style

Merge branch 'master' into eigenSolverInterface
Merge branch 'master' of https://github.com/mfem/mfem
2026-02-10 12:48:56 -08:00 · 2026-02-10 10:47:01 -08:00 · 2026-02-10 10:46:20 -08:00 · 2026-02-10 10:45:28 -08:00 · 2026-02-03 22:40:04 -08:00 · 2026-02-02 23:34:11 -08:00
145 changed files with 1587 additions and 8129 deletions
@@ -25,7 +25,7 @@ runs:
  steps:
    - uses: ./.github/actions/sanitize/config

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

-    - uses: actions/cache@v5
+    - uses: actions/cache@v4
      if: ${{env.DEBUG == 'true' && inputs.cache-skip != 'true'}}
      id: debug
      with:
@@ -23,7 +23,7 @@ inputs:
 runs:
  using: 'composite'
  steps:
-    - uses: actions/cache/restore@v5  # Cache for LLVM libcxx
+    - uses: actions/cache/restore@v4  # 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@v5  # Cache for Hypre
+    - uses: actions/cache/restore@v4  # 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@v5  # Cache for Metis
+    - uses: actions/cache/restore@v4  # 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@v5  # Cache for LSAN suppression file
+    - uses: actions/cache/restore@v4  # Cache for LSAN suppression file
      with:
        path: ${{env.LSAN_DIR}}
        fail-on-cache-miss: true
        key: build-lsan-suppression-file

-    - uses: actions/checkout@v6  # Checkout the repository
+    - uses: actions/checkout@v4  # Checkout the repository
      with:
        path: mfem
        # ref: ${{env.BRANCH}}
@@ -43,7 +43,7 @@ jobs:
          remove-docker-images: 'true'

      - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4

      # It's easier to reference named variables than indexes of the matrix
      - name: Set Environment
@@ -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@v6
+        uses: actions/checkout@v4
        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@v5
+        uses: actions/cache@v4
        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@v5
+        uses: actions/cache@v4
        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@v5
+        uses: actions/cache@v4
        with:
          path: vcpkg_cache
          key: ${{ runner.os }}-${{ matrix.mpi }}-vcpkg-v1
@@ -295,8 +295,7 @@ jobs:
          export HOMEBREW_NO_INSTALL_CLEANUP=1
          brew update
          brew install enzyme
-          ENZYME_LLVM=$(brew info enzyme | sed -n 's/^Required.*:.*\(llvm[^ ]*\).*/\1/p')
-          echo "ENZYME_LLVM=$ENZYME_LLVM"
+          ENZYME_LLVM=$(brew info enzyme | sed -n 's/^Required:.*\(llvm[^ ]*\).*/\1/p')
          LLVM_PREFIX=$(brew --prefix $ENZYME_LLVM)
          echo "LLVM_PREFIX=$LLVM_PREFIX" >> $GITHUB_ENV
          echo "OMPI_CC=$LLVM_PREFIX/bin/clang" >> $GITHUB_ENV
@@ -40,11 +40,11 @@ jobs:

    steps:
      - name: Checkout repository
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4

      # Initializes the CodeQL tools for scanning.
      - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4
+        uses: github/codeql-action/init@v2
        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@v4
+        uses: github/codeql-action/autobuild@v2

      # 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@v4
+        uses: github/codeql-action/analyze@v2
@@ -39,7 +39,7 @@ jobs:

    steps:
      - name: checkout MFEM
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
        with:
          path: mfem

@@ -50,7 +50,7 @@ jobs:

      - name: Cache Hypre Install
        id: hypre-cache
-        uses: actions/cache@v5
+        uses: actions/cache@v4
        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@v5
+        uses: actions/cache@v4
        with:
          path: ${{ env.METIS_TOP_DIR }}
          key: ${{ runner.os }}-build-${{ env.METIS_TOP_DIR }}-v2.5
@@ -38,7 +38,7 @@ jobs:
       github.event.pull_request.head.repo.full_name != github.repository)
    steps:
      - name: checkout mfem
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4

      - 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@v6
+        uses: actions/checkout@v4

      - 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@v6
+        uses: actions/checkout@v4

      - name: get doxygen and graphviz
        run: |
@@ -135,7 +135,7 @@ jobs:
    runs-on: ubuntu-latest
    steps:
      - name: checkout mfem
-        uses: actions/checkout@v6
+        uses: actions/checkout@v4
        with:
          fetch-depth: 0

@@ -17,11 +17,11 @@ jobs:
    runs-on: ubuntu-latest
    name: 2.19.0
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/config
      - name: Cache
        id: cache
-        uses: actions/cache@v5
+        uses: actions/cache@v4
        with:
          path: ${{env.HYPRE_DIR}}
          key: ${{runner.os}}-ompi-build-${{env.HYPRE_DIR}}-int32-fp64-v2.5
@@ -27,13 +27,13 @@ jobs:
            llvm_use_sanitizer: "Undefined"
    name: ${{matrix.sanitizer}}
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/config
        with:
          NO_FLAGS: true
      - name: Cache
        id: cache
-        uses: actions/cache@v5
+        uses: actions/cache@v4
        with:
          path: ${{env.LLVM_DIR}}
          key: build-libcxx-${{env.LLVM_VER}}-${{matrix.sanitizer}}
@@ -17,11 +17,11 @@ jobs:
    runs-on: ubuntu-latest
    name: lsan.supp
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/config
      - name: Cache
        id: cache
-        uses: actions/cache@v5
+        uses: actions/cache@v4
        with:
          path: ${{env.LSAN_DIR}}
          key: build-lsan-suppression-file
@@ -17,11 +17,11 @@ jobs:
    runs-on: ubuntu-latest
    name: 4.0.3
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/config
      - name: Cache
        id: cache
-        uses: actions/cache@v5
+        uses: actions/cache@v4
        with:
          path: ${{env.METIS_DIR}}
          key: ${{runner.os}}-build-${{env.METIS_DIR}}-v2.5
@@ -28,7 +28,7 @@ jobs:
  build:
    runs-on: ubuntu-latest
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/mfem
        with:
          par: ${{inputs.par}}
@@ -40,7 +40,7 @@ jobs:
    env:
      ex: ${{inputs.par && 'ex1p' || 'ex1'}}
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/restore
        id: restore
        with:
@@ -58,7 +58,7 @@ jobs:
    env:
      exclude: ${{inputs.par && '-E "_ser"' || ''}}
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/restore
        id: restore
        with:
@@ -82,7 +82,7 @@ jobs:
    env:
      exclude: ${{inputs.par && '-E "_ser"' || ''}}
    steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@v4
      - 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@v6
+      - uses: actions/checkout@v4
      - 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@v6
+      - uses: actions/checkout@v4
      - 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@v6
+      - uses: actions/checkout@v4
      - uses: ./.github/actions/sanitize/restore
        id: restore
        with:
@@ -443,10 +443,6 @@ 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
@@ -8,22 +8,6 @@
                               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)
 ===========================

@@ -33,9 +17,6 @@ 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
@@ -652,8 +652,6 @@ 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)
@@ -1017,7 +1015,5 @@ 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()
@@ -109,10 +109,6 @@ 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)
@@ -14,12 +14,12 @@
 #   - UMPIRE_LIBRARIES
 #   - UMPIRE_INCLUDE_DIRS

-if (NOT umpire_ROOT AND UMPIRE_DIR)
-  set(umpire_ROOT ${UMPIRE_DIR})
+if (NOT umpire_DIR AND UMPIRE_DIR)
+  set(umpire_DIR ${UMPIRE_DIR}/lib/cmake/umpire)
 endif()
 message(STATUS "Looking for UMPIRE ...")
 message(STATUS "   in UMPIRE_DIR = ${UMPIRE_DIR}")
-message(STATUS "      umpire_ROOT = ${umpire_ROOT}")
+message(STATUS "      umpire_DIR = ${umpire_DIR}")
 find_package(umpire CONFIG)
 set(UMPIRE_FOUND ${umpire_FOUND})
 set(UMPIRE_LIBRARIES "umpire")
@@ -701,6 +701,7 @@ 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()
@@ -798,12 +799,7 @@ function(mfem_get_target_options Target CompileOptsVar LinkOptsVar)
          # message(STATUS "Lib = ${Lib}")
          # Filter-out generator expressions
          if (NOT ("${Lib}" MATCHES "^\\$"))
-            if(NOT ("${Lib}" STREQUAL "dl"))
-              list(APPEND LinkOpts "${Lib}")
-            else()
-              # for some reason libdl doesn't include the "-l"
-              list(APPEND LinkOpts "-ldl")
-            endif()
+            list(APPEND LinkOpts "${Lib}")
          endif()
        else()
          mfem_get_target_options(${Lib} COpts LOpts)
@@ -892,18 +888,9 @@ function(mfem_export_mk_files)
      set(${var} NO)
    endif()
  endforeach()
-  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()
+  # TODO: Add support for MFEM_USE_CUDA=YES
+  set(MFEM_CXX ${CMAKE_CXX_COMPILER})
+  set(MFEM_HOST_CXX ${MFEM_CXX})
  set(MFEM_CPPFLAGS "")
  get_target_property(cxx_std mfem CXX_STANDARD)
  # For now, we ignore the setting of the CXX_EXTENSIONS property. If this
@@ -913,50 +900,6 @@ function(mfem_export_mk_files)
  string(STRIP
         "${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${dir}")
@@ -987,9 +930,6 @@ function(mfem_export_mk_files)
    set(MFEM_SHARED NO)
    set(MFEM_STATIC YES)
  endif()
-  if (MFEM_USE_CUDA)
-    set(MFEM_EXT_LIBS "${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
@@ -998,15 +938,8 @@ 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 ?= ${PROJECT_BINARY_DIR}")
-  if (MFEM_USE_CUDA AND MFEM_EXPORT_GPU_CONFIG)
-    if (MFEM_CUDA_COMPILER_IS_NVCC)
-      set(MFEM_XLINKER "-Xlinker=")
-    else()
-      set(MFEM_XLINKER "${CMAKE_CUDA_LINKER_WRAPPER_FLAG}")
-    endif()
-  else()
-    set(MFEM_XLINKER "${CMAKE_CXX_LINKER_WRAPPER_FLAG}")
-  endif()
+  # TODO: CUDA/HIP support:
+  set(MFEM_XLINKER "${CMAKE_CXX_LINKER_WRAPPER_FLAG}")
  set(MFEM_MPIEXEC ${MPIEXEC})
  if (NOT MFEM_MPIEXEC)
    set(MFEM_MPIEXEC "mpirun")
@@ -1054,21 +987,16 @@ function(mfem_export_mk_files)
    # handle interfaces (e.g., SCOREC::apf)
    if ("${lib}" MATCHES "SCOREC::.*" OR "${lib}" MATCHES "Ginkgo::.*" OR "${lib}" MATCHES "ParMoonolith::.*")
    elseif (TARGET "${lib}")
-      mfem_get_target_options(${lib} CompileOpts2 LinkOpts2)
-      # remove generator expressions
-      string(GENEX_STRIP "${CompileOpts2}" CompileOpts)
-      string(GENEX_STRIP "${LinkOpts2}" LinkOpts)
+      mfem_get_target_options(${lib} CompileOpts LinkOpts)
      # Removing duplicates may lead to issues:
      # list(REMOVE_DUPLICATES CompileOpts)
      # list(REMOVE_DUPLICATES LinkOpts)
-      # message(WARNING "${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} ${COpt}")
-      endforeach()
+      string(REPLACE ";" " " COpts "${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} ${LOpts}")
      # message(FATAL_ERROR "***** interface lib found ... exiting *****")
      # handle static and shared libs
    elseif ("${suffix}" STREQUAL "${CMAKE_SHARED_LIBRARY_SUFFIX}")
@@ -1076,7 +1004,7 @@ 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} ${lib}")
    endif()
@@ -1085,7 +1013,7 @@ function(mfem_export_mk_files)
  # Create the build-tree version of 'config.mk'
  configure_file(
    "${PROJECT_SOURCE_DIR}/config/config.mk.in"
-    "${PROJECT_BINARY_DIR}/config/config.mk" @ONLY)
+    "${PROJECT_BINARY_DIR}/config/config.mk")
  # Copy 'test.mk' from the source-tree to the build-tree
  configure_file(
    "${PROJECT_SOURCE_DIR}/config/test.mk"
@@ -1103,7 +1031,7 @@ function(mfem_export_mk_files)
  # Create the install-tree version of 'config.mk'
  configure_file(
    "${PROJECT_SOURCE_DIR}/config/config.mk.in"
-    "${PROJECT_BINARY_DIR}/config/config-install.mk" @ONLY)
+    "${PROJECT_BINARY_DIR}/config/config-install.mk")

  # Install rules for 'config.mk' and 'test.mk'
  install(FILES ${PROJECT_SOURCE_DIR}/config/test.mk
@@ -97,9 +97,6 @@
 // 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
@@ -32,7 +32,6 @@ 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@
@@ -178,7 +178,6 @@ 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
@@ -428,14 +427,6 @@ 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)
@@ -49,13 +49,6 @@ 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
@@ -1,298 +0,0 @@
-//                       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
@@ -72,8 +72,6 @@ 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;

@@ -99,10 +97,6 @@ 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.");
@@ -119,11 +113,6 @@ 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)
@@ -254,119 +243,70 @@ 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;
-
-      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)
+   else
   {
-      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
+#ifdef MFEM_USE_SUPERLU
+      if (slu_solver)
      {
+         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
-   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
+      if (sp_solver)
      {
+         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
-   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
+      if (cpardiso_solver)
      {
+         auto cpardiso = new CPardisoSolver(A->GetComm());
+         cpardiso->SetMatrixType(CPardisoSolver::MatType::REAL_STRUCTURE_SYMMETRIC);
+         cpardiso->SetPrintLevel(1);
+         cpardiso->SetOperator(*A);
         precond = cpardiso;
      }
-   }
 #endif
-
-   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);
+   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);

   // 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;
-   eig_solver->Solve();
-   eig_solver->GetEigenvalues(eigenvalues);
+   lobpcg->Solve();
+   lobpcg->GetEigenvalues(eigenvalues);
   ParGridFunction x(fespace);

   // 10. Save the refined mesh and the modes in parallel. This output can be
@@ -381,8 +321,8 @@ int main(int argc, char *argv[])

      for (int i=0; i<nev; i++)
      {
-         // convert eigenvector from Vector to ParGridFunction
-         x.Distribute(eig_solver->GetEigenvector(i));
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x = lobpcg->GetEigenvector(i);

         mode_name << "mode_" << setfill('0') << setw(2) << i << "."
                   << setfill('0') << setw(6) << myid;
@@ -410,8 +350,8 @@ int main(int argc, char *argv[])
                 << ", Lambda = " << eigenvalues[i] << endl;
         }

-         // convert eigenvector from Vector to ParGridFunction
-         x.Distribute(eig_solver->GetEigenvector(i));
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x = lobpcg->GetEigenvector(i);

         mode_sock << "parallel " << num_procs << " " << myid << "\n"
                   << "solution\n" << *pmesh << x << flush
@@ -435,8 +375,7 @@ int main(int argc, char *argv[])
   }

   // 12. Free the used memory.
-   delete eig_solver;
-   delete solver;
+   delete lobpcg;
   delete precond;
   delete M;
   delete A;
@@ -1,381 +0,0 @@
-//                       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;
-}
@@ -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 464 -n 10 -o 2 -elast
+//    mpirun -np 4 ex12p -m ../data/beam-tet.mesh -s 462 -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 82
+//    mpirun -np 4 ex12p -m ../data/beam-wedge.mesh -s 81
 //    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 Vector to ParGridFunction
-         x.Distribute(lobpcg->GetEigenvector(i));
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x = 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.Distribute(lobpcg->GetEigenvector(i));
+         x = 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 Vector to ParGridFunction
-         x.Distribute(lobpcg->GetEigenvector(i));
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x = lobpcg->GetEigenvector(i);

         mode_sock << "parallel " << num_procs << " " << myid << "\n"
                   << "solution\n" << *pmesh << x << flush
@@ -1,282 +0,0 @@
-//                       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
@@ -215,8 +215,8 @@ int main(int argc, char *argv[])

      for (int i=0; i<nev; i++)
      {
-         // convert eigenvector from Vector to ParGridFunction
-         x.Distribute(ame->GetEigenvector(i));
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x = 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 Vector to ParGridFunction
-         x.Distribute(ame->GetEigenvector(i));
+         // convert eigenvector from HypreParVector to ParGridFunction
+         x = ame->GetEigenvector(i);

         mode_sock << "parallel " << num_procs << " " << myid << "\n"
                   << "solution\n" << *pmesh << x << flush
@@ -302,21 +302,15 @@ 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
@@ -540,21 +534,15 @@ 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)
   {
@@ -563,21 +551,15 @@ 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)
   {
@@ -228,7 +228,7 @@ int main(int argc, char *argv[])
      for (int i=0; i<nev; i++)
      {
         // convert eigenvector from HypreParVector to ParGridFunction
-         x.Distribute(ame->GetEigenvector(i));
+         x = 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.Distribute(ame->GetEigenvector(i));
+            x = ame->GetEigenvector(i);
            curl.Mult(x, dx);

            {
@@ -469,7 +469,7 @@ int main(int argc, char *argv[])
            }

            // convert eigenvector from HypreParVector to ParGridFunction
-            x.Distribute(ame->GetEigenvector(i));
+            x = ame->GetEigenvector(i);
            curl.Mult(x, dx);

