFunction::ProjectCoefficient(
    VectorCoefficient &vcoeff, Array<int> &dofs)
 {
+   MFEM_VERIFY(VectorDim() == vcoeff.GetVDim(), "vcoeff vdim != VectorDim()");
    int el = -1;
    ElementTransformation *T = NULL;
    const FiniteElement *fe = NULL;
@@ -2973,6 +2973,7 @@ void GridFunction::ProjectCoefficient(
 
 void GridFunction::ProjectCoefficient(VectorCoefficient &vcoeff, int attribute)
 {
+   MFEM_VERIFY(VectorDim() == vcoeff.GetVDim(), "vcoeff vdim != VectorDim()");
    int i;
    Array<int> vdofs;
    Vector vals;
@@ -3029,9 +3030,14 @@ void GridFunction::ProjectCoefficient(Coefficient *coeff[])
    }
 }
 
-void GridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff,
-                                          Array<int> &dof_attr)
+void GridFunction::ProjectDiscCoefficient(
+   std::variant<Coefficient*, VectorCoefficient*> coeff, Array<int> &dof_attr)
 {
+   std::visit([&](auto* c)
+   {
+      MFEM_VERIFY(VectorDim() == c->GetVDim(), "coeff vdim != VectorDim()");
+   }, coeff);
+
    Array<int> vdofs;
    Vector vals;
 
@@ -3045,7 +3051,10 @@ void GridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff,
    {
       fes->GetElementVDofs(i, vdofs);
       vals.SetSize(vdofs.Size());
-      fes->GetFE(i)->Project(coeff, *fes->GetElementTransformation(i), vals);
+      std::visit([&](auto* c)
+      {
+         fes->GetFE(i)->Project(*c, *fes->GetElementTransformation(i), vals);
+      }, coeff);
 
       // the values in shared dofs are determined from the element with maximal
       // attribute
@@ -3061,17 +3070,15 @@ void GridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff,
    }
 }
 
-void GridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff)
-{
-   Array<int> dof_attr;
-   ProjectDiscCoefficient(coeff, dof_attr);
-}
-
 void GridFunction::ProjectDiscCoefficient(Coefficient &coeff, AvgType type)
 {
    // Harmonic  (x1 ... xn) = [ (1/x1 + ... + 1/xn) / n ]^-1.
    // Arithmetic(x1 ... xn) = (x1 + ... + xn) / n.
 
+   MFEM_VERIFY(
+      VectorDim() == 1,
+      "Cannot project a scalar coefficient onto a vector GridFunction");
+
    Array<int> zones_per_vdof;
    AccumulateAndCountZones(coeff, type, zones_per_vdof);
 
@@ -3081,6 +3088,7 @@ void GridFunction::ProjectDiscCoefficient(Coefficient &coeff, AvgType type)
 void GridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff,
                                           AvgType type)
 {
+   MFEM_VERIFY(VectorDim() == coeff.GetVDim(), "coeff vdim != VectorDim()");
    Array<int> zones_per_vdof;
    AccumulateAndCountZones(coeff, type, zones_per_vdof);
 
@@ -3136,52 +3144,33 @@ void GridFunction::ProjectBdrCoefficient(Coefficient *coeff[],
 }
 
 void GridFunction::ProjectBdrCoefficientNormal(
-   VectorCoefficient &vcoeff, const Array<int> &bdr_attr)
+   Coefficient *coeff, VectorCoefficient *vcoeff, const Array<int> &bdr_attr)
 {
-#if 0
-   // implementation for the case when the face dofs are integrals of the
-   // normal component.
-   const FiniteElement *fe;
-   ElementTransformation *T;
-   Array<int> dofs;
-   int dim = vcoeff.GetVDim();
-   Vector vc(dim), nor(dim), lvec, shape;
-
-   for (int i = 0; i < fes->GetNBE(); i++)
+   MFEM_VERIFY(fes->GetVDim() == 1, "fespace VDim != 1");
+   MFEM_VERIFY(fes->GetTypicalBE()->GetRangeType() == FiniteElement::SCALAR &&
+               fes->GetTypicalBE()->GetMapType() == FiniteElement::INTEGRAL,
+               "Not an RT FE space!");
+   if (vcoeff)
    {
-      if (bdr_attr[fes->GetBdrAttribute(i)-1] == 0)
-      {
-         continue;
-      }
-      fe = fes->GetBE(i);
-      T = fes->GetBdrElementTransformation(i);
-      int intorder = 2*fe->GetOrder(); // !!!
-      const IntegrationRule &ir = IntRules.Get(fe->GetGeomType(), intorder);
-      int nd = fe->GetDof();
-      lvec.SetSize(nd);
-      shape.SetSize(nd);
-      lvec = 0.0;
-      for (int j = 0; j < ir.GetNPoints(); j++)
-      {
-         const IntegrationPoint &ip = ir.IntPoint(j);
-         T->SetIntPoint(&ip);
-         vcoeff.Eval(vc, *T, ip);
-         CalcOrtho(T->Jacobian(), nor);
-         fe->CalcShape(ip, shape);
-         lvec.Add(ip.weight * (vc * nor), shape);
-      }
-      fes->GetBdrElementDofs(i, dofs);
-      SetSubVector(dofs, lvec);
+      MFEM_VERIFY(vcoeff->GetVDim() == fes->GetMesh()->SpaceDimension(),
+                  "vcoeff vdim (" << vcoeff->GetVDim()
+                  << ") != SpaceDimension ("
+                  << fes->GetMesh()->SpaceDimension() << ")");
    }
-#else
+
    // implementation for the case when the face dofs are scaled point
    // values of the normal component.
    const FiniteElement *fe;
    ElementTransformation *T;
    Array<int> dofs;
-   int dim = vcoeff.GetVDim();
-   Vector vc(dim), nor(dim), lvec;
+   Vector vc, nor, lvec;
    DofTransformation doftrans;
+   if (vcoeff)
+   {
+      const int dim = vcoeff->GetVDim();
+      vc.SetSize(dim);
+      nor.SetSize(dim);
+   }
 
    for (int i = 0; i < fes->GetNBE(); i++)
    {
@@ -3197,15 +3186,22 @@ void GridFunction::ProjectBdrCoefficientNormal(
       {
          const IntegrationPoint &ip = ir.IntPoint(j);
          T->SetIntPoint(&ip);
-         vcoeff.Eval(vc, *T, ip);
-         CalcOrtho(T->Jacobian(), nor);
-         lvec(j) = (vc * nor);
+         if (coeff)
+         {
+            const real_t c = coeff->Eval(*T, ip);
+            lvec(j) = c * T->Weight();
+         }
+         else if (vcoeff)
+         {
+            vcoeff->Eval(vc, *T, ip);
+            CalcOrtho(T->Jacobian(), nor);
+            lvec(j) = (vc * nor);
+         }
       }
       fes->GetBdrElementDofs(i, dofs, doftrans);
       doftrans.TransformPrimal(lvec);
       SetSubVector(dofs, lvec);
    }
-#endif
 }
 
 void GridFunction::ProjectBdrCoefficientTangent(
@@ -5006,6 +5002,14 @@ real_t ExtrudeCoefficient::Eval(ElementTransformation &T,
    return sol_in.Eval(*T_in, ip);
 }
 
+void VectorExtrudeCoefficient::Eval(Vector &v, ElementTransformation &T,
+                                    const IntegrationPoint &ip)
+{
+   ElementTransformation *T_in =
+      mesh_in->GetElementTransformation(T.ElementNo / n);
+   T_in->SetIntPoint(&ip);
+   sol_in.Eval(v, *T_in, ip);
+}
 
 GridFunction *Extrude1DGridFunction(Mesh *mesh, Mesh *mesh2d,
                                     GridFunction *sol, const int ny)
@@ -5056,10 +5060,17 @@ GridFunction *Extrude1DGridFunction(Mesh *mesh, Mesh *mesh2d,
       return NULL;
    }
    FiniteElementSpace *solfes2d;
-   // assuming sol is scalar
-   solfes2d = new FiniteElementSpace(mesh2d, solfec2d);
+   const int vdim = sol->FESpace()->GetVDim();
+   solfes2d = new FiniteElementSpace(mesh2d, solfec2d, vdim);
    sol2d = new GridFunction(solfes2d);
    sol2d->MakeOwner(solfec2d);
+   if (vdim > 1)
+   {
+      VectorGridFunctionCoefficient vcsol(sol);
+      VectorExtrudeCoefficient vc2d(mesh, vcsol, ny);
+      sol2d->ProjectCoefficient(vc2d);
+   }
+   else
    {
       GridFunctionCoefficient csol(sol);
       ExtrudeCoefficient c2d(mesh, csol, ny);
@@ -5117,6 +5128,103 @@ void GridFunction::GetElementBoundsAtControlPoints(const int elem,
    }
 }
 
+void GridFunction::GetElementBoundsAtControlPoints(const int elem,
+                                                   const PLBound &plb,
+                                                   const Vector &ref_range,
+                                                   const int vdim,
+                                                   Vector &lower, Vector &upper,
+                                                   Vector &control_pos) const
+{
+   const FiniteElement *fe = fes->GetFE(elem);
+   const IntegrationRule ir_in = fe->GetNodes();
+   IntegrationRule ir_new(ir_in.GetNPoints());
+   const int dim = fes->GetMesh()->Dimension();
+   const L2_FECollection *l2fec = dynamic_cast<const L2_FECollection *>
+                                  (fes->FEColl());
+
+   const TensorBasisElement *tbe =
+      dynamic_cast<const TensorBasisElement *>(fe);
+   MFEM_VERIFY(tbe != NULL, "TensorBasis FiniteElement expected.");
+
+   const Array<int> &dof_map = tbe->GetDofMap();
+   bool lexico = (dof_map.Size() == 0);
+   bool bern = (tbe->GetBasisType() == BasisType::Positive);
+   bool h1   = (l2fec == nullptr);
+
+   Vector loc_data; // gridfunction values
+   // Construct an integration rule to evaluate the gridfunction in
+   // subinterval.
+   for (int i = 0; i < ir_in.GetNPoints(); i++)
+   {
+      IntegrationPoint &ip_new = ir_new.IntPoint(i);
+      const IntegrationPoint &ip_old =
+         ir_in.IntPoint((lexico || bern) ? i : dof_map[i]);
+      Vector ip_coord(dim);
+      ip_old.Get(ip_coord.GetData(), dim);
+      for (int d = 0; d < dim; d++)
+      {
+         ip_coord(d) = ref_range(d) +
+                       (ref_range(dim+d) - ref_range(d)) * ip_coord(d);
+      }
+      ip_new.Set(ip_coord.GetData(), dim);
+   }
+   GetValues(elem, ir_new, loc_data, vdim);
+   // At this point, the loc_data contains function values ordered
+   // lexicographically, unless we are using Bernstein bases.
+   // For Bernstein, we need to project and get coefficients first.
+
+   // For bernstein, we get coefficients corresponding to these function values
+   if (bern)
+   {
+      int bt = 4; // BasisType::ClosedUniform
+      int o = fe->GetOrder();
+      DenseMatrix projmat;
+      NodalTensorFiniteElement *ntfe = nullptr;
+      if (dim == 1)
+      {
+         if (h1) { ntfe = new H1_SegmentElement(o, bt); }
+         else    { ntfe = new L2_SegmentElement(o, bt); }
+      }
+      else if (dim == 2)
+      {
+         if (h1) { ntfe = new H1_QuadrilateralElement(o, bt); }
+         else    { ntfe = new L2_QuadrilateralElement(o, bt); }
+      }
+      else if (dim == 3)
+      {
+         if (h1) { ntfe = new H1_HexahedronElement(o, bt); }
+         else    { ntfe = new L2_HexahedronElement(o, bt); }
+      }
+      // projection matrix from H1 to Positive
+      ElementTransformation *eltran = fes->GetElementTransformation(elem);
+      fe->Project(*ntfe, *eltran, projmat);
+      Vector loc_data_temp(loc_data.Size());
+      projmat.Mult(loc_data, loc_data_temp);
+      for (int i = 0; i < dof_map.Size(); i++)
+      {
+         loc_data(i) = loc_data_temp(dof_map[i]);
+      }
+      if (dof_map.Size() == 0) { loc_data = loc_data_temp; }
+      delete ntfe;
+   }
+
+   // Get bounds at control points
+   plb.GetNDBounds(dim, loc_data, lower, upper);
+
+   // Save control point positions
+   int ncp = plb.GetNControlPoints();
+   control_pos.SetSize(dim * ncp);
+   const Vector control_pos_1D = plb.GetControlPoints();
+   for (int i = 0; i < ncp; i++)
+   {
+      for (int d = 0; d < dim; d++)
+      {
+         control_pos(i + d*ncp) =
+            ref_range(d) + (ref_range(dim+d)-ref_range(d))*control_pos_1D(i);
+      }
+   }
+}
+
 void GridFunction::GetElementBounds(const int elem, const PLBound &plb,
                                     Vector &lower, Vector &upper,
                                     const int vdim) const
@@ -5197,6 +5305,467 @@ PLBound GridFunction::GetBounds(Vector &lower, Vector &upper,
    return plb;
 }
 
+struct IntervalNode
+{
+   real_t val_min;
+   real_t val_max;
+   Array<IntervalNode *> child;
+   IntervalNode(real_t vmin, real_t vmax)
+      : val_min(vmin), val_max(vmax)
+   {
+      child.SetSize(0);
+   }
+   void AddChild(IntervalNode *ch) { child.Append(ch); }
+   real_t GetChildMinLower()
+   {
+      if (child.Size() == 0)
+      {
+         return val_min;
+      }
+      real_t valmin = numeric_limits<real_t>::max();
+      for (int i = 0; i < child.Size(); i++)
+      {
+         real_t candidate = child[i]->GetChildMinLower();
+         valmin = std::min(valmin, candidate);
+      }
+      return valmin;
+   }
+   real_t GetChildMinUpper()
+   {
+      if (child.Size() == 0)
+      {
+         return val_max;
+      }
+      real_t valmax = numeric_limits<real_t>::max();
+      for (int i = 0; i < child.Size(); i++)
+      {
+         real_t candidate = child[i]->GetChildMinUpper();
+         valmax = std::min(valmax, candidate);
+      }
+      return valmax;
+   }
+   real_t GetChildMaxLower()
+   {
+      if (child.Size() == 0)
+      {
+         return val_min;
+      }
+      real_t valmin = numeric_limits<real_t>::lowest();
+      for (int i = 0; i < child.Size(); i++)
+      {
+         real_t candidate = child[i]->GetChildMaxLower();
+         valmin = std::max(valmin, candidate);
+      }
+      return valmin;
+   }
+   real_t GetChildMaxUpper()
+   {
+      if (child.Size() == 0)
+      {
+         return val_max;
+      }
+      real_t valmax = numeric_limits<real_t>::lowest();
+      for (int i = 0; i < child.Size(); i++)
+      {
+         real_t candidate = child[i]->GetChildMaxUpper();
+         valmax = std::max(valmax, candidate);
+      }
+      return valmax;
+   }
+   void DeleteChildren()
+   {
+      for (int i = 0; i < child.Size(); i++)
+      {
+         child[i]->DeleteChildren();
+         delete child[i];
+      }
+      child.SetSize(0);
+   }
+};
+
+struct SearchInterval
+{
+   Vector ref_range;
+   int depth;
+   IntervalNode *node;
+   SearchInterval(const Vector &ref_range_in, int d, IntervalNode *n)
+      : ref_range(ref_range_in), depth(d), node(n)
+   { }
+};
+
+struct IntervalCompareMin
+{
+   bool operator()(const SearchInterval *a, const SearchInterval *b) const
+   {
+      return a->node->val_min > b->node->val_min;
+   }
+};
+
+struct IntervalCompareMax
+{
+   bool operator()(const SearchInterval *a, const SearchInterval *b) const
+   {
+      return a->node->val_max < b->node->val_max;
+   }
+};
+
+std::pair<real_t, real_t> GridFunction::EstimateFunctionMinimum(
+   const int elem, const PLBound &plb, const int vdim,
+   const int max_depth, const real_t tol) const
+{
+   real_t min_threshold = std::numeric_limits<real_t>::max();
+   return EstimateFunctionMinimum(elem, plb, vdim, max_depth, tol,
+                                  min_threshold);
 }
 
+std::pair<real_t, real_t> GridFunction::EstimateFunctionMinimum(
+   const int elem, const PLBound &plb, const int vdim,
+   const int max_depth, const real_t tol, real_t &min_threshold) const
+{
+   const int dim = this->FESpace()->GetMesh()->Dimension();
+   const int ncp = plb.GetNControlPoints();
+   Vector pos_range(2*dim); pos_range = 0.0;
+   for (int d = 0; d < dim; d++) { pos_range(d+dim) = 1.0; }
+   Vector lower, upper, cp_ref_loc;
 
