Merge branch 'master' into delete-indices-dev

Use `HipMemcpyDtoD` instead of `HipMemcpyDtoDAsync`

.github/actions/sanitize/config/action.yml

@@ -0,0 +1,154 @@
+# 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.
+---
+name: Sanitizer Config
+description: Sets up environment variables for MFEM sanitizer workflow
+
+inputs:
+  DEBUG:
+    description: If true, use intermediate caches to speed up the workflow
+                 by reusing previous builds.
+    default: false
+
+  REPOSITORY:
+    description: Repository to checkout
+    default: mfem/mfem
+
+  BRANCH:
+    description: Branch to checkout
+    default: ubsan
+
+  CLANG_VER:
+    description: CLANG version to use
+    default: 18
+
+  # https://github.com/llvm/llvm-project/releases
+  LLVM_VER:
+    description: LLVM version to use
+    default: 19.1.7
+
+  # https://github.com/hypre-space/hypre/releases
+  HYPRE_VER:
+    description: HYPRE version to use
+    default: 2.19.0
+
+  METIS_VER:
+    description: METIS version to use
+    default: 4.0.3
+
+  CTEST:
+    description: CTest command to use
+    default: ctest -j --test-load $(nproc)
+                      --schedule-random
+                      --stop-on-failure --output-on-failure
+                      --test-dir
+
+  # https://clang.llvm.org/docs/AddressSanitizer.html
+  ASAN_OPTIONS:
+    default: detect_leaks=1,
+             strict_init_order=1,
+             strict_string_checks=1,
+             check_initialization_order=1,
+             detect_stack_use_after_return=1
+  ASAN_CXXFLAGS:
+    default: -fsanitize=address
+             -fsanitize-address-use-after-scope
+  ASAN_LDFLAGS:
+    default: -fsanitize=address
+
+  # https://clang.llvm.org/docs/UndefinedBehaviorSanitizer.html
+  UBSAN_OPTIONS:
+    default: halt_on_error=1, print_stacktrace=1
+  UBSAN_CXXFLAGS:
+    default: -fsanitize=undefined
+  UBSAN_LDFLAGS:
+    default: -fsanitize=undefined
+
+  # https://clang.llvm.org/docs/MemorySanitizer.html
+  MSAN_OPTIONS:
+    default: "poison_in_dtor=1"
+  MSAN_CXXFLAGS:
+    default: -fsanitize=memory
+             -fsanitize-memory-track-origins
+             -fsanitize-memory-use-after-dtor
+  MSAN_LDFLAGS:
+    default: -fsanitize=memory
+
+  LSAN_DIR:
+    description: LSAN suppression directory
+    default: lsan
+
+  LSAN_FILE:
+    description: LSAN suppression file
+    default: lsan.supp
+
+  NO_FLAGS:
+    description: If true, do not set any CXXFLAGS or LDFLAGS.
+    default: false
+
+runs:
+  using: 'composite'
+  steps:
+    - name: Env (Inputs)
+      run: |
+        echo DEBUG=${{inputs.DEBUG}} >> $GITHUB_ENV
+        echo REPOSITORY=${{inputs.REPOSITORY}} >> $GITHUB_ENV
+        echo BRANCH=${{inputs.BRANCH}} >> $GITHUB_ENV
+        echo CLANG_VER=${{inputs.CLANG_VER}} >> $GITHUB_ENV
+        echo LLVM_VER=${{inputs.LLVM_VER}} >> $GITHUB_ENV
+        echo HYPRE_VER=${{inputs.HYPRE_VER}} >> $GITHUB_ENV
+        echo METIS_VER=${{inputs.METIS_VER}} >> $GITHUB_ENV
+        echo CTEST=${{inputs.CTEST}} >> $GITHUB_ENV
+        echo ASAN_OPTIONS=${{inputs.ASAN_OPTIONS}} >> $GITHUB_ENV
+        echo UBSAN_OPTIONS=${{inputs.UBSAN_OPTIONS}} >> $GITHUB_ENV
+        echo MSAN_OPTIONS=${{inputs.MSAN_OPTIONS}} >> $GITHUB_ENV
+        echo LSAN_DIR=${{inputs.LSAN_DIR}} >> $GITHUB_ENV
+        echo LSAN_FILE=${{inputs.LSAN_FILE}} >> $GITHUB_ENV
+        echo ASAN_CXXFLAGS=${{inputs.ASAN_CXXFLAGS}} >> $GITHUB_ENV
+        echo ASAN_LDFLAGS=${{inputs.ASAN_LDFLAGS}} >> $GITHUB_ENV
+        echo UBSAN_CXXFLAGS=${{inputs.UBSAN_CXXFLAGS}} >> $GITHUB_ENV
+        echo UBSAN_LDFLAGS=${{inputs.UBSAN_LDFLAGS}} >> $GITHUB_ENV
+        echo MSAN_CXXFLAGS=${{inputs.MSAN_CXXFLAGS}} >> $GITHUB_ENV
+        echo MSAN_LDFLAGS=${{inputs.MSAN_LDFLAGS}} >> $GITHUB_ENV
+      shell: bash
+
+    - name: Env (dir)
+      run: |
+        echo LLVM_DIR=${{github.workspace}}/llvm >> $GITHUB_ENV
+        echo HYPRE_DIR=hypre-${{inputs.HYPRE_VER}} >> $GITHUB_ENV
+        echo METIS_DIR=metis-${{inputs.METIS_VER}} >> $GITHUB_ENV
+      shell: bash
+
+    - name: Env (bis)
+      run: |
+        echo CC=clang-${{inputs.CLANG_VER}} >> $GITHUB_ENV
+        echo CXX=clang++-${{inputs.CLANG_VER}} >> $GITHUB_ENV
+        echo LLVM_INC=${{env.LLVM_DIR}}/include/c++/v1 >> $GITHUB_ENV
+        echo LLVM_LIB=${{env.LLVM_DIR}}/lib >> $GITHUB_ENV
+        echo HYPRE_TGZ=v${{inputs.HYPRE_VER}}.tar.gz >> $GITHUB_ENV
+        echo METIS_TGZ=metis-${{inputs.METIS_VER}}.tar.gz >> $GITHUB_ENV
+        LSAN_SUPPRESSIONS="${{github.workspace}}/${{inputs.LSAN_DIR}}/${{inputs.LSAN_FILE}}"
+        echo "LSAN_OPTIONS=suppressions=$LSAN_SUPPRESSIONS" >> $GITHUB_ENV
+      shell: bash
+
+    - name: Env (ter)
+      if: ${{ inputs.NO_FLAGS != 'true' }}
+      run: |
+        echo LLVM_CXXFLAGS=-stdlib=libc++ -I${{env.LLVM_INC}} -Isystem${{env.LLVM_INC}} >> $GITHUB_ENV
+        echo LLVM_LDFLAGS=-L${{env.LLVM_LIB}} -lc++abi -Wl,-rpath,${{env.LLVM_LIB}} >> $GITHUB_ENV
+      shell: bash
+
+    - name: Env (quater)
+      if: ${{ inputs.NO_FLAGS != 'true' }}
+      run: |
+        echo CXXFLAGS=${{env.LLVM_CXXFLAGS}} >> $GITHUB_ENV
+        echo LDFLAGS=${{env.LLVM_LDFLAGS}} >> $GITHUB_ENV
+      shell: bash

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

@@ -0,0 +1,91 @@
+# 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.
+---
+name: 'MFEM Compilation'
+description: 'MFEM Compilation'
+
+inputs:
+  par:
+    description: 'Whether to build for parallel (true/false)'
+    default: false
+  sanitizer:
+    description: 'Sanitizer to use (asan, msan, ubsan)'
+    default: asan
+
+runs:
+  using: 'composite'
+  steps:
+    - uses: ./.github/actions/sanitize/config
+
+    - uses: actions/cache@v4
+      if: ${{env.DEBUG == 'true'}}
+      id: debug
+      with:
+        path: mfem/build
+        key: build-${{inputs.par}}-${{inputs.sanitizer}}
+
+    - uses: ./.github/actions/sanitize/setup
+      if: ${{steps.debug.outputs.cache-hit != 'true'}}
+      with:
+        par: ${{inputs.par}}
+        sanitizer: ${{inputs.sanitizer}}
+
+    - name: Build with ASAN
+      if: inputs.sanitizer == 'asan'
+      run: echo CXXFLAGS=${{env.CXXFLAGS}} ${{env.ASAN_CXXFLAGS}} >> $GITHUB_ENV
+      shell: bash
+
+    - name: Build with MSAN
+      if: inputs.sanitizer == 'msan'
+      run: echo CXXFLAGS=${{env.CXXFLAGS}} ${{env.MSAN_CXXFLAGS}} >> $GITHUB_ENV
+      shell: bash
+
+    - name: Build with UBSAN
+      if: inputs.sanitizer == 'ubsan'
+      run: echo CXXFLAGS=${{env.CXXFLAGS}} ${{env.UBSAN_CXXFLAGS}} >> $GITHUB_ENV
+      shell: bash
+
+    - uses: mfem/github-actions/build-mfem@v2.5
+      if: ${{steps.debug.outputs.cache-hit != 'true'}}
+      env:
+        CXXFLAGS: ${{env.CXXFLAGS}}
+        LDFLAGS: ${{env.LDFLAGS}}
+      with:
+        mpi: ${{inputs.par == 'false' && 'seq' || 'par'}}
+        mfem-dir: mfem
+        os: ${{runner.os}}
+        library-only: true
+        build-system: cmake
+        hypre-dir: ${{env.HYPRE_DIR}}
+        metis-dir: ${{env.METIS_DIR}}
+        config-options: >-
+          -GNinja
+          -DMPICXX=${{env.CXX}}
+          -DCMAKE_CXX_STANDARD=17
+          -DMFEM_USE_MEMALLOC=OFF
+          -DCMAKE_BUILD_TYPE=Release
+          -DCMAKE_VERBOSE_MAKEFILE=ON
+          -DCMAKE_CXX_COMPILER=${{env.CXX}}
+          -DCMAKE_CXX_FLAGS_RELEASE='-g -O1 -fno-omit-frame-pointer'
+
+    - name: Delete object files
+      if: ${{steps.debug.outputs.cache-hit != 'true'}}
+      working-directory: mfem/build
+      run: find . -type f -name '*.o' -delete
+      shell: bash
+
+    - uses: actions/upload-artifact@v4
+      with:
+        name: build-${{inputs.par}}-${{inputs.sanitizer}}
+        path: mfem/build
+        if-no-files-found: error
+        retention-days: 1
+        overwrite: false

.github/actions/sanitize/mpi/action.yml

@@ -0,0 +1,33 @@
+# 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.
+---
+name: 'Install MPI'
+description: 'Installs MPI and set up its environment variables'
+
+runs:
+  using: 'composite'
+  steps:
+    - name: Install
+      run: sudo apt-get install openmpi-bin libopenmpi-dev
+      shell: bash
+
+    - name: Env
+      run: |
+        echo PRTE_MCA_rmaps_default_mapping_policy=:oversubscribe >> $GITHUB_ENV
+        echo MPI_INC=$(mpicxx --showme:compile) >> $GITHUB_ENV
+        echo MPI_LIB=$(mpicxx --showme:link) >> $GITHUB_ENV
+      shell: bash
+
+    - name: Env (bis)
+      run: |
+        echo CXXFLAGS=${{env.CXXFLAGS}} ${{env.MPI_INC}} >> $GITHUB_ENV
+        echo LDFLAGS=${{env.LDFLAGS}} ${{env.MPI_LIB}} >> $GITHUB_ENV
+      shell: bash

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

@@ -0,0 +1,71 @@
+# 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.
+---
+name: 'Restore state'
+description: 'Restore state to be able to run checks, tests'
+
+inputs:
+  par:
+    description: 'Whether to build for parallel (true/false)'
+    default: false
+  sanitizer:
+    description: 'Sanitizer to use (asan, msan, ubsan)'
+    default: asan
+  cache-path:
+    description: 'path to what needs to be restored'
+    default: none
+  cache-skip:
+    description: 'Skip cache restoration'
+    default: false
+
+outputs:
+  cache-hit:
+    description: 'Output from a specific step'
+    value: ${{steps.debug.outputs.cache-hit}}
+
+runs:
+  using: 'composite'
+  steps:
+    - uses: ./.github/actions/sanitize/config
+
+    - uses: actions/cache@v4
+      if: ${{env.DEBUG == 'true' && inputs.cache-skip != 'true'}}
+      id: debug
+      with:
+        path: ${{inputs.cache-path}}
+        key: ${{github.job}}-${{inputs.par}}-${{inputs.sanitizer}}
+
+    - uses: ./.github/actions/sanitize/setup
+      if: ${{steps.debug.outputs.cache-hit != 'true'}}
+      with:
+        par: ${{inputs.par}}
+        sanitizer: ${{inputs.sanitizer}}
+
+    - uses: actions/download-artifact@v4
+      with:
+        name: build-${{inputs.par}}-${{inputs.sanitizer}}
+        path: mfem/build
+
+    - name: Ninja Patch
+      working-directory: mfem/build
+      run: |
+        sed -i -e 's/CXX_STATIC_LIBRARY_LINKER__mfem_Release.*/CUSTOM_COMMAND/' build.ninja
+        sed -i -e '/build tests\/unit\/all:/ s/tests\/unit\/[^ ]*unit_tests[^ ]*//g' build.ninja
+        sed -i -e '/^add_test(\[=\[\(unit_tests\|punit_tests\)\]=\]/ s/)/ "--input-file .\/list-test-names-${{matrix.tag}}" "--min-duration 1")/' tests/unit/CTestTestfile.cmake
+      shell: bash
+
+    - name: Copy Data
+      if: ${{steps.debug.outputs.cache-hit != 'true'}}
+      working-directory: mfem/build
+      run: |
+        ninja cmake_object_order_depends_target_unit_tests
+        cp -pR ../tests/unit/data tests/unit
+      shell: bash

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

@@ -0,0 +1,64 @@
+# 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.
+---
+name: 'Setup state'
+description: 'Sets up the state to be able to run build & run'
+
+inputs:
+  par:
+    description: 'Whether to build for parallel (true/false)'
+    default: false
+  sanitizer:
+    description: 'Sanitizer to use (asan, msan, ubsan)'
+    default: asan
+
+runs:
+  using: 'composite'
+  steps:
+    - uses: actions/cache/restore@v4  # Cache for LLVM libcxx
+      with:
+        path: ${{env.LLVM_DIR}}
+        fail-on-cache-miss: true
+        key: build-libcxx-${{env.LLVM_VER}}-${{inputs.sanitizer}}
+
+    - uses: ./.github/actions/sanitize/mpi
+      if: ${{inputs.par == 'true'}}
+
+    - 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@v4  # Cache for Metis
+      if: ${{inputs.par == 'true'}}
+      with:
+        path: ${{env.METIS_DIR}}
+        fail-on-cache-miss: true
+        key: ${{runner.os}}-build-${{env.METIS_DIR}}-v2.5
+
+    - name: Hypre/Metis links
+      if: ${{inputs.par == 'true'}}
+      run: ln -s -f ${{env.HYPRE_DIR}} hypre && ln -s -f ${{env.METIS_DIR}} metis-4.0
+      shell: bash
+
+    - uses: actions/cache/restore@v4  # Cache for LSAN suppression file
+      with:
+        path: ${{env.LSAN_DIR}}
+        fail-on-cache-miss: true
+        key: build-lsan-suppression-file
+
+    - uses: actions/checkout@v4  # Checkout the repository
+      with:
+        path: mfem
+        # ref: ${{env.BRANCH}}
+        # repository: ${{env.REPOSITORY}}

.github/workflows/README.md

@@ -7,18 +7,17 @@
 
                                https://mfem.org
 
-
 This directory contains the GitHub CI scripts for MFEM.
 
 Note that some of these scripts use the shared MFEM GitHub Actions from the external mfem/github-actions repository:
 
-  https://github.com/mfem/github-actions
+  <https://github.com/mfem/github-actions>
 
-For a particular action, e.g. `mfem/github-actions/build-mfem@v2.1`, the `v2.1` suffix denotes the branch in the above from which the action is taken.
+For a particular action, e.g. `mfem/github-actions/build-mfem@v2.5`, the `v2.5` suffix denotes the branch in the above from which the action is taken.
 
 The current CI workflows are:
 
-### `repo-check.yml`
+## `repo-check.yml`
 
 Runs a number of static repository-level sanity checks.
 
@@ -30,19 +29,39 @@ Runs a number of static repository-level sanity checks.
 
 - `branch-history` guards against accidental commits of large files using the `--history` option of the `config/githooks/pre-push` script.
 
-### `mfem-analysis.yml` (`build-analysis`)
+## `mfem-analysis.yml` (`build-analysis`)
 
 Checks if the code builds and satisfies minimal requirements.
 
 - `gitignore` builds hypre, METIS, and MFEM using `mfem/github-actions/build-hypre`, `mfem/github-actions/build-metis`, and `mfem/github-actions/build-mfem` and checks for correct `.gitignore` settings by running the `tests/scripts/gitignore` script.
 
-### `builds-and-tests.yml`
+## `builds-and-tests.yml`
 
 Runs a matrix of builds and tests runs with different compilers, OS, mfem/hypre settings, etc. Also processes and upload Codecov reports.
 