            {
@@ -599,7 +599,7 @@ int main(int argc, char *argv[])
            }

            // convert eigenvector from HypreParVector to ParGridFunction
-            x.Distribute(ame->GetEigenvector(i));
+            x = ame->GetEigenvector(i);
            curl.Mult(x, dx);

            mode_sock << "parallel " << num_procs << " " << myid << "\n"
@@ -658,7 +658,7 @@ void ScalarWaveGuide(int mode, ParGridFunction &x)
   lobpcg.SetOperator(*A);
   lobpcg.Solve();

-   x.Distribute(lobpcg.GetEigenvector(mode));
+   x = lobpcg.GetEigenvector(mode);

   delete A;
   delete M;
@@ -714,7 +714,7 @@ void VectorWaveGuide(int mode, ParGridFunction &x)
   ame.SetOperator(*A);
   ame.Solve();

-   x.Distribute(ame.GetEigenvector(mode));
+   x = ame.GetEigenvector(mode);

   delete A;
   delete M;
@@ -780,7 +780,7 @@ void PseudoScalarWaveGuide(int mode, ParGridFunction &x_l2)
   lobpcg.SetOperator(*A);
   lobpcg.Solve();

-   x.Distribute(lobpcg.GetEigenvector(mode));
+   x = lobpcg.GetEigenvector(mode);

   x_l2.ProjectCoefficient(xCoef);

@@ -5,8 +5,8 @@
 // Sample runs:
 //     ex37 -alpha 10
 //     ex37 -alpha 10 -pv
-//     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 -lambda 0.1 -mu 0.1
+//     ex37 -o 2 -alpha 5.0 -mi 50 -vf 0.4 -ntol 1e-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
@@ -55,6 +55,53 @@
 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
@@ -133,11 +180,10 @@ 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-2;
+   real_t itol = 1e-1;
   real_t ntol = 1e-4;
   real_t rho_min = 1e-6;
   real_t lambda = 1.0;
@@ -152,8 +198,6 @@ 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",
@@ -288,7 +332,6 @@ 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)));
@@ -342,7 +385,7 @@ int main(int argc, char *argv[])
   // 11. Iterate:
   for (int k = 1; k <= max_it; k++)
   {
-      if (k > 1) { alpha = std::pow((real_t) k,growth); }
+      if (k > 1) { alpha *= ((real_t) k) / ((real_t) k-1); }

      mfem::out << "\nStep = " << k << std::endl;

@@ -379,9 +422,7 @@ int main(int argc, char *argv[])

      // Step 5 - Update design variable ψ ← proj(ψ - αG)
      psi.Add(-alpha, grad);
-      GridFunction alpha_grad(grad);
-      alpha_grad *= alpha;
-      const real_t material_volume = proj(psi, alpha_grad, target_volume);
+      const real_t material_volume = proj(psi, target_volume);

      // Compute ||ρ - ρ_old|| in control fes.
      real_t norm_increment = zerogf.ComputeL1Error(succ_diff_rho);
@@ -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");
   }
@@ -231,12 +231,9 @@ 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;
@@ -270,8 +267,6 @@ public:
   void ResetFEM();
   void SetupFEM();

-   void UpdateEssentialTDofs();
-   void AssembleDiffusionBilinear(bool update_ess_tdofs=true);
   void Solve();
   GridFunction * GetFEMSolution();
   LinearForm * GetLinearForm() {return b;}
@@ -376,130 +371,6 @@ 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

@@ -551,8 +422,12 @@ void DiffusionSolver::SetupFEM()
   }
 }

-void DiffusionSolver::UpdateEssentialTDofs()
+void DiffusionSolver::Solve()
 {
+   OperatorPtr A;
+   Vector B, X;
+   Array<int> ess_tdof_list;
+
 #ifdef MFEM_USE_MPI
   if (parallel)
   {
@@ -565,39 +440,7 @@ void DiffusionSolver::UpdateEssentialTDofs()
 #else
   fes->GetEssentialTrueDofs(ess_bdr,ess_tdof_list);
 #endif
-}
-
-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;
-
+   *u=0.0;
   if (b)
   {
      delete b;
@@ -632,33 +475,31 @@ void DiffusionSolver::Solve()

   b->Assemble();

-   *u=0.0;
-   if (essbdr_cf)
-   {
-      u->ProjectBdrCoefficient(*essbdr_cf,ess_bdr);
-   }
+   BilinearForm * a = nullptr;

 #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);
+      a = new ParBilinearForm(pfes);
   }
   else
   {
-      X.NewDataAndSize(u->GetData(), u->Size());
-      B.NewDataAndSize(b->GetData(), b->Size());
-      a->EliminateVDofsInRHS(ess_tdof_list, X, B);
+      a = new BilinearForm(fes);
   }
 #else
-   X.NewDataAndSize(u->GetData(), u->Size());
-   B.NewDataAndSize(b->GetData(), b->Size());
-   a->EliminateVDofsInRHS(ess_tdof_list, X, B);
+   a = new BilinearForm(fes);
 #endif
+   a->AddDomainIntegrator(new DiffusionIntegrator(*diffcf));
+   if (masscf)
+   {
+      a->AddDomainIntegrator(new MassIntegrator(*masscf));
+   }
+   a->Assemble();
+   if (essbdr_cf)
+   {
+      u->ProjectBdrCoefficient(*essbdr_cf,ess_bdr);
+   }
+   a->FormLinearSystem(ess_tdof_list, *u, *b, A, X, B);

   CGSolver * cg = nullptr;
   Solver * M = nullptr;
@@ -687,6 +528,7 @@ void DiffusionSolver::Solve()
   delete M;
   delete cg;
   a->RecoverFEMSolution(X, *b, *u);
+   delete a;
 }

 GridFunction * DiffusionSolver::GetFEMSolution()
@@ -718,8 +560,6 @@ DiffusionSolver::~DiffusionSolver()
 #endif
   delete fec; fec = nullptr;
   delete b;
-   A.Clear();
-   delete a;
 }


@@ -4,8 +4,8 @@
 //
 // Sample runs:
 //    mpirun -np 4 ex37p -alpha 10 -pv
-//    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 -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 -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
@@ -54,6 +54,61 @@
 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
@@ -138,11 +193,10 @@ 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-2;
+   real_t itol = 1e-1;
   real_t ntol = 1e-4;
   real_t rho_min = 1e-6;
   real_t lambda = 1.0;
@@ -157,8 +211,6 @@ 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",
@@ -307,7 +359,6 @@ 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)));
@@ -361,7 +412,7 @@ int main(int argc, char *argv[])
   // 11. Iterate:
   for (int k = 1; k <= max_it; k++)
   {
-      if (k > 1) { alpha = std::pow((real_t) k,growth); }
+      if (k > 1) { alpha *= ((real_t) k) / ((real_t) k-1); }

      if (myid == 0)
      {
@@ -401,9 +452,7 @@ int main(int argc, char *argv[])

      // Step 5 - Update design variable ψ ← proj(ψ - αG)
      psi.Add(-alpha, grad);
-      ParGridFunction alpha_grad(grad);
-      alpha_grad *= alpha;
-      const real_t material_volume = proj(psi, alpha_grad, target_volume);
+      const real_t material_volume = proj(psi, target_volume);

      // Compute ||ρ - ρ_old|| in control fes.
      real_t norm_increment = zerogf.ComputeL1Error(succ_diff_rho);
@@ -31,9 +31,6 @@ 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
@@ -160,8 +157,6 @@ 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
@@ -729,8 +729,7 @@ void BilinearForm::Assemble(int skip_zeros)
         tr = mesh -> GetBdrFaceTransformations (i);
         if (tr != NULL)
         {
-            mfem::DofTransformation doftrans;
-            fes -> GetElementVDofs (tr -> Elem1No, vdofs, doftrans);
+            fes -> GetElementVDofs (tr -> Elem1No, vdofs);
            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
@@ -744,7 +743,6 @@ 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);
            }
         }
@@ -1725,7 +1723,6 @@ 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);
@@ -1734,8 +1731,8 @@ void MixedBilinearForm::Assemble(int skip_zeros)
         ftr = mesh -> GetBdrFaceTransformations (i);
         if (ftr != NULL)
         {
-            trial_fes->GetElementVDofs(ftr->Elem1No, trial_vdofs, dom_dof_trans);
-            test_fes->GetElementVDofs(ftr->Elem1No, test_vdofs, ran_dof_trans);
+            trial_fes->GetElementVDofs(ftr->Elem1No, trial_vdofs);
+            test_fes->GetElementVDofs(ftr->Elem1No, test_vdofs);
            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
@@ -1751,7 +1748,6 @@ 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);
            }
         }
@@ -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:
@@ -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(ncp, nb);
-   ubound.SetSize(ncp, nb);
+   lbound.SetSize(nb, ncp);
+   ubound.SetSize(nb, ncp);
   nodes.SetSize(nb);
   weights.SetSize(nb);
   control_points.SetSize(ncp);
@@ -125,25 +125,21 @@ void PLBound::Setup(const int nb_i, const int ncp_i,
      {
         if (j == 0)
         {
-            lbound(j,i) = bv(i);
-            ubound(j,i) = bv(i);
+            lbound(i, j) = bv(i);
+            ubound(i, j) = bv(i);
         }
         else if (j == ncp-1)
         {
-            lbound(j,i) = bv(i);
-            ubound(j,i) = bv(i);
+            lbound(i, j) = bv(i);
+            ubound(i, j) = bv(i);
         }
         else
         {
            vals(0)  = bv(i);
            vals(1) =  bmv(i) +  dm*bdmv(i);
            vals(2) =  bpv(i) +  dp*bdpv(i);
-            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);
-            }
+            lbound(i, j) = vals.Min()-tol; // tolerance for good measure
+            ubound(i, j) = vals.Max()+tol; // tolerance for good measure
         }
      }
   }
@@ -277,7 +273,8 @@ void PLBound::Get1DBounds(const Vector &coeff, Vector &intmin,
   intmax.SetSize(ncp);
   intmin = 0.0;
   intmax = 0.0;
-   Vector coeffm;
+   Vector coeffm(nb);
+   coeffm = 0.0;

   real_t a0 = 0.0;
   real_t a1 = 0.0;
@@ -305,8 +302,6 @@ 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;
@@ -347,8 +342,8 @@ void PLBound::Get1DBounds(const Vector &coeff, Vector &intmin,
      real_t c = coeffm(i);
      for (int j = 0; j < ncp; j++)
      {
-         intmin(j) += min(lbound(j,i)*c, ubound(j,i)*c);
-         intmax(j) += max(lbound(j,i)*c, ubound(j,i)*c);
+         intmin(j) += min(lbound(i,j)*c, ubound(i,j)*c);
+         intmax(j) += max(lbound(i,j)*c, ubound(i,j)*c);
      }
   }
 }
@@ -479,10 +474,10 @@ 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(k,j);
-            vals(1) = w0*ubound(k,j);
-            vals(2) = w1*lbound(k,j);
-            vals(3) = w1*ubound(k,j);
+            vals(0) = w0*lbound(j,k);
+            vals(1) = w0*ubound(j,k);
+            vals(2) = w1*lbound(j,k);
+            vals(3) = w1*ubound(j,k);
            intmin(k*ncp+i) += vals.Min();
            intmax(k*ncp+i) += vals.Max();
         }
@@ -558,17 +553,17 @@ void PLBound::Get3DBounds(const Vector &coeff, Vector &intmin,
            for (int i = 0; i < nb; i++)
            {
               x = 2.0*nodes(i)-1; // x-coordinate
-               minNodalVals(i) -= a0V(j) + a1V(j)*x;
-               maxNodalVals(i) -= a0V(j) + a1V(j)*x;
+               minBounds(i) -= a0V(j) + a1V(j)*x;
+               maxBounds(i) -= a0V(j) + a1V(j)*x;
            }
            // Compute Bernstein coefficients
            LUFactors lu(basisMatLU.GetData(), lu_ip.GetData());
-            lu.Solve(nb, 1, minNodalVals.GetData());
-            lu.Solve(nb, 1, maxNodalVals.GetData());
+            lu.Solve(nb, 1, minBounds.GetData());
+            lu.Solve(nb, 1, maxBounds.GetData());
            for (int i = 0; i < nb; i++)
            {
-               intminT(i*ncp2+j) = minNodalVals(i);
-               intmaxT(i*ncp2+j) = maxNodalVals(i);
+               intminT(i*ncp2+j) = minBounds(i);
+               intmaxT(i*ncp2+j) = maxBounds(i);
            }
         }
      }
@@ -622,10 +617,10 @@ 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(k,j);
-            vals(1) = w0*ubound(k,j);
-            vals(2) = w1*lbound(k,j);
-            vals(3) = w1*ubound(k,j);
+            vals(0) = w0*lbound(j,k);
+            vals(1) = w0*ubound(j,k);
+            vals(2) = w1*lbound(j,k);
+            vals(3) = w1*ubound(j,k);
            intmin(k*ncp2+i) += vals.Min();
            intmax(k*ncp2+i) += vals.Max();
         }
@@ -658,8 +653,7 @@ 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);
@@ -672,39 +666,6 @@ 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];
@@ -755,4 +716,4 @@ void PLBound::Print(std::ostream &outp) const
   ubound.Print(outp);
 }

-}
+}
@@ -19,18 +19,14 @@ 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.
@@ -39,9 +35,7 @@ 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.

@@ -60,7 +54,7 @@ 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; // ncp x nb matrices with bounds of all bases
+   DenseMatrix lbound, ubound; // nb x ncp 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
@@ -86,9 +80,6 @@ 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,
@@ -101,82 +92,40 @@ 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;

-   /** @brief Enable (default) or disable linear projection before bounding.
-    *
-    *  @details This projection increases the computational cost but results in
-    *  tighter bounds.
-    */
+   // Enable (default) or disable linear projection before bounding.
+   // This projection increases the computational cost but results in tighter
+   // bounds.
   void SetProjectionFlagForBounding(bool proj_) { proj = proj_; }

-   /** @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.
-    */
+   /// Compute piecewise linear bounds for the lexicographically-ordered
+   /// coefficients in @a coeff in 1D/2D/3D.
   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:
-   /** @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.
-    */
+   /// Compute piecewise linear bounds for the lexicographically-ordered
+   /// coefficients in @a coeff in 1D.
   void Get1DBounds(const Vector &coeff, Vector &intmin, Vector &intmax) const;

-   /** @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.
-    */
+   /// Compute piecewise linear bounds for the lexicographically-ordered
+   /// coefficients in @a coeff in 2D.
   void Get2DBounds(const Vector &coeff, Vector &intmin, Vector &intmax) const;

-   /** @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.
-    */
+   /// Compute piecewise linear bounds for the lexicographically-ordered
+   /// coefficients in @a coeff in 3D.
   void Get3DBounds(const Vector &coeff, Vector &intmin, Vector &intmax) const;

-   /** @brief Setup matrix used to compute values at given 1D locations in [0,1]
-    *  for Bernstein bases.
-    */
+   /// 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,
@@ -52,9 +52,6 @@ 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
@@ -82,25 +82,6 @@ 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; }
@@ -492,8 +492,6 @@ 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)
   {
@@ -979,10 +977,7 @@ void ParaViewDataCollection::Save()
   // Save the local part of the mesh and grid functions fields to the local
   // VTU file. Also save coefficient fields.
   {
-      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);
+      std::ofstream os(vtu_prefix + GenerateVTUFileName("proc", myid));
      os.precision(precision);
      SaveDataVTU(os, levels_of_detail);
   }
@@ -994,10 +989,7 @@ void ParaViewDataCollection::Save()
                  "QuadratureFunction output is not supported for "
                  "ParaViewDataCollection on domain boundary!");
      const std::string &field_name = qfield.first;
-      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);
+      std::ofstream os(vtu_prefix + GenerateVTUFileName(field_name, myid));
      qfield.second->SaveVTU(os, pv_data_format, GetCompressionLevel(), field_name);
   }

@@ -1008,10 +1000,7 @@ void ParaViewDataCollection::Save()
   {
      // Create the main PVTU file
      {
-         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);
+         std::ofstream pvtu_out(vtu_prefix + GeneratePVTUFileName("data"));
         WritePVTUHeader(pvtu_out);

         // Grid function fields and coefficient fields
@@ -1066,10 +1055,8 @@ void ParaViewDataCollection::Save()
         const std::string &q_field_name = q_field.first;
         std::string q_fname = GeneratePVTUPath() + "/"
                               + GeneratePVTUFileName(q_field_name);
-         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);
+
+         std::ofstream pvtu_out(col_path + "/" + q_fname);
         WritePVTUHeader(pvtu_out);
         int vec_dim = q_field.second->GetVDim();
         pvtu_out << "<PPointData>\n";
@@ -90,8 +90,8 @@ void map_quadrature_data_to_fields_impl(
   }
   else
   {
-      MFEM_ABORT_KERNEL("quadrature data mapping to field is not implemented"
-                        " for this field descriptor");
+      MFEM_ABORT("quadrature data mapping to field is not implemented for"
+                 " this field descriptor");
   }
 }

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

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

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

@@ -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 method
-    ComputeElementFlux().
+    The required BilinearFormIntegrator must implement the methods
+    ComputeElementFlux() and ComputeFluxEnergy().