+   GetElementBoundsAtControlPoints(elem, plb, lower, upper, vdim);
+   real_t val_min = lower.Min();
+   real_t val_max = upper.Min();
+
+   min_threshold = std::min(min_threshold, val_max);
+
+   // Pruning: if the element's lower bound is greater than the current global
+   // upper bound, this element cannot contain the global minimum.
+   if (val_min >= min_threshold)
+   {
+      return std::make_pair(val_min, val_max);
+   }
+
+   if (val_min == val_max || max_depth == 0)
+   {
+      min_threshold = std::min(min_threshold, val_min);
+      return std::make_pair(val_min, val_max);
+   }
+   real_t abs_tol = tol*(val_max-val_min);
+
+   IntervalNode *initial_node = new IntervalNode(val_min, val_max);
+   SearchInterval *initial_interval = new SearchInterval(pos_range, 0,
+                                                         initial_node);
+
+   std::priority_queue<SearchInterval*,
+       std::vector<SearchInterval*>, IntervalCompareMin> pq;
+   pq.push(initial_interval);
+
+   real_t min_upper_bound = upper.Min();
+   real_t min_lower_bound = lower.Min();
+
+   while (!pq.empty())
+   {
+      SearchInterval *current = pq.top();
+      pq.pop();
+      int curr_depth = current->depth;
+
+      // Reached max depth or this interval cannot contain the global minimum
+      if (current->node->val_min >= min_threshold || curr_depth >= max_depth)
+      {
+         delete current;
+         continue;
+      }
+
+      min_lower_bound = initial_node->GetChildMinLower();
+      if (min_upper_bound - min_lower_bound < abs_tol)
+      {
+         delete current;
+         break;
+      }
+
+      // Subdivide the interval and get bounds on it
+      GetElementBoundsAtControlPoints(elem, plb, current->ref_range,
+                                      vdim, lower, upper, cp_ref_loc);
+
+      // process the bounds and create sub-intervals
+      for (int k = 0; k < (dim == 3 ? ncp-1 : 1); k++)
+      {
+         for (int j = 0; j < (dim >= 2 ? ncp-1 : 1); j++)
+         {
+            for (int i = 0; i < ncp-1; i++)
+            {
+               real_t lv = 0.0, uv = 0.0;
+               if (dim == 1)
+               {
+                  lv = std::min(lower(i), lower(i+1));
+                  uv = std::min(upper(i), upper(i+1));
+               }
+               else if (dim == 2)
+               {
+                  lv = std::min({lower(i + j*ncp), lower((i+1) + j*ncp),
+                                 lower(i + (j+1)*ncp),
+                                 lower((i+1) + (j+1)*ncp)});
+                  uv = std::min({upper(i + j*ncp), upper((i+1) + j*ncp),
+                                 upper(i + (j+1)*ncp),
+                                 upper((i+1) + (j+1)*ncp)});
+               }
+               else if (dim == 3)
+               {
+                  lv = std::min({lower(i + j*ncp + k*ncp*ncp),
+                                 lower((i+1) + j*ncp + k*ncp*ncp),
+                                 lower(i + (j+1)*ncp + k*ncp*ncp),
+                                 lower((i+1) + (j+1)*ncp + k*ncp*ncp),
+                                 lower(i + j*ncp + (k+1)*ncp*ncp),
+                                 lower((i+1) + j*ncp + (k+1)*ncp*ncp),
+                                 lower(i + (j+1)*ncp + (k+1)*ncp*ncp),
+                                 lower((i+1) + (j+1)*ncp + (k+1)*ncp*ncp)});
+                  uv = std::min({upper(i + j*ncp + k*ncp*ncp),
+                                 upper((i+1) + j*ncp + k*ncp*ncp),
+                                 upper(i + (j+1)*ncp + k*ncp*ncp),
+                                 upper((i+1) + (j+1)*ncp + k*ncp*ncp),
+                                 upper(i + j*ncp + (k+1)*ncp*ncp),
+                                 upper((i+1) + j*ncp + (k+1)*ncp*ncp),
+                                 upper(i + (j+1)*ncp + (k+1)*ncp*ncp),
+                                 upper((i+1) + (j+1)*ncp + (k+1)*ncp*ncp)});
+               }
+               IntervalNode *child_node = new IntervalNode(lv, uv);
+               current->node->AddChild(child_node);
+
+               if (lv < min_threshold)
+               {
+                  min_upper_bound = std::min(min_upper_bound, uv);
+                  min_threshold = std::min(min_threshold, uv);
+                  if (curr_depth < max_depth)
+                  {
+                     pos_range(0) = cp_ref_loc(i);
+                     pos_range(0+dim) = cp_ref_loc(i+1);
+                     if (dim >= 2)
+                     {
+                        pos_range(1) = cp_ref_loc(ncp + j);
+                        pos_range(1+dim) = cp_ref_loc(ncp + j+1);
+                     }
+                     if (dim == 3)
+                     {
+                        pos_range(2) = cp_ref_loc(2*ncp + k);
+                        pos_range(2+dim) = cp_ref_loc(2*ncp + k+1);
+                     }
+                     SearchInterval *child_interval =
+                        new  SearchInterval(pos_range, curr_depth + 1,
+                                            child_node);
+                     pq.push(child_interval);
+                  }
+               }
+            }
+         }
+      }
+      delete current;
+   }
+
+   // clean up remaining intervals in queue
+   while (!pq.empty())
+   {
+      delete pq.top();
+      pq.pop();
+   }
+
+   min_lower_bound = initial_node->GetChildMinLower();
+   initial_node->DeleteChildren();
+   delete initial_node;
+
+   min_threshold = std::min(min_threshold, min_lower_bound);
+   return std::make_pair(min_lower_bound, min_upper_bound);
+}
+
+std::pair<real_t, real_t> GridFunction::EstimateFunctionMaximum(
+   const int elem, const PLBound &plb, const int vdim,
+   const int max_depth, const real_t tol) const
+{
+   real_t max_threshold = std::numeric_limits<real_t>::lowest();
+   return EstimateFunctionMaximum(elem, plb, vdim, max_depth, tol,
+                                  max_threshold);
+}
+
+std::pair<real_t, real_t> GridFunction::EstimateFunctionMaximum(
+   const int elem, const PLBound &plb, const int vdim,
+   const int max_depth, const real_t tol, real_t &max_threshold) const
+{
+   const int dim = this->FESpace()->GetMesh()->Dimension();
+   const int ncp = plb.GetNControlPoints();
+   Vector pos_range(2*dim); pos_range = 0.0;
+   for (int d = 0; d < dim; d++) { pos_range(d+dim) = 1.0; }
+   Vector lower, upper, cp_ref_loc;
+
+   GetElementBoundsAtControlPoints(elem, plb, lower, upper, vdim);
+   real_t val_min = lower.Max();
+   real_t val_max = upper.Max();
+
+   max_threshold = std::max(max_threshold, val_min);
+
+   // Pruning: if the element's upper bound is less than the current global
+   // lower bound, this element cannot contain the global maximum.
+   if (val_max <= max_threshold)
+   {
+      return std::make_pair(val_min, val_max);
+   }
+
+   if (val_min == val_max || max_depth == 0)
+   {
+      max_threshold = std::max(max_threshold, val_max);
+      return std::make_pair(val_min, val_max);
+   }
+   real_t abs_tol = tol*(val_max-val_min);
+
+   IntervalNode *initial_node = new IntervalNode(val_min, val_max);
+   SearchInterval *initial_interval = new SearchInterval(pos_range, 0,
+                                                         initial_node);
+
+   std::priority_queue<SearchInterval*,
+       std::vector<SearchInterval*>, IntervalCompareMax> pq;
+   pq.push(initial_interval);
+
+   real_t max_lower_bound = val_min;
+   real_t max_upper_bound = val_max;
+
+   while (!pq.empty())
+   {
+      SearchInterval *current = pq.top();
+      pq.pop();
+      int curr_depth = current->depth;
+
+      // Reached max depth or this interval cannot contain the global maximum.
+      if (current->node->val_max <= max_threshold || curr_depth >= max_depth)
+      {
+         delete current;
+         continue;
+      }
+
+      max_upper_bound = initial_node->GetChildMaxUpper();
+      if (max_upper_bound - max_lower_bound < abs_tol)
+      {
+         delete current;
+         break;
+      }
+
+      // Subdivide the interval and get bounds on it
+      GetElementBoundsAtControlPoints(elem, plb, current->ref_range,
+                                      vdim, lower, upper, cp_ref_loc);
+
+      // process the bounds and create sub-intervals
+      for (int k = 0; k < (dim == 3 ? ncp-1 : 1); k++)
+      {
+         for (int j = 0; j < (dim >= 2 ? ncp-1 : 1); j++)
+         {
+            for (int i = 0; i < ncp-1; i++)
+            {
+               real_t lv = 0.0, uv = 0.0;
+               if (dim == 1)
+               {
+                  lv = std::max(lower(i), lower(i+1));
+                  uv = std::max(upper(i), upper(i+1));
+               }
+               else if (dim == 2)
+               {
+                  lv = std::max({lower(i + j*ncp), lower((i+1) + j*ncp),
+                                 lower(i + (j+1)*ncp),
+                                 lower((i+1) + (j+1)*ncp)});
+                  uv = std::max({upper(i + j*ncp), upper((i+1) + j*ncp),
+                                 upper(i + (j+1)*ncp),
+                                 upper((i+1) + (j+1)*ncp)});
+               }
+               else if (dim == 3)
+               {
+                  lv = std::max({lower(i + j*ncp + k*ncp*ncp),
+                                 lower((i+1) + j*ncp + k*ncp*ncp),
+                                 lower(i + (j+1)*ncp + k*ncp*ncp),
+                                 lower((i+1) + (j+1)*ncp + k*ncp*ncp),
+                                 lower(i + j*ncp + (k+1)*ncp*ncp),
+                                 lower((i+1) + j*ncp + (k+1)*ncp*ncp),
+                                 lower(i + (j+1)*ncp + (k+1)*ncp*ncp),
+                                 lower((i+1) + (j+1)*ncp + (k+1)*ncp*ncp)});
+                  uv = std::max({upper(i + j*ncp + k*ncp*ncp),
+                                 upper((i+1) + j*ncp + k*ncp*ncp),
+                                 upper(i + (j+1)*ncp + k*ncp*ncp),
+                                 upper((i+1) + (j+1)*ncp + k*ncp*ncp),
+                                 upper(i + j*ncp + (k+1)*ncp*ncp),
+                                 upper((i+1) + j*ncp + (k+1)*ncp*ncp),
+                                 upper(i + (j+1)*ncp + (k+1)*ncp*ncp),
+                                 upper((i+1) + (j+1)*ncp + (k+1)*ncp*ncp)});
+               }
+               IntervalNode *child_node = new IntervalNode(lv, uv);
+               current->node->AddChild(child_node);
+
+               if (uv > max_threshold)
+               {
+                  max_lower_bound = std::max(max_lower_bound, lv);
+                  max_threshold = std::max(max_threshold, lv);
+                  if (curr_depth < max_depth)
+                  {
+                     pos_range(0) = cp_ref_loc(i);
+                     pos_range(0+dim) = cp_ref_loc(i+1);
+                     if (dim >= 2)
+                     {
+                        pos_range(1) = cp_ref_loc(ncp + j);
+                        pos_range(1+dim) = cp_ref_loc(ncp + j+1);
+                     }
+                     if (dim == 3)
+                     {
+                        pos_range(2) = cp_ref_loc(2*ncp + k);
+                        pos_range(2+dim) = cp_ref_loc(2*ncp + k+1);
+                     }
+                     SearchInterval *child_interval =
+                        new SearchInterval(pos_range, curr_depth + 1,
+                                           child_node);
+                     pq.push(child_interval);
+                  }
+               }
+            }
+         }
+      }
+      delete current;
+   }
+   // clean up remaining intervals in queue
+   while (!pq.empty())
+   {
+      delete pq.top();
+      pq.pop();
+   }
+
+   max_upper_bound = initial_node->GetChildMaxUpper();
+   initial_node->DeleteChildren();
+   delete initial_node;
+   max_threshold = std::max(max_threshold, max_upper_bound);
+
+   return std::make_pair(max_lower_bound, max_upper_bound);
+}
+
+std::pair<real_t, real_t> GridFunction::EstimateFunctionMinimum(
+   const int vdim, const PLBound &plb, const int max_depth,
+   const real_t tol) const
+{
+   real_t global_min_lower = std::numeric_limits<real_t>::max();
+   real_t global_min_upper = std::numeric_limits<real_t>::max();
+
+   for (int i = 0; i < fes->GetNE(); i++)
+   {
+      std::pair<real_t, real_t> min_pair =
+         EstimateFunctionMinimum(i, plb, vdim, max_depth, tol,
+                                 global_min_lower);
+      global_min_upper = std::min(global_min_upper, min_pair.second);
+   }
+   return std::make_pair(global_min_lower, global_min_upper);
+}
+
+std::pair<real_t, real_t> GridFunction::EstimateFunctionMaximum(
+   const int vdim, const PLBound &plb, const int max_depth,
+   const real_t tol) const
+{
+   real_t global_max_lower = std::numeric_limits<real_t>::lowest();
+   real_t global_max_upper = std::numeric_limits<real_t>::lowest();
+
+   for (int i = 0; i < fes->GetNE(); i++)
+   {
+      std::pair<real_t, real_t> max_pair =
+         EstimateFunctionMaximum(i, plb, vdim, max_depth, tol,
+                                 global_max_upper);
+      global_max_lower = std::max(global_max_lower, max_pair.first);
+   }
+   return std::make_pair(global_max_lower, global_max_upper);
+}
+
+}

fem/gridfunc.hpp

@@ -23,6 +23,7 @@
 #include <limits>
 #include <ostream>
 #include <string>
+#include <variant>
 
 namespace mfem
 {
@@ -79,10 +80,18 @@ protected:
                         bool wcoef,
                         int subdomain);
 
-   /** Project a discontinuous vector coefficient in a continuous space and
-       return in dof_attr the maximal attribute of the elements containing each
-       degree of freedom. */
-   void ProjectDiscCoefficient(VectorCoefficient &coeff, Array<int> &dof_attr);
+   /** @brief Project a discontinuous (vector) coefficient as a grid function on
+       a continuous finite element space. Return in dof_attr the maximal
+       attribute of the elements containing each degree of freedom. */
+   virtual void ProjectDiscCoefficient(
+      std::variant<Coefficient*, VectorCoefficient*> coeff, Array<int> &dof_attr);
+
+   /** @brief Project a discontinuous (vector) coefficient as a grid function on
+       a continuous finite element space. The values in shared dofs are
+       determined from the element with maximal attribute. */
+   virtual void ProjectDiscCoefficient(
+      std::variant<Coefficient*, VectorCoefficient*> coeff)
+   { Array<int> dof_attr; ProjectDiscCoefficient(coeff, dof_attr); };
 
    /** Helper function for ProjectCoefficientElementL2 */
    void ProjectCoefficientElementL2_(Coefficient &coeff, Vector &sol, Vector &Va);
@@ -150,11 +159,13 @@ public:
 
    FiniteElementCollection *OwnFEC() { return fec_owned; }
 
-   /// Shortcut for calling FiniteElementSpace::GetVectorDim() on the underlying #fes
-   int VectorDim() const;
+   /** @brief Shortcut for calling FiniteElementSpace::GetVectorDim() on the
+       underlying #fes */
+   int VectorDim() const { return fes->GetVectorDim(); }
 
-   /// Shortcut for calling FiniteElementSpace::GetCurlDim() on the underlying #fes
-   int CurlDim() const;
+   /** @brief Shortcut for calling FiniteElementSpace::GetCurlDim() on the
+       underlying #fes */
+   int CurlDim() const { return fes->GetCurlDim(); }
 
    /// Read only access to the (optional) internal true-dof Vector.
    const Vector &GetTrueVector() const
@@ -513,10 +524,17 @@ public:
        but using an array of scalar coefficients for each component. */
    void ProjectCoefficient(Coefficient *coeff[]);
 
+   /** @brief Project a discontinuous coefficient as a grid function on
+       a continuous finite element space. The values in shared dofs are
+       determined from the element with maximal attribute. */
+   virtual void ProjectDiscCoefficient(Coefficient &coeff)
+   { ProjectDiscCoefficient(&coeff); }
+
    /** @brief Project a discontinuous vector coefficient as a grid function on
        a continuous finite element space. The values in shared dofs are
        determined from the element with maximal attribute. */
-   virtual void ProjectDiscCoefficient(VectorCoefficient &coeff);
+   virtual void ProjectDiscCoefficient(VectorCoefficient &coeff)
+   { ProjectDiscCoefficient(&coeff); }
 
    enum AvgType {ARITHMETIC, HARMONIC};
    /** @brief Projects a discontinuous coefficient so that the values in shared
@@ -532,6 +550,9 @@ public:
    std::unique_ptr<GridFunction> ProlongateToMaxOrder() const;
 
 protected:
+   void ProjectBdrCoefficientNormal(Coefficient *coeff, VectorCoefficient *vcoeff,
+                                    const Array<int> &attr);
+
    /** @brief Accumulates (depending on @a type) the values of @a coeff at all
        shared vdofs and counts in how many zones each vdof appears. */
    void AccumulateAndCountZones(Coefficient &coeff, AvgType type,
@@ -564,6 +585,70 @@ protected:
    /// P-refinement version of Update().
    void UpdatePRef();
 
+   /** @brief Estimate the minimum value of the GridFunction in element @a elem
+    *  if it is below a certain @a min_threshold.
+    *
+    *  @details For a given element \p elem and grid function component \p vdim
+    *  an estimate of the function minimum is the minimum of the piecewise
+    *  linear lower bound obtained using the given PLBound object. The actual
+    *  minimum is between [minimum lower bound, minimum upper bound]. We
+    *  improve the estimate of the function minimum by recursively
+    *  subdividing the interval with the lowest lower bound, and computing
+    *  bounds on the sub-intervals.
+    *  This process continues until (i) the maximum recursion depth is reached
+    *  or (ii) the difference between the minimum upper bound and minimum lower
+    *  bound is less than a certain tolerance (\p tol * [initial maximum
+    *  upper bound - initial minimum lower bound]).
+    *  The function also terminates if the lowest minima estimate is found
+    *  to be above the given threshold \p min_threshold. This is useful when
+    *  we are interested in computing the global minimum of the function
+    *  over all elements. In this case we can reject elements where the lowest
+    *  bound is above the current global minimum. In case the function
+    *  minimum on the element is below the global minimum, we update
+    *  \p min_threshold.
+    *
+    *  We return a pair of values that bracket the actual minimum, i.e.
+    *  [min_lower_bound, min_upper_bound].
+    */
+   std::pair<real_t,real_t> EstimateFunctionMinimum(const int elem,
+                                                    const PLBound &plb,
+                                                    const int vdim,
+                                                    const int max_depth,
+                                                    const real_t tol,
+                                                    real_t &min_threshold)const;
+
+   /** @brief Estimate the maximum value of the GridFunction in element @a elem
+    *  if it is below a certain @a max_threshold.
+    *
+    *  @details For a given element \p elem and grid function component \p vdim
+    *  an estimate of the function maximum is the maximum of the piecewise
+    *  linear upper bound obtained using the given PLBound object. The actual
+    *  maximum is between [maximum lower bound, maximum upper bound]. We
+    *  improve the estimate of the function maximum by recursively
+    *  subdividing the interval with the highest upper bound, and computing
+    *  bounds on the sub-intervals.
+    *  This process continues until (i) the maximum recursion depth is reached
+    *  or (ii) the difference between the maximum upper bound and maximum lower
+    *  bound is less than a certain tolerance (\p tol * [initial maximum
+    *  upper bound - initial maximum lower bound]).
+    *  The function also terminates if the highest maxima estimate is found
+    *  to be below the given threshold \p max_threshold. This is useful when
+    *  we are interested in computing the global maximum of the function
+    *  over all elements. In this case we can reject elements where the upper
+    *  bound is below the current global maximum. In case the function
+    *  maximum on the element is above the global maximum, we update
+    *  \p max_threshold.
+    *
+    *  We return a pair of values that bracket the actual maximum, i.e.
+    *  [max_lower_bound, max_upper_bound].
+    */
+   std::pair<real_t,real_t> EstimateFunctionMaximum(const int elem,
+                                                    const PLBound &plb,
+                                                    const int vdim,
+                                                    const int max_depth,
+                                                    const real_t tol,
+                                                    real_t &max_threshold)const;
+
 public:
    /** @brief For each vdof, counts how many elements contain the vdof,
        as containment is determined by FiniteElementSpace::GetElementVDofs(). */
@@ -592,15 +677,26 @@ public:
    virtual void ProjectBdrCoefficient(Coefficient *coeff[],
                                       const Array<int> &attr);
 
-   /** Project the normal component of the given VectorCoefficient on
-       the boundary. Only boundary attributes that are marked in
-       'bdr_attr' are projected. Assumes RT-type VectorFE GridFunction. */
+   /** @brief Project the normal component of the given VectorCoefficient on
+       the boundary. */
+   /** Only boundary attributes that are marked in @a bdr_attr are
+       projected. Assumes RT-type vector finite element GridFunction. */
    void ProjectBdrCoefficientNormal(VectorCoefficient &vcoeff,
-                                    const Array<int> &bdr_attr);
+                                    const Array<int> &bdr_attr)
+   { ProjectBdrCoefficientNormal(NULL, &vcoeff, bdr_attr); }
+
+   /** @brief Project the given Coefficient in the normal direction on the
+       boundary. */
+   /** Only boundary attributes that are marked in @a bdr_attr are projected.
+       Assumes RT-type vector finite element GridFunction. */
+   void ProjectBdrCoefficientNormal(Coefficient &coeff,
+                                    const Array<int> &bdr_attr)
+   { ProjectBdrCoefficientNormal(&coeff, NULL, bdr_attr); }
 
    /** @brief Project the tangential components of the given VectorCoefficient
-       on the boundary. Only boundary attributes that are marked in @a bdr_attr
-       are projected. Assumes ND-type VectorFE GridFunction. */
+       on the boundary. */
+   /** Only boundary attributes that are marked in @a bdr_attr
+       are projected. Assumes ND-type vector finite element GridFunction. */
    virtual void ProjectBdrCoefficientTangent(VectorCoefficient &vcoeff,
                                              const Array<int> &bdr_attr);
 
@@ -1662,21 +1758,21 @@ public:
     */
    ///@{
    /// Computes the \ref PLBound for the gridfunction with number of control
-   /// points based on @a ref_factor, and returns the overall bounds for each
-   /// vdim (across all elements) in @b lower and @b upper. We also return the
+   /// points based on \p ref_factor, and returns the overall bounds for each
+   /// vdim (across all elements) in \p lower and \p upper. We also return the
    /// PLBound object used to compute the bounds.
-   /// We compute the bounds for each vdim if @a vdim < 1.
+   /// We compute the bounds for each vdim if \p vdim < 1.
    /// Note: For most cases, this method/interface will be sufficient.
    virtual PLBound GetBounds(Vector &lower, Vector &upper,
                              const int ref_factor=1, const int vdim=-1) const;
 
    /// Computes the \ref PLBound for the gridfunction with number of control
-   /// points based on @a ref_factor, and returns the bounds for each element
-   /// ordered byVDim:
+   /// points based on \p ref_factor, and returns the bounds for each element
+   /// ordered byNodes:
    /// lower_{0,0}, lower_{1,0}, ..., lower_{ne-1,0},
    /// lower_{0,1}, ..., lower_{ne-1,vdim-1}. We also return the
    /// PLBound object used to compute the bounds.
-   /// We compute the bounds for each vdim if @a vdim < 1.
+   /// We compute the bounds for each vdim if \p vdim < 1.
    PLBound GetElementBounds(Vector &lower, Vector &upper,
                             const int ref_factor=1, const int vdim=-1) const;
 