-Uses the following GitHub Actions from https://github.com/mfem/github-actions:
+Uses the following GitHub Actions from <https://github.com/mfem/github-actions>:
 
 - `mfem/github-actions/build-hypre`
 - `mfem/github-actions/build-metis`
 - `mfem/github-actions/build-mfem`
 - `mfem/github-actions/upload-coverage`
+
+## Sanitizer Workflow for MFEM Verification
+
+This workflow validates MFEM unit tests, examples, and miniapps using sanitizer tools.
+
+- `sanitizers.yml` orchestrates:
+  - Building and caching dependencies: HYPRE, METIS, LSAN suppression file, and LLVM libcxx.
+  - Launching fine-grained jobs for serial (ASAN, MSAN, UBSAN) and parallel (ASAN, UBSAN) sanitizers.
+- `sanitize-tests.yml` is a reusable workflow accepting `par` mode (`true` for parallel) and `sanitizer` (ASAN, MSAN, or UBSAN) as inputs. It executes the following jobs:
+  - **Build**: Compiles the MFEM library with specified parallel and sanitizer settings.
+  - **Check**: Runs verification checks.
+  - Parallel jobs to test the following: **Examples**, **Miniapps** and **Unit tests**
+
+The workflow leverages composite actions in `.github/actions/sanitize/`:
+
+- `config`: Centralizes settings for the sanitizer workflow.
+- `mfem`: Manages the MFEM library build process.
+- `mpi`: Installs MPI and applies additional compilation flags.
+- `restore`: Restores the testing environment state.
+- `setup`: Builds or restores cached dependencies.

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

@@ -289,10 +289,10 @@ jobs:
         run: |
           export HOMEBREW_NO_INSTALL_CLEANUP=1
           brew update
-          brew install llvm@19 enzyme
-          echo "LLVM_PREFIX=$(brew --prefix llvm@19)" >> $GITHUB_ENV
-          echo "OMPI_CC=$(brew --prefix llvm@19)/bin/clang" >> $GITHUB_ENV
-          echo "OMPI_CXX=$(brew --prefix llvm@19)/bin/clang++" >> $GITHUB_ENV
+          brew install llvm@20 enzyme
+          echo "LLVM_PREFIX=$(brew --prefix llvm@20)" >> $GITHUB_ENV
+          echo "OMPI_CC=$(brew --prefix llvm@20)/bin/clang" >> $GITHUB_ENV
+          echo "OMPI_CXX=$(brew --prefix llvm@20)/bin/clang++" >> $GITHUB_ENV
 
       # MFEM build and test
       - name: build

.github/workflows/mfem-sanitizer.yml

@@ -1,69 +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.
-
-name: "Sanitizer"
-
-permissions:
-  actions: write
-
-on:
-  push:
-    branches:
-      - master
-      - next
-  pull_request:
-  workflow_dispatch:
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  Serial:
-    runs-on: ubuntu-24.04
-
-    steps:
-      - name: MFEM Checkout
-        uses: actions/checkout@v4
-        with:
-          path: mfem
-
-      - name: MFEM Build
-        uses: mfem/github-actions/build-mfem@v2.5
-        with:
-          os: ${{ runner.os }}
-          target: opt
-          mpi: seq
-          hypre-dir: unused-hypre-dir
-          metis-dir: unused-metis-dir
-          mfem-dir: mfem
-          build-system: make
-          library-only: false
-          config-options:
-            CXX="clang++-18"
-            CXXFLAGS="-g -O1 -std=c++17
-                      -fsanitize=address
-                      -fno-omit-frame-pointer
-                      -fsanitize-address-use-after-scope"
-
-      - name: MFEM Info
-        working-directory: mfem
-        run: make info
-
-      - name: MFEM Sanitize
-        working-directory: mfem
-        run:
-          ASAN_OPTIONS="detect_leaks=1,
-                        strict_init_order=1,
-                        strict_string_checks=1,
-                        check_initialization_order=1,
-                        detect_stack_use_after_return=1"
-          make test

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

@@ -0,0 +1,39 @@
+# 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.
+---
+name: build-hypre
+on:
+  workflow_call:
+jobs:
+  build-hypre:
+    runs-on: ubuntu-latest
+    name: 2.19.0
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/config
+      - name: Cache
+        id: cache
+        uses: actions/cache@v4
+        with:
+          path: ${{env.HYPRE_DIR}}
+          key: ${{runner.os}}-ompi-build-${{env.HYPRE_DIR}}-int32-fp64-v2.5
+      - name: Setup
+        if: steps.cache.outputs.cache-hit != 'true'
+        uses: ./.github/actions/sanitize/mpi
+      - name: Build
+        if: steps.cache.outputs.cache-hit != 'true'
+        uses: mfem/github-actions/build-hypre@v2.5
+        with:
+          archive: ${{env.HYPRE_TGZ}}
+          dir: ${{env.HYPRE_DIR}}
+          target: int32
+          precision: fp64
+          build-system: make

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

@@ -0,0 +1,76 @@
+# 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.
+---
+name: build-libcxx
+on:
+  workflow_call:
+jobs:
+  build-llvm-libcxx:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        sanitizer: [asan, msan, ubsan]
+        include:
+          - sanitizer: asan
+            llvm_use_sanitizer: "Address"
+          - sanitizer: msan
+            llvm_use_sanitizer: "MemoryWithOrigins"
+          - sanitizer: ubsan
+            llvm_use_sanitizer: "Undefined"
+    name: ${{matrix.sanitizer}}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/config
+        with:
+          NO_FLAGS: true
+      - name: Cache
+        id: cache
+        uses: actions/cache@v4
+        with:
+          path: ${{env.LLVM_DIR}}
+          key: build-libcxx-${{env.LLVM_VER}}-${{matrix.sanitizer}}
+      - name: Clone
+        if: ${{ steps.cache.outputs.cache-hit != 'true' }}
+        run: >
+          git clone --filter=blob:none --depth=1
+          --branch llvmorg-${{env.LLVM_VER}}
+          --no-checkout https://github.com/llvm/llvm-project.git llvm-project
+      - name: Checkout
+        if: ${{ steps.cache.outputs.cache-hit != 'true' }}
+        working-directory: llvm-project
+        run: |
+          git sparse-checkout set --cone
+          git checkout llvmorg-${{env.LLVM_VER}}
+          git sparse-checkout set cmake llvm/cmake runtimes libcxx libcxxabi
+      - name: Mkdir
+        if: ${{ steps.cache.outputs.cache-hit != 'true' }}
+        run: mkdir ${{env.LLVM_DIR}}
+      - name: CMake
+        if: ${{ steps.cache.outputs.cache-hit != 'true' }}
+        working-directory: ${{env.LLVM_DIR}}
+        run: >
+          VERBOSE=1
+          cmake -GNinja ../llvm-project/runtimes/
+          -DCMAKE_C_COMPILER=${{env.CC}}
+          -DCMAKE_CXX_COMPILER=${{env.CXX}}
+          -DCMAKE_BUILD_TYPE=RelWithDebInfo
+          -DCMAKE_INSTALL_PREFIX=/usr
+          -DLLVM_USE_SANITIZER=${{matrix.llvm_use_sanitizer}}
+          -DLLVM_BUILD_32_BITS=OFF
+          -DLIBCXXABI_USE_LLVM_UNWINDER=OFF
+          -DLLVM_INCLUDE_TESTS=OFF
+          -DLIBCXX_INCLUDE_TESTS=OFF
+          -DLIBCXX_INCLUDE_BENCHMARKS=OFF
+          -DLLVM_ENABLE_RUNTIMES='libcxx;libcxxabi'
+      - name: Build
+        if: ${{ steps.cache.outputs.cache-hit != 'true' }}
+        working-directory: ${{env.LLVM_DIR}}
+        run: cmake --build . -- cxx cxxabi

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

@@ -0,0 +1,38 @@
+# 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.
+---
+name: build-file-lsan
+on:
+  workflow_call:
+jobs:
+  build-file-lsan:
+    runs-on: ubuntu-latest
+    name: lsan.supp
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/config
+      - name: Cache
+        id: cache
+        uses: actions/cache@v4
+        with:
+          path: ${{env.LSAN_DIR}}
+          key: build-lsan-suppression-file
+      - name: Setup
+        if: steps.cache.outputs.cache-hit != 'true'
+        run: |
+          mkdir -p ${{env.LSAN_DIR}}
+          cat << EOF > ${{env.LSAN_DIR}}/${{env.LSAN_FILE}}
+          leak:libevent_core-2.1.so
+          leak:ompi_mpi_finalize
+          leak:ompi_mpi_init
+          leak:PMPI_Init
+          leak:strdup
+          EOF

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

@@ -0,0 +1,36 @@
+# 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.
+---
+name: build-metis
+on:
+  workflow_call:
+jobs:
+  build-metis:
+    runs-on: ubuntu-latest
+    name: 4.0.3
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/config
+      - name: Cache
+        id: cache
+        uses: actions/cache@v4
+        with:
+          path: ${{env.METIS_DIR}}
+          key: ${{runner.os}}-build-${{env.METIS_DIR}}-v2.5
+      - name: Setup
+        if: steps.cache.outputs.cache-hit != 'true'
+        uses: ./.github/actions/sanitize/mpi
+      - name: Build
+        if: steps.cache.outputs.cache-hit != 'true'
+        uses: mfem/github-actions/build-metis@v2.5
+        with:
+          archive: ${{env.METIS_TGZ}}
+          dir: ${{env.METIS_DIR}}

.github/workflows/sanitize-tests.yml

@@ -0,0 +1,197 @@
+# 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.
+---
+name: Sanitize
+on:
+  workflow_call:
+    inputs:
+      par:
+        description: 'Whether to build for parallel (true/false)'
+        required: false
+        default: false
+        type: boolean
+      sanitizer:
+        description: 'Sanitizer to use (asan, msan, ubsan)'
+        required: true
+        default: asan
+        type: string
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/mfem
+        with:
+          par: ${{inputs.par}}
+          sanitizer: ${{inputs.sanitizer}}
+
+  check:
+    needs: [build]
+    runs-on: ubuntu-latest
+    env:
+      ex: ${{inputs.par && 'ex1p' || 'ex1'}}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/restore
+        id: restore
+        with:
+          par: ${{inputs.par}}
+          sanitizer: ${{inputs.sanitizer}}
+          cache-path: mfem/build/examples/${{env.ex}}
+      - name: MFEM Check
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: ninja -v check
+
+  examples:
+    needs: [check]
+    runs-on: ubuntu-latest
+    env:
+      exclude: ${{inputs.par && '-E "_ser"' || ''}}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/restore
+        id: restore
+        with:
+          par: ${{inputs.par}}
+          sanitizer: ${{inputs.sanitizer}}
+          cache-path: mfem/build/examples/ex1
+      - name: Build Examples
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: ninja -v examples
+      - name: Test Examples
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: |
+          ${{env.CTEST}} examples ${{env.exclude}} --show-only
+          ${{env.CTEST}} examples ${{env.exclude}}
+
+  miniapps:
+    needs: [check]
+    runs-on: ubuntu-latest
+    env:
+      exclude: ${{inputs.par && '-E "_ser"' || ''}}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/restore
+        id: restore
+        with:
+          par: ${{inputs.par}}
+          sanitizer: ${{inputs.sanitizer}}
+          cache-path: mfem/build/miniapps/meshing/minimal-surface
+      - name: Build Miniapps
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: ninja -v miniapps
+      - name: Test Miniapps
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: |
+          ${{env.CTEST}} miniapps ${{env.exclude}} --show-only
+          ${{env.CTEST}} miniapps ${{env.exclude}}
+
+  tests-miniapps:
+    needs: [check]
+    runs-on: ubuntu-latest
+    env:
+      run: ${{inputs.par && '-R "_cpu_np"' || ''}}
+      exclude: ${{inputs.par && '"unit_tests|debug"' || '"^unit_tests$|debug"'}}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/restore
+        id: restore
+        with:
+          par: ${{inputs.par}}
+          sanitizer: ${{inputs.sanitizer}}
+          cache-path: mfem/build/tests/unit/sedov_tests_cpu
+      - name: Build Tests Unit Miniapps
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: ninja -v tests/unit/all
+      - name: Run Tests Unit Miniapps
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: |
+          ${{env.CTEST}} tests/unit -E ${{env.exclude}} ${{env.run}} --show-only
+          ${{env.CTEST}} tests/unit -E ${{env.exclude}} ${{env.run}}
+
+  tests-unit-build:
+    needs: [check]
+    runs-on: ubuntu-latest
+    env:
+      unit_tests: ${{inputs.par && 'punit_tests' || 'unit_tests'}}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/restore
+        id: restore
+        with:
+          par: ${{inputs.par}}
+          sanitizer: ${{inputs.sanitizer}}
+          cache-path: mfem/build/tests/unit/${{env.unit_tests}}
+      - name: Build Unit Tests
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: ninja -v ${{env.unit_tests}}
+      - name: Delete object files
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build/tests/unit
+        run: find . -type f -name '*.o' -delete
+      - uses: actions/upload-artifact@v4
+        with:
+          name: tests-${{inputs.par}}-${{inputs.sanitizer}}
+          path: mfem/build/tests/unit/${{env.unit_tests}}
+          if-no-files-found: error
+          retention-days: 1
+          overwrite: false
+
+  tests-unit-run:
+    needs: [tests-unit-build]
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        tag: [0, 1, 2, 3]
+    name: tests-unit-run-${{matrix.tag}}
+    env:
+      unit_tests: ${{inputs.par && 'punit_tests' || 'unit_tests'}}
+      np: ${{inputs.par && '_np=2' || ''}}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/sanitize/restore
+        id: restore
+        with:
+          par: ${{inputs.par}}
+          sanitizer: ${{inputs.sanitizer}}
+          cache-path: mfem/build/tests/unit/${{env.unit_tests}}
+      - uses: actions/download-artifact@v4
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        with:
+          name: tests-${{inputs.par}}-${{inputs.sanitizer}}
+          path: mfem/build/tests/unit
+      - name: Split Unit Tests
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build/tests/unit
+        run: |
+          chmod 755 ${{env.unit_tests}}
+          ./${{env.unit_tests}} --list-test-names-only | tail -n +2 > list-test-names
+          shuf list-test-names -o list-test-names
+          split --verbose -n l/4 -d -a 1 list-test-names list-test-names-
+      - name: Cat Unit Tests ${{matrix.tag}}
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build/tests/unit
+        run: cat list-test-names-${{matrix.tag}}
+      - name: Run Unit Tests ${{matrix.tag}}
+        if: ${{steps.restore.outputs.cache-hit != 'true'}}
+        working-directory: mfem/build
+        run: |
+          ${{env.CTEST}} tests/unit -R "${{env.unit_tests}}${{env.np}}" --show-only
+          ${{env.CTEST}} tests/unit -R "${{env.unit_tests}}${{env.np}}"

.github/workflows/sanitizers.yml

@@ -0,0 +1,73 @@
+# 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.
+---
+name: Sanitizers
+
+permissions:
+  actions: write
+
+on:
+  push:
+    branches: ["master", "next"]
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: ${{github.workflow}}-${{github.ref}}
+  cancel-in-progress: true
+
+jobs:
+
+  # Build steps for dependencies
+  build-hypre:
+    uses: ./.github/workflows/sanitize-build-hypre.yml
+
+  build-metis:
+    uses: ./.github/workflows/sanitize-build-metis.yml
+
+  build-lsan:
+    uses: ./.github/workflows/sanitize-build-lsan.yml
+
+  build-libcxx:
+    uses: ./.github/workflows/sanitize-build-libcxx.yml
+
+  # Serial sanitizers: asan, msan, ubsan
+  seq-asan:
+    needs: [build-libcxx]
+    uses: ./.github/workflows/sanitize-tests.yml
+    with:
+      sanitizer: asan
+
+  seq-msan:
+    needs: [build-libcxx]
+    uses: ./.github/workflows/sanitize-tests.yml
+    with:
+      sanitizer: msan
+
+  seq-ubsan:
+    needs: [build-libcxx]
+    uses: ./.github/workflows/sanitize-tests.yml
+    with:
+      sanitizer: ubsan
+
+  # Parallel sanitizers: asan, ubsan
+  par-asan:
+    needs: [build-libcxx, build-hypre, build-metis]
+    uses: ./.github/workflows/sanitize-tests.yml
+    with:
+      par: true
+      sanitizer: asan
+  par-ubsan:
+    needs: [build-libcxx, build-hypre, build-metis]
+    uses: ./.github/workflows/sanitize-tests.yml
+    with:
+      par: true
+      sanitizer: ubsan

.gitignore

@@ -211,7 +211,7 @@ miniapps/electromagnetics/joule
 miniapps/electromagnetics/Volta-AMR*
 miniapps/electromagnetics/Tesla-AMR*
 miniapps/electromagnetics/Maxwell-Parallel*
-miniapps/electromagnetics/Joule_*
+miniapps/electromagnetics/Joule_[0-9]*
 
 miniapps/gslib/field-diff
 miniapps/gslib/field-interp
@@ -267,9 +267,9 @@ miniapps/meshing/bounding-box*
 miniapps/meshing/jacobian-determinant*
 
 miniapps/mtop/parheat
-miniapps/mtop/ParHeat*
+miniapps/mtop/ParHeat/*
 miniapps/mtop/seqheat
-miniapps/mtop/SeqHeat*
+miniapps/mtop/SeqHeat/*
 
 miniapps/autodiff/paradiff
 miniapps/autodiff/seqadiff
@@ -277,7 +277,7 @@ miniapps/autodiff/seqtest
 miniapps/autodiff/par_example
 miniapps/autodiff/seq_example
 miniapps/autodiff/seq_test
-miniapps/autodiff/Exampl*
+miniapps/autodiff/Example/*
 
 miniapps/navier/navier_mms
 miniapps/navier/navier_kovasznay
@@ -300,6 +300,7 @@ miniapps/nurbs/nurbs_solenoidal
 miniapps/nurbs/nurbs_printfunc
 miniapps/nurbs/nurbs_patch_ex1
 miniapps/nurbs/nurbs_curveint
+miniapps/nurbs/nurbs_surface
 miniapps/nurbs/refined.mesh
 miniapps/nurbs/mesh.*
 miniapps/nurbs/sol_?.gf
@@ -318,6 +319,7 @@ miniapps/nurbs/nurbs_naca_cmesh
 miniapps/nurbs/naca-cmesh.mesh
 miniapps/nurbs/glvis_naca-cmesh.mesh
 miniapps/nurbs/Naca_cmesh
+miniapps/nurbs/*-Surface.mesh
 
 miniapps/performance/ex1
 miniapps/performance/ex1p
@@ -413,8 +415,8 @@ miniapps/diag-smoothers/mg-abs-l1-jacobi
 tests/unit/output_meshes
 tests/unit/unit_tests
 tests/unit/punit_tests
-tests/unit/cunit_tests
-tests/unit/pcunit_tests
+tests/unit/gpu_unit_tests
+tests/unit/pgpu_unit_tests
 tests/unit/sedov_tests_*
 tests/unit/psedov_tests_*
 tests/unit/tmop_pa_tests_*

.gitlab/configs/ruby-config.yml

@@ -52,4 +52,4 @@ variables:
     - echo ${JOBID}
     - echo ${MFEM_DATA_DIR}
     - echo ${SPEC}
-    - srun $( [[ -n "${JOBID}" ]] && echo "--jobid=${JOBID}" ) --reservation=ci -t 45 -N 1 tests/gitlab/build_and_test --spec "${SPEC}" --data-dir "${MFEM_DATA_DIR}" --data
+    - srun $( [[ -n "${JOBID}" ]] && echo "--jobid=${JOBID}" ) --reservation=ci -t 60 -N 1 tests/gitlab/build_and_test --spec "${SPEC}" --data-dir "${MFEM_DATA_DIR}" --data

CHANGELOG

@@ -29,9 +29,14 @@ Discretization improvements
 
 Meshing improvements
 --------------------
+
 - Added support for higher order meshes in Mesh::MakeSimplicial and
   ParMesh::MakeSimplicial.
 