    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 method
-                       ComputeElementFlux().
+       @param integ    This BilinearFormIntegrator must implement the methods
+                       ComputeElementFlux() and ComputeFluxEnergy().
       @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 method
-                       ComputeElementFlux().
+       @param integ    This BilinearFormIntegrator must implement the methods
+                       ComputeElementFlux() and ComputeFluxEnergy().
       @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
@@ -663,59 +663,58 @@ const
   #pragma omp critical (DofToQuad)
 #endif
   {
-      // Do not run if the new Dof2Quad is already present, e.g. added in a
-      // previous call or added by another omp thread.
+      // If the new Dof2Quad is already present, e.g. added in a previous call
+      // or added by another omp thread, return.
      if (DofToQuad::SearchArray(dof2quad_array, ir,
-                                 DofToQuad::LEXICOGRAPHIC_FULL) == nullptr)
+                                 DofToQuad::LEXICOGRAPHIC_FULL))
+      { return; }
+
+      // 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++)
      {
-         // 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 d = 0; d < b_dim; d++)
         {
-            for (int d = 0; d < b_dim; d++)
+            for (int j = 0; j < dof; j++)
            {
-               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 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)
-            {
-               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);
      }

+      const int g_dim = [this]()
+      {
+         switch (deriv_type)
+         {
+            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);
   }
 }

@@ -1044,50 +1043,9 @@ void VectorFiniteElement::SetDerivMembers()
   switch (map_type)
   {
      case H_DIV:
-         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);
-         }
+         deriv_type = DIV;
+         deriv_range_type = SCALAR;
+         deriv_map_type = INTEGRAL;
         break;
      case H_CURL:
         switch (dim)
@@ -1105,49 +1063,13 @@ void VectorFiniteElement::SetDerivMembers()
               break;
            case 1:
               deriv_type = NONE;
-               deriv_range_type = UNKNOWN_RANGE_TYPE;
-               deriv_map_type = UNKNOWN_MAP_TYPE;
+               deriv_range_type = SCALAR;
+               deriv_map_type = INTEGRAL;
               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);
   }
@@ -295,20 +295,10 @@ 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
@@ -340,28 +330,12 @@ 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 and the
-       width of the DenseMatrix argument in
-       CalcVShape(const IntegrationPoint &ip, DenseMatrix &shape). */
+       which is also the dimension of the interpolation operation. */
   int GetRangeDim() const { return vdim; }

-   /** @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). */
+   /// Returns the dimension of the curl for vector-valued finite elements.
   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; }

@@ -1016,8 +990,6 @@ 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
@@ -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*(dim+1))/2);
+   DenseMatrix ddu(dof, dim);
 #endif

   poly1d.CalcBasis(p, ip.x, shape_x, dshape_x, ddshape_x);
@@ -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_R1D, FunctionSpace::Pk)
+                         H_CURL, 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_R1D, FunctionSpace::Pk),
+                         H_CURL, 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_R2D, FunctionSpace::Pk),
+                         H_CURL, 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_R2D, FunctionSpace::Pk),
+                         H_CURL, FunctionSpace::Pk),
     tk(tk_fe),
     dof_map(dof),
     dof2tk(dof)
@@ -663,9 +663,6 @@ 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;

@@ -708,9 +705,6 @@ 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;

@@ -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_R1D, FunctionSpace::Pk),
+                         H_DIV, 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_R2D, FunctionSpace::Pk),
+                         H_DIV, 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_R2D, FunctionSpace::Pk),
+                         H_DIV, FunctionSpace::Pk),
     nk(nk_fe),
     dof_map(dof),
     dof2nk(dof)
@@ -510,9 +510,6 @@ 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;

@@ -550,9 +547,6 @@ 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,
@@ -282,7 +282,14 @@ 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++) { vdof[i] = UnsignIndex(vdof[i]); }
+   for (int i = 0; i < n; i++)
+   {
+      int j;
+      if ((j = vdof[i]) < 0)
+      {
+         vdof[i] = -1-j;
+      }
+   }
 }

 void FiniteElementSpace::GetElementVDofs(int i, Array<int> &vdofs,
@@ -476,14 +483,13 @@ void FiniteElementSpace::ReorderElementToDofTable()
   for (int k = 0, dof_counter = 0; k < nnz; k++)
   {
      const int sdof = J[k]; // signed dof
-      const int dof = UnsignIndex(sdof);
+      const int dof = (sdof < 0) ? -1-sdof : sdof;
      int new_dof = dof_marker[dof];
      if (new_dof < 0)
      {
         dof_marker[dof] = new_dof = dof_counter++;
      }
-      // Preserve the sign of sdof
-      J[k] = (sdof < 0) ? FlipIndexSign(new_dof) : new_dof;
+      J[k] = (sdof < 0) ? -1-new_dof : new_dof; // preserve the sign of sdof
   }
 }

@@ -541,7 +547,7 @@ void MarkDofs(const Array<int> &dofs, Array<int> &mark_array)
 {
   for (auto d : dofs)
   {
-      mark_array[UnsignIndex(d)] = -1;
+      mark_array[d >= 0 ? d : -1 - d] = -1;
   }
 }

@@ -925,7 +931,7 @@ void FiniteElementSpace::AddDependencies(
            if (std::abs(coef) > 1e-12)
            {
               const int mdof = master_dofs[j];
-               if (mdof != sdof && mdof != FlipIndexSign(sdof))
+               if (mdof != sdof && mdof != (-1-sdof))
               {
                  deps.Add(sdof, mdof, coef);
               }
@@ -1018,7 +1024,7 @@ int FiniteElementSpace::GetDegenerateFaceDofs(int index, Array<int> &dofs,
   // FiniteElementSpace::AddDependencies.

   Array<int> edof;
-   int order = GetEdgeDofs(FlipIndexSign(index), edof, variant);
+   int order = GetEdgeDofs(-1 - index, edof, variant);

   int nv = fec->DofForGeometry(Geometry::POINT);
   int ne = fec->DofForGeometry(Geometry::SEGMENT);
@@ -1704,8 +1710,8 @@ SparseMatrix *FiniteElementSpace::RefinementMatrix_main(

         for (int i = 0; i < fine_ldof; i++)
         {
-            const int r = DofToVDof(dofs[i], vd);
-            const int m = UnsignIndex(r);
+            int r = DofToVDof(dofs[i], vd);
+            int m = (r >= 0) ? r : (-1 - r);

            if (!mark[m])
            {
@@ -1766,7 +1772,7 @@ SparseMatrix *FiniteElementSpace::VariableOrderRefinementMatrix(
         for (int i = 0; i < fine_ldof; i++)
         {
            const int r = DofToVDof(dofs[i], vd);
-            const int m = UnsignIndex(r);
+            int m = (r >= 0) ? r : (-1 - r);

            if (!mark[m])
            {
@@ -2476,8 +2482,8 @@ SparseMatrix* FiniteElementSpace::DerefinementMatrix(int old_ndofs,
         {
            if (!std::isfinite(lR(i, 0))) { continue; }

-            const int r = DofToVDof(dofs[i], vd);
-            const int m = UnsignIndex(r);
+            int r = DofToVDof(dofs[i], vd);
+            int m = (r >= 0) ? r : (-1 - r);

            if (is_dg || !mark[m])
            {
@@ -3195,7 +3201,7 @@ void FiniteElementSpace::CalcEdgeFaceVarOrders(
            else
            {
               // degenerate face (i.e., edge-face constraint)
-               slave_orders |= edge_orders[FlipIndexSign(slave.index)];
+               slave_orders |= edge_orders[-1 - slave.index];
            }
         }

@@ -3934,16 +3940,6 @@ 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");
@@ -3974,11 +3970,6 @@ 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
 {
@@ -839,7 +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 function would give 15, not 10.
+       Then this fucntion would give 15, not 10.
       */
   int GetVectorDim() const;

@@ -1150,7 +1150,7 @@ public:

   /// Helper to return the DOF associated with a sign encoded DOF
   static inline int DecodeDof(int dof)
-   { return UnsignIndex(dof); }
+   { return (dof >= 0) ? dof : (-1 - dof); }

   /// Helper to determine the DOF and sign of a sign encoded DOF
   static inline int DecodeDof(int dof, real_t& sign)
@@ -1323,24 +1323,12 @@ 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;
@@ -30,7 +30,6 @@
 #include <cmath>
 #include <iostream>
 #include <algorithm>
-#include <queue>

 namespace mfem
 {
@@ -345,6 +344,27 @@ 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();
@@ -2029,18 +2049,6 @@ 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;

@@ -2193,9 +2201,6 @@ 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;
@@ -2349,9 +2354,6 @@ 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;
@@ -2627,7 +2629,6 @@ 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;
@@ -2943,7 +2944,6 @@ 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;
@@ -2973,7 +2973,6 @@ 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;
@@ -3030,14 +3029,9 @@ void GridFunction::ProjectCoefficient(Coefficient *coeff[])
   }
 }

-void GridFunction::ProjectDiscCoefficient(
-   std::variant<Coefficient*, VectorCoefficient*> coeff, Array<int> &dof_attr)
+void GridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff,
+                                          Array<int> &dof_attr)
 {
-   std::visit([&](auto* c)
-   {
-      MFEM_VERIFY(VectorDim() == c->GetVDim(), "coeff vdim != VectorDim()");
-   }, coeff);
-
   Array<int> vdofs;
   Vector vals;

@@ -3051,10 +3045,7 @@ void GridFunction::ProjectDiscCoefficient(
   {
      fes->GetElementVDofs(i, vdofs);
      vals.SetSize(vdofs.Size());
-      std::visit([&](auto* c)
-      {
-         fes->GetFE(i)->Project(*c, *fes->GetElementTransformation(i), vals);
-      }, coeff);
+      fes->GetFE(i)->Project(coeff, *fes->GetElementTransformation(i), vals);

      // the values in shared dofs are determined from the element with maximal
      // attribute
@@ -3070,15 +3061,17 @@ void GridFunction::ProjectDiscCoefficient(
   }
 }

+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);

@@ -3088,7 +3081,6 @@ 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);

@@ -3144,33 +3136,52 @@ void GridFunction::ProjectBdrCoefficient(Coefficient *coeff[],
 }

 void GridFunction::ProjectBdrCoefficientNormal(
-   Coefficient *coeff, VectorCoefficient *vcoeff, const Array<int> &bdr_attr)
+   VectorCoefficient &vcoeff, const Array<int> &bdr_attr)
 {
-   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)
-   {
-      MFEM_VERIFY(vcoeff->GetVDim() == fes->GetMesh()->SpaceDimension(),
-                  "vcoeff vdim (" << vcoeff->GetVDim()
-                  << ") != SpaceDimension ("
-                  << fes->GetMesh()->SpaceDimension() << ")");
-   }
+#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++)
+   {
+      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);
+   }
+#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;
-   Vector vc, nor, lvec;
+   int dim = vcoeff.GetVDim();
+   Vector vc(dim), nor(dim), lvec;
   DofTransformation doftrans;
-   if (vcoeff)
-   {
-      const int dim = vcoeff->GetVDim();
-      vc.SetSize(dim);
-      nor.SetSize(dim);
-   }

   for (int i = 0; i < fes->GetNBE(); i++)
   {
@@ -3186,22 +3197,15 @@ void GridFunction::ProjectBdrCoefficientNormal(
      {
         const IntegrationPoint &ip = ir.IntPoint(j);
         T->SetIntPoint(&ip);
-         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);
-         }
+         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(
@@ -5002,14 +5006,6 @@ 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)
@@ -5060,17 +5056,10 @@ GridFunction *Extrude1DGridFunction(Mesh *mesh, Mesh *mesh2d,
      return NULL;
   }
   FiniteElementSpace *solfes2d;
-   const int vdim = sol->FESpace()->GetVDim();
-   solfes2d = new FiniteElementSpace(mesh2d, solfec2d, vdim);
+   // assuming sol is scalar
+   solfes2d = new FiniteElementSpace(mesh2d, solfec2d);
   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);
@@ -5128,103 +5117,6 @@ 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
@@ -5305,467 +5197,6 @@ 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);
-}
-
-}
@@ -23,7 +23,6 @@
 #include <limits>
 #include <ostream>
 #include <string>
-#include <variant>

 namespace mfem
 {
@@ -80,18 +79,10 @@ protected:
                        bool wcoef,
                        int subdomain);

-   /** @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); };
+   /** 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);

   /** Helper function for ProjectCoefficientElementL2 */
   void ProjectCoefficientElementL2_(Coefficient &coeff, Vector &sol, Vector &Va);
@@ -159,13 +150,11 @@ public:

   FiniteElementCollection *OwnFEC() { return fec_owned; }

-   /** @brief Shortcut for calling FiniteElementSpace::GetVectorDim() on the
-       underlying #fes */
-   int VectorDim() const { return fes->GetVectorDim(); }
+   /// Shortcut for calling FiniteElementSpace::GetVectorDim() on the underlying #fes
+   int VectorDim() const;

-   /** @brief Shortcut for calling FiniteElementSpace::GetCurlDim() on the
-       underlying #fes */
-   int CurlDim() const { return fes->GetCurlDim(); }
+   /// Shortcut for calling FiniteElementSpace::GetCurlDim() on the underlying #fes
+   int CurlDim() const;

   /// Read only access to the (optional) internal true-dof Vector.
   const Vector &GetTrueVector() const
@@ -524,17 +513,10 @@ 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)
-   { ProjectDiscCoefficient(&coeff); }
+   virtual void ProjectDiscCoefficient(VectorCoefficient &coeff);

   enum AvgType {ARITHMETIC, HARMONIC};
   /** @brief Projects a discontinuous coefficient so that the values in shared
@@ -550,9 +532,6 @@ 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,
@@ -585,70 +564,6 @@ 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(). */
@@ -677,26 +592,15 @@ public:
   virtual void ProjectBdrCoefficient(Coefficient *coeff[],
                                      const Array<int> &attr);

-   /** @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. */
+   /** 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. */
   void ProjectBdrCoefficientNormal(VectorCoefficient &vcoeff,
-                                    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); }
+                                    const Array<int> &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 vector finite element GridFunction. */
+       on the boundary. Only boundary attributes that are marked in @a bdr_attr
+       are projected. Assumes ND-type VectorFE GridFunction. */
   virtual void ProjectBdrCoefficientTangent(VectorCoefficient &vcoeff,
                                             const Array<int> &bdr_attr);

@@ -1758,21 +1662,21 @@ public:
    */
   ///@{
   /// Computes the \ref PLBound for the gridfunction with number of control
-   /// 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
+   /// 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
   /// PLBound object used to compute the bounds.
-   /// We compute the bounds for each vdim if \p vdim < 1.
+   /// We compute the bounds for each vdim if @a 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 \p ref_factor, and returns the bounds for each element
-   /// ordered byNodes:
+   /// points based on @a ref_factor, and returns the bounds for each element
+   /// ordered byVDim:
   /// 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 \p vdim < 1.
+   /// We compute the bounds for each vdim if @a vdim < 1.
   PLBound GetElementBounds(Vector &lower, Vector &upper,
                            const int ref_factor=1, const int vdim=-1) const;

@@ -1783,18 +1687,6 @@ 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,
@@ -1802,45 +1694,11 @@ 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 byNodes:
+   /// are returned in @b lower and @b upper, ordered byVDim:
   /// 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.
@@ -1946,7 +1804,7 @@ real_t ComputeElementLpDistance(real_t p, int i,
                                GridFunction& gf1, GridFunction& gf2);


-/// Class used for extruding a scalar coefficient
+/// Class used for extruding scalar GridFunctions
 class ExtrudeCoefficient : public Coefficient
 {
 private:
@@ -1954,53 +1812,13 @@ 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)
-   { MFEM_VERIFY(n > 0, "Number of transverse elements must be positive!"); }
-
+      : n(n_), mesh_in(m), sol_in(s) { }
   real_t Eval(ElementTransformation &T, const IntegrationPoint &ip) override;
-
   virtual ~ExtrudeCoefficient() { }
 };

-/// 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
- */
+/// Extrude a scalar 1D GridFunction, after extruding the mesh with Extrude1D.
 GridFunction *Extrude1DGridFunction(Mesh *mesh, Mesh *mesh2d,
                                    GridFunction *sol, const int ny);

@@ -490,7 +490,7 @@ void FindPointsGSLIB::FindPointsOnDevice(const Vector &point_pos,
   }
   DEV.find_device = true;

-   const unsigned int id = gsl_comm->id, np = gsl_comm->np;
+   const int id = gsl_comm->id, np = gsl_comm->np;

   gsl_mfem_ref.SetSize(points_cnt * dim);
   gsl_mfem_elem.SetSize(points_cnt);
@@ -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 (static_cast<unsigned>(pp) == p->proc)
+            if (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 (size_t index = 0; index < outpt.n; index++)
+         for (int index = 0; index < outpt.n; index++)
         {
            int idx = ordering == Ordering::byNODES ?
                      opt->index + i*points_cnt :
@@ -1413,7 +1413,7 @@ void FindPointsGSLIB::SetupSplitMeshesAndIntegrationRules(const int order)
 {
   MFEM_VERIFY(mesh, "Setup FindPointsGSLIB with mesh first.");
   const int dof1D = order+1;
-   dim = mesh->Dimension();
+   const int dim = mesh->Dimension();

   SetupSplitMeshes();
   if (dim == 2)
@@ -2254,8 +2254,7 @@ void FindPointsGSLIB::DistributeInterpolatedValues(const Vector &int_vals,
      sarray_transfer(struct out_pt, outpt, proc, 1, cr);

      // Store received data
-      MFEM_VERIFY(outpt->n == static_cast<size_t>(points_cnt),
-                  "Incompatible size. Number of points "
+      MFEM_VERIFY(outpt->n == points_cnt, "Incompatible size. Number of points "
                  "received does not match the number of points originally "
                  "found using FindPoints.");