@@ -1687,6 +1783,18 @@ public:
                                         Vector &lower, Vector &upper,
                                         const int vdim = -1) const;
 
+   /** @brief Gets the bounds on given reference range inside an element.
+    *
+    *  @details @a ref_range is a vector of size 2*dim that specifies the
+    *  lower and upper limits in each dimension of the reference element.
+    *  For example, in 2D, ref_range = [rmin, smin, rmax, smax].
+    */
+   void GetElementBoundsAtControlPoints(const int elem, const PLBound &plb,
+                                        const Vector &ref_range,
+                                        const int vdim,
+                                        Vector &lower, Vector &upper,
+                                        Vector &control_pos) const;
+
    /// Compute bounds on the grid function for the given element.
    /// The bounds are stored in @b lower and @b upper.
    void GetElementBounds(const int elem, const PLBound &plb,
@@ -1694,11 +1802,45 @@ public:
                          const int vdim = -1) const;
 
    /// Compute bounds on the grid function for all the elements. The bounds
-   /// are returned in @b lower and @b upper, ordered byVDim:
+   /// are returned in @b lower and @b upper, ordered byNodes:
    /// lower_{0,0}, lower_{1,0}, ..., lower_{ne-1,0},
    /// lower_{0,1}, ..., lower_{ne-1,vdim-1}
    void GetElementBounds(const PLBound &plb, Vector &lower, Vector &upper,
                          const int vdim=-1) const;
+
+   /** @brief Estimate the minimum value of the GridFunction in element @a elem.
+    *
+    *  @details See the protected version of EstimateFunctionMinimum for
+    *  details.
+    */
+   std::pair<real_t, real_t> EstimateFunctionMinimum(const int elem,
+                                                     const PLBound &plb,
+                                                     const int vdim,
+                                                     const int max_depth,
+                                                     const real_t tol) const;
+
+   /** @brief Estimate the minimum value of the GridFunction in element @a elem.
+    *
+    *  @details See the protected version of EstimateFunctionMaximum for
+    *  details.
+    */
+   std::pair<real_t, real_t> EstimateFunctionMaximum(const int elem,
+                                                     const PLBound &plb,
+                                                     const int vdim,
+                                                     const int max_depth,
+                                                     const real_t tol) const;
+
+   /** @brief Estimate the GridFunction minimum across all elements. */
+   virtual std::pair<real_t,real_t> EstimateFunctionMinimum(const int vdim,
+                                                            const PLBound &plb,
+                                                            const int max_depth,
+                                                            const real_t tol) const;
+
+   /** @brief Estimate the GridFunction maximum across all elements. */
+   virtual std::pair<real_t,real_t> EstimateFunctionMaximum(const int vdim,
+                                                            const PLBound &plb,
+                                                            const int max_depth,
+                                                            const real_t tol) const;
    ///@}
 
    /// Destroys grid function.
@@ -1804,7 +1946,7 @@ real_t ComputeElementLpDistance(real_t p, int i,
                                 GridFunction& gf1, GridFunction& gf2);
 
 
-/// Class used for extruding scalar GridFunctions
+/// Class used for extruding a scalar coefficient
 class ExtrudeCoefficient : public Coefficient
 {
 private:
@@ -1812,13 +1954,53 @@ private:
    Mesh *mesh_in;
    Coefficient &sol_in;
 public:
+   /// Constructs an instance of VectorExtrudeCoefficient
+   /**
+    * @param m      1D mesh
+    * @param s      1D vector coefficient
+    * @param n_     number of transverse elements of the extruded mesh
+    */
    ExtrudeCoefficient(Mesh *m, Coefficient &s, int n_)
-      : n(n_), mesh_in(m), sol_in(s) { }
+      : n(n_), mesh_in(m), sol_in(s)
+   { MFEM_VERIFY(n > 0, "Number of transverse elements must be positive!"); }
+
    real_t Eval(ElementTransformation &T, const IntegrationPoint &ip) override;
+
    virtual ~ExtrudeCoefficient() { }
 };
 
-/// Extrude a scalar 1D GridFunction, after extruding the mesh with Extrude1D.
+/// Class used for extruding a vector coefficient
+class VectorExtrudeCoefficient : public VectorCoefficient
+{
+private:
+   int n;
+   Mesh *mesh_in;
+   VectorCoefficient &sol_in;
+public:
+   /// Constructs an instance of VectorExtrudeCoefficient
+   /**
+    * @param m      1D mesh
+    * @param s      1D vector coefficient
+    * @param n_     number of transverse elements of the extruded mesh
+    */
+   VectorExtrudeCoefficient(Mesh *m, VectorCoefficient &s, int n_)
+      : VectorCoefficient(s.GetVDim()), n(n_), mesh_in(m), sol_in(s)
+   { MFEM_VERIFY(n > 0, "Number of transverse elements must be positive!"); }
+
+   void Eval(Vector &v, ElementTransformation &T,
+             const IntegrationPoint &ip) override;
+   using VectorCoefficient::Eval;
+
+   virtual ~VectorExtrudeCoefficient() { }
+};
+
+/// Extrude a 1D GridFunction, after extruding the mesh with Extrude1D()
+/**
+ * @param mesh      1D mesh
+ * @param mesh2d    extruded mesh
+ * @param sol       grid function
+ * @param ny        number of transverse elements of the extruded mesh
+ */
 GridFunction *Extrude1DGridFunction(Mesh *mesh, Mesh *mesh2d,
                                     GridFunction *sol, const int ny);
 

fem/gslib.cpp

@@ -234,7 +234,7 @@ void FindPointsGSLIB::Setup(Mesh &m, const double bb_t, const double newt_tol,
 }
 
 void FindPointsGSLIB::FindPoints(const Vector &point_pos,
-                                 int point_pos_ordering)
+                                 const int point_pos_ordering)
 {
    MFEM_VERIFY(setupflag, "Use FindPointsGSLIB::Setup before finding points.");
    bool dev_mode = (point_pos.UseDevice() && Device::IsEnabled());
@@ -482,7 +482,7 @@ void FindPointsGSLIB::SetupDevice()
 }
 
 void FindPointsGSLIB::FindPointsOnDevice(const Vector &point_pos,
-                                         int point_pos_ordering)
+                                         const int point_pos_ordering)
 {
    if (!DEV.setup_device)
    {
@@ -490,7 +490,7 @@ void FindPointsGSLIB::FindPointsOnDevice(const Vector &point_pos,
    }
    DEV.find_device = true;
 
-   const int id = gsl_comm->id, np = gsl_comm->np;
+   const unsigned int id = gsl_comm->id, np = gsl_comm->np;
 
    gsl_mfem_ref.SetSize(points_cnt * dim);
    gsl_mfem_elem.SetSize(points_cnt);
@@ -505,13 +505,13 @@ void FindPointsGSLIB::FindPointsOnDevice(const Vector &point_pos,
 
    if (dim == 2)
    {
-      FindPointsLocal2(point_pos, point_pos_ordering, gsl_code, gsl_elem, gsl_ref,
-                       gsl_dist, points_cnt);
+      FindPointsLocal2(point_pos, point_pos_ordering, gsl_code, gsl_elem,
+                       gsl_ref, gsl_dist, points_cnt);
    }
    else
    {
-      FindPointsLocal3(point_pos, point_pos_ordering, gsl_code, gsl_elem, gsl_ref,
-                       gsl_dist, points_cnt);
+      FindPointsLocal3(point_pos, point_pos_ordering, gsl_code, gsl_elem,
+                       gsl_ref, gsl_dist, points_cnt);
    }
 
    // Sync from device to host
@@ -652,7 +652,7 @@ void FindPointsGSLIB::FindPointsOnDevice(const Vector &point_pos,
          {
             const int pp = hash_offset[i];
             /* don't send back to where it just came from */
-            if (pp == p->proc)
+            if (static_cast<unsigned>(pp) == p->proc)
             {
                continue;
             }
@@ -1068,7 +1068,7 @@ void FindPointsGSLIB::InterpolateOnDevice(const Vector &field_in_evec,
          sarray_transfer(struct evalOutPt_t, &outpt, proc, 1, cr);
 
          opt = (evalOutPt_t *)outpt.ptr;
-         for (int index = 0; index < outpt.n; index++)
+         for (size_t index = 0; index < outpt.n; index++)
          {
             int idx = ordering == Ordering::byNODES ?
                       opt->index + i*points_cnt :
@@ -1085,7 +1085,7 @@ void FindPointsGSLIB::InterpolateOnDevice(const Vector &field_in_evec,
 #else
 void FindPointsGSLIB::SetupDevice() {};
 void FindPointsGSLIB::FindPointsOnDevice(const Vector &point_pos,
-                                         int point_pos_ordering) {};
+                                         const int point_pos_ordering) {};
 void FindPointsGSLIB::InterpolateOnDevice(const Vector &field_in_evec,
                                           Vector &field_out,
                                           const int nel, const int ncomp,
@@ -1094,7 +1094,8 @@ void FindPointsGSLIB::InterpolateOnDevice(const Vector &field_in_evec,
 #endif
 
 void FindPointsGSLIB::FindPoints(Mesh &m, const Vector &point_pos,
-                                 int point_pos_ordering, const double bb_t,
+                                 const int point_pos_ordering,
+                                 const double bb_t,
                                  const double newt_tol, const int npt_max)
 {
    if (!setupflag || (mesh != &m) )
@@ -1105,16 +1106,28 @@ void FindPointsGSLIB::FindPoints(Mesh &m, const Vector &point_pos,
 }
 
 void FindPointsGSLIB::Interpolate(const Vector &point_pos,
-                                  const GridFunction &field_in, Vector &field_out,
-                                  int point_pos_ordering)
+                                  const GridFunction &field_in,
+                                  Vector &field_out,
+                                  const int point_pos_ordering)
 {
    FindPoints(point_pos, point_pos_ordering);
    Interpolate(field_in, field_out);
 }
 
+void FindPointsGSLIB::Interpolate(const Vector &point_pos,
+                                  const GridFunction &field_in,
+                                  Vector &field_out,
+                                  const int point_pos_ordering,
+                                  const int field_out_ordering)
+{
+   FindPoints(point_pos, point_pos_ordering);
+   Interpolate(field_in, field_out, field_out_ordering);
+}
+
 void FindPointsGSLIB::Interpolate(Mesh &m, const Vector &point_pos,
-                                  const GridFunction &field_in, Vector &field_out,
-                                  int point_pos_ordering)
+                                  const GridFunction &field_in,
+                                  Vector &field_out,
+                                  const int point_pos_ordering)
 {
    FindPoints(m, point_pos, point_pos_ordering);
    Interpolate(field_in, field_out);
@@ -1400,7 +1413,7 @@ void FindPointsGSLIB::SetupSplitMeshesAndIntegrationRules(const int order)
 {
    MFEM_VERIFY(mesh, "Setup FindPointsGSLIB with mesh first.");
    const int dof1D = order+1;
-   const int dim = mesh->Dimension();
+   dim = mesh->Dimension();
 
    SetupSplitMeshes();
    if (dim == 2)
@@ -1470,7 +1483,7 @@ void FindPointsGSLIB::SetupSplitMeshesAndIntegrationRules(const int order)
 }
 
 void FindPointsGSLIB::GetNodalValues(const GridFunction *gf_in,
-                                     Vector &node_vals)
+                                     Vector &node_vals) const
 {
    const GridFunction *nodes     = gf_in;
    const FiniteElementSpace *fes = nodes->FESpace();
@@ -1758,6 +1771,13 @@ void FindPointsGSLIB::MapRefPosAndElemIndices()
 
 void FindPointsGSLIB::Interpolate(const GridFunction &field_in,
                                   Vector &field_out)
+{
+   Interpolate(field_in, field_out, field_in.FESpace()->GetOrdering());
+}
+
+void FindPointsGSLIB::Interpolate(const GridFunction &field_in,
+                                  Vector &field_out,
+                                  const int field_out_ordering)
 {
    const int  gf_order   = field_in.FESpace()->GetMaxElementOrder(),
               mesh_order = mesh->GetNodalFESpace()->GetMaxElementOrder();
@@ -1800,7 +1820,7 @@ void FindPointsGSLIB::Interpolate(const GridFunction &field_in,
       const int maxOrder = field_in.FESpace()->GetMaxElementOrder();
 
       InterpolateOnDevice(node_vals, field_out, NE_split_total, ncomp,
-                          maxOrder+1, field_in.FESpace()->GetOrdering());
+                          maxOrder+1, field_out_ordering);
       return;
 #endif
    }
@@ -1812,12 +1832,13 @@ void FindPointsGSLIB::Interpolate(const GridFunction &field_in,
        field_in.FESpace()->IsVariableOrder() ==
        mesh->GetNodalFESpace()->IsVariableOrder())
    {
-      InterpolateH1(field_in, field_out);
+      InterpolateH1(field_in, field_out, field_out_ordering);
       return;
    }
    else
    {
-      InterpolateGeneral(field_in, field_out);
+      InterpolateGeneral(field_in, field_out,
+                         field_out_ordering);
       if (!fec_l2 || avgtype == AvgType::NONE) { return; }
    }
 
@@ -1861,11 +1882,11 @@ void FindPointsGSLIB::Interpolate(const GridFunction &field_in,
 
       if (gf_order_h1 == mesh_order) // basis is GaussLobatto by default
       {
-         InterpolateH1(field_in_h1, field_out_l2);
+         InterpolateH1(field_in_h1, field_out_l2, field_out_ordering);
       }
       else
       {
-         InterpolateGeneral(field_in_h1, field_out_l2);
+         InterpolateGeneral(field_in_h1, field_out_l2, field_out_ordering);
       }
 
       // Copy interpolated values for the points on element border
@@ -1873,7 +1894,7 @@ void FindPointsGSLIB::Interpolate(const GridFunction &field_in,
       {
          for (int i = 0; i < indl2.Size(); i++)
          {
-            int idx = field_in_h1.FESpace()->GetOrdering() == Ordering::byNODES?
+            int idx = field_out_ordering == Ordering::byNODES?
                       indl2[i] + j*points_cnt:
                       indl2[i]*ncomp + j;
             field_out(idx) = field_out_l2(idx);
@@ -1883,7 +1904,8 @@ void FindPointsGSLIB::Interpolate(const GridFunction &field_in,
 }
 
 void FindPointsGSLIB::InterpolateH1(const GridFunction &field_in,
-                                    Vector &field_out)
+                                    Vector &field_out,
+                                    const int field_out_ordering)
 {
    FiniteElementSpace ind_fes(mesh, field_in.FESpace()->FEColl());
    if (field_in.FESpace()->IsVariableOrder())
@@ -1913,7 +1935,8 @@ void FindPointsGSLIB::InterpolateH1(const GridFunction &field_in,
                 dataptrout = i*points_cnt;
       if (field_in.FESpace()->GetOrdering() == Ordering::byNODES)
       {
-         field_in_scalar.NewDataAndSize(field_in.GetData()+dataptrin, points_fld);
+         field_in_scalar.NewDataAndSize(field_in.GetData()+dataptrin,
+                                        points_fld);
       }
       else
       {
@@ -1945,7 +1968,7 @@ void FindPointsGSLIB::InterpolateH1(const GridFunction &field_in,
                         (gslib::findpts_data_3 *)this->fdataD);
       }
    }
-   if (field_in.FESpace()->GetOrdering() == Ordering::byVDIM)
+   if (field_out_ordering == Ordering::byVDIM)
    {
       Vector field_out_temp = field_out;
       for (int i = 0; i < ncomp; i++)
@@ -1959,7 +1982,8 @@ void FindPointsGSLIB::InterpolateH1(const GridFunction &field_in,
 }
 
 void FindPointsGSLIB::InterpolateGeneral(const GridFunction &field_in,
-                                         Vector &field_out)
+                                         Vector &field_out,
+                                         const int field_out_ordering)
 {
    int ncomp   = field_in.VectorDim(),
        nptorig = points_cnt,
@@ -1979,7 +2003,7 @@ void FindPointsGSLIB::InterpolateGeneral(const GridFunction &field_in,
          if (dim == 3) { ip.z = gsl_mfem_ref(index*dim + 2); }
          Vector localval(ncomp);
          field_in.GetVectorValue(gsl_mfem_elem[index], ip, localval);
-         if (field_in.FESpace()->GetOrdering() == Ordering::byNODES)
+         if (field_out_ordering == Ordering::byNODES)
          {
             for (int i = 0; i < ncomp; i++)
             {
@@ -2014,7 +2038,10 @@ void FindPointsGSLIB::InterpolateGeneral(const GridFunction &field_in,
       for (int index = 0; index < npt; index++)
       {
          if (gsl_code[index] == 2) { continue; }
-         for (int d = 0; d < dim; ++d) { pt->r[d]= gsl_mfem_ref(index*dim + d); }
+         for (int d = 0; d < dim; ++d)
+         {
+            pt->r[d]= gsl_mfem_ref(index*dim + d);
+         }
          pt->index = index;
          pt->proc  = gsl_proc[index];
          pt->el    = gsl_mfem_elem[index];
@@ -2104,7 +2131,7 @@ void FindPointsGSLIB::InterpolateGeneral(const GridFunction &field_in,
             sdpt = (struct send_pt *)sendpt->ptr;
             for (int index = 0; index < static_cast<int>(sendpt->n); index++)
             {
-               int idx = field_in.FESpace()->GetOrdering() == Ordering::byNODES ?
+               int idx = field_out_ordering == Ordering::byNODES ?
                          sdpt->index + j*nptorig :
                          sdpt->index*ncomp + j;
                field_out(idx) = sdpt->ival;
@@ -2227,7 +2254,8 @@ void FindPointsGSLIB::DistributeInterpolatedValues(const Vector &int_vals,
       sarray_transfer(struct out_pt, outpt, proc, 1, cr);
 
       // Store received data
-      MFEM_VERIFY(outpt->n == points_cnt, "Incompatible size. Number of points "
+      MFEM_VERIFY(outpt->n == static_cast<size_t>(points_cnt),
+                  "Incompatible size. Number of points "
                   "received does not match the number of points originally "
                   "found using FindPoints.");
 
@@ -2246,7 +2274,7 @@ void FindPointsGSLIB::DistributeInterpolatedValues(const Vector &int_vals,
    }
 }
 
-void FindPointsGSLIB::GetAxisAlignedBoundingBoxes(Vector &aabb)
+void FindPointsGSLIB::GetAxisAlignedBoundingBoxes(Vector &aabb) const
 {
    MFEM_VERIFY(setupflag, "Call FindPointsGSLIB::Setup method first");
    auto *findptsData3 = (gslib::findpts_data_3 *)this->fdataD;
@@ -2317,7 +2345,7 @@ void FindPointsGSLIB::GetAxisAlignedBoundingBoxes(Vector &aabb)
 }
 
 void FindPointsGSLIB::GetOrientedBoundingBoxes(DenseTensor &obbA, Vector &obbC,
-                                               Vector &obbV)
+                                               Vector &obbV) const
 {
    MFEM_VERIFY(setupflag, "Call FindPointsGSLIB::Setup method first");
    auto *findptsData3 = (gslib::findpts_data_3 *)this->fdataD;
@@ -2502,8 +2530,8 @@ void OversetFindPointsGSLIB::Setup(Mesh &m, const int meshid,
 }
 
 void OversetFindPointsGSLIB::FindPoints(const Vector &point_pos,
-                                        Array<unsigned int> &point_id,
-                                        int point_pos_ordering)
+                                        const Array<unsigned int> &point_id,
+                                        const int point_pos_ordering)
 {
    MFEM_VERIFY(setupflag, "Use OversetFindPointsGSLIB::Setup before "
                "finding points.");
@@ -2582,10 +2610,10 @@ void OversetFindPointsGSLIB::FindPoints(const Vector &point_pos,
 }
 
 void OversetFindPointsGSLIB::Interpolate(const Vector &point_pos,
-                                         Array<unsigned int> &point_id,
+                                         const Array<unsigned int> &point_id,
                                          const GridFunction &field_in,
                                          Vector &field_out,
-                                         int point_pos_ordering)
+                                         const int point_pos_ordering)
 {
    FindPoints(point_pos, point_id, point_pos_ordering);
    Interpolate(field_in, field_out);

fem/gslib.hpp

@@ -119,11 +119,13 @@ protected:
    } DEV;
 