+- Added a new miniapp for interpolating a surface grid of points in 3D using a
+  smooth NURBS surface, that can then be sampled at arbitrary resolution while
+  staying close to the original geometry. See miniapps/nurbs/nurbs_surface.
+
 GPU computing
 -------------
 - The function Vector::SetSubVector(const Array<int> &, const real_t) now
@@ -39,6 +44,13 @@ GPU computing
   set. This is most often used for setting constant essential boundary
   conditions. A new function Vector::SetSubVectorHost has been added in cases
   where host execution is always needed (e.g. when the DOFs array is small).
+- Introduced MFEM_FOREACH_THREAD_DIRECT, which directly maps loop tasks to GPU
+  threads, assigning one task per thread.
+- Implemented a GPU-accelerated matrix-free AMR derefinement `GridFunction`
+  update operator. This supports mixed geometry meshes and variable order
+  spaces, and is the default derefinement operator constructed by
+  `FiniteElementSpace::Update` and `ParFiniteElementSpace::Update`.
+  The operator requires `FiniteElementSpace::Nonconforming() == true`.
 
 New and updated examples and miniapps
 -------------------------------------
@@ -48,13 +60,26 @@ New and updated examples and miniapps
   operators as smoothers.
   These miniapps can be found in `miniapps/diag-smoothers`.
 
-API changes:
+API changes
 -----------
 - mfem::internal::tensor and mfem::internal::dual have been moved to
   mfem::future::tensor and mfem::future::dual.
 - API addition: in class `Operator`, added virtual functions: `AbsMult`, and
   `AbsMultTranspose`; in class `Vector`, added `Abs` and `Pow`.
 
+Miscellaneous
+-------------
+- Added the "gpu", "raja-gpu", and "ceed-gpu" backend aliases/shortcuts which
+  automatically select between CUDA or HIP.
+- The CUDA-specific names used by some of the unit tests like 'cunit_tests' and
+  'pcunit_tests' were replaced by names using 'gpu' instead of 'c' (short for
+  CUDA) or 'cuda'. These tests automatically run the CUDA/HIP tests based on the
+  MFEM build configuration.
+- Added the option to enable GPU-aware MPI in MFEM using the environment
+  variable 'MFEM_GPU_AWARE_MPI' set to any value. Setting this environment
+  variable is an alternative to calling 'Device::SetGPUAwareMPI(true)'.
+- Added parallel Address Sanitizer, serial and parallel Undefined Behavior
+  Sanitizer and serial Memory Sanitizer GitHub actions tests on Ubuntu.
 
 Version 4.8, released on Apr 9, 2025
 ====================================

CMakeLists.txt

@@ -598,14 +598,20 @@ set(MFEM_TPLS OPENMP HYPRE LAPACK BLAS SuperLUDist STRUMPACK METIS SuiteSparse
     BENCHMARK PARELAG TRIBOL MPI_CXX HIP HIPBLAS HIPSPARSE MOONOLITH BLITZ
     ALGOIM ENZYME)
 
-# Add all *_FOUND libraries in the variable TPL_LIBRARIES.
+# Add all created targets and *_FOUND libraries in the variables TPL_TARGETS and
+# TPL_LIBRARIES, respectively.
+set(TPL_TARGETS)
 set(TPL_LIBRARIES "")
 set(TPL_INCLUDE_DIRS "")
 foreach(TPL IN LISTS MFEM_TPLS)
-  if (${TPL}_FOUND)
+  if (${TPL}_FOUND OR TARGET ${TPL})
     message(STATUS "MFEM: using package ${TPL}")
-    list(APPEND TPL_LIBRARIES ${${TPL}_LIBRARIES})
-    list(APPEND TPL_INCLUDE_DIRS ${${TPL}_INCLUDE_DIRS})
+    if (TARGET ${TPL})
+      list(APPEND TPL_TARGETS ${TPL})
+    else()
+      list(APPEND TPL_LIBRARIES ${${TPL}_LIBRARIES})
+      list(APPEND TPL_INCLUDE_DIRS ${${TPL}_INCLUDE_DIRS})
+    endif()
   endif()
 endforeach(TPL)
 list(REVERSE TPL_LIBRARIES)
@@ -680,7 +686,10 @@ set(MFEM_INSTALL_DIR ${CMAKE_INSTALL_PREFIX})
 # Declaring the library
 mfem_add_library(mfem ${SOURCES} ${HEADERS} ${MASTER_HEADERS})
 # message(STATUS "TPL_LIBRARIES = ${TPL_LIBRARIES}")
-target_link_libraries(mfem PUBLIC ${TPL_LIBRARIES})
+target_link_libraries(mfem PUBLIC ${TPL_LIBRARIES} ${TPL_TARGETS})
+if (TPL_TARGETS)
+  add_dependencies(mfem ${TPL_TARGETS})
+endif()
 if (MINGW)
   target_link_libraries(mfem PRIVATE ws2_32)
 endif()

INSTALL

@@ -121,6 +121,11 @@ Parallel build:
    make -j 4
 (For METIS 5, see https://mfem.org/building/#parallel-build-using-metis-5)
 
+Parallel build with fetching of hypre and METIS:
+   mkdir <mfem-buil-dir> ; cd <mfem-build-dir>
+   cmake <mfem-source-dir> -DMFEM_USE_MPI=YES -DFETCH_TPLS=YES
+   make -j 4
+
 CUDA build:
    (this build requires CMake 3.17 or newer)
    mkdir <mfem-build-dir> ; cd <mfem-build-dir>
@@ -842,6 +847,7 @@ The specific libraries and their options are:
 - HIP (optional), used when MFEM_USE_HIP = YES.
   URL: https://rocmdocs.amd.com
   Options: HIP_CXX, HIP_ARCH, HIP_OPT, HIP_LIB.
+  Versions: ROCm >= 5.6.1.
 
 - OCCA (optional), used when MFEM_USE_OCCA = YES.
   URL: https://libocca.org
@@ -1074,6 +1080,9 @@ The following options are CMake specific:
 MFEM_ENABLE_TESTING  - Enable the ctest framework for testing.
 MFEM_ENABLE_EXAMPLES - Build all of the examples by default.
 MFEM_ENABLE_MINIAPPS - Build all of the miniapps by default.
+FETCH_TPLS           - Enable fetching of all supported third-party libraries.
+HYPRE_FETCH          - Enable fetching of hypre.
+METIS_FETCH          - Enable fetching of metis.
 
 External libraries (CMake):
 ---------------------------
@@ -1135,6 +1144,12 @@ The following built-in CMake packages are also used:
       set the <LIBNAME>_LIBRARIES option directly; the configuration option
       <LIBNAME>_DIR is not supported.
 
+The MFEM CMake build system also provides fetching (automated building) for the
+packages/libraries listed below. Note that when fetching is enabled, any related
+auto-detection functionality is disabled.
+
+ - HYPRE
+ - METIS
 
 Building without GNU make or CMake
 ==================================

config/cmake/modules/FindHYPRE.cmake

@@ -9,15 +9,18 @@
 # terms of the BSD-3 license. We welcome feedback and contributions, see file
 # CONTRIBUTING.md for details.
 
-# Defines the following variables:
+# Defines the following variables if fetching of TPLs is disabled (default):
 #   - HYPRE_FOUND
 #   - HYPRE_LIBRARIES
 #   - HYPRE_INCLUDE_DIRS
 #   - HYPRE_VERSION
 #   - HYPRE_USING_CUDA (internal)
 #   - HYPRE_USING_HIP (internal)
+# otherwise, the following are defined:
+#   - HYPRE (imported library target)
+#   - HYPRE_VERSION (cache variable)
 
-if (HYPRE_FOUND)
+if (HYPRE_FOUND OR TARGET HYPRE)
   if (HYPRE_USING_CUDA)
     find_package(CUDAToolkit REQUIRED)
   endif()
@@ -33,6 +36,55 @@ if (HYPRE_FOUND)
   endif()
 endif()
 
+if (HYPRE_FETCH OR FETCH_TPLS)
+  set(HYPRE_FETCH_VERSION 2.33.0)
+  add_library(HYPRE STATIC IMPORTED)
+  # set options and associated dependencies
+  set(CMAKE_OPTIONS)
+  list(APPEND CMAKE_OPTIONS -DCMAKE_BUILD_TYPE:STRING=${CMAKE_BUILD_TYPE})
+  if (MFEM_USE_CUDA)
+    list(APPEND CMAKE_OPTIONS -DHYPRE_WITH_CUDA:BOOL=ON)
+    find_package(CUDAToolkit REQUIRED)
+    target_link_libraries(HYPRE INTERFACE CUDA::cusparse CUDA::curand CUDA::cublas)
+  elseif (MFEM_USE_HIP)
+    list(APPEND CMAKE_OPTIONS -DHYPRE_WITH_HIP:BOOL=ON)
+    find_package(rocsparse REQUIRED)
+    find_package(rocrand REQUIRED)
+    target_link_libraries(HYPRE INTERFACE rocsparse rocrand)
+  endif()
+  if (MFEM_USE_SINGLE)
+    list(APPEND CMAKE_OPTIONS -DHYPRE_ENABLE_SINGLE:BOOL=ON)
+  endif()
+  # define external project and create future include directory so it is present
+  # to pass CMake checks at end of MFEM configuration step
+  message(STATUS "Will fetch HYPRE ${HYPRE_FETCH_VERSION} to be built with ${CMAKE_OPTIONS}")
+  set(PREFIX ${CMAKE_BINARY_DIR}/fetch/hypre)
+  include(ExternalProject)
+  ExternalProject_Add(hypre
+    GIT_REPOSITORY https://github.com/hypre-space/hypre.git
+    GIT_TAG v${HYPRE_FETCH_VERSION}
+    GIT_SHALLOW TRUE
+    UPDATE_DISCONNECTED TRUE
+    SOURCE_SUBDIR src
+    PREFIX ${PREFIX}
+    CMAKE_CACHE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=${PREFIX} -DCMAKE_INSTALL_LIBDIR:PATH=lib ${CMAKE_OPTIONS})
+  file(MAKE_DIRECTORY ${PREFIX}/include)
+  # set imported library target properties
+  add_dependencies(HYPRE hypre)
+  set_target_properties(HYPRE PROPERTIES
+    IMPORTED_LOCATION ${PREFIX}/lib/libHYPRE.a
+    INTERFACE_INCLUDE_DIRECTORIES ${PREFIX}/include)
+  # convert HYPRE version to integer
+  string(REGEX MATCHALL "[0-9]+" HYPRE_SPLIT_VERSION ${HYPRE_FETCH_VERSION})
+  list(GET HYPRE_SPLIT_VERSION 0 HYPRE_MAJOR_VERSION)
+  list(GET HYPRE_SPLIT_VERSION 1 HYPRE_MINOR_VERSION)
+  list(GET HYPRE_SPLIT_VERSION 2 HYPRE_PATCH_VERSION)
+  math(EXPR HYPRE_VERSION "10000*${HYPRE_MAJOR_VERSION} + 100*${HYPRE_MINOR_VERSION} + ${HYPRE_PATCH_VERSION}")
+  # set cache variables that would otherwise be set after mfem_find_package call
+  set(HYPRE_VERSION ${HYPRE_VERSION} CACHE STRING "HYPRE version." FORCE)
+  return()
+endif()
+
 include(MfemCmakeUtilities)
 mfem_find_package(HYPRE HYPRE HYPRE_DIR "include" "HYPRE.h" "lib" "HYPRE"
   "Paths to headers required by HYPRE." "Libraries required by HYPRE."

config/cmake/modules/FindMETIS.cmake

@@ -9,10 +9,38 @@
 # terms of the BSD-3 license. We welcome feedback and contributions, see file
 # CONTRIBUTING.md for details.
 
-# Defines the following variables:
+# Defines the following variables if fetching of TPLs is disabled (default):
 #   - METIS_FOUND
 #   - METIS_LIBRARIES
 #   - METIS_INCLUDE_DIRS
+#   - METIS_VERSION_5
+# otherwise, the following are defined:
+#   - METIS (imported library target)
+#   - METIS_VERSION_5 (cache variable)
+
+if (METIS_FETCH OR FETCH_TPLS)
+  set(METIS_FETCH_VERSION 4.0.3)
+  add_library(METIS STATIC IMPORTED)
+  # define external project
+  message(STATUS "Will fetch METIS ${METIS_FETCH_VERSION} to be built with default options")
+  set(PREFIX ${CMAKE_BINARY_DIR}/fetch/metis)
+  include(ExternalProject)
+  ExternalProject_Add(metis
+    GIT_REPOSITORY https://github.com/mfem/tpls
+    GIT_TAG b60352fbe9675d374b00828055e55be4584c7995 # tag from 1/16/25
+    GIT_SHALLOW TRUE
+    UPDATE_DISCONNECTED TRUE
+    PREFIX ${PREFIX}
+    CONFIGURE_COMMAND tar -xzf ../metis/metis-${METIS_FETCH_VERSION}-mac.tgz --strip=1
+    INSTALL_COMMAND mkdir -p ${PREFIX}/lib && cp libmetis.a ${PREFIX}/lib/)
+  # set imported library target properties
+  add_dependencies(METIS metis)
+  set_target_properties(METIS PROPERTIES
+    IMPORTED_LOCATION ${PREFIX}/lib/libmetis.a)
+  # set cache variables that would otherwise be set after mfem_find_package call
+  set(METIS_VERSION_5 FALSE CACHE BOOL "Is METIS version 5?")
+  return()
+endif()
 
 include(MfemCmakeUtilities)
 mfem_find_package(METIS METIS METIS_DIR "include;Lib" "metis.h"

config/config.hpp

@@ -27,7 +27,7 @@ namespace mfem
 {
 
 #if (defined(MFEM_USE_CUDA) && defined(__CUDACC__)) || \
-    (defined(MFEM_USE_HIP) && defined(__HIPCC__))
+    (defined(MFEM_USE_HIP) && defined(__HIP__))
 #define MFEM_HOST_DEVICE __host__ __device__
 #else
 #define MFEM_HOST_DEVICE

config/defaults.cmake

@@ -89,6 +89,12 @@ option(MFEM_ENABLE_EXAMPLES "Build all of the examples" OFF)
 option(MFEM_ENABLE_MINIAPPS "Build all of the miniapps" OFF)
 option(MFEM_ENABLE_BENCHMARKS "Build all of the benchmarks" OFF)
 
+# Allow a user to specify fetching of certain third-party libraries instead of
+# searching for existing installations.
+option(FETCH_TPLS "Enable fetching of all supported third-party libraries" OFF)
+option(HYPRE_FETCH "Enable fetching of hypre" OFF)
+option(METIS_FETCH "Enable fetching of METIS" OFF)
+
 # Setting CXX/MPICXX on the command line or in user.cmake will overwrite the
 # autodetected C++ compiler.
 # set(CXX g++)

fem/CMakeLists.txt

@@ -82,6 +82,8 @@ set(SRCS
   fe/fe_ser.cpp
   fe_coll.cpp
   fespace.cpp
+  derefmat_op.cpp
+  pderefmat_op.cpp
   geom.cpp
   gridfunc.cpp
   hybridization.cpp
@@ -247,6 +249,7 @@ set(HDRS
   nonlinearform_ext.hpp
   nonlininteg.hpp
   qfunction.hpp
+  qinterp/det.hpp
   qinterp/eval.hpp
   qinterp/eval_hdiv.hpp
   qinterp/grad.hpp

fem/batchitrans.cpp

@@ -515,6 +515,7 @@ struct InvTNewtonSolver<Geometry::SEGMENT, SDim, SType, max_team_x>
             phys_tol += pptr[idx + d * npts] * pptr[idx + d * npts];
          }
          phys_tol = fmax(phys_rtol * phys_rtol, phys_tol * phys_rtol * phys_rtol);
+         hit_bdr[0] = prev_hit_bdr[0] = false;
       }
       // for each iteration
       while (true)

fem/bilininteg.hpp

@@ -812,7 +812,7 @@ protected:
       const FiniteElement & test_fe) const
    {
       return (trial_fe.GetDim() == 1 && test_fe.GetDim() == 1 &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD  &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD &&
               test_fe.GetRangeType()  == mfem::FiniteElement::SCALAR );
    }
 