@@ -202,19 +202,13 @@ 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);
@@ -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 (static_cast<unsigned>(side_init) != (1u << ei))
+   if (side_init != (1u << ei))
   {
 #define ELX(d, j, k) elx[d][j + k * pN] // assumes lexicographic ordering
      for (int d = 0; d < 2; ++d)
@@ -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 (static_cast<unsigned>(side_init) != (1u << fi))
+   if (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 (static_cast<unsigned>(side_init) != (64u << ei))
+   if (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]]
@@ -197,21 +197,15 @@ 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 - ic * NDOF_C; // idx_i % NDOF_C
+         const int idx_ii = idx_i % NDOF_C;

         const int nx_i = (ic == 0) ? D1D : D1D-1;
         const int ny_i = (ic == 1) ? D1D : D1D-1;

-         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 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 real_t (&Bi1)[MQ1][MD1] = (ic == 0) ? r_Bc : r_Bo;
         const real_t (&Bi2)[MQ1][MD1] = (ic == 1) ? r_Bc : r_Bo;
@@ -220,18 +214,14 @@ 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 - jc * NDOF_C; // idx_j % NDOF_C
+            const int idx_jj = idx_j % NDOF_C;

            const int nx_j = (jc == 0) ? D1D : D1D-1;
            const int ny_j = (jc == 1) ? D1D : D1D-1;

-            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 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 real_t (&Bj1)[MQ1][MD1] = (jc == 0) ? r_Bc : r_Bo;
            const real_t (&Bj2)[MQ1][MD1] = (jc == 1) ? r_Bc : r_Bo;
@@ -171,15 +171,15 @@ template<int DIM, int T_SDIM, int T_D1D, int T_Q1D>
 VectorDiffusionIntegrator::ApplyKernelType
 VectorDiffusionIntegrator::ApplyPAKernels::Kernel()
 {
-   if constexpr (DIM == 2)
+   if (DIM == 2)
   {
      return internal::SmemPAVectorDiffusionApply2D<T_SDIM, T_D1D, T_Q1D>;
   }
-   else if constexpr (DIM == 3)
+   else if (DIM == 3)
   {
      return internal::SmemPAVectorDiffusionApply3D<T_SDIM, T_D1D, T_Q1D>;
   }
-   MFEM_ABORT("Unsupported kernel");
+   else { MFEM_ABORT("Unsupported kernel"); }
 }

 inline VectorDiffusionIntegrator::ApplyKernelType
@@ -182,15 +182,15 @@ template<int DIM, int T_D1D, int T_Q1D>
 VectorMassIntegrator::VectorMassAddMultPAType
 VectorMassIntegrator::VectorMassAddMultPA::Kernel()
 {
-   if constexpr (DIM == 2)
+   if (DIM == 2)
   {
      return internal::SmemPAVectorMassApply2D<T_D1D,T_Q1D>;
   }
-   else if constexpr (DIM == 3)
+   else if (DIM == 3)
   {
      return internal::SmemPAVectorMassApply3D<T_D1D, T_Q1D>;
   }
-   MFEM_ABORT("Unsupported kernel");
+   else { MFEM_ABORT("Unsupported kernel"); }
 }

 inline VectorMassIntegrator::VectorMassAddMultPAType
@@ -301,14 +301,18 @@ template <int DIM, int T_D1D, int T_Q1D>
 DomainLFIntegrator::AssembleKernelType
 DomainLFIntegrator::AssembleKernels::Kernel()
 {
-   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>; }
+   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>;
+   }
   MFEM_ABORT("");
 }
-
 /// \endcond DO_NOT_DOCUMENT

 } // namespace mfem
-
-#endif // MFEM_LININTEG_DOMAIN_KERNELS_HPP
+#endif
@@ -43,52 +43,56 @@ 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);
-      switch (dim)
+      x = p[0];
+      if (dim > 1)
      {
-         case 3: Set3(p); break;
-         case 2: Set2(p); break;
-         case 1: Set1(p); break;
+         y = p[1];
+         if (dim > 2)
+         {
+            z = p[2];
+         }
      }
   }

   void Get(real_t *p, const int dim) const
   {
      MFEM_ASSERT(1 <= dim && dim <= 3, "invalid dim: " << dim);
-      switch (dim)
+      p[0] = x;
+      if (dim > 1)
      {
-         case 3: p[2] = z;
-         case 2: p[1] = y;
-         case 1: p[0] = x;
+         p[1] = y;
+         if (dim > 2)
+         {
+            p[2] = z;
+         }
      }
   }
+
+   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.
@@ -121,6 +125,18 @@ 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)
   {
@@ -167,6 +183,14 @@ 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)
   {
@@ -185,37 +209,14 @@ private:
      AddTetPoints6(off + 6, a, bc, cb, 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)
+   // 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)
   {
-      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);
+      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);
   }

 public:
@@ -297,8 +297,7 @@ void LinearForm::Assemble()
         tr = mesh->GetBdrFaceTransformations(i);
         if (tr != NULL)
         {
-            mfem::DofTransformation doftrans;
-            fes -> GetElementVDofs (tr -> Elem1No, vdofs, doftrans);
+            fes -> GetElementVDofs (tr -> Elem1No, vdofs);
            for (int k = 0; k < boundary_face_integs.Size(); k++)
            {
               if (boundary_face_integs_marker[k] &&
@@ -308,7 +307,6 @@ void LinearForm::Assemble()
               boundary_face_integs[k]->
               AssembleRHSElementVect(*fes->GetFE(tr->Elem1No),
                                      *tr, elemvect);
-               doftrans.TransformDual(elemvect);
               AddElementVector (vdofs, elemvect);
            }
         }
@@ -164,8 +164,8 @@ private:

 public:
   /// Constructs the domain integrator $ (Q, \nabla v) $
-   DomainLFGradIntegrator(VectorCoefficient &QF, const IntegrationRule *ir = NULL)
-      : DeltaLFIntegrator(QF, ir), Q(QF) { }
+   DomainLFGradIntegrator(VectorCoefficient &QF)
+      : DeltaLFIntegrator(QF), Q(QF) { }

   bool SupportsDevice() const override { return true; }

@@ -158,16 +158,15 @@ 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[UnsignIndex(i)];
+               int idof_lor = vdof_lor[absdof(i)];
               i = dofmap_ho[off_ho + i1*n1 + i2*n2];
               int s2 = i < 0 ? -1 : 1;
-               int idof_ho = vdof_ho[UnsignIndex(i)];
+               int idof_ho = vdof_ho[absdof(i)];
               int s3 = idof_lor < 0 ? -1 : 1;
               int s4 = idof_ho < 0 ? -1 : 1;
               int s = s1*s2*s3*s4;
-               i = UnsignIndex(idof_ho);
-               perm_[UnsignIndex(idof_lor)] = s < 0 ? -1-UnsignIndex(i) :
-                                              UnsignIndex(i);
+               i = absdof(idof_ho);
+               perm_[absdof(idof_lor)] = s < 0 ? -1-absdof(i) : absdof(i);
            }
         }
      };
@@ -233,7 +232,7 @@ 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(UnsignIndex(j));
+         int t_j = pfes_ho->GetLocalTDofNumber(absdof(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))
         {
@@ -57,6 +57,8 @@ 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 };

@@ -424,7 +424,7 @@ void ParFiniteElementSpace::GetGroupComm(
            {
               if (ind[l] < 0)
               {
-                  dofs[l] = m + FlipIndexSign(ind[l]);
+                  dofs[l] = m + (-1-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 + FlipIndexSign(ind[l]);
+                  dofs[l] = m + (-1-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 + FlipIndexSign(ind[l]);
+                  dofs[l] = m + (-1-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[FlipIndexSign(dofs[i])] < 0)
+         if (ldof_sign[-1-dofs[i]] < 0)
         {
-            dofs[i] = FlipIndexSign(dofs[i]);
+            dofs[i] = -1-dofs[i];
         }
      }
      else
      {
         if (ldof_sign[dofs[i]] < 0)
         {
-            dofs[i] = FlipIndexSign(dofs[i]);
+            dofs[i] = -1-dofs[i];
         }
      }
   }
@@ -699,8 +699,7 @@ void ParFiniteElementSpace::GetSharedEdgeDofs(
      for (int i = 0; i < dofs.Size(); i++)
      {
         const int di = dofs[i];
-         dofs[i] = di >= 0 ? rdofs[di] :
-                   FlipIndexSign(rdofs[FlipIndexSign(di)]);
+         dofs[i] = (di >= 0) ? rdofs[di] : -1-rdofs[-1-di];
      }
   }
 }
@@ -724,8 +723,7 @@ void ParFiniteElementSpace::GetSharedTriangleDofs(
      for (int i = 0; i < dofs.Size(); i++)
      {
         const int di = dofs[i];
-         dofs[i] = di >= 0 ? rdofs[di] :
-                   FlipIndexSign(rdofs[FlipIndexSign(di)]);
+         dofs[i] = (di >= 0) ? rdofs[di] : -1-rdofs[-1-di];
      }
   }
 }
@@ -749,8 +747,7 @@ void ParFiniteElementSpace::GetSharedQuadrilateralDofs(
      for (int i = 0; i < dofs.Size(); i++)
      {
         const int di = dofs[i];
-         dofs[i] = (di >= 0) ? rdofs[di] :
-                   FlipIndexSign(rdofs[FlipIndexSign(di)]);
+         dofs[i] = (di >= 0) ? rdofs[di] : -1-rdofs[-1-di];
      }
   }
 }
@@ -1490,7 +1487,7 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()
         GetElementVDofs(my_elems[i], ldofs);
         for (int j = 0; j < ldofs.Size(); j++)
         {
-            int ldof = UnsignIndex(ldofs[j]);
+            int ldof = (ldofs[j] >= 0 ? ldofs[j] : -1-ldofs[j]);

            if (ldof_marker[ldof] != fn)
            {
@@ -1551,7 +1548,7 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()
         GetElementVDofs(my_elems[i], ldofs);
         for (int j = 0; j < ldofs.Size(); j++)
         {
-            int ldof = UnsignIndex(ldofs[j]);
+            int ldof = (ldofs[j] >= 0 ? ldofs[j] : -1-ldofs[j]);

            if (ldof_marker[ldof] != fn)
            {
@@ -1576,15 +1573,14 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()

      for (int i = 0; i < num_ldofs; i++)
      {
-         int ldof = UnsignIndex(ldofs_fn[i]);
+         int ldof = (ldofs_fn[i] >= 0 ? ldofs_fn[i] : -1-ldofs_fn[i]);
         ldof_marker[ldof] = i;
      }

      for ( ; j < j_end; j++)
      {
-         const int ldof = UnsignIndex(send_J[j]);
-         send_J[j] = (send_J[j] >= 0 ? ldof_marker[ldof] :
-                      FlipIndexSign(ldof_marker[ldof]));
+         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]);
      }
   }

@@ -1676,7 +1672,12 @@ void ParFiniteElementSpace::ExchangeFaceNbrData()
   {
      for (int j_end = face_nbr_ldof.GetI()[fn+1]; j < j_end; j++)
      {
-         const int ldof = UnsignIndex(face_nbr_ldof.GetJ()[j]);
+         int ldof = face_nbr_ldof.GetJ()[j];
+         if (ldof < 0)
+         {
+            ldof = -1-ldof;
+         }
+
         face_nbr_glob_dof_map[j] = dof_face_nbr_offsets[fn] + ldof;
      }
   }
@@ -1720,7 +1721,7 @@ 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 = FlipIndexSign(el2);
+   el2 = -1 - 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);
@@ -1736,8 +1737,7 @@ 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] :
-                 FlipIndexSign(vol_vdofs[FlipIndexSign(ldof)]);
+      vdofs[j] = (ldof >= 0) ? vol_vdofs[ldof] : -1-vol_vdofs[-1-ldof];
   }
 }

@@ -2061,8 +2061,8 @@ void ParFiniteElementSpace::GetGhostFaceDofs(const MeshId &face_id,

         for (int j = 0; j < ne; j++)
         {
-            dofs[offset++] = (ind[j] >= 0) ? (first + ind[j]) :
-                             FlipIndexSign(first + FlipIndexSign(ind[j]));
+            dofs[offset++] = (ind[j] >= 0) ? (first + ind[j])
+                             /*         */ : (-1 - (first + (-1 - ind[j])));
         }
      }
      else
@@ -2072,8 +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]) :
-                             FlipIndexSign(first + FlipIndexSign(ind[j]));
+            dofs[offset++] = (ind[j] >= 0) ? (first + ind[j])
+                             /*         */ : (-1 - (first + (-1 - ind[j])));
         }
      }
   }
@@ -2866,7 +2866,7 @@ void NeighborRowMessage::Encode(int rank)

            if (ind && (edof = ind[edof]) < 0)
            {
-               edof = FlipIndexSign(edof);
+               edof = -1 - edof;
               s = -1;
            }

@@ -3067,10 +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 = UnsignIndex(edof);
+         edof = (edof < 0) ? -1 - edof : edof;
         if (ind && (edof = ind[edof]) < 0)
         {
-            edof = FlipIndexSign(edof);
+            edof = -1 - edof;
            s *= -1.0;
         }

@@ -3121,10 +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 = UnsignIndex(edof);
+            edof = (edof < 0) ? -1 - edof : edof;
            if (ind && (edof = ind[edof]) < 0)
            {
-               edof = FlipIndexSign(edof);
+               edof = -1 - edof;
               s *= -1.0;
            }

@@ -4405,9 +4405,12 @@ ParFiniteElementSpace::RebalanceMatrix(int old_ndofs,
         {
            for (int j = 0; j < dofs.Size(); j++)
            {
-               const int row = UnsignIndex(DofToVDof(dofs[j], vd));
-               const int col = UnsignIndex(DofToVDof(old_dofs[j], vd,
-                                                     old_ndofs));
+               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; }
+
               i_diag[row] = col;
            }
         }
@@ -4432,7 +4435,9 @@ ParFiniteElementSpace::RebalanceMatrix(int old_ndofs,
      {
         for (int j = 0; j < dofs.Size(); j++)
         {
-            const int row = UnsignIndex(DofToVDof(dofs[j], vd));
+            int row = DofToVDof(dofs[j], vd);
+            if (row < 0) { row = -1 - row; }
+
            if (i_diag[row] == i_diag[row+1]) // diag row empty?
            {
               i_offd[row] = old_dofs[j + vd * dofs.Size()];
@@ -4541,9 +4546,9 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
   {
      const Embedding &emb = dtrans.embeddings[k];

-      const int fine_rank = old_ranks[k];
-      const int coarse_rank = (emb.parent < 0) ? FlipIndexSign(emb.parent)
-                              : old_pncmesh->ElementRank(emb.parent);
+      int fine_rank = old_ranks[k];
+      int coarse_rank = (emb.parent < 0) ? (-1 - emb.parent)
+                        : old_pncmesh->ElementRank(emb.parent);

      if (coarse_rank != MyRank && fine_rank == MyRank)
      {
@@ -4631,8 +4636,8 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
            {
               if (!std::isfinite(lR(i, 0))) { continue; }

-               const int r = DofToVDof(dofs[i], vd);
-               const int m = UnsignIndex(r);
+               int r = DofToVDof(dofs[i], vd);
+               int m = (r >= 0) ? r : (-1 - r);

               if (is_dg || !mark[m])
               {
@@ -4681,7 +4686,8 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
            {
               if (!std::isfinite(lR(i, 0))) { continue; }

-               const int m = UnsignIndex(DofToVDof(dofs[i], vd));
+               int r = DofToVDof(dofs[i], vd);
+               int m = (r >= 0) ? r : (-1 - r);

               if (is_dg || !mark[m])
               {
@@ -545,8 +545,6 @@ 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)
@@ -717,8 +715,7 @@ void ParGridFunction::ProjectCoefficientElementL2(VectorCoefficient &vcoeff)
 }


-void ParGridFunction::ProjectDiscCoefficient(
-   std::variant<Coefficient*, VectorCoefficient*> coeff)
+void ParGridFunction::ProjectDiscCoefficient(VectorCoefficient &coeff)
 {
   // local maximal element attribute for each dof
   Array<int> ldof_attr;
@@ -764,9 +761,6 @@ void ParGridFunction::ProjectDiscCoefficient(

 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.