    /// Use GSLIB for communication and interpolation
-   virtual void InterpolateH1(const GridFunction &field_in, Vector &field_out);
+   virtual void InterpolateH1(const GridFunction &field_in, Vector &field_out,
+                              const int field_out_ordering);
    /// Uses GSLIB Crystal Router for communication followed by MFEM's
    /// interpolation functions
    virtual void InterpolateGeneral(const GridFunction &field_in,
-                                   Vector &field_out);
+                                   Vector &field_out,
+                                   const int field_out_ordering);
 
    /// Since GSLIB is designed to work with quads/hexes, we split every
    /// triangle/tet/prism/pyramid element into quads/hexes.
@@ -140,7 +142,7 @@ protected:
    virtual void SetupSplitMeshesAndIntegrationRules(const int order);
 
    /// Get GridFunction value at the points expected by GSLIB.
-   virtual void GetNodalValues(const GridFunction *gf_in, Vector &node_vals);
+   virtual void GetNodalValues(const GridFunction *gf_in, Vector &node_vals) const;
 
    /// Map {r,s,t} coordinates from [-1,1] to [0,1] for MFEM. For simplices,
    /// find the original element number (that was split into micro quads/hexes)
@@ -182,7 +184,7 @@ protected:
        These positions can be ordered byNodes: (XXX...,YYY...,ZZZ) or
        byVDim: (XYZ,XYZ,....XYZ) specified by @a point_pos_ordering. */
    void FindPointsOnDevice(const Vector &point_pos,
-                           int point_pos_ordering = Ordering::byNODES);
+                           const int point_pos_ordering = Ordering::byNODES);
 
    /** Interpolation of field values at prescribed reference space positions.
        @param[in] field_in_evec E-vector of grid function to be interpolated.
@@ -200,13 +202,19 @@ protected:
                             const int dof1dsol, const int ordering);
 
 public:
+   /// Serial constructor
    FindPointsGSLIB();
+
+   /// Serial constructor + setup with given Mesh (see \ref Setup)
    FindPointsGSLIB(Mesh &mesh_in, const double bb_t = 0.1,
                    const double newt_tol = 1.0e-12,
                    const int npt_max = 256);
 
 #ifdef MFEM_USE_MPI
+   /// Constructor for ParMesh
    FindPointsGSLIB(MPI_Comm comm_);
+
+   /// Constructor + setup with given ParMesh (see \ref Setup)
    FindPointsGSLIB(ParMesh &mesh_in, const double bb_t = 0.1,
                    const double newt_tol = 1.0e-12,
                    const int npt_max = 256);
@@ -253,10 +261,15 @@ public:
        #gsl_dist        Distance between the sought and the found point
                         in physical space. */
    void FindPoints(const Vector &point_pos,
-                   int point_pos_ordering = Ordering::byNODES);
+                   const int point_pos_ordering = Ordering::byNODES);
+   /// Convenience function when point positions are in a ParticleVector
+   void FindPoints(const ParticleVector &point_pos)
+   {
+      FindPoints(point_pos, point_pos.GetOrdering());
+   }
    /// Setup FindPoints and search positions
    void FindPoints(Mesh &m, const Vector &point_pos,
-                   int point_pos_ordering = Ordering::byNODES,
+                   const int point_pos_ordering = Ordering::byNODES,
                    const double bb_t = 0.1, const double newt_tol = 1.0e-12,
                    const int npt_max = 256);
 
@@ -266,20 +279,28 @@ public:
                               \p field_in is in H1 and in the same space as the
                               mesh that was given to Setup().
        @param[out] field_out  Interpolated values. For points that are not found
-                              the value is set to #default_interp_value. */
+                              the value is set to #default_interp_value.
+                              The output ordering is determined from field_in.*/
    virtual void Interpolate(const GridFunction &field_in, Vector &field_out);
+   /// Interpolation of field values, with output ordering specification.
+   virtual void Interpolate(const GridFunction &field_in, Vector &field_out,
+                            const int field_out_ordering);
    /** Search positions and interpolate. The ordering (byNODES or byVDIM) of
        the output values in \p field_out corresponds to the ordering used
        in the input GridFunction \p field_in. */
    void Interpolate(const Vector &point_pos, const GridFunction &field_in,
                     Vector &field_out,
-                    int point_pos_ordering = Ordering::byNODES);
+                    const int point_pos_ordering = Ordering::byNODES);
+   /// Search positions and interpolate with given point and output ordering.
+   void Interpolate(const Vector &point_pos, const GridFunction &field_in,
+                    Vector &field_out, const int point_pos_ordering,
+                    const int field_out_ordering);
    /** Setup FindPoints, search positions and interpolate. The ordering (byNODES
        or byVDIM) of the output values in \p field_out corresponds to the
        ordering used in the input GridFunction \p field_in. */
    void Interpolate(Mesh &m, const Vector &point_pos,
                     const GridFunction &field_in, Vector &field_out,
-                    int point_pos_ordering = Ordering::byNODES);
+                    const int point_pos_ordering = Ordering::byNODES);
 
    /// Average type to be used for L2 functions in-case a point is located at
    /// an element boundary where the function might be multi-valued.
@@ -376,7 +397,7 @@ public:
    /// The size of the returned vector is (nel x nverts x dim), where nel is the
    /// number of elements (after splitting for simplcies), nverts is number of
    /// vertices (4 in 2D, 8 in 3D), and dim is the spatial dimension.
-   void GetAxisAlignedBoundingBoxes(Vector &aabb);
+   void GetAxisAlignedBoundingBoxes(Vector &aabb) const;
 
    /// Return the oriented bounding boxes (OBB) computed during \ref Setup.
    /// Each OBB is represented using the inverse transformation (A^{-1}) and
@@ -386,7 +407,8 @@ public:
    /// size (dim x dim x nel), and the OBB centers are returned in \p obbC,
    /// a vector of size (nel x dim). The vertices of the OBBs are returned in
    /// \p obbV, a vector of size (nel x nverts x dim) .
-   void GetOrientedBoundingBoxes(DenseTensor &obbA, Vector &obbC, Vector &obbV);
+   void GetOrientedBoundingBoxes(DenseTensor &obbA, Vector &obbC,
+                                 Vector &obbV) const;
 };
 
 /** \brief OversetFindPointsGSLIB enables use of findpts for arbitrary number of
@@ -446,13 +468,14 @@ public:
                                        byNodes: (XXX...,YYY...,ZZZ) or
                                        byVDim: (XYZ,XYZ,....XYZ) */
    void FindPoints(const Vector &point_pos,
-                   Array<unsigned int> &point_id,
-                   int point_pos_ordering = Ordering::byNODES);
+                   const Array<unsigned int> &point_id,
+                   const int point_pos_ordering = Ordering::byNODES);
 
    /** Search positions and interpolate */
-   void Interpolate(const Vector &point_pos, Array<unsigned int> &point_id,
+   void Interpolate(const Vector &point_pos,
+                    const Array<unsigned int> &point_id,
                     const GridFunction &field_in, Vector &field_out,
-                    int point_pos_ordering = Ordering::byNODES);
+                    const int point_pos_ordering = Ordering::byNODES);
    using FindPointsGSLIB::Interpolate;
 };
 

fem/gslib/findpts_local_2.cpp

@@ -254,7 +254,7 @@ get_edge(const double *elx[2], const double *wtend, int ei,
       edge.dxdn[d] = workspace + (2 + d) * pN; //dxdn and dydn at DOFs along edge
    }
 
-   if (side_init != (1u << ei))
+   if (static_cast<unsigned>(side_init) != (1u << ei))
    {
 #define ELX(d, j, k) elx[d][j + k * pN] // assumes lexicographic ordering
       for (int d = 0; d < 2; ++d)

fem/gslib/findpts_local_3.cpp

@@ -294,7 +294,7 @@ get_face(const double *elx[3], const double *wtend, int fi, double *workspace,
       face.dxdn[d] = workspace+(3+d)*p_Nfr;
    }
 
-   if (side_init != (1u << fi))
+   if (static_cast<unsigned>(side_init) != (1u << fi))
    {
       const int e_stride[3] = {1, pN, pN*pN};
 #define ELX(d, j, k, l) elx[d][j*e_stride[d1]+k*e_stride[d2]+l*e_stride[dn]]
@@ -342,7 +342,7 @@ get_edge(const double *elx[3], const double *wtend, int ei, double *workspace,
 
    if (jidx >= 3*pN) { return edge; }
 
-   if (side_init != (64u << ei))
+   if (static_cast<unsigned>(side_init) != (64u << ei))
    {
       const int e_stride[3] = {1, pN, pN*pN};
 #define ELX(d, j, k, l) elx[d][j*e_stride[de]+k*e_stride[dn1]+l*e_stride[dn2]]

fem/hybridization.cpp

@@ -789,7 +789,6 @@ void Hybridization::ComputeH()
    }
    else
    {
-      // TODO: add ones on the diagonal of zero rows
       V->Finalize();
       Array<HYPRE_BigInt> V_J(V->NumNonZeroElems());
       MFEM_ASSERT(c_pfes, "");
@@ -823,6 +822,13 @@ void Hybridization::ComputeH()
       MFEM_VERIFY(pH.Type() != Operator::PETSC_MATIS, "To be implemented");
       pH.MakePtAP(plpH, pP);
       delete lpH;
+
+      HypreParMatrix *hH = pH.As<HypreParMatrix>();
+      MFEM_ASSERT(hH, "");
+
+      SparseMatrix H_diag;
+      hH->GetDiag(H_diag);
+      H_diag.SetDiagIdentity();
    }
 #endif
 }

fem/hybridization_ext.hpp

@@ -14,8 +14,11 @@
 
 #include "../config/config.hpp"
 #include "../general/array.hpp"
+#include "../linalg/operator.hpp"
 #include "../linalg/vector.hpp"
 
+#include <memory>
+
 namespace mfem
 {
 
@@ -45,15 +48,30 @@ protected:
    Array<int> hat_dof_gather_map;
    Array<DofType> hat_dof_marker;
 
-   Array<int> el_to_face;
-   Array<int> face_to_el;
+   Array<int> el_to_face; ///< Element to face connectivity.
+   Array<int> el_face_offsets; ///< Per-element offsets into @a el_to_face.
+   Array<int> face_to_el; ///< Face-to-element connectivity.
+   Array<int> face_face_offsets; ///< Face-to-face offsets.
+
+   int n_el_face; ///< Total number of element-to-face connections.
+   int n_face_face; ///< Total number of face-to-face connections.
+
    Vector Ct_mat; ///< Constraint matrix (transposed) stored element-wise.
 
+   /// @name For parallel non-conforming meshes
+   ///@{
+   std::unique_ptr<Operator> P_pc; ///< Partially conforming prolongation.
+   std::unique_ptr<Operator> P_nbr; ///< Face-neighbor prolongation.
+   ///@}
+
    Array<int> idofs, bdofs;
 
    Vector Ahat, Ahat_ii, Ahat_ib, Ahat_bi, Ahat_bb;
    Array<int> Ahat_ii_piv, Ahat_bb_piv;
 
+   /// Return the (partially) conforming prolongation on the constraint space.
+   const Operator &GetProlongation() const;
+
 public:
    /// Construct the constraint matrix.
    void ConstructC();

fem/integ/bilininteg_diffusion_kernels.hpp

@@ -1004,13 +1004,16 @@ inline void SmemPADiffusionApply3D(const int NE,
    const int max_d1d = T_D1D ? T_D1D : DeviceDofQuadLimits::Get().MAX_D1D;
    MFEM_VERIFY(D1D <= max_d1d, "");
    MFEM_VERIFY(Q1D <= max_q1d, "");
-   auto b = Reshape(b_.Read(), Q1D, D1D);
-   auto g = Reshape(g_.Read(), Q1D, D1D);
-   auto d = Reshape(d_.Read(), Q1D, Q1D, Q1D, symmetric ? 6 : 9, NE);
-   auto x = Reshape(x_.Read(), D1D, D1D, D1D, NE);
+   const auto b = Reshape(b_.Read(), Q1D, D1D);
+   const auto g = Reshape(g_.Read(), Q1D, D1D);
+   const auto d = Reshape(d_.Read(), Q1D, Q1D, Q1D, symmetric ? 6 : 9, NE);
+   const auto x = Reshape(x_.Read(), D1D, D1D, D1D, NE);
    auto y = Reshape(y_.ReadWrite(), D1D, D1D, D1D, NE);
    MFEM_VERIFY(D1D <= Q1D, "THREAD_DIRECT requires D1D <= Q1D");
-   mfem::forall_3D(NE, Q1D, Q1D, Q1D, [=] MFEM_HOST_DEVICE (int e)
+
+   mfem::forall_3D<T_Q1D*T_Q1D*T_Q1D>(NE,
+                                      Q1D, Q1D, Q1D,
+                                      [=] MFEM_HOST_DEVICE (int e)
    {
       const int D1D = T_D1D ? T_D1D : d1d;
       const int Q1D = T_Q1D ? T_Q1D : q1d;

fem/integ/bilininteg_hdiv_ea.cpp

@@ -197,15 +197,21 @@ static void EAHdivAssemble3D(const int NE,
       // Assemble (one row per thread)
       MFEM_FOREACH_THREAD(idx_i, x, NDOF)
       {
+         // NOTE: due to an llvm backend bug, usage of the modulus operator
+         // has been removed from this foreach section.
          const int ic = idx_i / NDOF_C;
-         const int idx_ii = idx_i % NDOF_C;
+         const int idx_ii = idx_i - ic * NDOF_C; // idx_i % NDOF_C
 
          const int nx_i = (ic == 0) ? D1D : D1D-1;
          const int ny_i = (ic == 1) ? D1D : D1D-1;
 
-         const int ix = idx_ii % nx_i;
-         const int iy = (idx_ii / nx_i) % ny_i;
-         const int iz = (idx_ii / nx_i) / ny_i;
+         const int qx_i = idx_ii / nx_i;
+         const int ix = idx_ii - qx_i * nx_i; // idx_ii % nx_i
+
+         const int qy_i = qx_i / ny_i;
+         const int iy = qx_i - qy_i * ny_i; // (idx_ii / nx_i) % ny_i
+
+         const int iz = qy_i; // (idx_ii / nx_i) / ny_i
 
          const real_t (&Bi1)[MQ1][MD1] = (ic == 0) ? r_Bc : r_Bo;
          const real_t (&Bi2)[MQ1][MD1] = (ic == 1) ? r_Bc : r_Bo;
@@ -214,14 +220,18 @@ static void EAHdivAssemble3D(const int NE,
          for (int idx_j = 0; idx_j < NDOF; ++idx_j)
          {
             const int jc = idx_j / NDOF_C;
-            const int idx_jj = idx_j % NDOF_C;
+            const int idx_jj = idx_j - jc * NDOF_C; // idx_j % NDOF_C
 
             const int nx_j = (jc == 0) ? D1D : D1D-1;
             const int ny_j = (jc == 1) ? D1D : D1D-1;
 
-            const int jx = idx_jj % nx_j;
-            const int jy = (idx_jj / nx_j) % ny_j;
-            const int jz = (idx_jj / nx_j) / ny_j;
+            const int qx_j = idx_jj / nx_j;
+            const int jx = idx_jj - qx_j * nx_j; // idx_jj % nx_j
+
+            const int qy_j = qx_j / ny_j;
+            const int jy = qx_j - qy_j * ny_j; // (idx_jj / nx_j) % ny_j
+
+            const int jz = qy_j; // (idx_jj / nx_j) / ny_j
 
             const real_t (&Bj1)[MQ1][MD1] = (jc == 0) ? r_Bc : r_Bo;
             const real_t (&Bj2)[MQ1][MD1] = (jc == 1) ? r_Bc : r_Bo;

fem/integ/bilininteg_mass_kernels.hpp

@@ -1133,11 +1133,11 @@ inline void SmemPAMassApply3D(const int NE,
    const int max_d1d = T_D1D ? T_D1D : DeviceDofQuadLimits::Get().MAX_D1D;
    MFEM_VERIFY(D1D <= max_d1d, "");
    MFEM_VERIFY(Q1D <= max_q1d, "");
-   auto b = b_.Read();
-   auto d = d_.Read();
-   auto x = x_.Read();
+   const auto b = b_.Read();
+   const auto d = d_.Read();
+   const auto x = x_.Read();
    auto y = y_.ReadWrite();
-   mfem::forall_2D(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE (int e)
+   mfem::forall_2D<T_Q1D*T_Q1D>(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE (int e)
    {
       internal::SmemPAMassApply3D_Element<T_D1D,T_Q1D>(e, NE, b, d, x, y, d1d, q1d);
    });
@@ -1156,8 +1156,8 @@ inline void EAMassAssemble1D(const int NE,
    const int Q1D = T_Q1D ? T_Q1D : q1d;
    MFEM_VERIFY(D1D <= DeviceDofQuadLimits::Get().MAX_D1D, "");
    MFEM_VERIFY(Q1D <= DeviceDofQuadLimits::Get().MAX_Q1D, "");
-   auto B = Reshape(basis.Read(), Q1D, D1D);
-   auto D = Reshape(padata.Read(), Q1D, NE);
+   const auto B = Reshape(basis.Read(), Q1D, D1D);
+   const auto D = Reshape(padata.Read(), Q1D, NE);
    auto M = Reshape(add ? eadata.ReadWrite() : eadata.Write(), D1D, D1D, NE);
    mfem::forall_2D(NE, D1D, D1D, [=] MFEM_HOST_DEVICE (int e)
    {

fem/integ/bilininteg_trace_jump_ea.cpp

@@ -28,7 +28,7 @@ void NormalTraceJumpIntegrator::AssembleEAInteriorFaces(
    const FaceType ftype = FaceType::Interior;
    const int nf = mesh.GetNFbyType(ftype);
 
-   const Geometry::Type geom = mesh.GetFaceGeometry(0);
+   const Geometry::Type geom = mesh.GetTypicalFaceGeometry();
    const int trial_order = trial_fes.GetMaxElementOrder();
    const int test_order = test_fes.GetMaxElementOrder();
    const int qorder = test_order + trial_order - 1;
@@ -47,7 +47,7 @@ void NormalTraceJumpIntegrator::AssembleEAInteriorFaces(
       });
    }
 
-   const FiniteElement &trial_face_el = *trial_fes.GetFaceElement(0);
+   const FiniteElement &trial_face_el = *trial_fes.GetTypicalTraceElement();
    const auto maps = &trial_face_el.GetDofToQuad(ir, DofToQuad::TENSOR);
    const int ndof_face = trial_face_el.GetDof();
 
@@ -72,7 +72,7 @@ void NormalTraceJumpIntegrator::AssembleEAInteriorFaces(
       MFEM_ABORT("Unknown kernel.");
    }
 
-   const FiniteElement &test_el = *test_fes.GetFE(0);
+   const FiniteElement &test_el = *test_fes.GetTypicalFE();
    const int n_faces_per_el = 2*dim; // assuming tensor product
    // Get all the local face maps (mapping from lexicographic face index to
    // lexicographic volume index, depending on the local face index).
@@ -90,10 +90,10 @@ void NormalTraceJumpIntegrator::AssembleEAInteriorFaces(
    Array<int> face_info(nf * 4);
    {
       int fidx = 0;
-      for (int f = 0; f < mesh.GetNumFaces(); ++f)
+      for (int f = 0; f < mesh.GetNumFacesWithGhost(); ++f)
       {
          Mesh::FaceInformation finfo = mesh.GetFaceInformation(f);
-         if (!finfo.IsInterior()) { continue; }
+         if (!finfo.IsInterior() || finfo.IsNonconformingCoarse()) { continue; }
          face_info[0 + fidx*4] = finfo.element[0].local_face_id;
          face_info[1 + fidx*4] = finfo.element[0].orientation;
          face_info[2 + fidx*4] = finfo.element[1].local_face_id;
@@ -114,7 +114,7 @@ void NormalTraceJumpIntegrator::AssembleEAInteriorFaces(
    else
    {
       d_emat = emat.Write();
-      mfem::forall(emat.Size(), [=] MFEM_HOST_DEVICE (int i) { d_emat[i] = 0.0; });
+      emat = 0.0; // Will execute on device, since Write() sets the device flag
    }
 
    const auto face_mats = Reshape(mass_emat.Read(), ndof_face, ndof_face, nf);
@@ -133,26 +133,104 @@ void NormalTraceJumpIntegrator::AssembleEAInteriorFaces(
       }
    };
 