@@ -884,7 +884,7 @@ protected:
       const FiniteElement & trial_fe,
       const FiniteElement & test_fe) const
    {
-      return (trial_fe.GetDerivType() == mfem::FiniteElement::DIV  &&
+      return (trial_fe.GetDerivType() == mfem::FiniteElement::DIV &&
               test_fe.GetRangeType()  == mfem::FiniteElement::SCALAR );
    }
 
@@ -919,7 +919,7 @@ protected:
       const FiniteElement & trial_fe,
       const FiniteElement & test_fe) const
    {
-      return (trial_fe.GetDerivType() == mfem::FiniteElement::DIV  &&
+      return (trial_fe.GetDerivType() == mfem::FiniteElement::DIV &&
               test_fe.GetRangeType()  == mfem::FiniteElement::VECTOR );
    }
 
@@ -1600,7 +1600,7 @@ public:
    {
       return (trial_fe.GetCurlDim() == 3 && test_fe.GetRangeDim() == 3 &&
               trial_fe.GetRangeType() == mfem::FiniteElement::VECTOR &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::CURL   &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::CURL  &&
               test_fe.GetRangeType()  == mfem::FiniteElement::VECTOR );
    }
 
@@ -1635,7 +1635,7 @@ public:
    {
       return (trial_fe.GetDim() == 2 && test_fe.GetDim() == 2 &&
               trial_fe.GetRangeType() == mfem::FiniteElement::VECTOR &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::CURL   &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::CURL  &&
               test_fe.GetRangeType()  == mfem::FiniteElement::VECTOR );
    }
 
@@ -1669,7 +1669,7 @@ public:
    {
       return (trial_fe.GetDim() == 2 && test_fe.GetDim() == 2 &&
               trial_fe.GetRangeType() == mfem::FiniteElement::SCALAR &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD   &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD  &&
               test_fe.GetRangeType()  == mfem::FiniteElement::SCALAR );
    }
 
@@ -1760,7 +1760,7 @@ public:
       const FiniteElement & test_fe) const
    {
       return (trial_fe.GetRangeType() == mfem::FiniteElement::SCALAR &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD   &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD  &&
               test_fe.GetRangeType()  == mfem::FiniteElement::SCALAR );
    }
 
@@ -1793,7 +1793,7 @@ public:
       const FiniteElement & test_fe) const
    {
       return (trial_fe.GetRangeType() == mfem::FiniteElement::SCALAR &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD   &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::GRAD  &&
               test_fe.GetRangeType()  == mfem::FiniteElement::VECTOR &&
               test_fe.GetDerivType()  == mfem::FiniteElement::DIV   );
    }
@@ -1832,7 +1832,7 @@ public:
       const FiniteElement & test_fe) const
    {
       return (trial_fe.GetRangeType() == mfem::FiniteElement::VECTOR &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::DIV    &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::DIV   &&
               test_fe.GetRangeType()  == mfem::FiniteElement::SCALAR &&
               test_fe.GetDerivType()  == mfem::FiniteElement::GRAD
              );
@@ -1973,7 +1973,7 @@ protected:
       const FiniteElement & test_fe) const override
    {
       return (trial_fe.GetCurlDim() == 3 && test_fe.GetRangeDim() == 3 &&
-              trial_fe.GetDerivType() == mfem::FiniteElement::CURL  &&
+              trial_fe.GetDerivType() == mfem::FiniteElement::CURL &&
               test_fe.GetRangeType()  == mfem::FiniteElement::VECTOR );
    }
 

fem/conduitdatacollection.cpp

@@ -912,7 +912,7 @@ ConduitDataCollection::GridFunctionToBlueprintField(mfem::GridFunction *gf,
 
    if (vdim == 1) // scalar case
    {
-      n_field["values"].set_external(gf->GetData(),
+      n_field["values"].set_external(const_cast<real_t *>(gf->HostRead()),
                                      ndofs);
    }
    else // vector case
@@ -925,18 +925,18 @@ ConduitDataCollection::GridFunctionToBlueprintField(mfem::GridFunction *gf,
       int vdim_stride  = (ordering == Ordering::byNODES ? ndofs : 1);
 
       index_t offset = 0;
-      index_t stride = sizeof(double) * entry_stride;
+      index_t stride = sizeof(real_t) * entry_stride;
 
       for (int d = 0;  d < vdim; d++)
       {
          std::ostringstream oss;
          oss << "v" << d;
          std::string comp_name = oss.str();
-         n_field["values"][comp_name].set_external(gf->GetData(),
+         n_field["values"][comp_name].set_external(const_cast<real_t *>(gf->HostRead()),
                                                    ndofs,
                                                    offset,
                                                    stride);
-         offset +=  sizeof(double) * vdim_stride;
+         offset +=  sizeof(real_t) * vdim_stride;
       }
    }
 

fem/datacollection.cpp

@@ -764,9 +764,9 @@ ParaViewDataCollectionBase::ParaViewDataCollectionBase(
 {
    cycle = 0;
 #ifdef MFEM_USE_ZLIB
-   compression = true; // if we have zlib, enable compression
-#else
-   compression = false; // otherwise, disable compression
+   // If we have zlib, enable compression. Otherwise, compression is disabled in
+   // the DataCollection base class constructor.
+   compression = true;
 #endif
 }
 
@@ -784,13 +784,8 @@ void ParaViewDataCollectionBase::SetCompressionLevel(int compression_level_)
 {
    MFEM_ASSERT(compression_level_ >= -1 && compression_level_ <= 9,
                "Compression level must be between -1 and 9 (inclusive).");
+   if (compression_level_ != 0) { SetCompression(true);}
    compression_level = compression_level_;
-   compression = compression_level_ != 0;
-}
-
-void ParaViewDataCollectionBase::SetCompression(bool compression_)
-{
-   compression = compression_;
 }
 
 int ParaViewDataCollectionBase::GetCompressionLevel() const
@@ -1174,7 +1169,14 @@ const char *ParaViewDataCollection::GetDataTypeString() const
 ParaViewHDFDataCollection::ParaViewHDFDataCollection(
    const std::string &collection_name, Mesh *mesh)
    : ParaViewDataCollectionBase(collection_name, mesh)
-{ }
+{
+   compression = true;
+}
+
+void ParaViewHDFDataCollection::SetCompression(bool compression_)
+{
+   compression = compression_;
+}
 
 void ParaViewHDFDataCollection::EnsureVTKHDF()
 {

fem/datacollection.hpp

@@ -537,13 +537,6 @@ public:
    /// Any nonzero compression level will enable compression.
    void SetCompressionLevel(int compression_level_);
 
-   /// @brief Enable or disable zlib compression.
-   ///
-   /// If the input is true, use the default zlib compression level (unless the
-   /// compression level has previously been set by calling
-   /// SetCompressionLevel()).
-   void SetCompression(bool compression_) override;
-
    /// @brief Sets whether or not to output the data as high-order elements
    /// (false by default).
    ///
@@ -633,6 +626,12 @@ public:
    ParaViewHDFDataCollection(const std::string& collection_name,
                              Mesh *mesh_ = nullptr);
 
+   /// @brief Enable or disable compression.
+   ///
+   /// The compression level can be set with SetCompressionLevel()). VTKHDF
+   /// compression does not require MFEM to be compiled with zlib support.
+   void SetCompression(bool compression_) override;
+
    /// Save the collection.
    void Save() override;
 

fem/derefmat_op.cpp

@@ -0,0 +1,266 @@
+// 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 "derefmat_op.hpp"
+#include "fes_kernels.hpp"
+
+/// \cond DO_NOT_DOCUMENT
+namespace mfem
+{
+
+namespace internal
+{
+template <Ordering::Type Order, bool Atomic>
+static void DerefMultKernelImpl(const DerefineMatrixOp &op, const Vector &x,
+                                Vector &y)
+{
+   DerefineMatrixOpMultFunctor<Order, Atomic> func;
+   func.xptr = x.Read();
+   y.UseDevice();
+   y = 0.;
+   func.yptr = y.ReadWrite();
+   func.bsptr = op.block_storage.Read();
+   func.boptr = op.block_offsets.Read();
+   func.brptr = op.block_row_idcs_offsets.Read();
+   func.bcptr = op.block_col_idcs_offsets.Read();
+   func.rptr = op.row_idcs.Read();
+   func.cptr = op.col_idcs.Read();
+   func.vdims = op.fespace->GetVDim();
+   func.nblocks = op.block_offsets.Size();
+   func.width = op.Width() / func.vdims;
+   func.height = op.Height() / func.vdims;
+   func.Run(op.max_rows);
+}
+
+} // namespace internal
+
+DerefineMatrixOp::DerefineMatrixOp(FiniteElementSpace &fespace_, int old_ndofs,
+                                   const Table *old_elem_dof,
+                                   const Table *old_elem_fos)
+   : Operator(fespace_.GetVSize(), old_ndofs * fespace_.GetVDim()),
+     fespace(&fespace_)
+{
+   static Kernels kernels;
+   constexpr int max_team_size = 256;
+   /// TODO: Implement DofTransformation support
+
+   MFEM_VERIFY(fespace->Nonconforming(),
+               "Not implemented for conforming meshes.");
+   MFEM_VERIFY(old_ndofs, "Missing previous (finer) space.");
+   MFEM_VERIFY(fespace->GetNDofs() <= old_ndofs,
+               "Previous space is not finer.");
+
+   const CoarseFineTransformations &dtrans =
+      fespace->GetMesh()->ncmesh->GetDerefinementTransforms();
+
+   MFEM_ASSERT(dtrans.embeddings.Size() == old_elem_dof->Size(), "");
+
+   const bool is_dg = fespace->FEColl()->GetContType()
+                      == FiniteElementCollection::DISCONTINUOUS;
+   DenseMatrix localRVO; // for variable-order only
+
+   DenseTensor localR[Geometry::NumGeom];
+   int total_rows = 0;
+   int total_cols = 0;
+   block_offsets.SetSize(dtrans.embeddings.Size());
+   block_offsets.HostWrite();
+   if (fespace->IsVariableOrder())
+   {
+      // TODO: any potential for some compression here?
+      // determine storage size and offsets
+      block_offsets[0] = 0;
+      int total_size = 0;
+      for (int k = 0; k < dtrans.embeddings.Size(); ++k)
+      {
+         const Embedding &emb = dtrans.embeddings[k];
+         const FiniteElement *fe = fespace->GetFE(emb.parent);
+         const int ldof = fe->GetDof();
+         if (k + 1 < dtrans.embeddings.Size())
+         {
+            block_offsets[k + 1] = block_offsets[k] + ldof * ldof;
+         }
+         total_rows += ldof;
+         total_cols += ldof;
+         total_size += ldof * ldof;
+      }
+      block_storage.SetSize(total_size);
+   }
+   else
+   {
+      // compression scheme:
+      // block_offsets is the start of each block, potentially repeated
+      // only need to store localR for used shapes
+      Mesh::GeometryList elem_geoms(*fespace->GetMesh());
+
+      int geom_offsets[Geometry::NumGeom];
+      {
+         int size = 0;
+         for (int i = 0; i < elem_geoms.Size(); ++i)
+         {
+            fespace->GetLocalDerefinementMatrices(elem_geoms[i],
+                                                  localR[elem_geoms[i]]);
+            geom_offsets[elem_geoms[i]] = size;
+            size += localR[elem_geoms[i]].TotalSize();
+         }
+         block_storage.SetSize(size);
+         // copy blocks into block_storage
+         auto bs_ptr = block_storage.HostWrite();
+         for (int i = 0; i < elem_geoms.Size(); ++i)
+         {
+            std::copy(localR[elem_geoms[i]].Data(),
+                      localR[elem_geoms[i]].Data()
+                      + localR[elem_geoms[i]].TotalSize(),
+                      bs_ptr);
+            bs_ptr += localR[elem_geoms[i]].TotalSize();
+         }
+      }
+      for (int k = 0; k < dtrans.embeddings.Size(); ++k)
+      {
+         const Embedding &emb = dtrans.embeddings[k];
+         Geometry::Type geom =
+            fespace->GetMesh()->GetElementBaseGeometry(emb.parent);
+
+         auto size = localR[geom].SizeI() * localR[geom].SizeJ();
+         total_rows += localR[geom].SizeI();
+         total_cols += localR[geom].SizeJ();
+         // set block offsets and sizes
+         block_offsets[k] = geom_offsets[geom] + size * emb.matrix;
+      }
+   }
+   row_idcs.SetSize(total_rows);
+   row_idcs.HostWrite();
+   col_idcs.SetSize(total_cols);
+   col_idcs.HostWrite();
+   block_row_idcs_offsets.SetSize(dtrans.embeddings.Size() + 1);
+   block_row_idcs_offsets.HostWrite();
+   block_col_idcs_offsets.SetSize(dtrans.embeddings.Size() + 1);
+   block_col_idcs_offsets.HostWrite();
+   block_row_idcs_offsets[0] = 0;
+   block_col_idcs_offsets[0] = 0;
+
+   // compute index information
+   Array<int> dofs, old_dofs;
+   max_rows = 1;
+
+   {
+      Array<int> mark(fespace->GetNDofs());
+      mark = 0;
+      auto bs_ptr = block_storage.HostWrite();
+      int ridx = 0;
+      int cidx = 0;
+      int num_marked = 0;
+      for (int k = 0; k < dtrans.embeddings.Size(); k++)
+      {
+         const Embedding &emb = dtrans.embeddings[k];
+         Geometry::Type geom =
+            fespace->GetMesh()->GetElementBaseGeometry(emb.parent);
+
+         if (fespace->IsVariableOrder())
+         {
+            const FiniteElement *fe = fespace->GetFE(emb.parent);
+            const DenseTensor &pmats = dtrans.point_matrices[geom];
+            const int ldof = fe->GetDof();
+
+            IsoparametricTransformation isotr;
+            isotr.SetIdentityTransformation(geom);
+
+            localRVO.SetSize(ldof, ldof);
+            isotr.SetPointMat(pmats(emb.matrix));
+            // Local restriction is size ldofxldof assuming that the parent
+            // and child are of same polynomial order.
+            fe->GetLocalRestriction(isotr, localRVO);
+            // copy block
+            auto size = localRVO.Height() * localRVO.Width();
+            std::copy(localRVO.Data(), localRVO.Data() + size, bs_ptr);
+            bs_ptr += size;
+         }
+         DenseMatrix &lR =
+            fespace->IsVariableOrder() ? localRVO : localR[geom](emb.matrix);
+         block_row_idcs_offsets[k + 1] =
+            block_row_idcs_offsets[k] + lR.Height();
+         block_col_idcs_offsets[k + 1] = block_col_idcs_offsets[k] + lR.Width();
+         max_rows = std::max(lR.Height(), max_rows);
+         // index information
+         fespace->elem_dof->GetRow(emb.parent, dofs);
+         old_elem_dof->GetRow(k, old_dofs);
+         MFEM_VERIFY(old_dofs.Size() == dofs.Size(),
+                     "Parent and child must have same #dofs.");
+         for (int i = 0; i < lR.Height(); ++i, ++ridx)
+         {
+            if (!std::isfinite(lR(i, 0)))
+            {
+               row_idcs[ridx] = INT_MAX;
+               continue;
+            }
+            int r = dofs[i];
+            int m = (r >= 0) ? r : (-1 - r);
+            if (is_dg || !mark[m])
+            {
+               row_idcs[ridx] = r;
+               mark[m] = 1;
+               ++num_marked;
+            }
+            else
+            {
+               row_idcs[ridx] = INT_MAX;
+            }
+         }
+         for (int i = 0; i < lR.Width(); ++i, ++cidx)
+         {
+            col_idcs[cidx] = old_dofs[i];
+         }
+      }
+      if (!is_dg && !fespace->IsVariableOrder())
+      {
+         MFEM_VERIFY(num_marked * fespace->GetVDim() == Height(),
+                     "internal error: not all rows were set.");
+      }
+   }
+   // if not using GPU, set max_rows/max_cols to zero
+   if (Device::Allows(Backend::DEVICE_MASK))
+   {
+      max_rows = std::min(max_rows, max_team_size);
+   }
+   else
+   {
+      max_rows = 1;
+   }
+}
+
+void DerefineMatrixOp::Mult(const Vector &x, Vector &y) const
+{
+   const bool is_dg = fespace->FEColl()->GetContType()
+                      == FiniteElementCollection::DISCONTINUOUS;
+   // DG needs atomic summation
+   MultKernel::Run(fespace->GetOrdering(), is_dg, *this, x, y);
+}
+
+DerefineMatrixOp::Kernels::Kernels()
+{
+   MultKernel::Specialization<Ordering::byNODES, false>::Add();
+   MultKernel::Specialization<Ordering::byVDIM, false>::Add();
+   MultKernel::Specialization<Ordering::byNODES, true>::Add();
+   MultKernel::Specialization<Ordering::byVDIM, true>::Add();
+}
+
+template <Ordering::Type Order, bool Atomic>
+DerefineMatrixOp::MultKernelType DerefineMatrixOp::MultKernel::Kernel()
+{
+   return internal::DerefMultKernelImpl<Order, Atomic>;
+}
+
+DerefineMatrixOp::MultKernelType
+DerefineMatrixOp::MultKernel::Fallback(Ordering::Type, bool)
+{
+   MFEM_ABORT("invalid MultKernel parameters");
+}
+} // namespace mfem
+/// \endcond DO_NOT_DOCUMENT