@@ -792,8 +786,6 @@ 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);
@@ -866,12 +858,6 @@ 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)
 {
@@ -1582,39 +1568,6 @@ 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
@@ -63,12 +63,6 @@ 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; }

@@ -274,6 +268,11 @@ 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;
@@ -281,7 +280,8 @@ public:
   using GridFunction::ProjectBdrCoefficient;

   void ProjectBdrCoefficient(VectorCoefficient &vcoeff,
-                              const Array<int> &attr) override;
+                              const Array<int> &attr) override
+   { ProjectBdrCoefficient(NULL, &vcoeff, attr); }

   void ProjectBdrCoefficient(Coefficient *coeff[],
                              const Array<int> &attr) override
@@ -609,18 +609,6 @@ 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. */
@@ -321,17 +321,12 @@ void ParL2FaceRestriction::DoubleValuedConformingMult(
   const int vd = vdim;
   const bool t = byvdim;
   const int threshold = ndofs;
-   const int nsdofs = pfes.GetFaceNbrVSize() / vd;
+   const int nsdofs = pfes.GetFaceNbrVSize();
   auto d_indices1 = scatter_indices1.Read();
   auto d_indices2 = scatter_indices2.Read();
   auto d_x = Reshape(x.Read(), t?vd:ndofs, t?ndofs: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_x_shared = Reshape(face_nbr_data.Read(),
+                             t?vd:nsdofs, t?nsdofs:vd);
   auto d_y = Reshape(y.Write(), nface_dofs, vd, 2, nf);
   mfem::forall(nfdofs, [=] MFEM_HOST_DEVICE (int i)
   {
@@ -351,9 +346,8 @@ void ParL2FaceRestriction::DoubleValuedConformingMult(
         }
         else if (idx2>=threshold) // shared boundary
         {
-            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);
+            d_y(dof, c, 1, face) = d_x_shared(t?c:(idx2-threshold),
+                                              t?(idx2-threshold):c);
         }
         else // true boundary
         {
@@ -271,7 +271,10 @@ 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
-   values.MakeRef(GetMemory(), vdim*s_offset, vdim, sl_size);
+   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);
 }

 inline void QuadratureFunction::GetValues(
@@ -334,16 +334,17 @@ template<int DIM, int SDIM, int D1D, int Q1D>
 QuadratureInterpolator::DetKernelType
 QuadratureInterpolator::DetKernels::Kernel()
 {
-   if constexpr (DIM == 1)
+   if (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>; }
+      if (SDIM == 1) { return internal::quadrature_interpolator::Det1D; }
+      else if (SDIM == 2) { return internal::quadrature_interpolator::Det1DSurface<D1D, Q1D, 2>; }
+      else if (SDIM == 3) { return internal::quadrature_interpolator::Det1DSurface<D1D, Q1D, 3>; }
+      else { MFEM_ABORT(""); }
   }
-   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("");
+   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(""); }
 }

 /// @endcond
@@ -203,10 +203,10 @@ template<int DIM, QVectorLayout Q_LAYOUT,
 QuadratureInterpolator::TensorEvalKernelType
 QuadratureInterpolator::TensorEvalKernels::Kernel()
 {
-   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("");
+   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(""); }
 }

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

 /// @endcond
@@ -592,10 +592,10 @@ template<int DIM, QVectorLayout Q_LAYOUT, bool GRAD_PHYS, int VDIM, int D1D,
 QuadratureInterpolator::GradKernelType
 QuadratureInterpolator::GradKernels::Kernel()
 {
-   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("");
+   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(""); }
 }

 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 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("");
+   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(""); }
 }

 /// @endcond
@@ -752,10 +752,10 @@ template <int DIM, int VDIM, int ND, int NQ>
 EvalKernel QuadratureInterpolator::EvalKernels::Kernel()
 {
   using namespace internal::quadrature_interpolator;
-   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("");
+   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(""); }
 }

 template <int DIM>
@@ -844,6 +844,8 @@ 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,
@@ -866,9 +868,9 @@ 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 = UnsignIndex(s_volume_dof);
+      const int volume_dof = absdof(s_volume_dof);
      const int s_global_dof = elem_map[elem_index*elem_dofs + volume_dof];
-      const int global_dof = UnsignIndex(s_global_dof);
+      const int global_dof = absdof(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];
@@ -895,10 +897,10 @@ 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 = UnsignIndex(s_volume_dof);
+      const int volume_dof = absdof(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 = UnsignIndex(s_global_dof);
+      const int global_dof = absdof(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;
@@ -1398,17 +1400,20 @@ 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];
-      // Encode the volume DOF index and element index
-      const int global_dof_elem2 = elem_index*elem_dofs + volume_dof_elem2;
+      const int global_dof_elem2 = face_nbr_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
 }
@@ -4102,11 +4102,8 @@ void TMOP_Integrator::GetSurfaceFittingErrors(const Vector &d_loc,
 #ifdef MFEM_USE_MPI
      // Don't count the overlapping DOFs in parallel.
      // The pfes might be ordered byVDIM, while the loop goes consecutively.
-      if (parallel)
-      {
-         const int dof_i = pfes->DofToVDof(i, 0);
-         if (pfes->GetLocalTDofNumber(dof_i) < 0) { continue; }
-      }
+      const int dof_i = pfes->DofToVDof(i, 0);
+      if (parallel && pfes->GetLocalTDofNumber(dof_i) < 0) { continue; }
 #endif

      dof_cnt++;
@@ -114,22 +114,10 @@ public:
   Array<T> &operator=(const Array<T> &src) { src.Copy(*this); return *this; }

   /// Move assignment operator
-   /** If *this is a non-owning view (e.g., from MakeRef()), the data is copied
-       so that the base is also modified. */
   Array<T> &operator=(Array<T> &&src)
   {
      if (this == &src) { return *this; }
-      // If *this is a non-owning view (alias), and its capacity is sufficient
-      // to contain src, then copy into *this so that the alias's base memory is
-      // modified.
-      if (!OwnsData() && Capacity() >= src.Size())
-      {
-         *this = src; // Copy assignment.
-      }
-      else
-      {
-         Swap(src); // Swap the pointers only.
-      }
+      Swap(src);  // Swap does not use move assignment!
      src.DeleteAll();
      return *this;
   }
@@ -263,9 +251,6 @@ public:
   /// Make this Array a reference to 'master'.
   inline void MakeRef(const Array &master);

-   /// Make this Array a reference to the given sub-Memory of @a base.
-   inline void MakeRef(Memory<T> &base, int offset, int size_);
-
   /// Reset the Array to use the given external Memory @a mem and size @a s.
   /** If @a own_mem is false, the Array will not own any of the pointers of
       @a mem.
@@ -1088,14 +1073,6 @@ inline void Array<T>::MakeRef(const Array &master)
   data.MakeAlias(master.GetMemory(), 0, size);
 }

-template <class T>
-inline void Array<T>::MakeRef(Memory<T> &base, int offset, int size_)
-{
-   data.Delete();
-   size = size_;
-   data.MakeAlias(base, offset, size_);
-}
-
 template <class T>
 inline void Array<T>::NewMemoryAndSize(
   const Memory<T> &mem, int s, bool own_mem)
@@ -14,7 +14,6 @@

 #include "../config/config.hpp"
 #include "array.hpp"
-#include "text.hpp"

 #include <iostream>
 #include <map>
@@ -248,8 +247,7 @@ inline void ArraysByName<T>::Print(std::ostream &os, int width) const
   os << data.size() << '\n';
   for (auto const &it : data)
   {
-      // Note: The method Load() can read any string formatted with std::quoted.
-      os << std::quoted(it.first) << '\n' << it.second.Size() << '\n';
+      os << '"' << it.first << '"' << '\n' << it.second.Size() << '\n';
      it.second.Print(os, width > 0 ? width : it.second.Size());
   }
 }
@@ -260,36 +258,31 @@ void ArraysByName<T>::Load(std::istream &in)
   int NumArrays;
   in >> NumArrays;

-   for (int i = 0; i < NumArrays; i++)
+   std::string ArrayLine, ArrayName;
+   for (int i=0; i < NumArrays; i++)
   {
      in >> std::ws;
-      // Read the name:
-      // - If the stream 'in' starts with " then parse it with the function
-      //   parse_quoted_string() from text.hpp. In this case, the name can be
-      //   empty. Note: this case allows for reading any string formatted using
-      //   std::quoted, e.g. as in the method Print().
-      // - If the name does not start with " then the name ends with the first
-      //   white space character (and the white space character is not included
-      //   in the name). Since white space characters are skipped before reading
-      //   the name, there will be at least one non-white-space character in the
-      //   name in this case.
-      std::string ArrayName;
-      if (in.peek() == '"')
+      getline(in, ArrayLine);
+
+      std::size_t q0 = ArrayLine.find('"');
+      std::size_t q1 = ArrayLine.rfind('"');
+
+      if (q0 != std::string::npos && q1 > q0)
      {
-         if (parse_quoted_string(ArrayName, in) != 0)
-         {
-            MFEM_ABORT("error parsing input!");
-         }
+         // Locate set name between first and last double quote
+         ArrayName = ArrayLine.substr(q0+1,q1-q0-1);
      }
      else
      {
-         in >> ArrayName;
-         MFEM_VERIFY(in.good(), "error parsing input!");
+         // If no double quotes found locate set name using white space
+         q1 = ArrayLine.find(' ');
+         ArrayName = ArrayLine.substr(0,q1-1);
      }

-      // Read the array
-      data[ArrayName].Load(in);
+      // Ignore the remainder of the line which may contain explanatory comments
+      data[ArrayName].Load(in, 0);
   }
+
 }

 }
@@ -726,16 +726,16 @@ std::string Device::GetUUID(const int device_id)
   MFEM_GPU_CHECK(cudaGetDeviceProperties(&prop, device_id));
   for (int i = 0; i < 16; ++i)
   {
-      const unsigned b = static_cast<unsigned char>(prop.uuid.bytes[i]);
-      res << std::setfill('0') << std::setw(2) << std::hex << b;
+      res << std::setfill('0') << std::setw(2) << std::hex
+          << static_cast<unsigned>(prop.uuid.bytes[i]);
   }
 #elif defined(MFEM_USE_HIP)
   hipUUID uuid;
   MFEM_GPU_CHECK(hipDeviceGetUuid(&uuid, device_id));
   for (int i = 0; i < 16; ++i)
   {
-      const unsigned b = static_cast<unsigned char>(uuid.bytes[i]);
-      res << std::setfill('0') << std::setw(2) << std::hex << b;
+      res << std::setfill('0') << std::setw(2) << std::hex
+          << static_cast<unsigned>(uuid.bytes[i]);
   }
 #endif
   return res.str();
@@ -113,10 +113,6 @@ void SetGlobalMPI_Comm(MPI_Comm comm);
 /// to suppress the warning.
 const char* GetEnv(const char* name);

-/// Signed indices i -> -1 - i are used as a convention to encode orientation.
-inline MFEM_HOST_DEVICE int FlipIndexSign(int i) { return -1 - i; }
-inline MFEM_HOST_DEVICE int UnsignIndex(int i) { return i < 0 ? -1 - i : i; }
-
 } // namespace mfem

 #endif
@@ -759,9 +759,7 @@ private:
   {
      switch (mt)
      {
-         case MT::HOST_DEBUG:
-            if (GetEnv("MFEM_MMU_STD")) { return new StdHostMemorySpace(); }
-            return new MmuHostMemorySpace();
+         case MT::HOST_DEBUG: return new MmuHostMemorySpace();
 #ifdef MFEM_USE_UMPIRE
         case MT::HOST_UMPIRE:
            return new UmpireHostMemorySpace(
@@ -790,9 +788,7 @@ private:
         case MT::DEVICE_UMPIRE: return new NoDeviceMemorySpace();
         case MT::DEVICE_UMPIRE_2: return new NoDeviceMemorySpace();
 #endif
-         case MT::DEVICE_DEBUG:
-            if (GetEnv("MFEM_MMU_STD")) { return new StdDeviceMemorySpace(); }
-            return new MmuDeviceMemorySpace();
+         case MT::DEVICE_DEBUG: return new MmuDeviceMemorySpace();
         case MT::DEVICE:
         {
 #if defined(MFEM_USE_CUDA)
@@ -50,48 +50,6 @@ inline void filter_dos(std::string &line)
   }
 }

-/** @brief Read a string formatted using std::quoted. Return nonzero on error.
-
-    The stream @a in must begin with @a delim. After clearing @a result and
-    extracting the opening @a delim, characters are extracted from @a in and
-    processed as follows:
-    - if the character is @a delim, return 0;
-    - if the character is different from @a escape, it is appended to @a result;
-    - if the character is @a escape, the next character from @a in is extracted
-      and if it is one of @a delim or @a escape, it is appended to @a result;
-      otherwise, both @a escape and the character after it are appended to
-      @a result; note that the latter case is not possible if the input was
-      formatted with std::quoted with the same @a delim and @a escape
-      characters.
-
-    If the stream @a in does not begin with @a delim, error code 1 is returned.
-    If reading the stream fails, error code 2 is returned. On success, zero is
-    returned and the closing @a delim character is the last character extracted
-    from @a in. */
-inline int parse_quoted_string(std::string &result, std::istream &in,
-                               char delim = '"', char escape = '\\')
-{
-   using tt = std::string::traits_type;  // std::char_traits<char>
-   auto equal = [](tt::int_type c1, tt::char_type c2) -> bool
-   {
-      return tt::eq_int_type(c1, tt::to_int_type(c2));
-   };
-   result.clear();
-   if (!equal(in.peek(), delim)) { return 1; }
-   in.get();  // extract delim
-   for (auto c = in.get(); !equal(c, delim); c = in.get())
-   {
-      if (equal(c, escape))
-      {
-         c = in.get();
-         if (!equal(c, escape) && !equal(c, delim)) { result += escape; }
-      }
-      if (!in) { return 2; }
-      result += tt::to_char_type(c);
-   }
-   return 0;
-}
-
 /// Convert an integer to a 0-padded string with the given number of @a digits
 inline std::string to_padded_string(int i, int digits)
 {
@@ -23,7 +23,6 @@ list(APPEND SRCS
  complex_operator.cpp
  constraints.cpp
  densemat.cpp
-  eigensolvers.cpp
  filteredsolver.cpp
  handle.cpp
  matrix.cpp
@@ -56,7 +55,7 @@ list(APPEND HDRS
  dinvariants.hpp
  dtensor.hpp
  dual.hpp
-  eigensolvers.hpp
+  eigensolver.hpp
  filteredsolver.hpp
  handle.hpp
  invariants.hpp
@@ -103,11 +102,6 @@ if (MFEM_USE_MPI)
  endif()
 endif()