-   mfem::forall_3D(nf, ndof_face, ndof_face, 2, [=] MFEM_HOST_DEVICE (int f)
+   auto permute_face_2 = [=] MFEM_HOST_DEVICE(int local_face_1, int local_face_2,
+                                              int orient, int size1d, int index)
    {
-      MFEM_FOREACH_THREAD(el_i, z, 2)
+      if (dim == 2)
       {
-         const int lf_i = d_face_info(0, el_i, f);
-         const int orient = d_face_info(1, el_i, f);
-         // Loop over face indices in "native ordering"
-         MFEM_FOREACH_THREAD(i_lex, x, ndof_face)
+         return internal::PermuteFace2D(local_face_1, local_face_2, orient,
+                                        size1d, index);
+      }
+      else // dim == 3
+      {
+         return internal::PermuteFace3D(local_face_1, local_face_2, orient,
+                                        size1d, index);
+      }
+   };
+
+   if (mesh.Conforming())
+   {
+      mfem::forall_3D(nf, ndof_face, ndof_face, 2, [=] MFEM_HOST_DEVICE (int f)
+      {
+         MFEM_FOREACH_THREAD(el_i, z, 2)
          {
-            // Convert to lexicographic relative to the face itself
-            const int i_face = permute_face(lf_i, orient, d1d, i_lex);
-            // Convert from lexicographic face DOF to volume DOF
-            const int i = d_face_maps(i_lex, lf_i);
-            MFEM_FOREACH_THREAD(j, y, ndof_face)
+            const int lf_i = d_face_info(0, el_i, f);
+            const int orient = d_face_info(1, el_i, f);
+            // Loop over face indices in "native ordering"
+            MFEM_FOREACH_THREAD(i_lex, x, ndof_face)
             {
-               el_mats(i, j, el_i, f) += face_mats(i_face, j, f);
+               // Convert to lexicographic relative to the face itself
+               const int i_face = permute_face(lf_i, orient, d1d, i_lex);
+               // Convert from lexicographic face DOF to volume DOF
+               const int i = d_face_maps(i_lex, lf_i);
+               MFEM_FOREACH_THREAD(j, y, ndof_face)
+               {
+                  el_mats(i, j, el_i, f) += face_mats(i_face, j, f);
+               }
             }
          }
-      }
-   });
+      });
+   }
+   else
+   {
+      const InterpolationManager &interp =
+         test_fes.GetInterpolationManager(ElementDofOrdering::LEXICOGRAPHIC, ftype);
+
+      auto interp_configs = interp.GetFaceInterpConfig().Read();
+      const int nc_size = interp.GetNumInterpolators();
+      auto d_interp = Reshape(interp.GetInterpolators().Read(),
+                              ndof_face, ndof_face, nc_size);
+
+      mfem::forall(nf, [=] MFEM_HOST_DEVICE (int f)
+      {
+         const InterpConfig conf = interp_configs[f];
+         const int master_side = conf.master_side;
+         const int interp_index = conf.index;
+
+         const int lf_0 = d_face_info(0, 0, f);
+
+         for (int el_i = 0; el_i < 2; ++el_i)
+         {
+            const int lf_i = d_face_info(0, el_i, f);
+            const int orient = d_face_info(1, el_i, f);
+
+            for (int j = 0; j < ndof_face; j++)
+            {
+               for (int i_lex = 0; i_lex < ndof_face; i_lex++)
+               {
+                  real_t val = 0.0;
+                  if (conf.is_non_conforming && el_i == master_side)
+                  {
+                     // Interpolate from el_i (coarse element) to the fine face.
+                     // The mapping is given by d_interp, which uses indices
+                     // relative to element 0.
+
+                     // i0 is lexicographic relative to element 0
+                     const int i0 = permute_face_2(lf_i, lf_0, orient, d1d, i_lex);
+
+                     // k0 is lexicographic relative to element 0
+                     for (int k0 = 0; k0 < ndof_face; k0++)
+                     {
+                        // k is relative to the face itself
+                        const int k = permute_face(lf_0, orient, d1d, k0);
+                        val += d_interp(k0, i0, interp_index)
+                               * face_mats(k, j, f);
+                     }
+                  }
+                  else
+                  {
+                     // Convert to lexicographic relative to the face itself
+                     const int i_face = permute_face(lf_i, orient, d1d, i_lex);
+                     val = face_mats(i_face, j, f);
+                  }
+                  // Convert from lexicographic face DOF to volume DOF
+                  const int i = d_face_maps(i_lex, lf_i);
+                  el_mats(i, j, el_i, f) += val;
+               }
+            }
+         }
+      });
+   }
 }
 
 }

fem/integ/bilininteg_vecdiffusion_pa.hpp

@@ -54,7 +54,7 @@ void SmemPAVectorDiffusionApply2D(const int NE,
    const auto XE = Reshape(x.Read(), D1D, D1D, SDIM, NE);
    auto YE = Reshape(y.ReadWrite(), D1D, D1D, SDIM, NE);
 
-   mfem::forall_2D(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
+   mfem::forall_2D<T_Q1D*T_Q1D>(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
    {
       constexpr int MD1 = T_D1D > 0 ? SetMaxOf(T_D1D) : DofQuadLimits::MAX_T1D;
       constexpr int MQ1 = T_Q1D > 0 ? SetMaxOf(T_Q1D) : DofQuadLimits::MAX_T1D;
@@ -120,7 +120,7 @@ void SmemPAVectorDiffusionApply3D(const int NE,
    const auto XE = Reshape(x.Read(), D1D, D1D, D1D, SDIM, NE);
    auto YE = Reshape(y.ReadWrite(), D1D, D1D, D1D, SDIM, NE);
 
-   mfem::forall_2D(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
+   mfem::forall_2D<T_Q1D*T_Q1D>(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
    {
       constexpr int MD1 = T_D1D > 0 ? SetMaxOf(T_D1D) : DofQuadLimits::MAX_T1D;
       constexpr int MQ1 = T_Q1D > 0 ? SetMaxOf(T_Q1D) : DofQuadLimits::MAX_T1D;
@@ -171,15 +171,15 @@ template<int DIM, int T_SDIM, int T_D1D, int T_Q1D>
 VectorDiffusionIntegrator::ApplyKernelType
 VectorDiffusionIntegrator::ApplyPAKernels::Kernel()
 {
-   if (DIM == 2)
+   if constexpr (DIM == 2)
    {
       return internal::SmemPAVectorDiffusionApply2D<T_SDIM, T_D1D, T_Q1D>;
    }
-   else if (DIM == 3)
+   else if constexpr (DIM == 3)
    {
       return internal::SmemPAVectorDiffusionApply3D<T_SDIM, T_D1D, T_Q1D>;
    }
-   else { MFEM_ABORT("Unsupported kernel"); }
+   MFEM_ABORT("Unsupported kernel");
 }
 
 inline VectorDiffusionIntegrator::ApplyKernelType

fem/integ/bilininteg_vecmass_pa.hpp

@@ -51,7 +51,7 @@ void SmemPAVectorMassApply2D(const int NE,
    const auto X = Reshape(x.Read(), D1D, D1D, VDIM, NE);
    auto Y = Reshape(y.ReadWrite(), D1D, D1D, VDIM, NE);
 
-   mfem::forall_2D(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
+   mfem::forall_2D<T_Q1D*T_Q1D>(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
    {
       constexpr int MD1 = T_D1D > 0 ? SetMaxOf(T_D1D) : DofQuadLimits::MAX_T1D;
       constexpr int MQ1 = T_Q1D > 0 ? SetMaxOf(T_Q1D) : DofQuadLimits::MAX_T1D;
@@ -119,7 +119,7 @@ void SmemPAVectorMassApply3D(const int NE,
    const auto X = Reshape(x.Read(), D1D, D1D, D1D, VDIM, NE);
    auto Y = Reshape(y.ReadWrite(), D1D, D1D, D1D, VDIM, NE);
 
-   mfem::forall_2D(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
+   mfem::forall_2D<T_Q1D*T_Q1D>(NE, Q1D, Q1D, [=] MFEM_HOST_DEVICE(int e)
    {
       constexpr int MD1 = T_D1D > 0 ? SetMaxOf(T_D1D) : DofQuadLimits::MAX_T1D;
       constexpr int MQ1 = T_Q1D > 0 ? SetMaxOf(T_Q1D) : DofQuadLimits::MAX_T1D;
@@ -182,15 +182,15 @@ template<int DIM, int T_D1D, int T_Q1D>
 VectorMassIntegrator::VectorMassAddMultPAType
 VectorMassIntegrator::VectorMassAddMultPA::Kernel()
 {
-   if (DIM == 2)
+   if constexpr (DIM == 2)
    {
       return internal::SmemPAVectorMassApply2D<T_D1D,T_Q1D>;
    }
-   else if (DIM == 3)
+   else if constexpr (DIM == 3)
    {
       return internal::SmemPAVectorMassApply3D<T_D1D, T_Q1D>;
    }
-   else { MFEM_ABORT("Unsupported kernel"); }
+   MFEM_ABORT("Unsupported kernel");
 }
 
 inline VectorMassIntegrator::VectorMassAddMultPAType

fem/integ/lininteg_domain_kernels.hpp

@@ -301,18 +301,14 @@ template <int DIM, int T_D1D, int T_Q1D>
 DomainLFIntegrator::AssembleKernelType
 DomainLFIntegrator::AssembleKernels::Kernel()
 {
-   switch (DIM)
-   {
-      case 1:
-         return DLFEvalAssemble1D<T_D1D, T_Q1D>;
-      case 2:
-         return DLFEvalAssemble2D<T_D1D, T_Q1D>;
-      case 3:
-         return DLFEvalAssemble3D<T_D1D, T_Q1D>;
-   }
+   if constexpr (DIM == 1) { return DLFEvalAssemble1D<T_D1D, T_Q1D>; }
+   if constexpr (DIM == 2) { return DLFEvalAssemble2D<T_D1D, T_Q1D>; }
+   if constexpr (DIM == 3) { return DLFEvalAssemble3D<T_D1D, T_Q1D>; }
    MFEM_ABORT("");
 }
+
 /// \endcond DO_NOT_DOCUMENT
 
 } // namespace mfem
-#endif
+
+#endif // MFEM_LININTEG_DOMAIN_KERNELS_HPP

fem/intrules.hpp

@@ -43,56 +43,52 @@ public:
       index = i;
    }
 
+   void Set3w(const real_t x1, const real_t x2, const real_t x3, const real_t w)
+   { x = x1; y = x2; z = x3; weight = w; }
+   void Set2w(const real_t x1, const real_t x2, const real_t w)
+   { x = x1; y = x2; weight = w; }
+   void Set1w(const real_t x1, const real_t w)
+   { x = x1; weight = w; }
+
+   void Set3w(const real_t *p) { Set3w(p[0], p[1], p[2], p[3]); }
+   void Set2w(const real_t *p) { Set2w(p[0], p[1], p[2]); }
+   void Set1w(const real_t *p) { Set1w(p[0], p[1]); }
+
+   void Set3(const real_t x1, const real_t x2, const real_t x3)
+   { x = x1; y = x2; z = x3; }
+   void Set2(const real_t x1, const real_t x2)
+   { x = x1; y = x2; }
+   void Set1(const real_t x1)
+   { x = x1; }
+
+   void Set3(const real_t *p) { Set3(p[0], p[1], p[2]); }
+   void Set2(const real_t *p) { Set2(p[0], p[1]); }
+   void Set1(const real_t *p) { Set1(p[0]); }
+
+   void Set(const real_t x1, const real_t x2, const real_t x3, const real_t w)
+   { Set3w(x1, x2, x3, w); }
+
    void Set(const real_t *p, const int dim)
    {
       MFEM_ASSERT(1 <= dim && dim <= 3, "invalid dim: " << dim);
-      x = p[0];
-      if (dim > 1)
+      switch (dim)
       {
-         y = p[1];
-         if (dim > 2)
-         {
-            z = p[2];
-         }
+         case 3: Set3(p); break;
+         case 2: Set2(p); break;
+         case 1: Set1(p); break;
       }
    }
 
    void Get(real_t *p, const int dim) const
    {
       MFEM_ASSERT(1 <= dim && dim <= 3, "invalid dim: " << dim);
-      p[0] = x;
-      if (dim > 1)
+      switch (dim)
       {
-         p[1] = y;
-         if (dim > 2)
-         {
-            p[2] = z;
-         }
+         case 3: p[2] = z;
+         case 2: p[1] = y;
+         case 1: p[0] = x;
       }
    }
-
-   void Set(const real_t x1, const real_t x2, const real_t x3, const real_t w)
-   { x = x1; y = x2; z = x3; weight = w; }
-
-   void Set3w(const real_t *p) { x = p[0]; y = p[1]; z = p[2]; weight = p[3]; }
-
-   void Set3(const real_t x1, const real_t x2, const real_t x3)
-   { x = x1; y = x2; z = x3; }
-
-   void Set3(const real_t *p) { x = p[0]; y = p[1]; z = p[2]; }
-
-   void Set2w(const real_t x1, const real_t x2, const real_t w)
-   { x = x1; y = x2; weight = w; }
-
-   void Set2w(const real_t *p) { x = p[0]; y = p[1]; weight = p[2]; }
-
-   void Set2(const real_t x1, const real_t x2) { x = x1; y = x2; }
-
-   void Set2(const real_t *p) { x = p[0]; y = p[1]; }
-
-   void Set1w(const real_t x1, const real_t w) { x = x1; weight = w; }
-
-   void Set1w(const real_t *p) { x = p[0]; weight = p[1]; }
 };
 
 /// Class for an integration rule - an Array of IntegrationPoint.
@@ -125,18 +121,6 @@ private:
    void AddTriPoints3b(const int off, const real_t b, const real_t weight)
    { AddTriPoints3(off, (1. - b)/2., b, weight); }
 
-   void AddTriPoints3R(const int off, const real_t a, const real_t b,
-                       const real_t c, const real_t weight)
-   {
-      IntPoint(off + 0).Set2w(a, b, weight);
-      IntPoint(off + 1).Set2w(c, a, weight);
-      IntPoint(off + 2).Set2w(b, c, weight);
-   }
-
-   void AddTriPoints3R(const int off, const real_t a, const real_t b,
-                       const real_t weight)
-   { AddTriPoints3R(off, a, b, 1. - a - b, weight); }
-
    void AddTriPoints6(const int off, const real_t a, const real_t b,
                       const real_t c, const real_t weight)
    {
@@ -183,14 +167,6 @@ private:
       AddTetPoints3(off + 1, a, 1. - 3.*a, weight);
    }
 
-   // given b, add the permutations of (a,a,a,b), where 3*a + b = 1
-   void AddTetPoints4b(const int off, const real_t b, const real_t weight)
-   {
-      const real_t a = (1. - b)/3.;
-      IntPoint(off).Set(a, a, a, weight);
-      AddTetPoints3(off + 1, a, b, weight);
-   }
-
    // add the permutations of (a,a,b,b), 2*(a + b) = 1
    void AddTetPoints6(const int off, const real_t a, const real_t weight)
    {
@@ -209,14 +185,37 @@ private:
       AddTetPoints6(off + 6, a, bc, cb, weight);
    }
 
-   // given (b,c), add the permutations of (a,a,b,c), 2*a + b + c = 1
-   void AddTetPoints12bc(const int off, const real_t b, const real_t c,
-                         const real_t weight)
+   // add all 24 permutations of (a,b,c,d) where a+b+c+d = 1, all distinct
+   void AddTetPoints24(const int off, const real_t a, const real_t b,
+                       const real_t c, const real_t weight)
    {
-      const real_t a = (1. - b - c)/2.;
-      AddTetPoints3(off,     a, b, weight);
-      AddTetPoints3(off + 3, a, c, weight);
-      AddTetPoints6(off + 6, a, b, c, weight);
+      const real_t d = 1. - a - b - c;
+      // all 24 permutations of 4 distinct barycentric coordinates
+      // permuting which coordinate goes to x, y, z (4th is 1-x-y-z)
+      IntPoint(off +  0).Set(a, b, c, weight);
+      IntPoint(off +  1).Set(a, b, d, weight);
+      IntPoint(off +  2).Set(a, c, b, weight);
+      IntPoint(off +  3).Set(a, c, d, weight);
+      IntPoint(off +  4).Set(a, d, b, weight);
+      IntPoint(off +  5).Set(a, d, c, weight);
+      IntPoint(off +  6).Set(b, a, c, weight);
+      IntPoint(off +  7).Set(b, a, d, weight);
+      IntPoint(off +  8).Set(b, c, a, weight);
+      IntPoint(off +  9).Set(b, c, d, weight);
+      IntPoint(off + 10).Set(b, d, a, weight);
+      IntPoint(off + 11).Set(b, d, c, weight);
+      IntPoint(off + 12).Set(c, a, b, weight);
+      IntPoint(off + 13).Set(c, a, d, weight);
+      IntPoint(off + 14).Set(c, b, a, weight);
+      IntPoint(off + 15).Set(c, b, d, weight);
+      IntPoint(off + 16).Set(c, d, a, weight);
+      IntPoint(off + 17).Set(c, d, b, weight);
+      IntPoint(off + 18).Set(d, a, b, weight);
+      IntPoint(off + 19).Set(d, a, c, weight);
+      IntPoint(off + 20).Set(d, b, a, weight);
+      IntPoint(off + 21).Set(d, b, c, weight);
+      IntPoint(off + 22).Set(d, c, a, weight);
+      IntPoint(off + 23).Set(d, c, b, weight);
    }
 
 public:

fem/kernel_dispatch.hpp

@@ -14,6 +14,7 @@
 
 #include "../config/config.hpp"
 #include "kernel_reporter.hpp"
+#include "../general/hash_util.hpp"
 #include <unordered_map>
 #include <tuple>
 #include <type_traits>
@@ -86,35 +87,6 @@ namespace mfem
     }                                                                          \
   }
 
-/// @brief Hashes variadic packs for which each type contained in the variadic
-/// pack has a specialization of `std::hash` available.
-///
-/// For example, packs containing int, bool, enum values, etc.
-template<typename ...KernelParameters>
-struct KernelDispatchKeyHash
-{
-private:
-   template<int N>
-   size_t operator()(std::tuple<KernelParameters...> value) const { return 0; }
-
-   // The hashing formula here is taken directly from the Boost library, with
-   // the magic number 0x9e3779b9 chosen to minimize hashing collisions.
-   template<std::size_t N, typename THead, typename... TTail>
-   size_t operator()(std::tuple<KernelParameters...> value) const
-   {
-      constexpr int Index = N - sizeof...(TTail) - 1;
-      auto lhs_hash = std::hash<THead>()(std::get<Index>(value));
-      auto rhs_hash = operator()<N, TTail...>(value);
-      return lhs_hash^(rhs_hash + 0x9e3779b9 + (lhs_hash<<6) + (lhs_hash>>2));
-   }
-public:
-   /// Returns the hash of the given @a value.
-   size_t operator()(std::tuple<KernelParameters...> value) const
-   {
-      return operator()<sizeof...(KernelParameters),KernelParameters...>(value);
-   }
-};
-
 namespace internal { template<typename... Types> struct KernelTypeList { }; }
 
 template<typename... T> class KernelDispatchTable { };
@@ -128,8 +100,8 @@ class KernelDispatchTable<Kernels,
          internal::KernelTypeList<Params...>,
          internal::KernelTypeList<OptParams...>>
 {
-   using TableType = std::unordered_map<std::tuple<Params...>,
-         Signature, KernelDispatchKeyHash<Params...>>;
+   using TableType =
+      std::unordered_map<std::tuple<Params...>, Signature, TupleHasher>;
    TableType table;
 
    /// @brief Call function @a f with arguments @a args (perfect forwaring).