fem/derefmat_op.hpp

@@ -0,0 +1,65 @@
+// 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_DEREFMAT_OP
+#define MFEM_DEREFMAT_OP
+
+#include "fespace.hpp"
+
+#include "kernel_dispatch.hpp"
+
+namespace mfem
+{
+
+/// \cond DO_NOT_DOCUMENT
+
+struct DerefineMatrixOp : public Operator
+{
+   FiniteElementSpace *fespace;
+   /// offsets into block_storage
+   Array<int> block_offsets;
+   /// offsets into row_idcs
+   Array<int> block_row_idcs_offsets;
+   /// offsets into col_idcs
+   Array<int> block_col_idcs_offsets;
+   /// mapping for row dofs, INT_MAX indicates the block row should be ignored.
+   /// negative means the row data should be negated.
+   Array<int> row_idcs;
+   /// mapping for col dofs, negative means the col data should be negated.
+   Array<int> col_idcs;
+   /// dense block matrices which can be reused to construct the full matrix
+   /// operation. These are stored contiguously and blocks have no restrictions
+   /// on shape (can be rectangle and differ from block to block).
+   Vector block_storage;
+   /// maximum height of any block in block_storage for GPU
+   /// parallelization, or 1 for CPU runs.
+   int max_rows;
+
+   using MultKernelType = void (*)(const DerefineMatrixOp &, const Vector &,
+                                   Vector &);
+   /// template args: ordering, atomic
+   MFEM_REGISTER_KERNELS(MultKernel, MultKernelType, (Ordering::Type, bool));
+
+   struct Kernels
+   {
+      Kernels();
+   };
+
+   void Mult(const Vector &x, Vector &y) const;
+
+   DerefineMatrixOp(FiniteElementSpace &fespace_, int old_ndofs,
+                    const Table *old_elem_dof, const Table *old_elem_fos);
+};
+
+/// \endcond DO_NOT_DOCUMENT
+
+} // namespace mfem
+#endif

fem/dfem/doperator.hpp

@@ -241,6 +241,7 @@ public:
    {
       MFEM_ASSERT(!action_callbacks.empty(), "no integrators have been set");
       prolongation(solutions, solutions_t, solutions_l);
+      residual_l = 0.0;
       for (auto &action : action_callbacks)
       {
          action(solutions_l, parameters_l, residual_l);

fem/dfem/parameterspace.hpp

@@ -101,10 +101,11 @@ public:
       // Setup DofToQuad information
       dtq.nqpt = (int)floor(std::pow(ir.GetNPoints(), 1.0 / mesh.Dimension()) + 0.5);
       dtq.ndof = dtq.nqpt;
+      dtq.mode = used_in_tensor_product ? DofToQuad::TENSOR : DofToQuad::FULL;
 
       // Calculate sizes
       const int num_qp = used_in_tensor_product ?
-                         std::pow(dtq.nqpt, mesh.Dimension()) :
+                         static_cast<int>(std::pow(dtq.nqpt, mesh.Dimension())) :
                          ir.GetNPoints();
 
       tsize = vdim * num_qp * mesh.GetNE();

fem/dfem/util.hpp

@@ -568,7 +568,7 @@ struct ThreadBlocks
    int z = 1;
 };
 
-#if (defined(MFEM_USE_CUDA) || defined(MFEM_USE_HIP))
+#if defined(MFEM_USE_CUDA_OR_HIP)
 template <typename func_t>
 __global__ void forall_kernel_shmem(func_t f, int n)
 {
@@ -591,7 +591,7 @@ void forall(func_t f,
    if (Device::Allows(Backend::CUDA_MASK) ||
        Device::Allows(Backend::HIP_MASK))
    {
-#if (defined(MFEM_USE_CUDA) || defined(MFEM_USE_HIP))
+#if defined(MFEM_USE_CUDA_OR_HIP)
       // int gridsize = (N + Z - 1) / Z;
       int num_bytes = num_shmem * sizeof(decltype(shmem));
       dim3 block_size(blocks.x, blocks.y, blocks.z);
@@ -987,7 +987,7 @@ get_restriction_transpose(
    {
       auto RT = [=](const Vector &v_e, Vector &v_l)
       {
-         v_l = v_e;
+         v_l += v_e;
       };
       return std::make_tuple(RT, 1);
    }
@@ -996,7 +996,7 @@ get_restriction_transpose(
       const Operator *R = get_restriction<entity_t>(f, o);
       std::function<void(const Vector&, Vector&)> RT = [=](const Vector &x, Vector &y)
       {
-         R->MultTranspose(x, y);
+         R->AddMultTranspose(x, y);
       };
       return std::make_tuple(RT, R->Height());
    }
@@ -1702,12 +1702,13 @@ std::array<DofToQuadMap, N> load_dtq_mem(
    std::array<DofToQuadMap, N> f;
    for (std::size_t i = 0; i < N; i++)
    {
-      const auto [nqp_b, dim_b, ndof_b] = dtq[i].B.GetShape();
-      const auto B = Reshape(&dtq[i].B[0], nqp_b, dim_b, ndof_b);
-      auto mem_Bi = Reshape(reinterpret_cast<real_t *>(mem) + offset, nqp_b, dim_b,
-                            ndof_b);
       if (dtq[i].which_input != -1)
       {
+         const auto [nqp_b, dim_b, ndof_b] = dtq[i].B.GetShape();
+         const auto B = Reshape(&dtq[i].B[0], nqp_b, dim_b, ndof_b);
+         auto mem_Bi = Reshape(reinterpret_cast<real_t *>(mem) + offset, nqp_b, dim_b,
+                               ndof_b);
+
          MFEM_FOREACH_THREAD(q, x, nqp_b)
          {
             MFEM_FOREACH_THREAD(d, y, ndof_b)
@@ -2158,7 +2159,7 @@ template <
    std::size_t... Is>
 std::array<DofToQuadMap, N> create_dtq_maps_impl(
    field_operator_ts &fops,
-   std::vector<const DofToQuad*> dtqs,
+   std::vector<const DofToQuad*> &dtqs,
    const std::array<int, N> &field_map,
    std::index_sequence<Is...>)
 {
@@ -2243,7 +2244,7 @@ template <
    std::size_t num_fields>
 std::array<DofToQuadMap, num_fields> create_dtq_maps(
    field_operator_ts &fops,
-   std::vector<const DofToQuad*> dtqmaps,
+   std::vector<const DofToQuad*> &dtqmaps,
    const std::array<int, num_fields> &to_field_map)
 {
    return create_dtq_maps_impl<entity_t>(

fem/fes_kernels.hpp

@@ -0,0 +1,249 @@
+// 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_FES_KERNELS_HPP
+#define MFEM_FES_KERNELS_HPP
+
+#include "../general/forall.hpp"
+
+#include <climits>
+
+namespace mfem
+{
+/// \cond DO_NOT_DOCUMENT
+namespace internal
+{
+
+///
+/// Implements matrix-vector multiply $y = A x$ for a sparse matrix composed of
+/// a sum of smaller dense blocks. There is additional permutation/sign
+/// information associated with each block. The base class only implements
+/// helper routines such as computing block widths, index into x, index into y,
+/// and column in A given sub-block information.
+/// @sa DerefineMatrixOpMultFunctor
+///
+/// @tparam Order vdim ordering for x and y. Note that for Diag = false this is
+/// ignored for x as x has a special interleaved order.
+/// @tparam Base used for the curious recurring template pattern (CRTP) so the
+/// base class can access child class fields without virtual functions
+/// @tparam Diag true if this corresponds to the diagonal block (coarse element
+/// and fine element are on our rank), false otherwise (coarse element is on our
+/// rank, fine element is on a different rank).
+///
+template <Ordering::Type Order, class Base, bool Diag = true>
+struct DerefineMatrixOpFunctorBase;
+
+template <class Base>
+struct DerefineMatrixOpFunctorBase<Ordering::byNODES, Base, true>
+{
+   /// block column indices offsets
+   const int *bcptr;
+   /// column indices
+   const int *cptr;
+
+   int MFEM_HOST_DEVICE BlockWidth(int k) const
+   {
+      return bcptr[k + 1] - bcptr[k];
+   }
+
+   void MFEM_HOST_DEVICE Col(int j, int k, int &col, int &sign) const
+   {
+      col = cptr[bcptr[k] + j];
+      if (col < 0)
+      {
+         col = -1 - col;
+         sign = -sign;
+      }
+   }
+
+   int MFEM_HOST_DEVICE IndexX(int col, int vdim, int) const
+   {
+      return col + vdim * static_cast<const Base *>(this)->width;
+   }
+   int MFEM_HOST_DEVICE IndexY(int row, int vdim) const
+   {
+      return row + vdim * static_cast<const Base *>(this)->height;
+   }
+};
+
+template <class Base>
+struct DerefineMatrixOpFunctorBase<Ordering::byVDIM, Base, true>
+{
+   /// block column indices offsets
+   const int *bcptr;
+   /// column indices
+   const int *cptr;
+
+   int MFEM_HOST_DEVICE BlockWidth(int k) const
+   {
+      return bcptr[k + 1] - bcptr[k];
+   }
+
+   void MFEM_HOST_DEVICE Col(int j, int k, int &col, int &sign) const
+   {
+      col = cptr[bcptr[k] + j];
+      if (col < 0)
+      {
+         col = -1 - col;
+         sign = -sign;
+      }
+   }
+
+   int MFEM_HOST_DEVICE IndexX(int col, int vdim, int) const
+   {
+      return vdim + col * static_cast<const Base *>(this)->vdims;
+   }
+   int MFEM_HOST_DEVICE IndexY(int row, int vdim) const
+   {
+      return vdim + row * static_cast<const Base *>(this)->vdims;
+   }
+};
+
+template <class Base>
+struct DerefineMatrixOpFunctorBase<Ordering::byNODES, Base, false>
+{
+   /// receive segment offsets
+   const int *segptr;
+   /// receive segment index
+   const int *rsptr;
+   /// off-diagonal block column offsets
+   const int *coptr;
+   /// off-diagonal block widths
+   const int *bwptr;
+
+   int MFEM_HOST_DEVICE BlockWidth(int k) const { return bwptr[k]; }
+
+   void MFEM_HOST_DEVICE Col(int j, int k, int &col, int &sign) const
+   {
+      col = coptr[k] + j;
+   }
+
+   int MFEM_HOST_DEVICE IndexX(int col, int vdim, int k) const
+   {
+      int tmp = rsptr[k];
+      int segwidth = segptr[tmp + 1] - segptr[tmp];
+      return segptr[tmp] * static_cast<const Base *>(this)->vdims + col +
+             vdim * segwidth;
+   }
+   int MFEM_HOST_DEVICE IndexY(int row, int vdim) const
+   {
+      return row + vdim * static_cast<const Base *>(this)->height;
+   }
+};
+
+template <class Base>
+struct DerefineMatrixOpFunctorBase<Ordering::byVDIM, Base, false>
+{
+   /// receive segment offsets
+   const int *segptr;
+   /// receive segment index
+   const int *rsptr;
+   /// off-diagonal block column offsets
+   const int *coptr;
+   /// off-diagonal block widths
+   const int *bwptr;
+
+   int MFEM_HOST_DEVICE BlockWidth(int k) const { return bwptr[k]; }
+
+   void MFEM_HOST_DEVICE Col(int j, int k, int &col, int &sign) const
+   {
+      col = coptr[k] + j;
+   }
+
+   int MFEM_HOST_DEVICE IndexX(int col, int vdim, int k) const
+   {
+      int tmp = rsptr[k];
+      int segwidth = segptr[tmp + 1] - segptr[tmp];
+      return segptr[tmp] * static_cast<const Base *>(this)->vdims + col +
+             vdim * segwidth;
+   }
+   int MFEM_HOST_DEVICE IndexY(int row, int vdim) const
+   {
+      return vdim + row * static_cast<const Base *>(this)->vdims;
+   }
+};
+
+/// internally used to implement the derefinement operator Mult diagonal
+/// block
+template <Ordering::Type Order, bool Atomic, bool Diag = true>
+struct DerefineMatrixOpMultFunctor
+   : public DerefineMatrixOpFunctorBase<
+     Order, DerefineMatrixOpMultFunctor<Order, Atomic, Diag>, Diag>
+{
+   const real_t *xptr;
+   real_t *yptr;
+   /// block storage
+   const real_t *bsptr;
+   /// block offsets
+   const int *boptr;
+   /// block row index offsets
+   const int *brptr;
+   /// row indices
+   const int *rptr;
+
+   // number of blocks
+   int nblocks;
+   // number of components
+   int vdims;
+   /// overall operator height (for vdim = 1)
+   int height;
+   /// overall operator width (for vdim = 1)
+   int width;
+   void MFEM_HOST_DEVICE operator()(int kidx) const
+   {
+      int k = kidx % nblocks;
+      int vdim = kidx / nblocks;
+
+      int block_height = brptr[k + 1] - brptr[k];
+      int block_width = this->BlockWidth(k);
+      MFEM_FOREACH_THREAD(i, x, block_height)
+      {
+         int row = rptr[brptr[k] + i];
+         int rsign = 1;
+         if (row < 0)
+         {
+            row = -1 - row;
+            rsign = -1;
+         }
+         if (row < INT_MAX)
+         {
+            // row not marked as unused
+            real_t sum = 0;
+            for (int j = 0; j < block_width; ++j)
+            {
+               int col, sign = rsign;
+               this->Col(j, k, col, sign);
+               sum += sign * bsptr[boptr[k] + i + j * block_height] *
+                      xptr[this->IndexX(col, vdim, k)];
+            }
+#if defined(__CUDA_ARCH__) or defined(__HIP_DEVICE_COMPILE__)
+            if (Atomic)
+            {
+               atomicAdd(yptr + this->IndexY(row, vdim), sum);
+            }
+            else
+#endif
+            {
+               yptr[this->IndexY(row, vdim)] += sum;
+            }
+         }
+      }
+   }
+
+   /// N is the max block row size (doesn't have to be a power of 2)
+   void Run(int N) const { forall_2D(nblocks * vdims, N, 1, *this); }
+};
+
+} // namespace internal
+/// \endcond DO_NOT_DOCUMENT
+} // namespace mfem
+
+#endif

fem/fespace.cpp

@@ -17,6 +17,9 @@
 #include "fem.hpp"
 #include "ceed/interface/util.hpp"
 
+#include "derefmat_op.hpp"
+
+#include <algorithm>
 #include <cmath>
 #include <cstdarg>
 
@@ -24,9 +27,9 @@ using namespace std;
 
 namespace mfem
 {
-
-template <> void Ordering::
-DofsToVDofs<Ordering::byNODES>(int ndofs, int vdim, Array<int> &dofs)
+template <>
+void Ordering::DofsToVDofs<Ordering::byNODES>(int ndofs, int vdim,
+                                              Array<int> &dofs)
 {
    // static method
    int size = dofs.Size();
@@ -40,8 +43,9 @@ DofsToVDofs<Ordering::byNODES>(int ndofs, int vdim, Array<int> &dofs)
    }
 }
 
-template <> void Ordering::
-DofsToVDofs<Ordering::byVDIM>(int ndofs, int vdim, Array<int> &dofs)
+template <>
+void Ordering::DofsToVDofs<Ordering::byVDIM>(int ndofs, int vdim,
+                                             Array<int> &dofs)
 {
    // static method
    int size = dofs.Size();
@@ -55,7 +59,6 @@ DofsToVDofs<Ordering::byVDIM>(int ndofs, int vdim, Array<int> &dofs)
    }
 }
 
-
 FiniteElementSpace::FiniteElementSpace()
    : mesh(NULL), fec(NULL), vdim(0), ordering(Ordering::byNODES),
      ndofs(0), nvdofs(0), nedofs(0), nfdofs(0), nbdofs(0),
@@ -4244,7 +4247,11 @@ void FiniteElementSpace::Update(bool want_transform)
          case Mesh::DEREFINE:
          {
             BuildConformingInterpolation();
+#if 0
             Th.Reset(DerefinementMatrix(old_ndofs, old_elem_dof, old_elem_fos));
+#else
+            Th.Reset(new DerefineMatrixOp(*this, old_ndofs, old_elem_dof, old_elem_fos));
+#endif
             if (IsVariableOrder())
             {
                if (cP && cR_hp)

fem/fespace.hpp

@@ -113,7 +113,7 @@ class QuadratureSpace;
 class QuadratureInterpolator;
 class FaceQuadratureInterpolator;
 class PRefinementTransferOperator;
-
+struct DerefineMatrixOp;
 
 /** @brief Class FiniteElementSpace - responsible for providing FEM view of the
     mesh, mainly managing the set of degrees of freedom.
@@ -246,6 +246,7 @@ class FiniteElementSpace
    friend class PRefinementTransferOperator;
    friend void Mesh::Swap(Mesh &, bool);
    friend class LORBase;
+   friend struct DerefineMatrixOp;
 
 protected:
    /// The mesh that FE space lives on (not owned).