-if (MFEM_USE_ARPACK)
-  list(APPEND SRCS arpack.cpp)
-  list(APPEND HDRS arpack.hpp)
-endif()
-
 if (MFEM_USE_SUNDIALS)
  list(APPEND SRCS sundials.cpp)
  list(APPEND HDRS sundials.hpp)
@@ -1,271 +0,0 @@
-// Copyright (c) 2010-2025, Lawrence Livermore National Security, LLC. Produced
-// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
-// LICENSE and NOTICE for details. LLNL-CODE-806117.
-//
-// This file is part of the MFEM library. For more information and source code
-// availability visit https://mfem.org.
-//
-// MFEM is free software; you can redistribute it and/or modify it under the
-// terms of the BSD-3 license. We welcome feedback and contributions, see file
-// CONTRIBUTING.md for details.
-
-#ifndef MFEM_ARPACK
-#define MFEM_ARPACK
-
-#include "../config/config.hpp"
-
-#ifdef MFEM_USE_ARPACK
-
-#include <string>
-
-#ifdef MFEM_USE_MPI
-#include <mpi.h>
-#include "hypre.hpp"
-#endif
-
-#include "operator.hpp"
-
-#define SSAUPD  ssaupd_
-#define SSEUPD  sseupd_
-#define DSAUPD  dsaupd_
-#define DSEUPD  dseupd_
-
-#ifdef MFEM_USE_MPI
-#define PSSAUPD pssaupd_
-#define PSSEUPD psseupd_
-#define PDSAUPD pdsaupd_
-#define PDSEUPD pdseupd_
-#endif
-
-extern "C" void SSAUPD(int *ido, char *bmat, int *n,
-                       char *which, int *nev, float *tol, float *resid,
-                       int *ncv, float *v, int *ldv,
-                       int *iparam, int *ipntr,
-                       float *workd, float *workl, int *lworkl, int *info);
-
-extern "C" void SSEUPD(int *, char *, int *, float *,
-                       float *, int *, float *, char *, int *, char *,
-                       int *, float *, float *, int *, float *,
-                       int *, int  *, int *, float *,
-                       float *, int *, int *);
-
-extern "C" void DSAUPD(int *ido, char *bmat, int *n,
-                       char *which, int *nev, double *tol, double *resid,
-                       int *ncv, double *v, int *ldv,
-                       int *iparam, int *ipntr,
-                       double *workd, double *workl, int *lworkl, int *info);
-
-extern "C" void DSEUPD(int *, char *, int *, double *,
-                       double *, int *, double *, char *, int *, char *,
-                       int *, double *, double *, int *, double *,
-                       int *, int  *, int *, double *,
-                       double *, int *, int *);
-
-#ifdef MFEM_USE_MPI
-
-extern "C" void PSSAUPD(int *comm, int *ido, char *bmat, int *n,
-                        char *which, int *nev, float *tol, float *resid,
-                        int *ncv, float *v, int *ldv,
-                        int *iparam, int *ipntr,
-                        float *workd, float *workl, int *lworkl, int *info);
-
-extern "C" void PSSEUPD(int *comm, int *, char *, int *, float *,
-                        float *, int *, float *, char *, int *, char *,
-                        int *, float *, float *, int *, float *,
-                        int *, int  *, int *, float *,
-                        float *, int *, int *);
-
-extern "C" void PDSAUPD(int *comm, int *ido, char *bmat, int *n,
-                        char *which, int *nev, double *tol, double *resid,
-                        int *ncv, double *v, int *ldv,
-                        int *iparam, int *ipntr,
-                        double *workd, double *workl, int *lworkl, int *info);
-
-extern "C" void PDSEUPD(int *comm, int *, char *, int *, double *,
-                        double *, int *, double *, char *, int *, char *,
-                        int *, double *, double *, int *, double *,
-                        int *, int  *, int *, double *,
-                        double *, int *, int *);
-
-#endif
-
-extern "C" {
-   void arpackgetcommdbg_(int *,int *,int *);
-   void arpacksetcommdbg_(int *,int *,int *);
-   void arpacksymdbg_(int *,int *,int *,int *,int *,int *,int *);
-   void arpacknonsymdbg_(int *,int *,int *,int *,int *,int *,int *);
-   void arpackcmplxdbg_(int *,int *,int *,int *,int *,int *,int *);
-}
-
-namespace mfem
-{
-
-/// Wrapper for the ARPACK routine SSAUPD or DSAUPD
-class ArPackSAUPD : public SymEigensolver, public SymGenEigensolver
-{
-public:
-
-   ArPackSAUPD();
-   virtual ~ArPackSAUPD();
-
-   /** ARPACK modes are described in section 3.5 of the ARPACK manual.
-       Mode 1: regular mode to solve A x = lambda x
-               No solver and no mass matrix are needed.
-       Mode 2: regular inverse mode to solve A x = lambda M x
-               Both A and M are needed and the solver should compute M^{-1}.
-       Mode 3: shift-invert mode to solve either A x = lambda x
-               or A x = lambda M x
-               Mass matrix is optional.  The solver should compute
-               (A-sigma I)^{-1} or (A-sigma M)^{-1}.  The shift parameter,
-               sigma, also needs to be set with SetShift().
-       Mode 4: Buckling mode to solve K x = lambda K_G x
-               K is set using SetMassMatrix(), K_G is set using SetOperator(),
-          and the solver should compute (K-sigma K_G)^{-1}.  The shift
-               parameter, sigma, also needs to be set with SetShift().
-       Mode 5: Cayley mode to solve A x = lambda M x
-               Both A and M are needed and the solver should compute
-               (A - sigma M)^{-1}.  The shift parameter, sigma, also needs
-               to be set with SetShift().
-    */
-   void SetMode(int mode);
-
-   inline void SetTol(real_t tol) override         {      tol_ = tol;      }
-   inline void SetMaxIter(int max_iter) override   { max_iter_ = max_iter; }
-   inline void SetPrintLevel(int logging) override {  logging_ = logging;  }
-   inline void SetShift(real_t sigma)              {    sigma_ = sigma;    }
-   inline void SetNumModes(int num_eigs) override  {      nev_ = num_eigs; }
-
-   virtual void SetSolver(Solver & solver);
-   virtual void SetOperator(const Operator & A) override;
-   virtual void SetMassMatrix(const Operator & M);
-   virtual void SetOperators(const Operator & A, const Operator & B) override
-   { SetOperator(A); SetMassMatrix(B); }
-
-   void Solve() override;
-
-   virtual int GetNumConverged() const override { return iparam_[4]; }
-
-   /// Collect the converged eigenvalues
-   virtual void GetEigenvalues(Array<real_t> & eigenvalues) const override;
-
-   /// Extract a single eigenvector
-   virtual const Vector & GetEigenvector(unsigned int i) const override;
-
-   /// Transfer ownership of the converged eigenvectors
-   Vector ** StealEigenvectors() override;
-
-protected:
-
-   int myid_;       // Index of this processor
-   int max_iter_;
-   int logging_;
-
-   // The following variables are for ARPACK
-   int nloc_;       // number of items stored locally
-   int nev_;        // number of requested eigenvalues
-   int ncv_;        // number of ritz vectors
-   int rvec_;       // boolean to return eigenvectors as well
-   int mode_;       // 1 = standard, 2 = generalized, 3 = shift invert,
-   // 4 = buckling, 5 = Cayley
-   int lworkl_;     // length of lworkl_ work array
-   int iparam_[12]; // arpack parameters
-   int ipntr_[12];  // arpack pointers
-
-   char bmat_;      // I for standard problem, G for generalized
-   char which_[3];  // spectrum portion: LA, SA, LM, SM, BE
-   char hwmny_;     // DSEUPD: A for all eigenvalues, S for some
-
-   real_t tol_;     // relative accuracy bound for Ritz values
-   real_t sigma_;   // eigenvalue shift parameter
-
-   int    * select_;// workspace used during eigenvalue computation
-   real_t * dv_;    // Ritz values
-   real_t * v_;     // ncv Lanczos basis vectors
-   real_t * resid_; // residual vector
-   real_t * workd_; // work array for 3 vectors used in Arnoldi iteration
-   real_t * workl_; // work array
-
-   // Operators and Vectors needed outside of ARPACK
-   Solver   * solver_;
-   const Operator * A_;
-   const Operator * B_;
-
-   Vector * w_;
-   Vector * x_;
-   Vector * y_;
-   Vector * z_;
-
-   mutable Vector ** eigenvectors_;
-
-   std::string solverName_;
-
-   void reverseComm();
-
-   int reverseCommMode1();
-   int reverseCommMode2();
-   int reverseCommMode3();
-   int reverseCommMode4();
-   int reverseCommMode5();
-
-   virtual void prepareEigenvectors() const;
-
-   void printErrors(const int & info, const int iparam[],
-                    const char & bmat, const int & n,
-                    const char which[],
-                    const int & nev, const int & ncv,
-                    const int & lworkl );
-
-private:
-
-   virtual int computeNlocf() { return nloc_; }
-   virtual int computeIter(int & ido);
-   virtual int computeEigs();
-
-};
-
-#ifdef MFEM_USE_MPI
-
-class ArPackPSAUPD : public ArPackSAUPD
-{
-public:
-   ArPackPSAUPD(MPI_Comm comm);
-   virtual ~ArPackPSAUPD() {}
-
-   void SetOperator(const Operator & A);
-   void SetMassMatrix(const Operator & M);
-
-   /// Collect the converged eigenvalues
-   void GetEigenvalues(Array<real_t> & eigenvalues) const;
-
-   /// Extract a single eigenvector
-   const Vector & GetEigenvector(unsigned int i) const;
-
-   /// Transfer ownership of the converged eigenvectors
-   // HypreParVector ** StealEigenvectors();
-   Vector ** StealEigenvectors();
-
-protected:
-
-   void prepareEigenvectors() const;
-
-private:
-
-   MPI_Comm comm_;
-   MPI_Fint commf_; // Fortran style MPI communicator
-   int numProcs_;   // Number of processors
-
-   mutable HYPRE_Int * part_; // parallel partitioning for eigenvectors
-
-   int computeNlocf();
-   int computeIter(int & ido);
-   int computeEigs();
-
-};
-
-#endif // MFEM_USE_MPI
-
-};
-
-#endif // MFEM_USE_ARPACK
-
-#endif // MFEM_ARPACK
@@ -82,15 +82,6 @@ public:
      }
   }

-   /// Make the DenseMatrix to reference the given sub-Memory of @a base.
-   /** The DenseMatrix does not assume ownership of the data array, i.e. it will
-       not delete the @a base Memory. */
-   void MakeRef(Memory<real_t> &base, int offset, int h, int w)
-   {
-      data.MakeRef(base, offset, h*w);
-      height = h; width = w;
-   }
-
   /// Change the data array and the size of the DenseMatrix.
   /** The DenseMatrix does not assume ownership of the data array, i.e. it will
       not delete the data array @a d. */
@@ -0,0 +1,203 @@
+// Copyright (c) 2010-2025, Lawrence Livermore National Security, LLC. Produced
+// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
+// LICENSE and NOTICE for details. LLNL-CODE-806117.
+//
+// This file is part of the MFEM library. For more information and source code
+// availability visit https://mfem.org.
+//
+// MFEM is free software; you can redistribute it and/or modify it under the
+// terms of the BSD-3 license. We welcome feedback and contributions, see file
+// CONTRIBUTING.md for details.
+
+/**
+ * @file eigensolver.hpp
+ *
+ * @brief This file contains a common interface for all eigensolver classes
+ */
+
+#ifndef MFEM_EIGENSOLVER
+#define MFEM_EIGENSOLVER
+
+#ifdef MFEM_HYPRE
+#include "hypre.hpp"
+#endif
+
+#ifdef MFEM_SLEPC
+#include "slepc.hpp"
+#endif
+
+namespace mfem
+{
+
+enum class EigenSolverType
+{
+   HYPRE,
+   SLEPC,
+   INVALID_TYPE
+};
+
+/// Provides base class for MFEM Eigensolvers
+class EigenSolverBase
+{
+public:
+   EigenSolverBase() {}
+
+   /// Destructor
+   virtual ~EigenSolverBase() = default;
+
+   /// Solves the eigenvalue problem
+   virtual void Solve() = 0;
+
+   /// Set the required number of modes
+   virtual void SetNumModes(int num_Modes)
+   {
+      numModes=num_Modes;
+   }
+
+   /// @brief  Set the operator to the eigenvalue problem
+   /// @param A - operator
+   virtual void SetOperator(Operator& A) = 0;
+
+   /// @brief Sets operators for the generalized eigenvalue problem
+   /// @param A - operator
+   /// @param M - mass matrix
+   virtual void SetOperator(Operator& A, Operator& M)
+   {
+      MFEM_ABORT("Generalized eigensolver is not supported!");
+   }
+
+   /// Optional method - sets preconditioner for the
+   /// eigenvalue solver.
+   virtual void SetPreconditioner(Solver& precond)
+   {
+      MFEM_ABORT("Preconditioner is not supported!");
+   }
+
+   /// Returns the converged eigenvalues
+   virtual void GetEigenvalues(Array<real_t>& eigen_vals) = 0;
+
+   /// Returns the vec_index eigenvector.
+   virtual void GetEigenvector(int vec_index, Vector& vector) = 0;
+
+   /// Returns the eigensolver type.
+   EigenSolverType GetSolverType() { return eigSolverType; }
+
+protected:
+   int numModes = 0;
+   EigenSolverType eigSolverType = EigenSolverType::INVALID_TYPE;
+};
+
+#ifdef MFEM_HYPRE
+class EigenSolverHypreLOBPCG : public EigenSolverBase
+{
+public:
+   EigenSolverHypreLOBPCG(MPI_Comm comm)
+   {
+      eigenSolver = std::make_unique<HypreLOBPCG>(comm);
+      eigSolverType = EigenSolverType::HYPRE;
+   }
+
+   ~EigenSolverHypreLOBPCG() {}
+
+   void Solve() override { eigenSolver->Solve(); }
+   void SetNumModes(int num_Modes) override
+   {
+      eigenSolver->SetNumModes(num_Modes);
+      numModes = num_Modes;
+   }
+
+   void SetOperator(Operator& A) override { eigenSolver->SetOperator(A); }
+
+   void SetOperator(Operator& A, Operator& M) override
+   {
+      eigenSolver->SetOperator(A);
+      eigenSolver->SetMassMatrix(M);
+   }
+
+   void SetPreconditioner(Solver& precond) override { eigenSolver->SetPreconditioner(precond); }
+   void GetEigenvalues(Array<real_t>& eigen_vals) override { eigenSolver->GetEigenvalues(eigen_vals); }
+   void GetEigenvector(int vec_index, Vector& vector) override
+   {
+      const HypreParVector& eigenvec = eigenSolver->GetEigenvector(vec_index);
+      vector = eigenvec;
+   }
+
+   void SetTol(real_t tol) { eigenSolver->SetTol(tol); }
+   void SetRelTol(real_t rel_tol) { eigenSolver->SetRelTol(rel_tol); }
+   void SetMaxIter(int max_iter) { eigenSolver->SetMaxIter(max_iter); }
+   void SetPrintLevel(int logging) { eigenSolver->SetPrintLevel(logging); }
+   void SetRandomSeed(int seed) { eigenSolver->SetRandomSeed(seed); }
+   void SetPrecondUsageMode(int usage_mode) { eigenSolver->SetPrecondUsageMode(usage_mode); }
+
+private:
+   std::unique_ptr<HypreLOBPCG> eigenSolver = nullptr;
+};
+#endif
+
+#ifdef MFEM_SLEPC
+class EigenSolverSlepc : public EigenSolverBase
+{
+public:
+   EigenSolverSlepc(MPI_Comm comm)
+   {
+      eigSolverType = EigenSolverType::SLEPC;
+      eigenSolver = std::make_unique<SlepcEigenSolver>(comm);
+
+      eigenSolver->SetWhichEigenpairs(SlepcEigenSolver::TARGET_REAL);
+      eigenSolver->SetTarget(0.0);
+      eigenSolver->SetSpectralTransformation(SlepcEigenSolver::SHIFT_INVERT);
+   }
+
+   ~EigenSolverSlepc() {}
+
+   void Solve() override { eigenSolver->Solve(); }
+   void SetNumModes(int num_Modes) override
+   {
+      eigenSolver->SetNumModes(num_Modes);
+      numModes = num_Modes;
+   }
+   /// @brief  Set the operator to the slepc eigenvalue problem. This method deep copies data to create a PetscParMatrix
+   /// @param A - operator, must be of type HypreParMatrix.
+   void SetOperator(Operator& A) override
+   {
+      petscMatA = std::make_unique<PetscParMatrix>
+                  (dynamic_cast<HypreParMatrix*>(&A));
+      eigenSolver->SetOperator(*petscMatA);
+   }
+   /// @brief  Set the operators to the slepc eigenvalue problem. This method deep copies data to create a PetscParMatrix
+   /// @param A - operator, must be of type HypreParMatrix.
+   /// @param M - operator, must be of type HypreParMatrix.
+   void SetOperator(Operator& A, Operator& M) override
+   {
+      petscMatA = std::make_unique<PetscParMatrix>
+                  (dynamic_cast<const HypreParMatrix*>(&A));
+      petscMatM = std::make_unique<PetscParMatrix>
+                  (dynamic_cast<const HypreParMatrix*>(&M));
+
+      eigenSolver->SetOperators(*petscMatA, *petscMatM);
+   }
+   void SetPreconditioner([[maybe_unused]] Solver& precond) override {}
+   void GetEigenvalues(Array<real_t>& eigen_vals) override
+   {
+      eigen_vals.SetSize(numModes);
+      for (int ik = 0; ik < numModes; ik++)
+      {
+         eigenSolver->GetEigenvalue(static_cast<unsigned int>(ik), eigen_vals[ik]);
+      }
+   }
+   void GetEigenvector( int vec_index, Vector& vector) override
+   { eigenSolver->GetEigenvector(vec_index, vector); }
+
+   void SetTol(real_t tol) { eigenSolver->SetTol(tol); }
+   void SetMaxIter(int max_iter) { eigenSolver->SetMaxIter(max_iter); }
+
+private:
+   std::unique_ptr<SlepcEigenSolver> eigenSolver = nullptr;
+   std::unique_ptr<PetscParMatrix> petscMatA = nullptr;
+   std::unique_ptr<PetscParMatrix> petscMatM = nullptr;
+};
+#endif
+
+}  // namespace mfem
+
+#endif
@@ -1,20 +0,0 @@
-// Copyright (c) 2010-2025, Lawrence Livermore National Security, LLC. Produced
-// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
-// LICENSE and NOTICE for details. LLNL-CODE-806117.
-//
-// This file is part of the MFEM library. For more information and source code
-// availability visit https://mfem.org.
-//
-// MFEM is free software; you can redistribute it and/or modify it under the
-// terms of the BSD-3 license. We welcome feedback and contributions, see file
-// CONTRIBUTING.md for details.
-
-#include "linalg.hpp"
-#include "eigensolvers.hpp"
-
-using namespace std;
-
-namespace mfem
-{
-
-};
@@ -1,396 +0,0 @@
-// Copyright (c) 2010-2025, Lawrence Livermore National Security, LLC. Produced
-// at the Lawrence Livermore National Laboratory. All Rights reserved. See files
-// LICENSE and NOTICE for details. LLNL-CODE-806117.
-//
-// This file is part of the MFEM library. For more information and source code
-// availability visit https://mfem.org.
-//
-// MFEM is free software; you can redistribute it and/or modify it under the
-// terms of the BSD-3 license. We welcome feedback and contributions, see file
-// CONTRIBUTING.md for details.
-
-#ifndef MFEM_EIGENSOLVERS
-#define MFEM_EIGENSOLVERS
-
-#include "vector.hpp"
-
-namespace mfem
-{
-
-/// Abstract Eigenequation
-/// Defines the operator of the linear eigenvalue equation
-///    A x_i = lambda_i x_i
-/// Where A is a real-valued operator, the lambda_i are the eigenvalues,
-/// and x_i are the eigenvectors.
-class Eigenequation
-{
-protected:
-   Eigenequation() = default;
-
-public:
-   virtual ~Eigenequation() = default;
-
-   /// @brief Set the operator A of the eigenvalue equation
-   virtual void SetOperator(const Operator & A) = 0;
-};
-
-/// Abstract Complex-valued Eigenequation
-/// Defines the operator of the linear eigenvalue equation
-///    A x_i = lambda_i x_i
-/// Where A is a complex-valued operator, the lambda_i are the eigenvalues,
-/// and x_i are the eigenvectors.
-class ComplexEigenequation
-{
-protected:
-   ComplexEigenequation() = default;
-
-public:
-   virtual ~ComplexEigenequation() = default;
-
-   /// @brief Set the real and imaginary parts of the operator A
-   virtual void SetOperator(const Operator & Ar, const Operator & Ai) = 0;
-};
-
-/// Abstract Generalized Eigenequation
-/// Defines the operator of the linear eigenvalue equation
-///    A x_i = lambda_i B x_i
-/// Where A and B are real-valued operators, the lambda_i are the eigenvalues,
-/// and x_i are the eigenvectors.
-class GenEigenequation
-{
-protected:
-   GenEigenequation() = default;
-
-public:
-   virtual ~GenEigenequation() = default;
-
-   /// @brief Set the operators A and B of the generalized eigenvalue equation
-   virtual void SetOperators(const Operator & A, const Operator & B) = 0;
-};
-
-/// Abstract Complex-valued Generalized Eigenequation
-/// Defines the operator of the linear eigenvalue equation
-///    A x_i = lambda_i B x_i
-/// Where A and B are complex-valued operators, the lambda_i are the
-/// eigenvalues, and x_i are the eigenvectors.
-class ComplexGenEigenequation
-{
-protected:
-   ComplexGenEigenequation() = default;
-
-public:
-   virtual ~ComplexGenEigenequation() = default;
-
-   /// @brief Set the real and imaginary parts of the operators A and B
-   virtual void SetOperators(const Operator & Ar, const Operator & Ai,
-                             const Operator & Br, const Operator & Bi) = 0;
-};
-
-/// Abstract Eigensolver
-/// Computes eigenvalue/eigenvector pairs for the linear system
-///    A x_i = lambda_i x_i
-/// Where the lambda_i are the eigenvalues and x_i are the eigenvectors.
-class EigensolverBase
-{
-protected:
-   EigensolverBase() = default;
-
-public:
-   virtual ~EigensolverBase() = default;
-
-   /// @brief Stopping criteria based on numerical tolerance
-   ///
-   /// @note This may be defined differently by different solvers.
-   virtual void SetTol(real_t tol) = 0;
-
-   /// @brief Stopping criteria based on number of iterations required to
-   /// reach convergence.
-   ///
-   /// @note This may also be defined differently in different solvers.
-   virtual void SetMaxIter(int max_iter) = 0;
-
-   /// @brief Controls the type and amount of information printed to
-   ///        standard output.
-   virtual void SetPrintLevel(int logging) = 0;
-
-   /// @brief Set the number of desired eigenmodes to compute
-   virtual void SetNumModes(int num_eigs) = 0;
-
-   /// @brief Get the number of converged eigenmodes
-   virtual int GetNumConverged() const = 0;
-
-   /// @brief Perform the eigenvalue solve
-   virtual void Solve() = 0;
-};
-
-/// Symmetric Eigensolver
-/// If A^T = A the linear system must have real-valued eigenvalues
-/// and eigenvectors.
-class SymEigensolver : public EigensolverBase, public Eigenequation
-{
-protected:
-   SymEigensolver() = default;
-
-public:
-   virtual ~SymEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should equal the number of converged eigenvalues.
-   virtual void GetEigenvalues(Array<real_t> & eigenvalues) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, numConverged). The
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain numConverged vectors.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-/// Symmetric Generalized Eigensolver
-/// If A^T = A and M^T = M the linear system must have real-valued eigenvalues
-/// and eigenvectors.
-class SymGenEigensolver : public EigensolverBase, public GenEigenequation
-{
-protected:
-   SymGenEigensolver() = default;
-
-public:
-   virtual ~SymGenEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should equal the number of converged eigenvalues.
-   virtual void GetEigenvalues(Array<real_t> & eigenvalues) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, numConverged). The
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain numConverged vectors.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-/// Hermetian Eigensolver
-/// If A^H = A the linear system must have real-valued eigenvalues
-/// but may have complex-valued eigenvectors.
-class HermEigensolver : public EigensolverBase, public ComplexEigenequation
-{
-protected:
-   HermEigensolver() = default;
-
-public:
-   virtual ~HermEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should equal the number of converged eigenvalues.
-   virtual void GetEigenvalues(Array<real_t> & eigenvalues) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, 2*numConverged). The
-   /// vectors corresponding to even indices are the real parts of the
-   /// converged eigenvectors and the odd indices correspond to the
-   /// imaginary parts.
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain 2*numConverged vectors with the even
-   /// indices corresponding to the real parts of the converged
-   /// eigenvectors and the odd indices corresponding to the imaginary
-   /// parts.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-/// Hermetian Generalized Eigensolver
-/// If A^H = A and M^H = M the linear system must have real-valued eigenvalues
-/// but may have complex-valued eigenvectors.
-class HermGenEigensolver :
-   public EigensolverBase, public ComplexGenEigenequation
-{
-protected:
-   HermGenEigensolver() = default;
-
-public:
-   virtual ~HermGenEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should equal the number of converged eigenvalues.
-   virtual void GetEigenvalues(Array<real_t> & eigenvalues) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, 2*numConverged). The
-   /// vectors corresponding to even indices are the real parts of the
-   /// converged eigenvectors and the odd indices correspond to the
-   /// imaginary parts.
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain 2*numConverged vectors with the even
-   /// indices corresponding to the real parts of the converged
-   /// eigenvectors and the odd indices corresponding to the imaginary
-   /// parts.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-/// Non-Symmetric Eigensolver
-/// For general real-valued operators A the linear system must have
-/// eigenvalues and eigenvectors which form complex conjugate pairs.
-class NonSymEigensolver : public EigensolverBase, public Eigenequation
-{
-protected:
-   NonSymEigensolver() = default;
-
-public:
-   virtual ~NonSymEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should be the number of converged
-   /// eigenvalues. The complex-valued eigenvalues can be constructed
-   /// as: lambda_{2*j} = eig[2*j]+i*eig[2*j+1] and
-   /// lambda_{2*j+1} = eig[2*j]-i*eig[2*j+1]
-   /// With j in the range [0, numConverged/2)
-   virtual void GetEigenvalues(Array<real_t> & eig) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, numConverged). The
-   /// vectors corresponding to even indices are the real parts of the
-   /// converged eigenvectors and the odd indices correspond to the
-   /// imaginary parts. If needed, the complex conjugate pairs of
-   /// eigenvectors can be constructed in the same manner described
-   /// for the eigenvalues.
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain numConverged vectors with the even
-   /// indices corresponding to the real parts of the converged
-   /// eigenvectors and the odd indices corresponding to the imaginary
-   /// parts.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-/// Non-Symmetric Eigensolver
-/// For general real-valued operators A and M the linear system must have
-/// eigenvalues and eigenvectors which form complex conjugate pairs.
-class NonSymGenEigensolver : public EigensolverBase, public GenEigenequation
-{
-protected:
-   NonSymGenEigensolver() = default;
-
-public:
-   virtual ~NonSymGenEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should be the number of converged
-   /// eigenvalues. The complex-valued eigenvalues can be constructed
-   /// as: lambda_{2*j} = eig[2*j]+i*eig[2*j+1] and
-   /// lambda_{2*j+1} = eig[2*j]-i*eig[2*j+1]
-   /// With j in the range [0, numConverged/2)
-   virtual void GetEigenvalues(Array<real_t> & eig) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, numConverged). The
-   /// vectors corresponding to even indices are the real parts of the
-   /// converged eigenvectors and the odd indices correspond to the
-   /// imaginary parts. If needed, the complex conjugate pairs of
-   /// eigenvectors can be constructed in the same manner described
-   /// for the eigenvalues.
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain numConverged vectors with the even
-   /// indices corresponding to the real parts of the converged
-   /// eigenvectors and the odd indices corresponding to the imaginary
-   /// parts.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-/// Complex Eigensolver
-/// Can have arbitrary complex-valued eigenvalues and eigenvectors
-class ComplexEigensolver : public EigensolverBase, public ComplexEigenequation
-{
-protected:
-   ComplexEigensolver() = default;
-
-public:
-   virtual ~ComplexEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should be twice the number of converged
-   /// eigenvalues. The complex-valued eigenvalues can be constructed
-   /// as: lambda_j = eig[2*j]+i*eig[2*j+1]
-   virtual void GetEigenvalues(Array<real_t> & eig) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, 2*numConverged). The
-   /// vectors corresponding to even indices are the real parts of the
-   /// converged eigenvectors and the odd indices correspond to the
-   /// imaginary parts.
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain 2*numConverged vectors with the even
-   /// indices corresponding to the real parts of the converged
-   /// eigenvectors and the odd indices corresponding to the imaginary
-   /// parts.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-/// Complex Generalized Eigensolver
-/// Can have arbitrary complex-valued eigenvalues and eigenvectors
-class ComplexGenEigensolver :
-   public EigensolverBase, public ComplexGenEigenequation
-{
-protected:
-   ComplexGenEigensolver() = default;
-
-public:
-   virtual ~ComplexGenEigensolver() = default;
-
-   /// @brief Collect the converged eigenvalues
-   ///
-   /// The length of the array should be twice the number of converged
-   /// eigenvalues. The complex-valued eigenvalues can be constructed
-   /// as: lambda_j = eig[2*j]+i*eig[2*j+1]
-   virtual void GetEigenvalues(Array<real_t> & eig) const = 0;
-
-   /// @brief Extract a single eigenvector
-   ///
-   /// The index i should be in the range [0, 2*numConverged). The
-   /// vectors corresponding to even indices are the real parts of the
-   /// converged eigenvectors and the odd indices correspond to the
-   /// imaginary parts.
-   virtual const Vector & GetEigenvector(unsigned int i) const = 0;
-
-   /// @brief Transfer ownership of the converged eigenvectors
-   ///
-   /// The array should contain 2*numConverged vectors with the even
-   /// indices corresponding to the real parts of the converged
-   /// eigenvectors and the odd indices corresponding to the imaginary
-   /// parts.
-   virtual Vector ** StealEigenvectors() = 0;
-};
-
-}
-
-#endif
@@ -317,9 +317,6 @@ void HypreParVector::WrapHypreParVector(hypre_ParVector *y, bool owner)