fem/linearform.cpp

@@ -297,7 +297,8 @@ void LinearForm::Assemble()
          tr = mesh->GetBdrFaceTransformations(i);
          if (tr != NULL)
          {
-            fes -> GetElementVDofs (tr -> Elem1No, vdofs);
+            mfem::DofTransformation doftrans;
+            fes -> GetElementVDofs (tr -> Elem1No, vdofs, doftrans);
             for (int k = 0; k < boundary_face_integs.Size(); k++)
             {
                if (boundary_face_integs_marker[k] &&
@@ -307,6 +308,7 @@ void LinearForm::Assemble()
                boundary_face_integs[k]->
                AssembleRHSElementVect(*fes->GetFE(tr->Elem1No),
                                       *tr, elemvect);
+               doftrans.TransformDual(elemvect);
                AddElementVector (vdofs, elemvect);
             }
          }

fem/lininteg.hpp

@@ -164,8 +164,8 @@ private:
 
 public:
    /// Constructs the domain integrator $ (Q, \nabla v) $
-   DomainLFGradIntegrator(VectorCoefficient &QF)
-      : DeltaLFIntegrator(QF), Q(QF) { }
+   DomainLFGradIntegrator(VectorCoefficient &QF, const IntegrationRule *ir = NULL)
+      : DeltaLFIntegrator(QF, ir), Q(QF) { }
 
    bool SupportsDevice() const override { return true; }
 

fem/lor/lor.cpp

@@ -158,15 +158,16 @@ void LORBase::ConstructLocalDofPermutation(Array<int> &perm_) const
                int i;
                i = dofmap_lor[off_lor + i1 + i2*2];
                int s1 = i < 0 ? -1 : 1;
-               int idof_lor = vdof_lor[absdof(i)];
+               int idof_lor = vdof_lor[UnsignIndex(i)];
                i = dofmap_ho[off_ho + i1*n1 + i2*n2];
                int s2 = i < 0 ? -1 : 1;
-               int idof_ho = vdof_ho[absdof(i)];
+               int idof_ho = vdof_ho[UnsignIndex(i)];
                int s3 = idof_lor < 0 ? -1 : 1;
                int s4 = idof_ho < 0 ? -1 : 1;
                int s = s1*s2*s3*s4;
-               i = absdof(idof_ho);
-               perm_[absdof(idof_lor)] = s < 0 ? -1-absdof(i) : absdof(i);
+               i = UnsignIndex(idof_ho);
+               perm_[UnsignIndex(idof_lor)] = s < 0 ? -1-UnsignIndex(i) :
+                                              UnsignIndex(i);
             }
          }
       };
@@ -232,7 +233,7 @@ void LORBase::ConstructDofPermutation() const
          int j = l_perm[i];
          int s = j < 0 ? -1 : 1;
          int t_i = pfes_lor->GetLocalTDofNumber(i);
-         int t_j = pfes_ho->GetLocalTDofNumber(absdof(j));
+         int t_j = pfes_ho->GetLocalTDofNumber(UnsignIndex(j));
          // Either t_i and t_j both -1, or both non-negative
          if ((t_i < 0 && t_j >=0) || (t_j < 0 && t_i >= 0))
          {

fem/lor/lor.hpp

@@ -57,8 +57,6 @@ private:
    /// values (after temporarily changing them for LOR assembly).
    void ResetIntegrationRules(GetIntegratorsFn get_integrators);
 
-   static inline int absdof(int i) { return i < 0 ? -1-i : i; }
-
 protected:
    enum FESpaceType { H1, ND, RT, L2, INVALID };
 

fem/pbilinearform.cpp

@@ -488,10 +488,16 @@ void ParBilinearForm::FormLinearSystem(
          R.Mult(x, true_X);
 
          FormSystemMatrix(ess_tdof_list, A);
-         ConstrainedOperator *A_constrained;
-         Operator::FormConstrainedSystemOperator(ess_tdof_list, A_constrained);
+
+         std::unique_ptr<ConstrainedOperator> A_constrained([&]()
+         {
+            Operator *op;
+            Operator::FormSystemOperator(ess_tdof_list, op);
+            return dynamic_cast<ConstrainedOperator*>(op);
+         }());
+         MFEM_ASSERT(A_constrained != nullptr, "");
+
          A_constrained->EliminateRHS(true_X, true_B);
-         delete A_constrained;
          R.MultTranspose(true_B, b);
          hybridization->ReduceRHS(true_B, B);
          X.SetSize(B.Size());

fem/pfespace.cpp

@@ -424,7 +424,7 @@ void ParFiniteElementSpace::GetGroupComm(
             {
                if (ind[l] < 0)
                {
-                  dofs[l] = m + (-1-ind[l]);
+                  dofs[l] = m + FlipIndexSign(ind[l]);
                   if (g_ldof_sign)
                   {
                      (*g_ldof_sign)[dofs[l]] = -1;
@@ -462,7 +462,7 @@ void ParFiniteElementSpace::GetGroupComm(
             {
                if (ind[l] < 0)
                {
-                  dofs[l] = m + (-1-ind[l]);
+                  dofs[l] = m + FlipIndexSign(ind[l]);
                   if (g_ldof_sign)
                   {
                      (*g_ldof_sign)[dofs[l]] = -1;
@@ -500,7 +500,7 @@ void ParFiniteElementSpace::GetGroupComm(
             {
                if (ind[l] < 0)
                {
-                  dofs[l] = m + (-1-ind[l]);
+                  dofs[l] = m + FlipIndexSign(ind[l]);
                   if (g_ldof_sign)
                   {
                      (*g_ldof_sign)[dofs[l]] = -1;
@@ -538,16 +538,16 @@ void ParFiniteElementSpace::ApplyLDofSigns(Array<int> &dofs) const
    {
       if (dofs[i] < 0)
       {
-         if (ldof_sign[-1-dofs[i]] < 0)
+         if (ldof_sign[FlipIndexSign(dofs[i])] < 0)
          {
-            dofs[i] = -1-dofs[i];
+            dofs[i] = FlipIndexSign(dofs[i]);
          }
       }
       else
       {
          if (ldof_sign[dofs[i]] < 0)
          {
-            dofs[i] = -1-dofs[i];
+            dofs[i] = FlipIndexSign(dofs[i]);
          }
       }
    }
@@ -646,39 +646,38 @@ const FaceRestriction *ParFiniteElementSpace::GetFaceRestriction(
    auto itr = L2F.find(key);
    if (itr != L2F.end())
    {
-      return itr->second;
+      return itr->second.get();
    }
    else
    {
-      FaceRestriction *res;
+      std::unique_ptr<FaceRestriction> res;
       if (is_dg_space)
       {
          if (Conforming())
          {
-            res = new ParL2FaceRestriction(*this, f_ordering, type, m);
+            res.reset(new ParL2FaceRestriction(*this, f_ordering, type, m));
          }
          else
          {
-            res = new ParNCL2FaceRestriction(*this, f_ordering, type, m);
+            res.reset(new ParNCL2FaceRestriction(*this, f_ordering, type, m));
          }
       }
       else if (dynamic_cast<const DG_Interface_FECollection*>(fec))
       {
-         res = new L2InterfaceFaceRestriction(*this, f_ordering, type);
+         res.reset(new L2InterfaceFaceRestriction(*this, f_ordering, type));
       }
       else
       {
          if (Conforming())
          {
-            res = new ConformingFaceRestriction(*this, f_ordering, type);
+            res.reset(new ConformingFaceRestriction(*this, f_ordering, type));
          }
          else
          {
-            res = new ParNCH1FaceRestriction(*this, f_ordering, type);
+            res.reset(new ParNCH1FaceRestriction(*this, f_ordering, type));
          }
       }
-      L2F[key] = res;
-      return res;
+      return L2F.emplace(key, std::move(res)).first->second.get();
    }
 }
 
@@ -700,7 +699,8 @@ void ParFiniteElementSpace::GetSharedEdgeDofs(
       for (int i = 0; i < dofs.Size(); i++)
       {
          const int di = dofs[i];
-         dofs[i] = (di >= 0) ? rdofs[di] : -1-rdofs[-1-di];
+         dofs[i] = di >= 0 ? rdofs[di] :
+                   FlipIndexSign(rdofs[FlipIndexSign(di)]);
       }
    }
 }
@@ -724,7 +724,8 @@ void ParFiniteElementSpace::GetSharedTriangleDofs(
       for (int i = 0; i < dofs.Size(); i++)
       {
          const int di = dofs[i];
-         dofs[i] = (di >= 0) ? rdofs[di] : -1-rdofs[-1-di];
+         dofs[i] = di >= 0 ? rdofs[di] :
+                   FlipIndexSign(rdofs[FlipIndexSign(di)]);
       }
    }
 }
@@ -748,7 +749,8 @@ void ParFiniteElementSpace::GetSharedQuadrilateralDofs(
       for (int i = 0; i < dofs.Size(); i++)
       {
          const int di = dofs[i];
-         dofs[i] = (di >= 0) ? rdofs[di] : -1-rdofs[-1-di];
+         dofs[i] = (di >= 0) ? rdofs[di] :
+                   FlipIndexSign(rdofs[FlipIndexSign(di)]);
       }
    }
 }
@@ -1488,7 +1490,7 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()
          GetElementVDofs(my_elems[i], ldofs);
          for (int j = 0; j < ldofs.Size(); j++)
          {
-            int ldof = (ldofs[j] >= 0 ? ldofs[j] : -1-ldofs[j]);
+            int ldof = UnsignIndex(ldofs[j]);
 
             if (ldof_marker[ldof] != fn)
             {
@@ -1549,7 +1551,7 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()
          GetElementVDofs(my_elems[i], ldofs);
          for (int j = 0; j < ldofs.Size(); j++)
          {
-            int ldof = (ldofs[j] >= 0 ? ldofs[j] : -1-ldofs[j]);
+            int ldof = UnsignIndex(ldofs[j]);
 
             if (ldof_marker[ldof] != fn)
             {
@@ -1574,14 +1576,15 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()
 
       for (int i = 0; i < num_ldofs; i++)
       {
-         int ldof = (ldofs_fn[i] >= 0 ? ldofs_fn[i] : -1-ldofs_fn[i]);
+         int ldof = UnsignIndex(ldofs_fn[i]);
          ldof_marker[ldof] = i;
       }
 
       for ( ; j < j_end; j++)
       {
-         int ldof = (send_J[j] >= 0 ? send_J[j] : -1-send_J[j]);
-         send_J[j] = (send_J[j] >= 0 ? ldof_marker[ldof] : -1-ldof_marker[ldof]);
+         const int ldof = UnsignIndex(send_J[j]);
+         send_J[j] = (send_J[j] >= 0 ? ldof_marker[ldof] :
+                      FlipIndexSign(ldof_marker[ldof]));
       }
    }
 
@@ -1673,12 +1676,7 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()
    {
       for (int j_end = face_nbr_ldof.GetI()[fn+1]; j < j_end; j++)
       {
-         int ldof = face_nbr_ldof.GetJ()[j];
-         if (ldof < 0)
-         {
-            ldof = -1-ldof;
-         }
-
+         const int ldof = UnsignIndex(face_nbr_ldof.GetJ()[j]);
          face_nbr_glob_dof_map[j] = dof_face_nbr_offsets[fn] + ldof;
       }
    }
@@ -1722,7 +1720,7 @@ void ParFiniteElementSpace::GetFaceNbrFaceVDofs(int i, Array<int> &vdofs) const
    MFEM_ASSERT(Nonconforming() && i >= pmesh->GetNumFaces(), "");
    int el1, el2, inf1, inf2;
    pmesh->GetFaceElements(i, &el1, &el2);
-   el2 = -1 - el2;
+   el2 = FlipIndexSign(el2);
    pmesh->GetFaceInfos(i, &inf1, &inf2);
    MFEM_ASSERT(0 <= el2 && el2 < face_nbr_element_dof.Size(), "");
    const int nd = face_nbr_element_dof.RowSize(el2);
@@ -1738,7 +1736,8 @@ void ParFiniteElementSpace::GetFaceNbrFaceVDofs(int i, Array<int> &vdofs) const
    for (int j = 0; j < vdofs.Size(); j++)
    {
       const int ldof = vdofs[j];
-      vdofs[j] = (ldof >= 0) ? vol_vdofs[ldof] : -1-vol_vdofs[-1-ldof];
+      vdofs[j] = (ldof >= 0) ? vol_vdofs[ldof] :
+                 FlipIndexSign(vol_vdofs[FlipIndexSign(ldof)]);
    }
 }
 
@@ -2062,8 +2061,8 @@ void ParFiniteElementSpace::GetGhostFaceDofs(const MeshId &face_id,
 
          for (int j = 0; j < ne; j++)
          {
-            dofs[offset++] = (ind[j] >= 0) ? (first + ind[j])
-                             /*         */ : (-1 - (first + (-1 - ind[j])));
+            dofs[offset++] = (ind[j] >= 0) ? (first + ind[j]) :
+                             FlipIndexSign(first + FlipIndexSign(ind[j]));
          }
       }
       else
@@ -2073,8 +2072,8 @@ void ParFiniteElementSpace::GetGhostFaceDofs(const MeshId &face_id,
          const int *ind = fec->DofOrderForOrientation(Geometry::SEGMENT, Eo[i]);
          for (int j = 0; j < ne; j++)
          {
-            dofs[offset++] = (ind[j] >= 0) ? (first + ind[j])
-                             /*         */ : (-1 - (first + (-1 - ind[j])));
+            dofs[offset++] = (ind[j] >= 0) ? (first + ind[j]) :
+                             FlipIndexSign(first + FlipIndexSign(ind[j]));
          }
       }
    }
@@ -2867,7 +2866,7 @@ void NeighborRowMessage::Encode(int rank)
 
             if (ind && (edof = ind[edof]) < 0)
             {
-               edof = -1 - edof;
+               edof = FlipIndexSign(edof);
                s = -1;
             }
 
@@ -3068,10 +3067,10 @@ void NeighborRowMessage::Decode(int rank)
 
          // If edof arrived with a negative index, flip it, and the scaling.
          real_t s = (edof < 0) ? -1.0 : 1.0;
-         edof = (edof < 0) ? -1 - edof : edof;
+         edof = UnsignIndex(edof);
          if (ind && (edof = ind[edof]) < 0)
          {
-            edof = -1 - edof;
+            edof = FlipIndexSign(edof);
             s *= -1.0;
          }
 
@@ -3122,10 +3121,10 @@ void NeighborRowMessage::Decode(int rank)
 
             // If edof arrived with a negative index, flip it, and the scaling.
             s = (edof < 0) ? -1.0 : 1.0;
-            edof = (edof < 0) ? -1 - edof : edof;
+            edof = UnsignIndex(edof);
             if (ind && (edof = ind[edof]) < 0)
             {
-               edof = -1 - edof;
+               edof = FlipIndexSign(edof);
                s *= -1.0;
             }
 
@@ -4406,12 +4405,9 @@ ParFiniteElementSpace::RebalanceMatrix(int old_ndofs,
          {
             for (int j = 0; j < dofs.Size(); j++)
             {
-               int row = DofToVDof(dofs[j], vd);
-               if (row < 0) { row = -1 - row; }
-
-               int col = DofToVDof(old_dofs[j], vd, old_ndofs);
-               if (col < 0) { col = -1 - col; }
-
+               const int row = UnsignIndex(DofToVDof(dofs[j], vd));
+               const int col = UnsignIndex(DofToVDof(old_dofs[j], vd,
+                                                     old_ndofs));
                i_diag[row] = col;
             }
          }
@@ -4436,9 +4432,7 @@ ParFiniteElementSpace::RebalanceMatrix(int old_ndofs,
       {
          for (int j = 0; j < dofs.Size(); j++)
          {
-            int row = DofToVDof(dofs[j], vd);
-            if (row < 0) { row = -1 - row; }
-
+            const int row = UnsignIndex(DofToVDof(dofs[j], vd));
             if (i_diag[row] == i_diag[row+1]) // diag row empty?
             {
                i_offd[row] = old_dofs[j + vd * dofs.Size()];
@@ -4547,9 +4541,9 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
    {
       const Embedding &emb = dtrans.embeddings[k];
 
-      int fine_rank = old_ranks[k];
-      int coarse_rank = (emb.parent < 0) ? (-1 - emb.parent)
-                        : old_pncmesh->ElementRank(emb.parent);
+      const int fine_rank = old_ranks[k];
+      const int coarse_rank = (emb.parent < 0) ? FlipIndexSign(emb.parent)
+                              : old_pncmesh->ElementRank(emb.parent);
 
       if (coarse_rank != MyRank && fine_rank == MyRank)
       {
@@ -4637,8 +4631,8 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
             {
                if (!std::isfinite(lR(i, 0))) { continue; }
 
-               int r = DofToVDof(dofs[i], vd);
-               int m = (r >= 0) ? r : (-1 - r);
+               const int r = DofToVDof(dofs[i], vd);
+               const int m = UnsignIndex(r);
 
                if (is_dg || !mark[m])
                {
@@ -4687,8 +4681,7 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
             {
                if (!std::isfinite(lR(i, 0))) { continue; }
 
-               int r = DofToVDof(dofs[i], vd);
-               int m = (r >= 0) ? r : (-1 - r);
+               const int m = UnsignIndex(DofToVDof(dofs[i], vd));
 
                if (is_dg || !mark[m])
                {

fem/pfespace.hpp

@@ -483,6 +483,8 @@ public:
    const FiniteElement *GetFaceNbrFaceFE(int i) const;
    const Array<HYPRE_BigInt> &GetFaceNbrGlobalDofMapArray() { return face_nbr_glob_dof_map; }
    const HYPRE_BigInt *GetFaceNbrGlobalDofMap() { return face_nbr_glob_dof_map; }
+   const Array<HYPRE_BigInt> &GetFaceNbrGlobalDofMapArray() const
+   { return face_nbr_glob_dof_map; }
    ElementTransformation *GetFaceNbrElementTransformation(int i) const
    { return pmesh->GetFaceNbrElementTransformation(i); }
 

fem/pgridfunc.cpp

@@ -545,6 +545,8 @@ void ParGridFunction::GetElementDofValues(int el, Vector &dof_vals) const
 
 void ParGridFunction::ProjectCoefficient(Coefficient &coeff, ProjectType type)
 {
+   MFEM_VERIFY(VectorDim() == 1,
+               "Cannot project scalar coefficient onto vector ParGridFunction");
    DeltaCoefficient *delta_c = dynamic_cast<DeltaCoefficient *>(&coeff);
 
    if (delta_c == NULL)
@@ -715,7 +717,8 @@ void ParGridFunction::ProjectCoefficientElementL2(VectorCoefficient &vcoeff)
 }
 
 
-void ParGridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff)
+void ParGridFunction::ProjectDiscCoefficient(
+   std::variant<Coefficient*, VectorCoefficient*> coeff)
 {
    // local maximal element attribute for each dof
    Array<int> ldof_attr;
@@ -761,6 +764,9 @@ void ParGridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff)
 
 void ParGridFunction::ProjectDiscCoefficient(Coefficient &coeff, AvgType type)
 {
+   MFEM_VERIFY(
+      VectorDim() == 1,
+      "Cannot project scalar coefficient onto a vector ParGridFunction");
    // Harmonic  (x1 ... xn) = [ (1/x1 + ... + 1/xn) / n ]^-1.
    // Arithmetic(x1 ... xn) = (x1 + ... + xn) / n.
 
@@ -786,6 +792,8 @@ void ParGridFunction::ProjectDiscCoefficient(VectorCoefficient &vcoeff,
    // Harmonic  (x1 ... xn) = [ (1/x1 + ... + 1/xn) / n ]^-1.
    // Arithmetic(x1 ... xn) = (x1 + ... + xn) / n.
 