fem/gridfunc.cpp

@@ -4334,7 +4334,7 @@ real_t LSZZErrorEstimator(BilinearFormIntegrator &blfi,  // input
          u.GetSubVector(udofs, ul);
          utrans.InvTransformPrimal(ul);
          Transf = ufes->GetElementTransformation(ielem);
-         FiniteElement *dummy = nullptr;
+         const auto *dummy = ufes->GetFE(ielem);
          blfi.ComputeElementFlux(*ufes->GetFE(ielem), *Transf, ul,
                                  *dummy, fl, with_coeff, ir);
 

fem/integ/bilininteg_diffusion_kernels.hpp

@@ -1009,6 +1009,7 @@ inline void SmemPADiffusionApply3D(const int NE,
    auto d = Reshape(d_.Read(), Q1D, Q1D, Q1D, symmetric ? 6 : 9, NE);
    auto x = Reshape(x_.Read(), D1D, D1D, D1D, NE);
    auto y = Reshape(y_.ReadWrite(), D1D, D1D, D1D, NE);
+   MFEM_VERIFY(D1D <= Q1D, "THREAD_DIRECT requires D1D <= Q1D");
    mfem::forall_3D(NE, Q1D, Q1D, Q1D, [=] MFEM_HOST_DEVICE (int e)
    {
       const int D1D = T_D1D ? T_D1D : d1d;
@@ -1038,11 +1039,11 @@ inline void SmemPADiffusionApply3D(const int NE,
       real_t (*QDD0)[MD1][MD1] = (real_t (*)[MD1][MD1]) (sm0+0);
       real_t (*QDD1)[MD1][MD1] = (real_t (*)[MD1][MD1]) (sm0+1);
       real_t (*QDD2)[MD1][MD1] = (real_t (*)[MD1][MD1]) (sm0+2);
-      MFEM_FOREACH_THREAD(dz,z,D1D)
+      MFEM_FOREACH_THREAD_DIRECT(dz,z,D1D)
       {
-         MFEM_FOREACH_THREAD(dy,y,D1D)
+         MFEM_FOREACH_THREAD_DIRECT(dy,y,D1D)
          {
-            MFEM_FOREACH_THREAD(dx,x,D1D)
+            MFEM_FOREACH_THREAD_DIRECT(dx,x,D1D)
             {
                X[dz][dy][dx] = x(dx,dy,dz,e);
             }
@@ -1050,9 +1051,9 @@ inline void SmemPADiffusionApply3D(const int NE,
       }
       if (MFEM_THREAD_ID(z) == 0)
       {
-         MFEM_FOREACH_THREAD(dy,y,D1D)
+         MFEM_FOREACH_THREAD_DIRECT(dy,y,D1D)
          {
-            MFEM_FOREACH_THREAD(qx,x,Q1D)
+            MFEM_FOREACH_THREAD_DIRECT(qx,x,Q1D)
             {
                B[qx][dy] = b(qx,dy);
                G[qx][dy] = g(qx,dy);
@@ -1060,11 +1061,11 @@ inline void SmemPADiffusionApply3D(const int NE,
          }
       }
       MFEM_SYNC_THREAD;
-      MFEM_FOREACH_THREAD(dz,z,D1D)
+      MFEM_FOREACH_THREAD_DIRECT(dz,z,D1D)
       {
-         MFEM_FOREACH_THREAD(dy,y,D1D)
+         MFEM_FOREACH_THREAD_DIRECT(dy,y,D1D)
          {
-            MFEM_FOREACH_THREAD(qx,x,Q1D)
+            MFEM_FOREACH_THREAD_DIRECT(qx,x,Q1D)
             {
                real_t u = 0.0, v = 0.0;
                MFEM_UNROLL(MD1)
@@ -1080,11 +1081,11 @@ inline void SmemPADiffusionApply3D(const int NE,
          }
       }
       MFEM_SYNC_THREAD;
-      MFEM_FOREACH_THREAD(dz,z,D1D)
+      MFEM_FOREACH_THREAD_DIRECT(dz,z,D1D)
       {
-         MFEM_FOREACH_THREAD(qy,y,Q1D)
+         MFEM_FOREACH_THREAD_DIRECT(qy,y,Q1D)
          {
-            MFEM_FOREACH_THREAD(qx,x,Q1D)
+            MFEM_FOREACH_THREAD_DIRECT(qx,x,Q1D)
             {
                real_t u = 0.0, v = 0.0, w = 0.0;
                MFEM_UNROLL(MD1)
@@ -1101,11 +1102,11 @@ inline void SmemPADiffusionApply3D(const int NE,
          }
       }
       MFEM_SYNC_THREAD;
-      MFEM_FOREACH_THREAD(qz,z,Q1D)
+      MFEM_FOREACH_THREAD_DIRECT(qz,z,Q1D)
       {
-         MFEM_FOREACH_THREAD(qy,y,Q1D)
+         MFEM_FOREACH_THREAD_DIRECT(qy,y,Q1D)
          {
-            MFEM_FOREACH_THREAD(qx,x,Q1D)
+            MFEM_FOREACH_THREAD_DIRECT(qx,x,Q1D)
             {
                real_t u = 0.0, v = 0.0, w = 0.0;
                MFEM_UNROLL(MD1)
@@ -1136,9 +1137,9 @@ inline void SmemPADiffusionApply3D(const int NE,
       MFEM_SYNC_THREAD;
       if (MFEM_THREAD_ID(z) == 0)
       {
-         MFEM_FOREACH_THREAD(dy,y,D1D)
+         MFEM_FOREACH_THREAD_DIRECT(dy,y,D1D)
          {
-            MFEM_FOREACH_THREAD(qx,x,Q1D)
+            MFEM_FOREACH_THREAD_DIRECT(qx,x,Q1D)
             {
                Bt[dy][qx] = b(qx,dy);
                Gt[dy][qx] = g(qx,dy);
@@ -1146,11 +1147,11 @@ inline void SmemPADiffusionApply3D(const int NE,
          }
       }
       MFEM_SYNC_THREAD;
-      MFEM_FOREACH_THREAD(qz,z,Q1D)
+      MFEM_FOREACH_THREAD_DIRECT(qz,z,Q1D)
       {
-         MFEM_FOREACH_THREAD(qy,y,Q1D)
+         MFEM_FOREACH_THREAD_DIRECT(qy,y,Q1D)
          {
-            MFEM_FOREACH_THREAD(dx,x,D1D)
+            MFEM_FOREACH_THREAD_DIRECT(dx,x,D1D)
             {
                real_t u = 0.0, v = 0.0, w = 0.0;
                MFEM_UNROLL(MQ1)
@@ -1167,11 +1168,11 @@ inline void SmemPADiffusionApply3D(const int NE,
          }
       }
       MFEM_SYNC_THREAD;
-      MFEM_FOREACH_THREAD(qz,z,Q1D)
+      MFEM_FOREACH_THREAD_DIRECT(qz,z,Q1D)
       {
-         MFEM_FOREACH_THREAD(dy,y,D1D)
+         MFEM_FOREACH_THREAD_DIRECT(dy,y,D1D)
          {
-            MFEM_FOREACH_THREAD(dx,x,D1D)
+            MFEM_FOREACH_THREAD_DIRECT(dx,x,D1D)
             {
                real_t u = 0.0, v = 0.0, w = 0.0;
                MFEM_UNROLL(Q1D)
@@ -1188,11 +1189,11 @@ inline void SmemPADiffusionApply3D(const int NE,
          }
       }
       MFEM_SYNC_THREAD;
-      MFEM_FOREACH_THREAD(dz,z,D1D)
+      MFEM_FOREACH_THREAD_DIRECT(dz,z,D1D)
       {
-         MFEM_FOREACH_THREAD(dy,y,D1D)
+         MFEM_FOREACH_THREAD_DIRECT(dy,y,D1D)
          {
-            MFEM_FOREACH_THREAD(dx,x,D1D)
+            MFEM_FOREACH_THREAD_DIRECT(dx,x,D1D)
             {
                real_t u = 0.0, v = 0.0, w = 0.0;
                MFEM_UNROLL(MQ1)

fem/integ/bilininteg_mass_pa.cpp

@@ -62,7 +62,7 @@ void MassIntegrator::AssemblePA(const FiniteElementSpace &fes)
 
    const int NE = ne;
    const int Q1D = quad1D;
-   const int NQ = pow(Q1D, dim);
+   const int NQ = static_cast<int>(std::pow(Q1D, dim));
    const bool const_c = coeff.Size() == 1;
    const bool by_val = map_type == FiniteElement::VALUE;
    const auto W = Reshape(ir->GetWeights().Read(), NQ);

fem/intrules_cut.hpp

@@ -346,13 +346,13 @@ private:
       template<typename T>
       T operator() (const blitz::TinyVector<T,3>& x) const
       {
-         int el_order=el->GetOrder();
-         T u1[el_order+1];
-         T u2[el_order+1];
-         T u3[el_order+1];
-         TmplPoly_1D::CalcBernstein(el_order, x[0], u1);
-         TmplPoly_1D::CalcBernstein(el_order, x[1], u2);
-         TmplPoly_1D::CalcBernstein(el_order, x[2], u3);
+         const int el_order = el->GetOrder();
+         std::vector<T> u1(el_order+1);
+         std::vector<T> u2(el_order+1);
+         std::vector<T> u3(el_order+1);
+         TmplPoly_1D::CalcBernstein(el_order, x[0], u1.data());
+         TmplPoly_1D::CalcBernstein(el_order, x[1], u2.data());
+         TmplPoly_1D::CalcBernstein(el_order, x[2], u3.data());
 
          const Array<int>& dof_map=el->GetDofMap();
 
@@ -370,17 +370,17 @@ private:
       template<typename T>
       blitz::TinyVector<T,3> grad(const blitz::TinyVector<T,3>& x) const
       {
-         int el_order=el->GetOrder();
-         T u1[el_order+1];
-         T u2[el_order+1];
-         T u3[el_order+1];
-         T d1[el_order+1];
-         T d2[el_order+1];
-         T d3[el_order+1];
+         const int el_order = el->GetOrder();
+         std::vector<T> u1(el_order+1);
+         std::vector<T> u2(el_order+1);
+         std::vector<T> u3(el_order+1);
+         std::vector<T> d1(el_order+1);
+         std::vector<T> d2(el_order+1);
+         std::vector<T> d3(el_order+1);
 
-         TmplPoly_1D::CalcBernstein(el_order,x[0], u1, d1);
-         TmplPoly_1D::CalcBernstein(el_order,x[1], u2, d2);
-         TmplPoly_1D::CalcBernstein(el_order,x[2], u3, d3);
+         TmplPoly_1D::CalcBernstein(el_order,x[0], u1.data(), d1.data());
+         TmplPoly_1D::CalcBernstein(el_order,x[1], u2.data(), d2.data());
+         TmplPoly_1D::CalcBernstein(el_order,x[2], u3.data(), d3.data());
 
          blitz::TinyVector<T,3> res(T(0.0),T(0.0),T(0.0));
 
@@ -415,11 +415,11 @@ private:
       template<typename T>
       T operator() (const blitz::TinyVector<T,2>& x) const
       {
-         int el_order=el->GetOrder();
-         T u1[el_order+1];
-         T u2[el_order+1];
-         TmplPoly_1D::CalcBernstein(el_order, x[0], u1);
-         TmplPoly_1D::CalcBernstein(el_order, x[1], u2);
+         const int el_order = el->GetOrder();
+         std::vector<T> u1(el_order+1);
+         std::vector<T> u2(el_order+1);
+         TmplPoly_1D::CalcBernstein(el_order, x[0], u1.data());
+         TmplPoly_1D::CalcBernstein(el_order, x[1], u2.data());
 
          const Array<int>& dof_map=el->GetDofMap();
 
@@ -437,14 +437,14 @@ private:
       template<typename T>
       blitz::TinyVector<T,2> grad(const blitz::TinyVector<T,2>& x) const
       {
-         int el_order=el->GetOrder();
-         T u1[el_order+1];
-         T u2[el_order+1];
-         T d1[el_order+1];
-         T d2[el_order+1];
+         const int el_order = el->GetOrder();
+         std::vector<T> u1(el_order+1);
+         std::vector<T> u2(el_order+1);
+         std::vector<T> d1(el_order+1);
+         std::vector<T> d2(el_order+1);
 
-         TmplPoly_1D::CalcBernstein(el_order,x[0], u1, d1);
-         TmplPoly_1D::CalcBernstein(el_order,x[1], u2, d2);
+         TmplPoly_1D::CalcBernstein(el_order,x[0], u1.data(), d1.data());
+         TmplPoly_1D::CalcBernstein(el_order,x[1], u2.data(), d2.data());
 
          blitz::TinyVector<T,2> res(T(0.0),T(0.0));
 

fem/lininteg.hpp

@@ -673,7 +673,7 @@ public:
       int myid;
       MPI_Comm_rank(comm, &myid);
 
-      int seed = (seed_ > 0) ? seed_ + myid : (int)time(0) + myid;
+      int seed = (seed_ > 0) ? seed_ + myid : time(nullptr) + myid;
       SetSeed(seed);
    }
 #else