 Vector * HypreParVector::GlobalVector() const
 {
-   MFEM_VERIFY(size > 0,
-               "GlobalVector method can only be called on vectors wherein each "
-               "process owns one or more entries");
   hypre_Vector *hv = hypre_ParVectorToVectorAll(*this);
   Vector *v = new Vector(hv->data, internal::to_int(hv->size));
   v->MakeDataOwner();
@@ -6556,7 +6553,7 @@ HypreLOBPCG::SetPreconditioner(Solver & precond)
 }

 void
-HypreLOBPCG::SetOperator(const Operator & A)
+HypreLOBPCG::SetOperator(Operator & A)
 {
   HYPRE_BigInt locSize = A.Width();

@@ -6603,7 +6600,7 @@ HypreLOBPCG::SetOperator(const Operator & A)
 }

 void
-HypreLOBPCG::SetMassMatrix(const Operator & M)
+HypreLOBPCG::SetMassMatrix(Operator & M)
 {
   matvec_fn.MatvecCreate  = this->OperatorMatvecCreate;
   matvec_fn.Matvec        = this->OperatorMatvec;
@@ -6624,7 +6621,7 @@ HypreLOBPCG::GetEigenvalues(Array<real_t> & eigs) const
   }
 }

-const Vector &
+const HypreParVector &
 HypreLOBPCG::GetEigenvector(unsigned int i) const
 {
   return multi_vec->GetVector(i);
@@ -6866,24 +6863,6 @@ HypreAME::SetPreconditioner(HypreSolver & precond)
   ams_precond = &precond;
 }

-void
-HypreAME::SetOperators(const Operator & opA, const Operator & opB)
-{
-   const HypreParMatrix * A = dynamic_cast<const HypreParMatrix *>(&opA);
-   if (A == NULL)
-   {
-      mfem_error("HypreAME::SetOperator : first operator not HypreParMatrix!");
-   }
-   SetOperator(*A);
-
-   const HypreParMatrix * B = dynamic_cast<const HypreParMatrix *>(&opB);
-   if (B == NULL)
-   {
-      mfem_error("HypreAME::SetOperator : second operator not HypreParMatrix!");
-   }
-   SetMassMatrix(*B);
-}
-
 void
 HypreAME::SetOperator(const HypreParMatrix & A)
 {
@@ -6942,7 +6921,7 @@ HypreAME::createDummyVectors() const
   }
 }

-const Vector &
+const HypreParVector &
 HypreAME::GetEigenvector(unsigned int i) const
 {
   if ( eigenvectors == NULL )
@@ -6953,7 +6932,7 @@ HypreAME::GetEigenvector(unsigned int i) const
   return *eigenvectors[i];
 }

-Vector **
+HypreParVector **
 HypreAME::StealEigenvectors()
 {
   if ( eigenvectors == NULL )
@@ -6962,11 +6941,11 @@ HypreAME::StealEigenvectors()
   }

   // Set the local pointers to NULL so that they won't be deleted later
-   Vector ** vecs = (Vector**)eigenvectors;
+   HypreParVector ** vecs = eigenvectors;
   eigenvectors = NULL;
   multi_vec = NULL;

-   return (Vector**)vecs;
+   return vecs;
 }

 }
@@ -18,9 +18,7 @@

 #include "../general/globals.hpp"
 #include "sparsemat.hpp"
-#include "eigensolvers.hpp"
 #include "hypre_parcsr.hpp"
-#include "eigensolvers.hpp"
 #include <mpi.h>

 // Enable internal hypre timing routines
@@ -2148,7 +2146,7 @@ public:
    A. Knyazev, M. Argentati, I. Lashuk, and E. Ovtchinnikov, SISC, 29(5),
    2224-2239, 2007.
 */
-class HypreLOBPCG : public SymGenEigensolver
+class HypreLOBPCG
 {
 private:
   MPI_Comm comm;
@@ -2238,43 +2236,38 @@ public:
   HypreLOBPCG(MPI_Comm comm);
   ~HypreLOBPCG();

-   void SetTol(real_t tol) override;
+   void SetTol(real_t tol);
   // not implemented in HYPRE
   // real_t GetTol() const;
   void SetRelTol(real_t rel_tol);
   // not implemented in HYPRE
   // real_t GetRelTol() const;
-   void SetMaxIter(int max_iter) override;
+   void SetMaxIter(int max_iter);
   // not implemented in HYPRE
   // int GetMaxIter() const;
-   void SetPrintLevel(int logging) override;
-   void SetNumModes(int num_eigs) override { nev = num_eigs; }
+   void SetPrintLevel(int logging);
+   void SetNumModes(int num_eigs) { nev = num_eigs; }
   void SetPrecondUsageMode(int pcg_mode);
   void SetRandomSeed(int s) { seed = s; }
   void SetInitialVectors(int num_vecs, HypreParVector ** vecs);

   // The following four methods support general operators
   void SetPreconditioner(Solver & precond);
-   void SetOperators(const Operator & A, const Operator & B) override
-   { SetOperator(A); SetMassMatrix(B); }
-   void SetOperator(const Operator & A);
-   void SetMassMatrix(const Operator & M);
+   void SetOperator(Operator & A);
+   void SetMassMatrix(Operator & M);
   void SetSubSpaceProjector(Operator & proj) { subSpaceProj = &proj; }

   /// Solve the eigenproblem
-   void Solve() override;
-
-   int GetNumConverged() const override { return nev; }
+   void Solve();

   /// Collect the converged eigenvalues
-   void GetEigenvalues(Array<real_t> & eigenvalues) const override;
+   void GetEigenvalues(Array<real_t> & eigenvalues) const;

   /// Extract a single eigenvector
-   const Vector & GetEigenvector(unsigned int i) const override;
+   const HypreParVector & GetEigenvector(unsigned int i) const;

   /// Transfer ownership of the converged eigenvectors
-   Vector ** StealEigenvectors() override
-   { return (Vector**)multi_vec->StealVectors(); }
+   HypreParVector ** StealEigenvectors() { return multi_vec->StealVectors(); }
 };

 /** AME eigenvalue solver in hypre
@@ -2299,7 +2292,7 @@ public:
    mass matrix but it seems unlikely that this would be useful so it is not the
    default behavior.
 */
-class HypreAME : public SymGenEigensolver
+class HypreAME
 {
 private:
   int myid;
@@ -2328,31 +2321,28 @@ public:
   HypreAME(MPI_Comm comm);
   ~HypreAME();

-   void SetTol(real_t tol) override;
+   void SetTol(real_t tol);
   void SetRelTol(real_t rel_tol);
-   void SetMaxIter(int max_iter) override;
-   void SetPrintLevel(int logging) override;
-   void SetNumModes(int num_eigs) override;
+   void SetMaxIter(int max_iter);
+   void SetPrintLevel(int logging);
+   void SetNumModes(int num_eigs);

   // The following four methods support operators of type HypreParMatrix.
   void SetPreconditioner(HypreSolver & precond);
-   void SetOperators(const Operator & opA, const Operator & opB) override;
   void SetOperator(const HypreParMatrix & A);
   void SetMassMatrix(const HypreParMatrix & M);

   /// Solve the eigenproblem
-   void Solve() override;
-
-   int GetNumConverged() const override { return nev; }
+   void Solve();

   /// Collect the converged eigenvalues
-   void GetEigenvalues(Array<real_t> & eigenvalues) const override;
+   void GetEigenvalues(Array<real_t> & eigenvalues) const;

   /// Extract a single eigenvector
-   const Vector & GetEigenvector(unsigned int i) const override;
+   const HypreParVector & GetEigenvector(unsigned int i) const;

   /// Transfer ownership of the converged eigenvectors
-   Vector ** StealEigenvectors() override;
+   HypreParVector ** StealEigenvectors();
 };

 }
@@ -28,7 +28,6 @@
 #include "symmat.hpp"
 #include "ode.hpp"
 #include "solvers.hpp"
-#include "eigensolvers.hpp"
 #include "handle.hpp"
 #include "invariants.hpp"
 #include "constraints.hpp"
@@ -58,10 +57,6 @@
 #include "ginkgo.hpp"
 #endif

-#ifdef MFEM_USE_ARPACK
-#include "arpack.hpp"
-#endif
-
 #ifdef MFEM_USE_MKL_PARDISO
 #include "pardiso.hpp"
 #endif
@@ -844,22 +844,6 @@ public:
 };