+   MFEM_VERIFY(VectorDim() == vcoeff.GetVDim(), "vcoeff vdim != VectorDim()");
+
    // Number of zones that contain a given dof.
    Array<int> zones_per_vdof;
    AccumulateAndCountZones(vcoeff, type, zones_per_vdof);
@@ -858,6 +866,12 @@ void ParGridFunction::ProjectBdrCoefficient(
 #endif
 }
 
+void ParGridFunction::ProjectBdrCoefficient(VectorCoefficient &vcoeff,
+                                            const Array<int> &attr)
+{
+   ProjectBdrCoefficient(NULL, &vcoeff, attr);
+}
+
 void ParGridFunction::ProjectBdrCoefficientTangent(VectorCoefficient &vcoeff,
                                                    const Array<int> &bdr_attr)
 {
@@ -1568,6 +1582,39 @@ PLBound ParGridFunction::GetBounds(Vector &lower, Vector &upper,
    return plb;
 }
 
+std::pair<real_t, real_t> ParGridFunction::EstimateFunctionMinimum(
+   const int vdim, const PLBound &plb, const int max_depth,
+   const real_t tol) const
+{
+   std::pair<real_t, real_t> minmax =
+      GridFunction::EstimateFunctionMinimum(vdim, plb, max_depth, tol);
+
+   real_t glob_min_lower = minmax.first;
+   real_t glob_min_upper = minmax.second;
+   MPI_Allreduce(MPI_IN_PLACE, &glob_min_lower, 1,
+                 MFEM_MPI_REAL_T, MPI_MIN, pfes->GetComm());
+   MPI_Allreduce(MPI_IN_PLACE, &glob_min_upper, 1,
+                 MFEM_MPI_REAL_T, MPI_MIN, pfes->GetComm());
+
+   return std::make_pair(glob_min_lower, glob_min_upper);
+}
+
+std::pair<real_t, real_t> ParGridFunction::EstimateFunctionMaximum(
+   const int vdim, const PLBound &plb, const int max_depth,
+   const real_t tol) const
+{
+   std::pair<real_t, real_t> minmax =
+      GridFunction::EstimateFunctionMaximum(vdim, plb, max_depth, tol);
+
+   real_t glob_max_lower = minmax.first;
+   real_t glob_max_upper = minmax.second;
+   MPI_Allreduce(MPI_IN_PLACE, &glob_max_lower, 1,
+                 MFEM_MPI_REAL_T, MPI_MAX, pfes->GetComm());
+   MPI_Allreduce(MPI_IN_PLACE, &glob_max_upper, 1,
+                 MFEM_MPI_REAL_T, MPI_MAX, pfes->GetComm());
+   return std::make_pair(glob_max_lower, glob_max_upper);
+}
+
 } // namespace mfem
 
 #endif // MFEM_USE_MPI

fem/pgridfunc.hpp

@@ -63,6 +63,12 @@ protected:
    void ProjectBdrCoefficient(Coefficient *coeff[], VectorCoefficient *vcoeff,
                               const Array<int> &attr);
 
+   /** @brief Project a discontinuous (vector) coefficient as a grid function on
+       a continuous finite element space. The values in shared dofs are
+       determined from the element with maximal attribute. */
+   virtual void ProjectDiscCoefficient(
+      std::variant<Coefficient*, VectorCoefficient*> coeff) override;
+
 public:
    ParGridFunction() { pfes = NULL; }
 
@@ -268,11 +274,6 @@ public:
                            ProjectType type = ProjectType::DEFAULT) override;
 
    using GridFunction::ProjectDiscCoefficient;
-   /** @brief Project a discontinuous vector coefficient as a grid function on
-       a continuous finite element space. The values in shared dofs are
-       determined from the element with maximal attribute. */
-   void ProjectDiscCoefficient(VectorCoefficient &coeff) override;
-
    void ProjectDiscCoefficient(Coefficient &coeff, AvgType type) override;
 
    void ProjectDiscCoefficient(VectorCoefficient &vcoeff, AvgType type) override;
@@ -280,8 +281,7 @@ public:
    using GridFunction::ProjectBdrCoefficient;
 
    void ProjectBdrCoefficient(VectorCoefficient &vcoeff,
-                              const Array<int> &attr) override
-   { ProjectBdrCoefficient(NULL, &vcoeff, attr); }
+                              const Array<int> &attr) override;
 
    void ProjectBdrCoefficient(Coefficient *coeff[],
                               const Array<int> &attr) override
@@ -609,6 +609,18 @@ public:
    PLBound GetBounds(Vector &lower, Vector &upper,
                      const int ref_factor=1, const int vdim=-1) const override;
 
+   /** @brief Estimate the GridFunction minimum across all elements. */
+   std::pair<real_t, real_t> EstimateFunctionMinimum(const int vdim,
+                                                     const PLBound &plb,
+                                                     const int max_depth,
+                                                     const real_t tol) const override;
+
+   /** @brief Estimate the GridFunction maximum across all elements. */
+   std::pair<real_t, real_t> EstimateFunctionMaximum(const int vdim,
+                                                     const PLBound &plb,
+                                                     const int max_depth,
+                                                     const real_t tol) const override;
+
    /** Save the local portion of the ParGridFunction. This differs from the
        serial GridFunction::Save in that it takes into account the signs of
        the local dofs. */

fem/prestriction.cpp

@@ -321,12 +321,17 @@ void ParL2FaceRestriction::DoubleValuedConformingMult(
    const int vd = vdim;
    const bool t = byvdim;
    const int threshold = ndofs;
-   const int nsdofs = pfes.GetFaceNbrVSize();
+   const int nsdofs = pfes.GetFaceNbrVSize() / vd;
    auto d_indices1 = scatter_indices1.Read();
    auto d_indices2 = scatter_indices2.Read();
    auto d_x = Reshape(x.Read(), t?vd:ndofs, t?ndofs:vd);
-   auto d_x_shared = Reshape(face_nbr_data.Read(),
-                             t?vd:nsdofs, t?nsdofs:vd);
+   const int ne_shared = nsdofs / elem_dofs;
+   const int nedof = elem_dofs;
+   // Note: the shape of face_nbr_data, as determined by
+   // ParFiniteElementSpace::ExchangeFaceNbrData, is (elem_dofs, vdim,
+   // ne_shared), independent of the ordering (byNODES or byVDIM) of the finite
+   // element space.
+   auto d_x_shared = Reshape(face_nbr_data.Read(), elem_dofs, vd, ne_shared);
    auto d_y = Reshape(y.Write(), nface_dofs, vd, 2, nf);
    mfem::forall(nfdofs, [=] MFEM_HOST_DEVICE (int i)
    {
@@ -346,8 +351,9 @@ void ParL2FaceRestriction::DoubleValuedConformingMult(
          }
          else if (idx2>=threshold) // shared boundary
          {
-            d_y(dof, c, 1, face) = d_x_shared(t?c:(idx2-threshold),
-                                              t?(idx2-threshold):c);
+            const int e_shared = (idx2 - threshold) / nedof;
+            const int i_shared = (idx2 - threshold) % nedof;
+            d_y(dof, c, 1, face) = d_x_shared(i_shared,c,e_shared);
          }
          else // true boundary
          {
@@ -994,7 +1000,6 @@ void ParNCL2FaceRestriction::ComputeScatterIndicesAndOffsets()
       {
          if ( face.IsConforming() )
          {
-            interpolations.RegisterFaceConformingInterpolation(face,f_ind);
             SetFaceDofsScatterIndices1(face,f_ind);
             if ( m==L2FaceValues::DoubleValued )
             {
@@ -1010,7 +1015,6 @@ void ParNCL2FaceRestriction::ComputeScatterIndicesAndOffsets()
          }
          else // Non-conforming face
          {
-            interpolations.RegisterFaceCoarseToFineInterpolation(face,f_ind);
             SetFaceDofsScatterIndices1(face,f_ind);
             if ( m==L2FaceValues::DoubleValued )
             {
@@ -1028,7 +1032,6 @@ void ParNCL2FaceRestriction::ComputeScatterIndicesAndOffsets()
       }
       else if (type==FaceType::Boundary && face.IsBoundary())
       {
-         interpolations.RegisterFaceConformingInterpolation(face,f_ind);
          SetFaceDofsScatterIndices1(face,f_ind);
          if ( m==L2FaceValues::DoubleValued )
          {
@@ -1046,10 +1049,6 @@ void ParNCL2FaceRestriction::ComputeScatterIndicesAndOffsets()
    {
       gather_offsets[i] += gather_offsets[i - 1];
    }
-
-   // Transform the interpolation matrix map into a contiguous memory structure.
-   interpolations.LinearizeInterpolatorMapIntoVector();
-   interpolations.InitializeNCInterpConfig();
 }
 
 void ParNCL2FaceRestriction::ComputeGatherIndices()

fem/prestriction.hpp

@@ -326,9 +326,7 @@ public:
        @param[in] keep_nbr_block When set to true the SparseMatrix will
                                  include the rows (in addition to the columns)
                                  corresponding to face-neighbor dofs. The
-                                 default behavior is to disregard those rows.
-
-       @warning This method is not implemented yet. */
+                                 default behavior is to disregard those rows. */
    void FillI(SparseMatrix &mat,
               const bool keep_nbr_block = false) const override;
 
@@ -364,9 +362,7 @@ public:
        @param[in] keep_nbr_block When set to true the SparseMatrix will
                                  include the rows (in addition to the columns)
                                  corresponding to face-neighbor dofs. The
-                                 default behavior is to disregard those rows.
-
-       @warning This method is not implemented yet. */
+                                 default behavior is to disregard those rows. */
    void FillJAndData(const Vector &fea_data,
                      SparseMatrix &mat,
                      const bool keep_nbr_block = false) const override;

fem/qfunction.hpp

@@ -271,10 +271,7 @@ inline void QuadratureFunction::GetValues(
    const int s_offset = qspace->Offset(idx);
    const int sl_size = qspace->Offset(idx + 1) - s_offset;
    // Make the values matrix memory an alias of the quadrature function memory
-   Memory<real_t> &values_mem = values.GetMemory();
-   values_mem.Delete();
-   values_mem.MakeAlias(GetMemory(), vdim*s_offset, vdim*sl_size);
-   values.SetSize(vdim, sl_size);
+   values.MakeRef(GetMemory(), vdim*s_offset, vdim, sl_size);
 }
 
 inline void QuadratureFunction::GetValues(

fem/qinterp/det.cpp

@@ -50,7 +50,13 @@ QuadratureInterpolator::DetKernelType
 QuadratureInterpolator::DetKernels::Fallback(
    int DIM, int SDIM, int D1D, int Q1D)
 {
-   if (DIM == 1) { return internal::quadrature_interpolator::Det1D; }
+   if (DIM == 1)
+   {
+      if (SDIM == 1) { return internal::quadrature_interpolator::Det1D; }
+      else if (SDIM == 2) { return internal::quadrature_interpolator::Det1DSurface<0,0,2>; }
+      else if (SDIM == 3) { return internal::quadrature_interpolator::Det1DSurface<0,0,3>; }
+      else { MFEM_ABORT(""); }
+   }
    else if (DIM == 2 && SDIM == 2) { return internal::quadrature_interpolator::Det2D; }
    else if (DIM == 2 && SDIM == 3) { return internal::quadrature_interpolator::Det2DSurface; }
    else if (DIM == 3)

fem/qinterp/det.hpp

@@ -56,6 +56,50 @@ inline void Det1D(const int NE,
    });
 }
 
+template<int T_D1D = 0, int T_Q1D = 0, int T_SDIM = 3>
+inline void Det1DSurface(const int NE,
+                         const real_t *b,
+                         const real_t *g,
+                         const real_t *x,
+                         real_t *y,
+                         const int d1d = 0,
+                         const int q1d = 0,
+                         Vector *d_buff = nullptr)
+{
+   MFEM_CONTRACT_VAR(b);
+   MFEM_CONTRACT_VAR(d_buff);
+
+   const int D1D = T_D1D ? T_D1D : d1d;
+   const int Q1D = T_Q1D ? T_Q1D : q1d;
+
+   const auto G = Reshape(g, Q1D, D1D);
+   const auto X = Reshape(x, D1D, T_SDIM, NE);
+   auto Y = Reshape(y, Q1D, NE);
+
+   mfem::forall(NE, [=] MFEM_HOST_DEVICE (int e)
+   {
+      for (int q = 0; q < Q1D; q++)
+      {
+         real_t grad[T_SDIM];
+         for (int s = 0; s < T_SDIM; s++) { grad[s] = 0.0; }
+         for (int d = 0; d < D1D; d++)
+         {
+            const real_t gval = G(q, d);
+            for (int s = 0; s < T_SDIM; s++)
+            {
+               grad[s] += gval * X(d, s, e);
+            }
+         }
+         real_t norm2 = 0.0;
+         for (int s = 0; s < T_SDIM; s++)
+         {
+            norm2 += grad[s] * grad[s];
+         }
+         Y(q, e) = std::sqrt(norm2);
+      }
+   });
+}
+
 template<int T_D1D = 0, int T_Q1D = 0>
 inline void Det2D(const int NE,
                   const real_t *b,
@@ -290,11 +334,16 @@ template<int DIM, int SDIM, int D1D, int Q1D>
 QuadratureInterpolator::DetKernelType
 QuadratureInterpolator::DetKernels::Kernel()
 {
-   if (DIM == 1) { return internal::quadrature_interpolator::Det1D; }
-   else if (DIM == 2 && SDIM == 2) { return internal::quadrature_interpolator::Det2D<D1D, Q1D>; }
-   else if (DIM == 2 && SDIM == 3) { return internal::quadrature_interpolator::Det2DSurface<D1D, Q1D>; }
-   else if (DIM == 3) { return internal::quadrature_interpolator::Det3D<D1D, Q1D>; }
-   else { MFEM_ABORT(""); }
+   if constexpr (DIM == 1)
+   {
+      if constexpr (SDIM == 1) { return internal::quadrature_interpolator::Det1D; }
+      else if constexpr (SDIM == 2) { return internal::quadrature_interpolator::Det1DSurface<D1D, Q1D, 2>; }
+      else if constexpr (SDIM == 3) { return internal::quadrature_interpolator::Det1DSurface<D1D, Q1D, 3>; }
+   }
+   else if constexpr (DIM == 2 && SDIM == 2) { return internal::quadrature_interpolator::Det2D<D1D, Q1D>; }
+   else if constexpr (DIM == 2 && SDIM == 3) { return internal::quadrature_interpolator::Det2DSurface<D1D, Q1D>; }
+   else if constexpr (DIM == 3) { return internal::quadrature_interpolator::Det3D<D1D, Q1D>; }
+   MFEM_ABORT("");
 }
 
 /// @endcond

fem/qinterp/eval.hpp

@@ -203,10 +203,10 @@ template<int DIM, QVectorLayout Q_LAYOUT,
 QuadratureInterpolator::TensorEvalKernelType
 QuadratureInterpolator::TensorEvalKernels::Kernel()
 {
-   if (DIM == 1) { return internal::quadrature_interpolator::Values1D<Q_LAYOUT>; }
-   else if (DIM == 2) { return internal::quadrature_interpolator::Values2D<Q_LAYOUT, VDIM, D1D, Q1D, NBZ>; }
-   else if (DIM == 3) { return internal::quadrature_interpolator::Values3D<Q_LAYOUT, VDIM, D1D, Q1D>; }
-   else { MFEM_ABORT(""); }
+   if constexpr (DIM == 1) { return internal::quadrature_interpolator::Values1D<Q_LAYOUT>; }
+   else if constexpr (DIM == 2) { return internal::quadrature_interpolator::Values2D<Q_LAYOUT, VDIM, D1D, Q1D, NBZ>; }
+   else if constexpr (DIM == 3) { return internal::quadrature_interpolator::Values3D<Q_LAYOUT, VDIM, D1D, Q1D>; }
+   MFEM_ABORT("");
 }
 
 /// @endcond

fem/qinterp/eval_hdiv.hpp

@@ -453,8 +453,15 @@ QuadratureInterpolator::TensorEvalHDivKernels::Kernel()
 {
    using namespace internal::quadrature_interpolator;
    static_assert(DIM == 2 || DIM == 3, "only DIM=2 and DIM=3 are implemented!");
-   if (DIM == 2) { return EvalHDiv2D<Q_LAYOUT, FLAGS, D1D, Q1D>; }
-   return EvalHDiv3D<Q_LAYOUT, FLAGS, D1D, Q1D>;
+   if constexpr (DIM == 2)
+   {
+      return EvalHDiv2D<Q_LAYOUT, FLAGS, D1D, Q1D>;
+   }
+   else if constexpr (DIM == 3)
+   {
+      return EvalHDiv3D<Q_LAYOUT, FLAGS, D1D, Q1D>;
+   }
+   MFEM_ABORT("only DIM=2 and DIM=3 are implemented!");
 }
 
 /// @endcond

fem/qinterp/grad.hpp

@@ -592,10 +592,10 @@ template<int DIM, QVectorLayout Q_LAYOUT, bool GRAD_PHYS, int VDIM, int D1D,
 QuadratureInterpolator::GradKernelType
 QuadratureInterpolator::GradKernels::Kernel()
 {
-   if (DIM == 1) { return internal::quadrature_interpolator::Derivatives1D<Q_LAYOUT, GRAD_PHYS>; }
-   else if (DIM == 2) { return internal::quadrature_interpolator::Derivatives2D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D, Q1D, NBZ>; }
-   else if (DIM == 3) { return internal::quadrature_interpolator::Derivatives3D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D, Q1D>; }
-   else { MFEM_ABORT(""); }
+   if constexpr (DIM == 1) { return internal::quadrature_interpolator::Derivatives1D<Q_LAYOUT, GRAD_PHYS>; }
+   else if constexpr (DIM == 2) { return internal::quadrature_interpolator::Derivatives2D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D, Q1D, NBZ>; }
+   else if constexpr (DIM == 3) { return internal::quadrature_interpolator::Derivatives3D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D, Q1D>; }
+   MFEM_ABORT("");
 }
 
 template<int DIM, QVectorLayout Q_LAYOUT, bool GRAD_PHYS, int VDIM, int D1D,
@@ -603,10 +603,10 @@ template<int DIM, QVectorLayout Q_LAYOUT, bool GRAD_PHYS, int VDIM, int D1D,
 QuadratureInterpolator::CollocatedGradKernelType
 QuadratureInterpolator::CollocatedGradKernels::Kernel()
 {
-   if (DIM == 1) { return internal::quadrature_interpolator::CollocatedDerivatives1D<Q_LAYOUT, GRAD_PHYS>; }
-   else if (DIM == 2) { return internal::quadrature_interpolator::CollocatedDerivatives2D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D, NBZ>; }
-   else if (DIM == 3) { return internal::quadrature_interpolator::CollocatedDerivatives3D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D>; }
-   else { MFEM_ABORT(""); }
+   if constexpr (DIM == 1) { return internal::quadrature_interpolator::CollocatedDerivatives1D<Q_LAYOUT, GRAD_PHYS>; }
+   else if constexpr (DIM == 2) { return internal::quadrature_interpolator::CollocatedDerivatives2D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D, NBZ>; }
+   else if constexpr (DIM == 3) { return internal::quadrature_interpolator::CollocatedDerivatives3D<Q_LAYOUT, GRAD_PHYS, VDIM, D1D>; }
+   MFEM_ABORT("");
 }
 
 /// @endcond

fem/quadinterpolator.cpp

@@ -542,7 +542,8 @@ void QuadratureInterpolator::Mult(const Vector &e_vec,
    }
 
    MFEM_ASSERT(!(eval_flags & DETERMINANTS) || dim == vdim ||
-               (dim == 2 && vdim == 3), "Invalid dimensions for determinants.");
+               (dim == 2 && vdim == 3) || (dim == 1 && vdim == 2) ||
+               (dim == 1 && vdim == 3), "Invalid dimensions for determinants.");
    MFEM_ASSERT(fespace->GetMesh()->GetNumGeometries(
                   fespace->GetMesh()->Dimension()) == 1,
                "mixed meshes are not supported");
@@ -751,10 +752,10 @@ template <int DIM, int VDIM, int ND, int NQ>
 EvalKernel QuadratureInterpolator::EvalKernels::Kernel()
 {
    using namespace internal::quadrature_interpolator;
-   if (DIM == 1) { return Eval1D; }
-   else if (DIM == 2) { return Eval2D<VDIM,ND,NQ>; }
-   else if (DIM == 3) { return Eval3D<VDIM,ND,NQ>; }
-   else { MFEM_ABORT(""); }
+   if constexpr (DIM == 1) { return Eval1D; }
+   else if constexpr (DIM == 2) { return Eval2D<VDIM,ND,NQ>; }
+   else if constexpr (DIM == 3) { return Eval3D<VDIM,ND,NQ>; }
+   MFEM_ABORT("");
 }
 
 template <int DIM>

fem/restriction.cpp

@@ -844,8 +844,6 @@ void ConformingFaceRestriction::ComputeGatherIndices(
    gather_offsets[0] = 0;
 }
 