fem/pderefmat_op.cpp

@@ -0,0 +1,591 @@
+// 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 "pderefmat_op.hpp"
+
+#ifdef MFEM_USE_MPI
+
+#include "fes_kernels.hpp"
+/// \cond DO_NOT_DOCUMENT
+namespace mfem
+{
+namespace internal
+{
+template <Ordering::Type Order, bool Atomic>
+static void ParDerefMultKernelImpl(const ParDerefineMatrixOp &op,
+                                   const Vector &x, Vector &y)
+{
+   // pack sends
+   if (op.xghost_send.Size())
+   {
+      auto src = x.Read();
+      auto idcs = op.send_permutations.Read();
+      auto dst = Device::GetGPUAwareMPI() ? op.xghost_send.Write()
+                 : op.xghost_send.HostWrite();
+      auto vdims = op.fespace->GetVDim();
+      auto sptr = op.send_segment_idcs.Read();
+      auto lptr = op.send_segments.Read();
+      auto old_ndofs = x.Size() / vdims;
+
+      forall(op.send_permutations.Size(), [=] MFEM_HOST_DEVICE(int i)
+      {
+         int seg = sptr[i];
+         int width = lptr[seg + 1] - lptr[seg];
+         auto tdst = dst + i + lptr[seg] * vdims;
+         int sign = 1;
+         int col = idcs[i];
+         if (col < 0)
+         {
+            sign = -1;
+            col = -1 - col;
+         }
+         for (int vdim = 0; vdim < vdims; ++vdim)
+         {
+            tdst[vdim * width] =
+               sign
+               * src[Order == Ordering::byNODES ? (col + vdim * old_ndofs)
+                           : (col * vdims + vdim)];
+         }
+      });
+      // TODO: is this needed so we can send the packed data correctly?
+      // unclear for GPU-aware MPI, definitely required otherwise
+      MFEM_DEVICE_SYNC;
+   }
+   // initialize off-diagonal receive and send
+   op.requests.clear();
+   if (op.xghost_recv.Size())
+   {
+      auto vdims = op.fespace->GetVDim();
+      auto rcv = Device::GetGPUAwareMPI() ? op.xghost_recv.Write()
+                 : op.xghost_recv.HostWrite();
+      for (int i = 0; i < op.recv_ranks.Size(); ++i)
+      {
+         op.requests.emplace_back();
+         MPI_Irecv(rcv + op.recv_segments[i] * vdims,
+                   (op.recv_segments[i + 1] - op.recv_segments[i]) * vdims,
+                   MPITypeMap<real_t>::mpi_type, op.recv_ranks[i],
+                   MessageTag::DEREFINEMENT_MATRIX_CONSTRUCTION_DATA,
+                   op.fespace->GetComm(), &op.requests.back());
+      }
+   }
+   if (op.xghost_send.Size())
+   {
+      auto vdims = op.fespace->GetVDim();
+      // only is a GPU mem ptr if GPU-aware MPI is enabled
+      auto dst = Device::GetGPUAwareMPI() ? op.xghost_send.Write()
+                 : op.xghost_send.HostWrite();
+      for (int i = 0; i < op.send_ranks.Size(); ++i)
+      {
+         op.requests.emplace_back();
+         MPI_Isend(dst + op.send_segments[i] * vdims,
+                   (op.send_segments[i + 1] - op.send_segments[i]) * vdims,
+                   MPITypeMap<real_t>::mpi_type, op.send_ranks[i],
+                   MessageTag::DEREFINEMENT_MATRIX_CONSTRUCTION_DATA,
+                   op.fespace->GetComm(), &op.requests.back());
+      }
+   }
+   {
+      // diagonal
+      DerefineMatrixOpMultFunctor<Order, Atomic, true> func;
+      func.xptr = x.Read();
+      y.UseDevice();
+      y = 0.;
+      func.yptr = y.ReadWrite();
+      func.bsptr = op.block_storage.Read();
+      func.boptr = op.block_offsets.Read();
+      func.brptr = op.block_row_idcs_offsets.Read();
+      func.bcptr = op.block_col_idcs_offsets.Read();
+      func.rptr = op.row_idcs.Read();
+      func.cptr = op.col_idcs.Read();
+      func.vdims = op.fespace->GetVDim();
+      func.nblocks = op.block_offsets.Size();
+      func.width = op.Width() / func.vdims;
+      func.height = op.Height() / func.vdims;
+      func.Run(op.max_rows);
+   }
+   // wait for comm to finish, if any
+   if (op.requests.size())
+   {
+      MPI_Waitall(op.requests.size(), op.requests.data(), MPI_STATUSES_IGNORE);
+      if (op.xghost_recv.Size())
+      {
+         // off-diagonal kernel
+         DerefineMatrixOpMultFunctor<Order, Atomic, false> func;
+         // directly read from host-pinned memory if not using GPU-aware MPI
+         func.xptr = Device::GetGPUAwareMPI() ? op.xghost_recv.Read()
+                     : op.xghost_recv.HostRead();
+         func.yptr = y.ReadWrite();
+         func.bsptr = op.block_storage.Read();
+         func.boptr = op.off_diag_block_offsets.Read();
+         func.brptr = op.block_off_diag_row_idcs_offsets.Read();
+         func.rsptr = op.recv_segment_idcs.Read();
+         func.segptr = op.recv_segments.Read();
+         func.coptr = op.block_off_diag_col_offsets.Read();
+         func.bwptr = op.block_off_diag_widths.Read();
+         func.rptr = op.row_off_diag_idcs.Read();
+         func.vdims = op.fespace->GetVDim();
+         func.nblocks = op.off_diag_block_offsets.Size();
+         func.width = op.xghost_recv.Size() / func.vdims;
+         func.height = op.Height() / func.vdims;
+         func.Run(op.max_rows);
+      }
+   }
+}
+} // namespace internal
+
+template <Ordering::Type Order, bool Atomic>
+ParDerefineMatrixOp::MultKernelType ParDerefineMatrixOp::MultKernel::Kernel()
+{
+   return internal::ParDerefMultKernelImpl<Order, Atomic>;
+}
+
+ParDerefineMatrixOp::MultKernelType
+ParDerefineMatrixOp::MultKernel::Fallback(Ordering::Type, bool)
+{
+   MFEM_ABORT("invalid MultKernel parameters");
+}
+
+ParDerefineMatrixOp::Kernels::Kernels()
+{
+   MultKernel::Specialization<Ordering::byNODES, false>::Add();
+   MultKernel::Specialization<Ordering::byVDIM, false>::Add();
+   MultKernel::Specialization<Ordering::byNODES, true>::Add();
+   MultKernel::Specialization<Ordering::byVDIM, true>::Add();
+}
+
+void ParDerefineMatrixOp::Mult(const Vector &x, Vector &y) const
+{
+   const bool is_dg = fespace->FEColl()->GetContType()
+                      == FiniteElementCollection::DISCONTINUOUS;
+   // DG needs atomic summation
+   MultKernel::Run(fespace->GetOrdering(), is_dg, *this, x, y);
+   // use this to prevent xghost* from being re-purposed for subsequent Mult
+   // calls
+   MFEM_DEVICE_SYNC;
+}
+
+ParDerefineMatrixOp::ParDerefineMatrixOp(ParFiniteElementSpace &fespace_,
+                                         int old_ndofs,
+                                         const Table *old_elem_dof,
+                                         const Table *old_elem_fos)
+   : Operator(fespace_.GetVSize(), old_ndofs * fespace_.GetVDim()),
+     fespace(&fespace_)
+{
+   static Kernels kernels;
+   constexpr int max_team_size = 256;
+
+   const int NRanks = fespace->GetNRanks();
+
+   const int nrk = HYPRE_AssumedPartitionCheck() ? 2 : NRanks;
+
+   MFEM_VERIFY(fespace->Nonconforming(),
+               "Not implemented for conforming meshes.");
+   MFEM_VERIFY(fespace->old_dof_offsets[nrk],
+               "Missing previous (finer) space.");
+
+   const int MyRank = fespace->GetMyRank();
+   ParNCMesh *old_pncmesh = fespace->GetParMesh()->pncmesh;
+   const CoarseFineTransformations &dtrans =
+      old_pncmesh->GetDerefinementTransforms();
+   const Array<int> &old_ranks = old_pncmesh->GetDerefineOldRanks();
+
+   const bool is_dg = fespace->FEColl()->GetContType()
+                      == FiniteElementCollection::DISCONTINUOUS;
+   DenseMatrix localRVO; // for variable-order only
+
+   DenseTensor localR[Geometry::NumGeom];
+   int diag_rows = 0;
+   int off_diag_rows = 0;
+   int diag_cols = 0;
+
+   auto get_ldofs = [&](int k) -> int
+   {
+      const Embedding &emb = dtrans.embeddings[k];
+      if (fespace->IsVariableOrder())
+      {
+         const FiniteElement *fe = fespace->GetFE(emb.parent);
+         return fe->GetDof();
+      }
+      else
+      {
+         Geometry::Type geom =
+         fespace->GetParMesh()->GetElementBaseGeometry(emb.parent);
+         return fespace->FEColl()->FiniteElementForGeometry(geom)->GetDof();
+      }
+   };
+   Array<int> dofs, old_dofs;
+   max_rows = 1;
+   // first pass:
+   // - determine memory block lengths
+   // - identify dofs in x we need to send/receive
+   // don't need to send the indices, fine rank will re-arrange and sign
+   // change x before transmitting the ghost data
+
+   // key: coarse rank to send to
+   // value: old dofs to send (with sign)
+   std::map<int, std::vector<int>> to_send;
+   // key: fine rank
+   // value: indices into dtrans.embeddings
+   std::map<int, std::vector<int>> od_ks;
+   // key: fine rank
+   // value: recv segment length
+   std::map<int, int> od_seg_lens;
+   int send_len = 0;
+   int recv_len = 0;
+   // size of block_storage, if fespace->IsVariableOrder()
+   // otherwise unused
+   int total_size = 0;
+   int num_diagonal_blocks = 0;
+   int num_offdiagonal_blocks = 0;
+   for (int k = 0; k < dtrans.embeddings.Size(); ++k)
+   {
+      const Embedding &emb = dtrans.embeddings[k];
+      int fine_rank = old_ranks[k];
+      int coarse_rank = (emb.parent < 0) ? (-1 - emb.parent)
+                        : old_pncmesh->ElementRank(emb.parent);
+      if (coarse_rank != MyRank && fine_rank == MyRank)
+      {
+         // this rank needs to send data in x to course_rank
+         old_elem_dof->GetRow(k, old_dofs);
+         auto &tmp = to_send[coarse_rank];
+         send_len += old_dofs.Size();
+         for (int i = 0; i < old_dofs.Size(); ++i)
+         {
+            tmp.emplace_back(old_dofs[i]);
+         }
+      }
+      else if (coarse_rank == MyRank && fine_rank != MyRank)
+      {
+         // this rank needs to receive data in x from fine_rank
+         MFEM_ASSERT(emb.parent >= 0, "");
+         auto ldofs = get_ldofs(k);
+         off_diag_rows += ldofs;
+         recv_len += ldofs;
+         od_ks[fine_rank].emplace_back(k);
+         od_seg_lens[fine_rank] += ldofs;
+         ++num_offdiagonal_blocks;
+         if (fespace->IsVariableOrder())
+         {
+            total_size += ldofs * ldofs;
+         }
+      }
+      else if (coarse_rank == MyRank && fine_rank == MyRank)
+      {
+         MFEM_ASSERT(emb.parent >= 0, "");
+         // diagonal
+         ++num_diagonal_blocks;
+         auto ldofs = get_ldofs(k);
+         diag_rows += ldofs;
+         diag_cols += ldofs;
+         if (fespace->IsVariableOrder())
+         {
+            total_size += ldofs * ldofs;
+         }
+      }
+   }
+   send_segments.SetSize(to_send.size() + 1);
+   send_segments.HostWrite();
+   send_ranks.SetSize(to_send.size());
+   send_ranks.HostWrite();
+   {
+      int idx = 0;
+      send_segments[0] = 0;
+      for (auto &tmp : to_send)
+      {
+         send_ranks[idx] = tmp.first;
+         send_segments[idx + 1] = send_segments[idx] + tmp.second.size();
+         ++idx;
+      }
+   }
+   recv_segment_idcs.SetSize(off_diag_rows);
+   recv_segment_idcs.HostWrite();
+   recv_segments.SetSize(od_ks.size() + 1);
+   recv_segments.HostWrite();
+   recv_ranks.SetSize(od_ks.size());
+   recv_ranks.HostWrite();
+
+   // set sizes
+   row_idcs.SetSize(diag_rows);
+   row_idcs.HostWrite();
+   row_off_diag_idcs.SetSize(off_diag_rows);
+   row_off_diag_idcs.HostWrite();
+   col_idcs.SetSize(diag_cols);
+   col_idcs.HostWrite();
+   block_row_idcs_offsets.SetSize(num_diagonal_blocks + 1);
+   block_row_idcs_offsets.HostWrite();
+   block_col_idcs_offsets.SetSize(num_diagonal_blocks + 1);
+   block_col_idcs_offsets.HostWrite();
+   block_off_diag_row_idcs_offsets.SetSize(num_offdiagonal_blocks + 1);
+   block_off_diag_row_idcs_offsets.HostWrite();
+   block_off_diag_col_offsets.SetSize(num_offdiagonal_blocks);
+   block_off_diag_col_offsets.HostWrite();
+   block_off_diag_widths.SetSize(num_offdiagonal_blocks);
+   block_off_diag_widths.HostWrite();
+   pack_col_idcs.SetSize(send_len);
+   // memory manager doesn't appear to have a graceful fallback for
+   // HOST_PINNED if not built with CUDA or HIP
+#if defined(MFEM_USE_CUDA) or defined(MFEM_USE_HIP)
+   xghost_send.SetSize(send_len * fespace->GetVDim(),
+                       Device::GetGPUAwareMPI() ? MemoryType::DEFAULT
+                       : MemoryType::HOST_PINNED);
+   xghost_recv.SetSize(recv_len * fespace->GetVDim(),
+                       Device::GetGPUAwareMPI() ? MemoryType::DEFAULT
+                       : MemoryType::HOST_PINNED);
+#else
+   xghost_send.SetSize(send_len * fespace->GetVDim());
+   xghost_recv.SetSize(recv_len * fespace->GetVDim());
+#endif
+   send_permutations.SetSize(send_len);
+   send_segment_idcs.SetSize(send_len);
+   block_offsets.SetSize(num_diagonal_blocks);
+   block_offsets.HostWrite();
+   off_diag_block_offsets.SetSize(num_offdiagonal_blocks);
+   off_diag_block_offsets.HostWrite();
+   int geom_offsets[Geometry::NumGeom];
+   real_t *bs_ptr;
+
+   if (fespace->IsVariableOrder())
+   {
+      block_storage.SetSize(total_size);
+      bs_ptr = block_storage.HostWrite();
+      // compute block data later
+   }
+   else
+   {
+      // compression scheme:
+      // block_offsets is the start of each block, potentially repeated
+      // only need to store localR for used shapes
+      Mesh::GeometryList elem_geoms(*fespace->GetMesh());
+
+      int size = 0;
+      for (int i = 0; i < elem_geoms.Size(); ++i)
+      {
+         fespace->GetLocalDerefinementMatrices(elem_geoms[i],
+                                               localR[elem_geoms[i]]);
+         geom_offsets[elem_geoms[i]] = size;
+         size += localR[elem_geoms[i]].TotalSize();
+      }
+      block_storage.SetSize(size);
+      bs_ptr = block_storage.HostWrite();
+      // copy blocks into block_storage
+      for (int i = 0; i < elem_geoms.Size(); ++i)
+      {
+         std::copy(localR[elem_geoms[i]].Data(),
+                   localR[elem_geoms[i]].Data()
+                   + localR[elem_geoms[i]].TotalSize(),
+                   bs_ptr);
+         bs_ptr += localR[elem_geoms[i]].TotalSize();
+      }
+   }
+
+   // second pass:
+   // - initialize buffers
+
+   {
+      auto ptr = send_permutations.HostWrite();
+      auto ptr2 = send_segment_idcs.HostWrite();
+      int i = 0;
+      for (auto &v : to_send)
+      {
+         ptr = std::copy(v.second.begin(), v.second.end(), ptr);
+         for (size_t idx = 0; idx < v.second.size(); ++idx)
+         {
+            *ptr2 = i;
+            ++ptr2;
+         }
+         ++i;
+      }
+   }
+
+   block_row_idcs_offsets[0] = 0;
+   block_col_idcs_offsets[0] = 0;
+   block_off_diag_row_idcs_offsets[0] = 0;
+   Array<int> mark(fespace->GetNDofs());
+   mark = 0;
+   {
+      int idx = 0;
+      recv_segments[0] = 0;
+      for (auto &v : od_seg_lens)
+      {
+         recv_ranks[idx] = v.first;
+         recv_segments[idx + 1] = recv_segments[idx] + v.second;
+         ++idx;
+      }
+   }
+   // key: index into dtrans.embeddings
+   // value: off-diagonal block offset, od_ridx, seg id
+   std::unordered_map<int, std::array<int, 3>> ks_map;
+   {
+      int od_ridx = 0;
+      int seg_id = 0;
+      for (auto &v1 : od_ks)
+      {
+         for (auto k : v1.second)
+         {
+            auto &tmp = ks_map[k];
+            tmp[0] = ks_map.size() - 1;
+            tmp[1] = od_ridx;
+            tmp[2] = seg_id;
+            od_ridx += get_ldofs(k);
+         }
+         ++seg_id;
+      }
+   }
+   int diag_idx = 0;
+   int var_offset = 0;
+   int ridx = 0;
+   int cidx = 0;
+   // can't break this up into separate diagonals/off-diagonals loops because
+   // of mark
+   for (int k = 0; k < dtrans.embeddings.Size(); ++k)
+   {
+      const Embedding &emb = dtrans.embeddings[k];
+      if (emb.parent < 0)
+      {
+         continue;
+      }
+      int fine_rank = old_ranks[k];
+      int coarse_rank = (emb.parent < 0) ? (-1 - emb.parent)
+                        : old_pncmesh->ElementRank(emb.parent);
+      if (coarse_rank == MyRank)
+      {
+         // either diagonal or off-diagonal
+         Geometry::Type geom =
+            fespace->GetMesh()->GetElementBaseGeometry(emb.parent);
+         if (fespace->IsVariableOrder())
+         {
+            const FiniteElement *fe = fespace->GetFE(emb.parent);
+            const DenseTensor &pmats = dtrans.point_matrices[geom];
+            const int ldof = fe->GetDof();
+
+            IsoparametricTransformation isotr;
+            isotr.SetIdentityTransformation(geom);
+
+            localRVO.SetSize(ldof, ldof);
+            isotr.SetPointMat(pmats(emb.matrix));
+            // Local restriction is size ldofxldof assuming that the parent
+            // and child are of same polynomial order.
+            fe->GetLocalRestriction(isotr, localRVO);
+            // copy block
+            auto s = localRVO.Height() * localRVO.Width();
+            std::copy(localRVO.Data(), localRVO.Data() + s, bs_ptr);
+            bs_ptr += s;
+         }
+         DenseMatrix &lR =
+            fespace->IsVariableOrder() ? localRVO : localR[geom](emb.matrix);
+         max_rows = std::max(lR.Height(), max_rows);
+         auto size = lR.Height() * lR.Width();
+         fespace->elem_dof->GetRow(emb.parent, dofs);
+         if (fine_rank == MyRank)
+         {
+            // diagonal
+            old_elem_dof->GetRow(k, old_dofs);
+            MFEM_VERIFY(old_dofs.Size() == dofs.Size(),
+                        "Parent and child must have same #dofs.");
+            block_row_idcs_offsets[diag_idx + 1] =
+               block_row_idcs_offsets[diag_idx] + lR.Height();
+            block_col_idcs_offsets[diag_idx + 1] =
+               block_col_idcs_offsets[diag_idx] + lR.Width();
+
+            if (fespace->IsVariableOrder())
+            {
+               block_offsets[diag_idx] = var_offset;
+               var_offset += size;
+            }
+            else
+            {
+               block_offsets[diag_idx] = geom_offsets[geom] + size * emb.matrix;
+            }
+            for (int i = 0; i < lR.Height(); ++i, ++ridx)
+            {
+               if (!std::isfinite(lR(i, 0)))
+               {
+                  row_idcs[ridx] = INT_MAX;
+                  continue;
+               }
+               int r = dofs[i];
+               int m = (r >= 0) ? r : (-1 - r);
+               if (is_dg || !mark[m])
+               {
+                  row_idcs[ridx] = r;
+                  mark[m] = 1;
+               }
+               else
+               {
+                  row_idcs[ridx] = INT_MAX;
+               }
+            }
+            for (int i = 0; i < lR.Width(); ++i, ++cidx)
+            {
+               col_idcs[cidx] = old_dofs[i];
+            }
+            ++diag_idx;
+         }
+         else
+         {
+            // off-diagonal
+            auto &tmp = ks_map.at(k);
+            auto od_idx = tmp[0];
+            auto od_ridx = tmp[1];
+            block_off_diag_row_idcs_offsets[od_idx + 1] =
+               block_off_diag_row_idcs_offsets[od_idx] + lR.Height();
+            block_off_diag_col_offsets[od_idx] = od_ridx;
+            block_off_diag_widths[od_idx] = lR.Width();
+            recv_segment_idcs[od_idx] = tmp[2];
+
+            if (fespace->IsVariableOrder())
+            {
+               off_diag_block_offsets[od_idx] = var_offset;
+               var_offset += size;
+            }
+            else
+            {
+               off_diag_block_offsets[od_idx] =
+                  geom_offsets[geom] + size * emb.matrix;
+            }
+            for (int i = 0; i < lR.Height(); ++i, ++od_ridx)
+            {
+               if (!std::isfinite(lR(i, 0)))
+               {
+                  row_off_diag_idcs[od_ridx] = INT_MAX;
+                  continue;
+               }
+               int r = dofs[i];
+               int m = (r >= 0) ? r : (-1 - r);
+               if (is_dg || !mark[m])
+               {
+                  row_off_diag_idcs[od_ridx] = r;
+                  mark[m] = 1;
+               }
+               else
+               {
+                  row_off_diag_idcs[od_ridx] = INT_MAX;
+               }
+            }
+            ++od_idx;
+         }
+      }
+   }
+   // if not using GPU, set max_rows/max_cols to zero
+   if (Device::Allows(Backend::DEVICE_MASK))
+   {
+      max_rows = std::min(max_rows, max_team_size);
+   }
+   else
+   {
+      max_rows = 1;
+   }
+   requests.reserve(recv_ranks.Size() + send_ranks.Size());
+}
+} // namespace mfem
+/// \endcond DO_NOT_DOCUMENT
+
+#endif