-/// Zero Operator N: x -> 0.
-class ZeroOperator : public Operator
-{
-public:
-   /// Create an zero operator of size @a n.
-   explicit ZeroOperator(int n) : Operator(n) { }
-
-   /// Operator application
-   void Mult(const Vector &x, Vector &y) const override
-   { y.SetSize(width); y = 0_r; }
-
-   /// Application of the transpose
-   void MultTranspose(const Vector &x, Vector &y) const override
-   { y.SetSize(width); y = 0_r; }
-};
-
 /// Identity Operator I: x -> x.
 class IdentityOperator : public Operator
 {
@@ -38,13 +38,6 @@
 #if PETSC_VERSION_LT(3,19,0)
 #define PETSC_SUCCESS 0
 #endif
-#if PETSC_VERSION_LT(3,23,0)
-#define PetscContainerSetCtxDestroy(A,B) PetscContainerSetUserDestroy(A,B)
-typedef PetscErrorCode (PetscCtxDestroyFn)(void**);
-#endif
-#if PETSC_VERSION_LT(3,24,0)
-typedef PetscErrorCode KSPMonitorFn(KSP,PetscInt,PetscReal,void*);
-#endif

 #include <fstream>
 #include <iomanip>
@@ -84,17 +77,13 @@ static PetscErrorCode __mfem_mat_shell_apply_transpose(Mat,Vec,Vec);
 static PetscErrorCode __mfem_mat_shell_destroy(Mat);
 static PetscErrorCode __mfem_mat_shell_copy(Mat,Mat,MatStructure);
 #if PETSC_VERSION_LT(3,23,0)
-typedef void *PetscCtxRt;
-#elif PETSC_VERSION_LT(3,25,0)
-typedef void **PetscCtxRt;
-#endif
-static PetscErrorCode __mfem_array_container_destroy(PetscCtxRt);
-static PetscErrorCode __mfem_matarray_container_destroy(PetscCtxRt);
-#if PETSC_VERSION_LT(3,23,0)
-static PetscErrorCode __mfem_monitor_ctx_destroy(void**);
+static PetscErrorCode __mfem_array_container_destroy(void*);
+static PetscErrorCode __mfem_matarray_container_destroy(void *);
 #else
-static PetscErrorCode __mfem_monitor_ctx_destroy(PetscCtxRt);
+static PetscErrorCode __mfem_array_container_destroy(void**);
+static PetscErrorCode __mfem_matarray_container_destroy(void**);
 #endif
+static PetscErrorCode __mfem_monitor_ctx_destroy(void**);

 // auxiliary functions
 static PetscErrorCode Convert_Array_IS(MPI_Comm,bool,const mfem::Array<int>*,
@@ -1328,7 +1317,11 @@ BlockDiagonalConstructor(MPI_Comm comm,

         ierr = PetscContainerCreate(comm,&c); CCHKERRQ(comm,ierr);
         ierr = PetscContainerSetPointer(c,ptrs[i]); CCHKERRQ(comm,ierr);
+#if PETSC_VERSION_LT(3,23,0)
+         ierr = PetscContainerSetUserDestroy(c,__mfem_array_container_destroy);
+#else
         ierr = PetscContainerSetCtxDestroy(c,__mfem_array_container_destroy);
+#endif
         CCHKERRQ(comm,ierr);
         ierr = PetscObjectCompose((PetscObject)A,names[i],(PetscObject)c);
         CCHKERRQ(comm,ierr);
@@ -1655,7 +1648,11 @@ void PetscParMatrix::ConvertOperator(MPI_Comm comm, const Operator &op, Mat* A,
         PetscContainer c;
         ierr = PetscContainerCreate(comm,&c); CCHKERRQ(comm,ierr);
         ierr = PetscContainerSetPointer(c,vmatsl2l); PCHKERRQ(c,ierr);
+#if PETSC_VERSION_LT(3,23,0)
+         ierr = PetscContainerSetUserDestroy(c,__mfem_matarray_container_destroy);
+#else
         ierr = PetscContainerSetCtxDestroy(c,__mfem_matarray_container_destroy);
+#endif
         PCHKERRQ(c,ierr);
         ierr = PetscObjectCompose((PetscObject)(*A),"_MatIS_PtAP_l2l",(PetscObject)c);
         PCHKERRQ((*A),ierr);
@@ -1751,7 +1748,11 @@ void PetscParMatrix::ConvertOperator(MPI_Comm comm, const Operator &op, Mat* A,

            ierr = PetscContainerCreate(PETSC_COMM_SELF,&c); PCHKERRQ(B,ierr);
            ierr = PetscContainerSetPointer(c,ptrs[i]); PCHKERRQ(B,ierr);
+#if PETSC_VERSION_LT(3,23,0)
+            ierr = PetscContainerSetUserDestroy(c,__mfem_array_container_destroy);
+#else
            ierr = PetscContainerSetCtxDestroy(c,__mfem_array_container_destroy);
+#endif
            PCHKERRQ(B,ierr);
            ierr = PetscObjectCompose((PetscObject)(B),names[i],(PetscObject)c);
            PCHKERRQ(B,ierr);
@@ -2197,7 +2198,11 @@ PetscParMatrix * RAP(PetscParMatrix *Rt, PetscParMatrix *A, PetscParMatrix *P)
         ierr = PetscContainerCreate(PetscObjectComm((PetscObject)B),&c);
         PCHKERRQ(B,ierr);
         ierr = PetscContainerSetPointer(c,vmatsl2l); PCHKERRQ(c,ierr);
+#if PETSC_VERSION_LT(3,23,0)
+         ierr = PetscContainerSetUserDestroy(c,__mfem_matarray_container_destroy);
+#else
         ierr = PetscContainerSetCtxDestroy(c,__mfem_matarray_container_destroy);
+#endif
         PCHKERRQ(c,ierr);
         ierr = PetscObjectCompose((PetscObject)B,"_MatIS_PtAP_l2l",(PetscObject)c);
         PCHKERRQ(B,ierr);
@@ -2480,6 +2485,7 @@ void PetscSolver::SetMaxIter(int max_iter)

 void PetscSolver::SetPrintLevel(int plev)
 {
+   typedef PetscErrorCode (*myPetscFunc)(void**);
   PetscViewerAndFormat *vf = NULL;
   PetscViewer viewer = PETSC_VIEWER_STDOUT_(PetscObjectComm(obj));

@@ -2492,6 +2498,7 @@ void PetscSolver::SetPrintLevel(int plev)
   {
      // there are many other options, see the function KSPSetFromOptions() in
      // src/ksp/ksp/interface/itcl.c
+      typedef PetscErrorCode (*myMonitor)(KSP,PetscInt,PetscReal,void*);
      KSP ksp = (KSP)obj;
      if (plev >= 0)
      {
@@ -2500,29 +2507,29 @@ void PetscSolver::SetPrintLevel(int plev)
      if (plev == 1)
      {
 #if PETSC_VERSION_LT(3,15,0)
-         ierr = KSPMonitorSet(ksp,(KSPMonitorFn *)KSPMonitorDefault,vf,
+         ierr = KSPMonitorSet(ksp,(myMonitor)KSPMonitorDefault,vf,
 #else
-         ierr = KSPMonitorSet(ksp,(KSPMonitorFn *)KSPMonitorResidual,vf,
+         ierr = KSPMonitorSet(ksp,(myMonitor)KSPMonitorResidual,vf,
 #endif
-                              (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy);
+                              (myPetscFunc)PetscViewerAndFormatDestroy);
         PCHKERRQ(ksp,ierr);
      }
      else if (plev > 1)
      {
         ierr = KSPSetComputeSingularValues(ksp,PETSC_TRUE); PCHKERRQ(ksp,ierr);
-         ierr = KSPMonitorSet(ksp,(KSPMonitorFn *)KSPMonitorSingularValue,vf,
-                              (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy);
+         ierr = KSPMonitorSet(ksp,(myMonitor)KSPMonitorSingularValue,vf,
+                              (myPetscFunc)PetscViewerAndFormatDestroy);
         PCHKERRQ(ksp,ierr);
         if (plev > 2)
         {
            ierr = PetscViewerAndFormatCreate(viewer,PETSC_VIEWER_DEFAULT,&vf);
            PCHKERRQ(viewer,ierr);
 #if PETSC_VERSION_LT(3,15,0)
-            ierr = KSPMonitorSet(ksp,(KSPMonitorFn *)KSPMonitorTrueResidualNorm,vf,
+            ierr = KSPMonitorSet(ksp,(myMonitor)KSPMonitorTrueResidualNorm,vf,
 #else
-            ierr = KSPMonitorSet(ksp,(KSPMonitorFn *)KSPMonitorTrueResidual,vf,
+            ierr = KSPMonitorSet(ksp,(myMonitor)KSPMonitorTrueResidual,vf,
 #endif
-                                 (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy);
+                                 (myPetscFunc)PetscViewerAndFormatDestroy);
            PCHKERRQ(ksp,ierr);
         }
      }
@@ -2538,7 +2545,7 @@ void PetscSolver::SetPrintLevel(int plev)
      if (plev > 0)
      {
         ierr = SNESMonitorSet(snes,(myMonitor)SNESMonitorDefault,vf,
-                               (PetscCtxDestroyFn *)PetscViewerAndFormatDestroy);
+                               (myPetscFunc)PetscViewerAndFormatDestroy);
         PCHKERRQ(snes,ierr);
      }
   }
@@ -4156,31 +4163,20 @@ void PetscNonlinearSolver::SetUpdate(void (*update)(Operator *,int,
 void PetscNonlinearSolver::Mult(const Vector &b, Vector &x) const
 {
   SNES snes = (SNES)obj;
-   MPI_Comm comm = PetscObjectComm(obj);

-   // Reduction needed: some processes may have null local size while others don't,
-   // and VecPlaceArray (used by PlaceMemory) is a logically collective operation.
-   PetscBool b_nonempty = b.Size() ? PETSC_TRUE : PETSC_FALSE;
-#if PETSC_VERSION_LT(3,24,0)
-   mpiierr = MPI_Allreduce(MPI_IN_PLACE,&b_nonempty,1,MPIU_BOOL,MPI_LOR,comm);
-#else
-   mpiierr = MPI_Allreduce(MPI_IN_PLACE,&b_nonempty,1,MPI_C_BOOL,MPI_LOR,comm);
-#endif
-   CCHKERRQ(comm,mpiierr);
-
-   // Always create B with allocate=false so that PlaceMemory can be called on
-   // it regardless of whether b was empty on a previous call.
-   if (!B) { B = new PetscParVector(comm, *this, true, false); }
-   if (!X) { X = new PetscParVector(comm, *this, false, false); }
+   bool b_nonempty = b.Size();
+   if (!B) { B = new PetscParVector(PetscObjectComm(obj), *this, true); }
+   if (!X) { X = new PetscParVector(PetscObjectComm(obj), *this, false, false); }
   X->PlaceMemory(x.GetMemory(),iterative_mode);
   if (b_nonempty) { B->PlaceMemory(b.GetMemory()); }
+   else { *B = 0.0; }

   Customize();

   if (!iterative_mode) { *X = 0.; }

-   // Solve the system. Pass nullptr for b when empty (PETSc treats it as zero RHS).
-   ierr = SNESSolve(snes, b_nonempty ? B->x : nullptr, X->x); PCHKERRQ(snes, ierr);
+   // Solve the system.
+   ierr = SNESSolve(snes, B->x, X->x); PCHKERRQ(snes, ierr);
   X->ResetMemory();
   if (b_nonempty) { B->ResetMemory(); }
 }
@@ -5333,27 +5329,21 @@ static PetscErrorCode __mfem_pc_shell_destroy(PC pc)
   PetscFunctionReturn(PETSC_SUCCESS);
 }

-static PetscErrorCode __mfem_array_container_destroy(PetscCtxRt ptr)
+#if PETSC_VERSION_LT(3,23,0)
+
+static PetscErrorCode __mfem_array_container_destroy(void *ptr)
 {
   PetscErrorCode ierr;

   PetscFunctionBeginUser;
-#if PETSC_VERSION_LT(3,23,0)
   ierr = PetscFree(ptr); CHKERRQ(ierr);
-#else
-   ierr = PetscFree(*(void**)ptr); CHKERRQ(ierr);
-#endif
   PetscFunctionReturn(PETSC_SUCCESS);
 }

-static PetscErrorCode __mfem_matarray_container_destroy(PetscCtxRt ptr)
+static PetscErrorCode __mfem_matarray_container_destroy(void *ptr)
 {
-#if PETSC_VERSION_LT(3,23,0)
   mfem::Array<Mat> *a = (mfem::Array<Mat>*)ptr;
-#else
-   mfem::Array<Mat> *a = *(mfem::Array<Mat>**)ptr;
-#endif
-   PetscErrorCode ierr;
+   PetscErrorCode   ierr;

   PetscFunctionBeginUser;
   for (int i=0; i<a->Size(); i++)
@@ -5366,16 +5356,41 @@ static PetscErrorCode __mfem_matarray_container_destroy(PetscCtxRt ptr)
   PetscFunctionReturn(PETSC_SUCCESS);
 }

-#if PETSC_VERSION_LT(3,23,0)
-static PetscErrorCode __mfem_monitor_ctx_destroy(void **ctx)
 #else
-static PetscErrorCode __mfem_monitor_ctx_destroy(PetscCtxRt ctx)
-#endif
+
+static PetscErrorCode __mfem_array_container_destroy(void **ptr)
 {
   PetscErrorCode ierr;

   PetscFunctionBeginUser;
-   ierr = PetscFree(*(void**)ctx); CHKERRQ(ierr);
+   ierr = PetscFree(*ptr); CHKERRQ(ierr);
+   PetscFunctionReturn(PETSC_SUCCESS);
+}
+
+static PetscErrorCode __mfem_matarray_container_destroy(void **ptr)
+{
+   mfem::Array<Mat> *a = (mfem::Array<Mat>*)*ptr;
+   PetscErrorCode   ierr;
+
+   PetscFunctionBeginUser;
+   for (int i=0; i<a->Size(); i++)
+   {
+      Mat M = (*a)[i];
+      MPI_Comm comm = PetscObjectComm((PetscObject)M);
+      ierr = MatDestroy(&M); CCHKERRQ(comm,ierr);
+   }
+   delete a;
+   PetscFunctionReturn(PETSC_SUCCESS);
+}
+
+#endif
+
+static PetscErrorCode __mfem_monitor_ctx_destroy(void **ctx)
+{
+   PetscErrorCode  ierr;
+
+   PetscFunctionBeginUser;
+   ierr = PetscFree(*ctx); CHKERRQ(ierr);
   PetscFunctionReturn(PETSC_SUCCESS);
 }

@@ -5620,7 +5635,11 @@ static PetscErrorCode MatConvert_hypreParCSR_AIJ(hypre_ParCSRMatrix* hA,Mat* pA)

      ierr = PetscContainerCreate(comm,&c); CHKERRQ(ierr);
      ierr = PetscContainerSetPointer(c,ptrs[i]); CHKERRQ(ierr);
+#if PETSC_VERSION_LT(3,23,0)
+      ierr = PetscContainerSetUserDestroy(c,__mfem_array_container_destroy);
+#else
      ierr = PetscContainerSetCtxDestroy(c,__mfem_array_container_destroy);
+#endif
      CHKERRQ(ierr);
      ierr = PetscObjectCompose((PetscObject)(*pA),names[i],(PetscObject)c);
      CHKERRQ(ierr);
@@ -5714,7 +5733,11 @@ static PetscErrorCode MatConvert_hypreParCSR_IS(hypre_ParCSRMatrix* hA,Mat* pA)

      ierr = PetscContainerCreate(PETSC_COMM_SELF,&c); CHKERRQ(ierr);
      ierr = PetscContainerSetPointer(c,ptrs[i]); CHKERRQ(ierr);
+#if PETSC_VERSION_LT(3,23,0)
+      ierr = PetscContainerSetUserDestroy(c,__mfem_array_container_destroy);
+#else
      ierr = PetscContainerSetCtxDestroy(c,__mfem_array_container_destroy);
+#endif
      CHKERRQ(ierr);
      ierr = PetscObjectCompose((PetscObject)lA,names[i],(PetscObject)c);
      CHKERRQ(ierr);
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
bslazarov	c01a9cb623	style	2026-02-10 12:48:56 -08:00
Mathias Rainer Schmidt	007183c70a	Merge branch 'master' into eigenSolverInterface	2026-02-10 10:47:01 -08:00
Mathias Rainer Schmidt	0e63fc90e3	Merge branch 'master' of https://github.com/mfem/mfem	2026-02-10 10:46:20 -08:00
Mathias Rainer Schmidt	06cb917637	- added comments to slepc interaface class	2026-02-10 10:45:28 -08:00
Mathias Rainer Schmidt	db97637c09	- minor changed to address PR	2026-02-03 22:40:04 -08:00
Mathias Rainer Schmidt	cbaf930388	- minor changes for PR	2026-02-02 23:34:11 -08:00
blaz	b53dd0fea1	Set he number of eigenmodes in the bas class	2026-01-26 10:45:18 -08:00
blaz	acf167ed86	resize the eigenvalue array	2026-01-25 23:01:32 -08:00
blaz	8a8ac07910	cleaner code and style	2026-01-25 22:38:31 -08:00
Mathias Rainer Schmidt	c2d5eed541	Merge branch 'master' of https://github.com/mfem/mfem	2026-01-13 15:19:05 -08:00
Mathias Rainer Schmidt	f8e71cf89c	- initial commit for eigen sovler interface	2026-01-13 15:18:35 -08:00