-static inline int absdof(int i) { return i < 0 ? -1-i : i; }
-
 void ConformingFaceRestriction::SetFaceDofsScatterIndices(
    const Mesh::FaceInformation &face,
    const int face_index,
@@ -868,9 +866,9 @@ void ConformingFaceRestriction::SetFaceDofsScatterIndices(
    {
       const int lex_volume_dof = face_map[face_dof];
       const int s_volume_dof = AsConst(vol_dof_map)[lex_volume_dof]; // signed
-      const int volume_dof = absdof(s_volume_dof);
+      const int volume_dof = UnsignIndex(s_volume_dof);
       const int s_global_dof = elem_map[elem_index*elem_dofs + volume_dof];
-      const int global_dof = absdof(s_global_dof);
+      const int global_dof = UnsignIndex(s_global_dof);
       const int restriction_dof = face_dofs*face_index + face_dof;
       scatter_indices[restriction_dof] = s_global_dof;
       ++gather_offsets[global_dof + 1];
@@ -897,10 +895,10 @@ void ConformingFaceRestriction::SetFaceDofsGatherIndices(
    {
       const int lex_volume_dof = face_map[face_dof];
       const int s_volume_dof = AsConst(vol_dof_map)[lex_volume_dof];
-      const int volume_dof = absdof(s_volume_dof);
+      const int volume_dof = UnsignIndex(s_volume_dof);
       const int s_global_dof = elem_map[elem_index*elem_dofs + volume_dof];
       const int sgn = (s_global_dof >= 0) ? 1 : -1;
-      const int global_dof = absdof(s_global_dof);
+      const int global_dof = UnsignIndex(s_global_dof);
       const int restriction_dof = face_dofs*face_index + face_dof;
       const int s_restriction_dof = (sgn >= 0) ? restriction_dof : -1 -
                                     restriction_dof;
@@ -1400,20 +1398,17 @@ void L2FaceRestriction::PermuteAndSetSharedFaceDofsScatterIndices2(
    const int dim = fes.GetMesh()->Dimension();
    const int dof1d = fes.GetTypicalFE()->GetOrder()+1;
    fes.GetTypicalFE()->GetFaceMap(face_id2, face_map);
-   Array<int> face_nbr_dofs;
-   const ParFiniteElementSpace &pfes =
-      static_cast<const ParFiniteElementSpace&>(this->fes);
-   pfes.GetFaceNbrElementVDofs(elem_index, face_nbr_dofs);
 
    for (int face_dof_elem1 = 0; face_dof_elem1 < face_dofs; ++face_dof_elem1)
    {
       const int face_dof_elem2 = PermuteFaceL2(dim, face_id1, face_id2,
                                                orientation, dof1d, face_dof_elem1);
       const int volume_dof_elem2 = face_map[face_dof_elem2];
-      const int global_dof_elem2 = face_nbr_dofs[volume_dof_elem2];
+      // Encode the volume DOF index and element index
+      const int global_dof_elem2 = elem_index*elem_dofs + volume_dof_elem2;
       const int restriction_dof_elem2 = face_dofs*face_index + face_dof_elem1;
       // Trick to differentiate dof location inter/shared
-      scatter_indices2[restriction_dof_elem2] = ndofs+global_dof_elem2;
+      scatter_indices2[restriction_dof_elem2] = ndofs + global_dof_elem2;
    }
 #endif
 }
@@ -1506,12 +1501,12 @@ void L2FaceRestriction::EnsureNormalDerivativeRestriction() const
    }
 }
 
-InterpolationManager::InterpolationManager(const FiniteElementSpace &fes,
-                                           ElementDofOrdering ordering,
+InterpolationManager::InterpolationManager(const FiniteElementSpace &fes_,
+                                           ElementDofOrdering ordering_,
                                            FaceType type)
-   : fes(fes),
-     ordering(ordering),
-     interp_config( fes.GetNFbyType(type) ),
+   : fes(fes_),
+     ordering(ordering_),
+     interp_config(fes.GetNFbyType(type)),
      nc_cpt(0)
 { }
 
@@ -1536,7 +1531,8 @@ void InterpolationManager::RegisterFaceCoarseToFineInterpolation(
                         face.element[0].local_face_id +
                         6*face.element[1].local_face_id +
                         36*face.element[1].orientation ;
-   // Unfortunately we can't trust unicity of the ptMat to identify the transformation.
+   // Unfortunately we can't trust uniqueness of the ptMat to identify the
+   // transformation.
    Key key(ptMat, face_key);
    auto itr = interp_map.find(key);
    if ( itr == interp_map.end() )
@@ -1583,17 +1579,27 @@ const DenseMatrix* InterpolationManager::GetCoarseToFineInterpolation(
    IsoparametricTransformation isotr;
    isotr.SetIdentityTransformation(trace_fe->GetGeomType());
    isotr.SetPointMat(*ptMat);
-   DenseMatrix& trans_pt_mat = isotr.GetPointMat();
-   // PointMatrix needs to be flipped in 2D
-   if ( trace_fe->GetGeomType()==Geometry::SEGMENT && !is_ghost_slave )
-   {
-      std::swap(trans_pt_mat(0,0),trans_pt_mat(0,1));
-   }
    DenseMatrix native_interpolator(face_dofs,face_dofs);
    trace_fe->GetLocalInterpolation(isotr, native_interpolator);
+
+   if (trace_fe->GetMapType() == FiniteElement::INTEGRAL)
+   {
+      // Handle potentially inverted Jacobian matrix
+      isotr.SetIntPoint(&Geometries.GetCenter(trace_fe->GetGeomType()));
+      native_interpolator *= (isotr.Weight() >= 0) ? 1.0 : -1.0;
+   }
+
    const int dim = trace_fe->GetDim()+1;
    const int dof1d = trace_fe->GetOrder()+1;
-   const int orientation = face.element[1].orientation;
+   int orientation_i = face.element[1].orientation;
+   const int orientation_j = face.element[1].orientation;
+
+   // In 2D, need to flip orientation of the segments`
+   if (trace_fe->GetGeomType() == Geometry::SEGMENT && !is_ghost_slave)
+   {
+      orientation_i = 1;
+   }
+
    for (int i = 0; i < face_dofs; i++)
    {
       const int ni = (dof_map.Size()==0) ? i : dof_map[i];
@@ -1602,7 +1608,7 @@ const DenseMatrix* InterpolationManager::GetCoarseToFineInterpolation(
       {
          // master side is elem 2, so we permute to order dofs as elem 1.
          li = PermuteFaceL2(dim, face_id2, face_id1,
-                            orientation, dof1d, li);
+                            orientation_i, dof1d, li);
       }
       for (int j = 0; j < face_dofs; j++)
       {
@@ -1611,7 +1617,7 @@ const DenseMatrix* InterpolationManager::GetCoarseToFineInterpolation(
          {
             // master side is elem 2, so we permute to order dofs as elem 1.
             lj = PermuteFaceL2(dim, face_id2, face_id1,
-                               orientation, dof1d, lj);
+                               orientation_j, dof1d, lj);
          }
          const int nj = (dof_map.Size()==0) ? j : dof_map[j];
          (*interpolator)(li,lj) = native_interpolator(ni,nj);
@@ -1676,7 +1682,7 @@ NCL2FaceRestriction::NCL2FaceRestriction(const FiniteElementSpace &fes,
                                          const L2FaceValues m,
                                          bool build)
    : L2FaceRestriction(fes, f_ordering, type, m, false),
-     interpolations(fes, f_ordering, type)
+     interpolations(fes.GetInterpolationManager(ordering, type))
 {
    if (!build) { return; }
    x_interp.UseDevice(true);
@@ -2202,14 +2208,6 @@ void NCL2FaceRestriction::ComputeScatterIndicesAndOffsets()
          {
             PermuteAndSetFaceDofsScatterIndices2(face,f_ind);
          }
-         if ( face.IsConforming() )
-         {
-            interpolations.RegisterFaceConformingInterpolation(face,f_ind);
-         }
-         else // Non-conforming face
-         {
-            interpolations.RegisterFaceCoarseToFineInterpolation(face,f_ind);
-         }
          f_ind++;
       }
       else if ( type==FaceType::Boundary && face.IsBoundary() )
@@ -2219,7 +2217,6 @@ void NCL2FaceRestriction::ComputeScatterIndicesAndOffsets()
          {
             SetBoundaryDofsScatterIndices2(face,f_ind);
          }
-         interpolations.RegisterFaceConformingInterpolation(face,f_ind);
          f_ind++;
       }
    }
@@ -2232,10 +2229,6 @@ void NCL2FaceRestriction::ComputeScatterIndicesAndOffsets()
    {
       gather_offsets[i] += gather_offsets[i - 1];
    }
-
-   // Transform the interpolation matrix map into a contiguous memory structure.
-   interpolations.LinearizeInterpolatorMapIntoVector();
-   interpolations.InitializeNCInterpConfig();
 }
 
 void NCL2FaceRestriction::ComputeGatherIndices()
@@ -2278,6 +2271,18 @@ void NCL2FaceRestriction::ComputeGatherIndices()
    gather_offsets[0] = 0;
 }
 
+static int GetSharedVSize(const FiniteElementSpace &fes)
+{
+#ifdef MFEM_USE_MPI
+   if (auto pfes = dynamic_cast<const ParFiniteElementSpace*>(&fes))
+   {
+      const_cast<ParFiniteElementSpace*>(pfes)->ExchangeFaceNbrData();
+      return pfes->GetFaceNbrVSize();
+   }
+#endif
+   return 0;
+}
+
 L2InterfaceFaceRestriction::L2InterfaceFaceRestriction(
    const FiniteElementSpace& fes_,
    const ElementDofOrdering ordering_,
@@ -2288,25 +2293,54 @@ L2InterfaceFaceRestriction::L2InterfaceFaceRestriction(
      nfaces(fes.GetNFbyType(type)),
      vdim(fes.GetVDim()),
      byvdim(fes.GetOrdering() == Ordering::byVDIM),
-     face_dofs(nfaces > 0 ? fes.GetFaceElement(0)->GetDof() : 0),
+     face_dofs(fes.GetTypicalTraceElement()->GetDof()),
      nfdofs(face_dofs*nfaces),
-     ndofs(fes.GetNDofs())
+     ndofs(fes.GetNDofs()),
+     nsdofs(GetSharedVSize(fes))
 {
    height = nfdofs;
    width = ndofs;
 
+#ifdef MFEM_USE_MPI
+   auto pfes = dynamic_cast<const ParFiniteElementSpace*>(&fes);
+#endif
+
    const Table &face2dof = fes.GetFaceToDofTable();
 
    const Mesh &mesh = *fes.GetMesh();
    int face_idx = 0;
-   gather_map.SetSize(nfdofs);
-   for (int f = 0; f < mesh.GetNumFaces(); ++f)
+   scatter_map.SetSize(nfdofs);
+   gather_map.SetSize(ndofs + nsdofs);
+   gather_map = -1;
+
+   Array<int> dofs;
+   for (int f = 0; f < mesh.GetNumFacesWithGhost(); ++f)
    {
       Mesh::FaceInformation face = mesh.GetFaceInformation(f);
-      if (!face.IsOfFaceType(type)) { continue; }
-      for (int i = 0; i < face_dofs; ++i)
+      if (!face.IsOfFaceType(type) || face.IsNonconformingCoarse()) { continue; }
+
+      if (f < mesh.GetNumFaces())
       {
-         gather_map[i + face_idx*face_dofs] = face2dof.GetJ()[i + f*face_dofs];
+         // Local face
+         face2dof.GetRow(f, dofs);
+         for (int i = 0; i < face_dofs; ++i)
+         {
+            scatter_map[i + face_idx*face_dofs] = dofs[i];
+            gather_map[dofs[i]] = i + face_idx*face_dofs;
+         }
+      }
+      else
+      {
+         // Shared (non-conforming) ghost face
+#ifdef MFEM_USE_MPI
+         MFEM_ASSERT(pfes != nullptr, "");
+         pfes->GetFaceNbrFaceVDofs(f, dofs);
+         for (int i = 0; i < face_dofs; ++i)
+         {
+            scatter_map[i + face_idx*face_dofs] = ndofs + dofs[i];
+            gather_map[ndofs + dofs[i]] = i + face_idx*face_dofs;
+         }
+#endif
       }
       ++face_idx;
    }
@@ -2314,13 +2348,19 @@ L2InterfaceFaceRestriction::L2InterfaceFaceRestriction(
 
 void L2InterfaceFaceRestriction::Mult(const Vector &x, Vector &y) const
 {
+   const int NDOFS = ndofs;
    const int nd = face_dofs;
    const int nf = nfaces;
    const int vd = vdim;
    const bool t = byvdim;
-   const int *map = gather_map.Read();
+   const int *map = scatter_map.Read();
+
+   Vector face_nbr_data = GetLVectorFaceNbrData(fes, x, type);
+   MFEM_ASSERT(face_nbr_data.Size() / vd == nsdofs, "");
 
    const auto d_x = Reshape(x.Read(), t?vd:ndofs, t?ndofs:vd);
+   const auto d_x_shared = Reshape(face_nbr_data.Read(),
+                                   t?vd:nsdofs, t?nsdofs:vd);
    auto d_y = Reshape(y.Write(), nd, vd, nf);
 
    mfem::forall(nd*nf, [=] MFEM_HOST_DEVICE (int i)
@@ -2328,7 +2368,8 @@ void L2InterfaceFaceRestriction::Mult(const Vector &x, Vector &y) const
       const int j = map[i];
       for (int c = 0; c < vd; ++c)
       {
-         d_y(i % nd, c, i / nd) = d_x(t?c:j, t?j:c);
+         if (j < NDOFS) { d_y(i % nd, c, i / nd) = d_x(t?c:j, t?j:c); }
+         else { d_y(i % nd, c, i / nd) = d_x_shared(t?c:(j-NDOFS), t?(j-NDOFS):c); }
       }
    });
 }
@@ -2343,15 +2384,39 @@ void L2InterfaceFaceRestriction::AddMultTranspose(
    const int *map = gather_map.Read();
 
    const auto d_x = Reshape(x.Read(), nd, vd, nf);
-   auto d_y = Reshape(y.Write(), t?vd:ndofs, t?ndofs:vd);
+   auto d_y = Reshape(y.ReadWrite(), t?vd:ndofs, t?ndofs:vd);
 
-   mfem::forall(ndofs, [=] MFEM_HOST_DEVICE (int i) { d_y[i] = 0.0; });
-   mfem::forall(nd*nf, [=] MFEM_HOST_DEVICE (int i)
+   mfem::forall(ndofs, [=] MFEM_HOST_DEVICE (int i)
    {
       const int j = map[i];
+      if (j < 0) { return; }
       for (int c = 0; c < vd; ++c)
       {
-         d_y(t?c:j, t?j:c) = d_x(i % nd, c, i / nd);
+         d_y(t?c:i, t?i:c) += a*d_x(j % nd, c, j / nd);
+      }
+   });
+}
+
+void L2InterfaceFaceRestriction::MultTransposeShared(
+   const Vector &x, Vector &y) const
+{
+   const int nd = face_dofs;
+   const int nf = nfaces;
+   const int vd = vdim;
+   const bool t = byvdim;
+   const int *map = gather_map.Read();
+
+   const auto d_x = Reshape(x.Read(), nd, vd, nf);
+   auto d_y = Reshape(y.Write(), t?vd:(ndofs+nsdofs), t?(ndofs+nsdofs):vd);
+   y = 0.0;
+
+   mfem::forall(ndofs + nsdofs, [=] MFEM_HOST_DEVICE (int i)
+   {
+      const int j = map[i];
+      if (j < 0) { return; }
+      for (int c = 0; c < vd; ++c)
+      {
+         d_y(t?c:i, t?i:c) = d_x(j % nd, c, j / nd);
       }
    });
 }
@@ -2361,6 +2426,11 @@ const Array<int> &L2InterfaceFaceRestriction::GatherMap() const
    return gather_map;
 }
 
+const Array<int> &L2InterfaceFaceRestriction::ScatterMap() const
+{
+   return scatter_map;
+}
+
 Vector GetLVectorFaceNbrData(
    const FiniteElementSpace &fes, const Vector &x, FaceType ftype)
 {
@@ -2382,6 +2452,7 @@ Vector GetLVectorFaceNbrData(
          {
             ParGridFunction gf(pfes, const_cast<Vector&>(x));
             gf.ExchangeFaceNbrData();
+            x.SyncMemory(gf);
             return std::move(gf.FaceNbrData());
          }
       }

fem/restriction.hpp

@@ -812,13 +812,12 @@ protected:
        PointMatrix and a local face identifier. */
    using Key = std::pair<const DenseMatrix*,int>;
    /// The temporary map used to store the different interpolators.
-   using Map = std::map<Key, std::pair<int,const DenseMatrix*>>;
+   using Map =
+      std::unordered_map<Key, std::pair<int,const DenseMatrix*>, PairHasher>;
    Map interp_map; // The temporary map that stores the interpolators.
 
 public:
-   InterpolationManager() = delete;
-
-   /** @brief main constructor.
+   /** @brief Constructor.
 
        @param[in] fes      The FiniteElementSpace on which this operates
        @param[in] ordering Request a specific element ordering.
@@ -909,7 +908,7 @@ private:
 class NCL2FaceRestriction : virtual public L2FaceRestriction
 {
 protected:
-   InterpolationManager interpolations;
+   const InterpolationManager &interpolations;
    mutable Vector x_interp;
 
    /** @brief Constructs an NCL2FaceRestriction, this is a specialization of a
@@ -996,9 +995,7 @@ public:
        @param[in] keep_nbr_block When set to true the SparseMatrix will
                                  include the rows (in addition to the columns)
                                  corresponding to face-neighbor dofs. The
-                                 default behavior is to disregard those rows.
-
-       @warning This method is not implemented yet. */
+                                 default behavior is to disregard those rows. */
    void FillI(SparseMatrix &mat,
               const bool keep_nbr_block = false) const override;
 
@@ -1016,9 +1013,7 @@ public:
        @param[in] keep_nbr_block When set to true the SparseMatrix will
                                  include the rows (in addition to the columns)
                                  corresponding to face-neighbor dofs. The
-                                 default behavior is to disregard those rows.
-
-       @warning This method is not implemented yet. */
+                                 default behavior is to disregard those rows. */
    void FillJAndData(const Vector &fea_data,
                      SparseMatrix &mat,
                      const bool keep_nbr_block = false) const override;
@@ -1036,9 +1031,7 @@ public:
                               added the face contributions.
                               The format is: dofs x dofs x ne, where dofs is the
                               number of dofs per element and ne the number of
-                              elements.
-
-       @warning This method is not implemented yet. */
+                              elements. */
    void AddFaceMatricesToElementMatrices(const Vector &fea_data,
                                          Vector &ea_data) const override;
 
@@ -1130,7 +1123,9 @@ protected:
    const int face_dofs; ///< Number of dofs on each face
    const int nfdofs; ///< Total number of dofs on the faces (E-vector size)
    const int ndofs; ///< Number of dofs in the space (L-vector size)
+   const int nsdofs; ///< Number of shared face neighbor (ghost) dofs
    Array<int> gather_map; ///< Gather map
+   Array<int> scatter_map; ///< Scatter map
 
 public:
    /** @brief Constructs an L2InterfaceFaceRestriction.
@@ -1168,7 +1163,24 @@ public:
    void AddMultTranspose(const Vector &x, Vector &y,
                          const real_t a = 1.0) const override;
 
+   /// @brief Gather degrees of freedom, from face E-vector to L-vector and
+   /// shared (ghost) DOFs.
+   ///
+   /// @param[in]     x The face E-Vector degrees of freedom with size
+   ///                  (face_dofs, vdim, nf), where nf is the number of
+   ///                  interior or boundary faces requested by @a type in the
+   ///                  constructor. The face_dofs should be ordered according
+   ///                  to the given ElementDofOrdering
+   /// @param[out]    y Vector of length vsize + face neighbor vsize
+   void MultTransposeShared(const Vector &x, Vector &y) const;
+
    const Array<int> &GatherMap() const override;
+
+   /// @brief Return the low-level mapping from L-dofs to E-dofs.
+   ///
+   /// L-dofs that do not correspond to an E-dof (e.g. that lie on a face of a
+   /// different type) are given index -1.
+   const Array<int> &ScatterMap() const;
 };
 
 /** @brief Convert a dof face index from Native ordering to lexicographic