fem/pderefmat_op.hpp

@@ -0,0 +1,111 @@
+// 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_PDEREFMAT_OP
+#define MFEM_PDEREFMAT_OP
+
+#include "../config/config.hpp"
+
+#ifdef MFEM_USE_MPI
+
+#include "pfespace.hpp"
+
+#include "kernel_dispatch.hpp"
+
+#include <vector>
+
+namespace mfem
+{
+
+/// \cond DO_NOT_DOCUMENT
+struct ParDerefineMatrixOp : public Operator
+{
+   ParFiniteElementSpace *fespace;
+   /// offsets into block_storage for diagonal
+   Array<int> block_offsets;
+   /// offsets into row_idcs for diagonal
+   Array<int> block_row_idcs_offsets;
+   /// offsets into col_idcs for diagonal
+   Array<int> block_col_idcs_offsets;
+
+   /// offsets into block_storage for off-diagonal
+   Array<int> off_diag_block_offsets;
+   /// offsets into row_idcs for off-diagonal
+   Array<int> block_off_diag_row_idcs_offsets;
+   Array<int> block_off_diag_col_offsets;
+   Array<int> block_off_diag_widths;
+   /// mapping for row dofs, INT_MAX indicates the block row should be ignored.
+   /// negative means the row data should be negated.
+   /// only for diagonal blocks
+   Array<int> row_idcs;
+   /// mapping for col dofs, negative means the col data should be negated.
+   /// only for diagonal blocks
+   Array<int> col_idcs;
+
+   Array<int> pack_col_idcs;
+
+   /// mapping for row dofs, INT_MAX indicates the block row should be ignored.
+   /// negative means the row data should be negated.
+   /// only for off-diagonal blocks
+   Array<int> row_off_diag_idcs;
+   /// dense block matrices which can be reused to construct the full matrix
+   /// operation. These are stored contiguously and blocks have no restrictions
+   /// on shape (can be rectangle and differ from block to block).
+   /// This is only for the diagonal block.
+   Vector block_storage;
+   /// maximum height of any block in block_storage for GPU
+   /// parallelization, or 1 for CPU runs.
+   int max_rows;
+
+   /// quasi Ordering::byNODES, broken into sections by ranks we need to send
+   /// the data to
+   mutable Vector xghost_send;
+   /// quasi Ordering::byNODES, broken into sections by ranks we received
+   /// the data from
+   mutable Vector xghost_recv;
+   /// maps off-diagonal k to segment
+   Array<int> recv_segment_idcs;
+   /// cumulative count of dofs which will be received from other ranks
+   Array<int> recv_segments;
+   /// Source rank of each recv segment
+   Array<int> recv_ranks;
+   /// What send segment each entry in send_permutations corresponds to
+   Array<int> send_segment_idcs;
+   /// cumulative count of dofs which will be sent to other ranks
+   Array<int> send_segments;
+   /// Destination rank of each send segment
+   Array<int> send_ranks;
+   /// how to permute/sign change values from our local x to send to other ranks
+   Array<int> send_permutations;
+   /// internal buffer for MPI requests
+   mutable std::vector<MPI_Request> requests;
+
+   using MultKernelType = void (*)(const ParDerefineMatrixOp &, const Vector &,
+                                   Vector &);
+   /// template args: ordering, atomic
+   MFEM_REGISTER_KERNELS(MultKernel, MultKernelType, (Ordering::Type, bool));
+
+   struct Kernels
+   {
+      Kernels();
+   };
+
+   void Mult(const Vector &x, Vector &y) const;
+
+   ParDerefineMatrixOp(ParFiniteElementSpace &fespace_, int old_ndofs,
+                       const Table *old_elem_dof, const Table *old_elem_fos);
+};
+/// \endcond DO_NOT_DOCUMENT
+} // namespace mfem
+
+#endif
+
+#endif

fem/pfespace.cpp

@@ -22,12 +22,13 @@
 #include "../mesh/mesh_headers.hpp"
 #include "../general/binaryio.hpp"
 
+#include "pderefmat_op.hpp"
+
 #include <limits>
 #include <list>
 
 namespace mfem
 {
-
 ParFiniteElementSpace::ParFiniteElementSpace(
    const ParFiniteElementSpace &orig, ParMesh *pmesh,
    const FiniteElementCollection *fec)
@@ -4487,13 +4488,6 @@ ParFiniteElementSpace::RebalanceMatrix(int old_ndofs,
    return M;
 }
 
-
-struct DerefDofMessage
-{
-   std::vector<HYPRE_BigInt> dofs;
-   MPI_Request request;
-};
-
 HypreParMatrix*
 ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
                                                   const Table* old_elem_dof,
@@ -4536,7 +4530,13 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
       old_pncmesh->GetDerefinementTransforms();
    const Array<int> &old_ranks = old_pncmesh->GetDerefineOldRanks();
 
-   std::map<int, DerefDofMessage> messages;
+   // key: other rank
+   // value: send or recieve buffer
+   std::map<int, std::vector<HYPRE_BigInt>> to_send;
+   std::map<int, std::vector<HYPRE_BigInt>> to_recv;
+   // key: index into dtrans.embeddings
+   // value: [start, stop]
+   std::unordered_map<int, std::array<size_t, 2>> recv_messages;
 
    HYPRE_BigInt old_offset = HYPRE_AssumedPartitionCheck()
                              ? old_dof_offsets[0] : old_dof_offsets[MyRank];
@@ -4556,30 +4556,46 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
          old_elem_dof->GetRow(k, dofs);
          DofsToVDofs(dofs, old_ndofs);
 
-         DerefDofMessage &msg = messages[k];
-         msg.dofs.resize(dofs.Size());
+         std::vector<HYPRE_BigInt>& send_buf = to_send[coarse_rank];
+         auto pos = send_buf.size();
+         send_buf.resize(pos + dofs.Size());
          for (int i = 0; i < dofs.Size(); i++)
          {
-            msg.dofs[i] = old_offset + dofs[i];
+            send_buf[pos + i] = old_offset + dofs[i];
          }
-
-         MPI_Isend(&msg.dofs[0], static_cast<int>(msg.dofs.size()), HYPRE_MPI_BIG_INT,
-                   coarse_rank, 291, MyComm, &msg.request);
       }
       else if (coarse_rank == MyRank && fine_rank != MyRank)
       {
          MFEM_ASSERT(emb.parent >= 0, "");
          Geometry::Type geom = mesh->GetElementBaseGeometry(emb.parent);
 
-         DerefDofMessage &msg = messages[k];
-         msg.dofs.resize(ldof[geom]*vdim);
-
-         MPI_Irecv(&msg.dofs[0], ldof[geom]*vdim, HYPRE_MPI_BIG_INT,
-                   fine_rank, 291, MyComm, &msg.request);
+         std::vector<HYPRE_BigInt>& recv_buf = to_recv[fine_rank];
+         auto& msg = recv_messages[k];
+         msg[0] = recv_buf.size();
+         recv_buf.resize(recv_buf.size() + ldof[geom] * vdim);
+         msg[1] = recv_buf.size();
       }
-      // TODO: coalesce Isends/Irecvs to the same rank. Typically, on uniform
-      // derefinement, there should be just one send to MyRank-1 and one recv
-      // from MyRank+1
+   }
+
+   // assume embedding orders are consistent (i.e. what we expect to receive
+   // first from a given rank is sent first, etc.)
+   std::vector<MPI_Request> requests;
+   requests.reserve(to_send.size() + to_recv.size());
+   // enqueue recvs
+   for (auto &v : to_recv)
+   {
+      requests.emplace_back();
+      MPI_Irecv(v.second.data(), v.second.size(), HYPRE_MPI_BIG_INT, v.first,
+                MessageTag::DEREFINEMENT_MATRIX_CONSTRUCTION_DATA, MyComm,
+                &requests.back());
+   }
+   // enqueue sends
+   for (auto &v : to_send)
+   {
+      requests.emplace_back();
+      MPI_Isend(v.second.data(), v.second.size(), HYPRE_MPI_BIG_INT, v.first,
+                MessageTag::DEREFINEMENT_MATRIX_CONSTRUCTION_DATA, MyComm,
+                &requests.back());
    }
 
    DenseTensor localR[Geometry::NumGeom];
@@ -4637,10 +4653,7 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
    diag->Finalize();
 
    // wait for all sends/receives to complete
-   for (auto it = messages.begin(); it != messages.end(); ++it)
-   {
-      MPI_Wait(&it->second.request, MPI_STATUS_IGNORE);
-   }
+   MPI_Waitall(requests.size(), requests.data(), MPI_STATUSES_IGNORE);
 
    // create the off-diagonal part of the derefinement matrix
    SparseMatrix *offd = new SparseMatrix(ndofs*vdim, 1);
@@ -4661,13 +4674,14 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
 
          elem_dof->GetRow(emb.parent, dofs);
 
-         DerefDofMessage &msg = messages[k];
-         MFEM_ASSERT(msg.dofs.size(), "");
+         auto& odofs = to_recv.at(fine_rank);
+         auto &msg = recv_messages[k];
+         MFEM_ASSERT(msg[1] > msg[0], "");
 
          for (int vd = 0; vd < vdim; vd++)
          {
             MFEM_ASSERT(ldof[geom], "");
-            HYPRE_BigInt* remote_dofs = &msg.dofs[vd*ldof[geom]];
+            HYPRE_BigInt *remote_dofs = odofs.data() + msg[0] + vd * ldof[geom];
 
             for (int i = 0; i < lR.Height(); i++)
             {
@@ -4694,7 +4708,6 @@ ParFiniteElementSpace::ParallelDerefinementMatrix(int old_ndofs,
       }
    }
 
-   messages.clear();
    offd->Finalize(0);
    offd->SetWidth(static_cast<int>(col_map.size()));
 
@@ -4946,8 +4959,13 @@ void ParFiniteElementSpace::Update(bool want_transform)
 
          case Mesh::DEREFINE:
          {
+#if 0
             Th.Reset(ParallelDerefinementMatrix(old_ndofs, old_elem_dof,
                                                 old_elem_fos));
+#else
+            Th.Reset(new ParDerefineMatrixOp(*this, old_ndofs, old_elem_dof,
+                                             old_elem_fos));
+#endif
             if (Nonconforming())
             {
                Th.SetOperatorOwner(false);
@@ -5259,7 +5277,7 @@ DeviceConformingProlongationOperator::DeviceConformingProlongationOperator(
       gc.GetNeighborLTDofTable(nbr_ltdof);
       const int nb_connections = nbr_ltdof.Size_of_connections();
       shr_ltdof.SetSize(nb_connections);
-      shr_ltdof.CopyFrom(nbr_ltdof.GetJ());
+      if (nb_connections > 0) { shr_ltdof.CopyFrom(nbr_ltdof.GetJ()); }
       shr_buf.SetSize(nb_connections);
       shr_buf.UseDevice(true);
       shr_buf_offsets = nbr_ltdof.GetIMemory();
@@ -5288,7 +5306,7 @@ DeviceConformingProlongationOperator::DeviceConformingProlongationOperator(
       gc.GetNeighborLDofTable(nbr_ldof);
       const int nb_connections = nbr_ldof.Size_of_connections();
       ext_ldof.SetSize(nb_connections);
-      ext_ldof.CopyFrom(nbr_ldof.GetJ());
+      if (nb_connections > 0) { ext_ldof.CopyFrom(nbr_ldof.GetJ()); }
       ext_ldof.GetMemory().UseDevice(true);
       ext_buf.SetSize(nb_connections);
       ext_buf.UseDevice(true);

fem/pfespace.hpp

@@ -24,9 +24,12 @@
 namespace mfem
 {
 
+struct ParDerefineMatrixOp;
+
 /// Abstract parallel finite element space.
 class ParFiniteElementSpace : public FiniteElementSpace
 {
+   friend struct ParDerefineMatrixOp;
 private:
    /// MPI data.
    MPI_Comm MyComm;

fem/qinterp/det.cpp

@@ -9,278 +9,16 @@
 // terms of the BSD-3 license. We welcome feedback and contributions, see file
 // CONTRIBUTING.md for details.
 
-#include "../quadinterpolator.hpp"
-#include "../../general/forall.hpp"
-#include "../../linalg/dtensor.hpp"
-#include "../../fem/kernels.hpp"
-#include "../../linalg/kernels.hpp"
-
-using namespace mfem;
+#include "det.hpp"
 
 namespace mfem
 {
 
 namespace internal
 {
-
 namespace quadrature_interpolator
 {
 
-static void Det1D(const int NE,
-                  const real_t *b,
-                  const real_t *g,
-                  const real_t *x,
-                  real_t *y,
-                  const int d1d,
-                  const int q1d,
-                  Vector *d_buff = nullptr)
-{
-   MFEM_CONTRACT_VAR(b);
-   MFEM_CONTRACT_VAR(d_buff);
-   const auto G = Reshape(g, q1d, d1d);
-   const auto X = Reshape(x, d1d, NE);
-
-   auto Y = Reshape(y, q1d, NE);
-
-   mfem::forall(NE, [=] MFEM_HOST_DEVICE (int e)
-   {
-      for (int q = 0; q < q1d; q++)
-      {
-         real_t u = 0.0;
-         for (int d = 0; d < d1d; d++)
-         {
-            u += G(q, d) * X(d, e);
-         }
-         Y(q, e) = u;
-      }
-   });
-}
-
-template<int T_D1D = 0, int T_Q1D = 0>
-static void Det2D(const int NE,
-                  const real_t *b,
-                  const real_t *g,
-                  const real_t *x,
-                  real_t *y,
-                  const int d1d = 0,
-                  const int q1d = 0,
-                  Vector *d_buff = nullptr)
-{
-   MFEM_CONTRACT_VAR(d_buff);
-   static constexpr int SDIM = 2;
-   static constexpr int NBZ = 1;
-
-   const int D1D = T_D1D ? T_D1D : d1d;
-   const int Q1D = T_Q1D ? T_Q1D : q1d;
-
-   const auto B = Reshape(b, Q1D, D1D);
-   const auto G = Reshape(g, Q1D, D1D);
-   const auto X = Reshape(x,  D1D, D1D, SDIM, NE);
-   auto Y = Reshape(y, Q1D, Q1D, NE);
-
-   mfem::forall_2D_batch(NE, Q1D, Q1D, NBZ, [=] MFEM_HOST_DEVICE (int e)
-   {
-      constexpr int MQ1 = T_Q1D ? T_Q1D : DofQuadLimits::MAX_Q1D;
-      constexpr int MD1 = T_D1D ? T_D1D : DofQuadLimits::MAX_D1D;
-      const int D1D = T_D1D ? T_D1D : d1d;
-      const int Q1D = T_Q1D ? T_Q1D : q1d;
-
-      MFEM_SHARED real_t BG[2][MQ1*MD1];
-      MFEM_SHARED real_t XY[SDIM][NBZ][MD1*MD1];
-      MFEM_SHARED real_t DQ[2*SDIM][NBZ][MD1*MQ1];
-      MFEM_SHARED real_t QQ[2*SDIM][NBZ][MQ1*MQ1];
-
-      kernels::internal::LoadX<MD1,NBZ>(e,D1D,X,XY);
-      kernels::internal::LoadBG<MD1,MQ1>(D1D,Q1D,B,G,BG);
-
-      kernels::internal::GradX<MD1,MQ1,NBZ>(D1D,Q1D,BG,XY,DQ);
-      kernels::internal::GradY<MD1,MQ1,NBZ>(D1D,Q1D,BG,DQ,QQ);
-
-      MFEM_FOREACH_THREAD(qy,y,Q1D)
-      {
-         MFEM_FOREACH_THREAD(qx,x,Q1D)
-         {
-            real_t J[4];
-            kernels::internal::PullGrad<MQ1,NBZ>(Q1D,qx,qy,QQ,J);
-            Y(qx,qy,e) = kernels::Det<2>(J);
-         }
-      }
-   });
-}
-
-template<int T_D1D = 0, int T_Q1D = 0>
-static void Det2DSurface(const int NE,
-                         const real_t *b,
-                         const real_t *g,
-                         const real_t *x,
-                         real_t *y,
-                         const int d1d = 0,
-                         const int q1d = 0,
-                         Vector *d_buff = nullptr)
-{
-   MFEM_CONTRACT_VAR(d_buff);
-
-   static constexpr int SDIM = 3;
-   static constexpr int NBZ = 1;
-
-   const int D1D = T_D1D ? T_D1D : d1d;
-   const int Q1D = T_Q1D ? T_Q1D : q1d;
-
-   const auto B = Reshape(b, Q1D, D1D);
-   const auto G = Reshape(g, Q1D, D1D);
-   const auto X = Reshape(x,  D1D, D1D, SDIM, NE);
-   auto Y = Reshape(y, Q1D, Q1D, NE);
-
-   mfem::forall_2D_batch(NE, Q1D, Q1D, NBZ, [=] MFEM_HOST_DEVICE (int e)
-   {
-      constexpr int MQ1 = T_Q1D ? T_Q1D : DofQuadLimits::MAX_Q1D;
-      constexpr int MD1 = T_D1D ? T_D1D : DofQuadLimits::MAX_D1D;
-      const int D1D = T_D1D ? T_D1D : d1d;
-      const int Q1D = T_Q1D ? T_Q1D : q1d;
-      const int tidz = MFEM_THREAD_ID(z);
-
-      MFEM_SHARED real_t BG[2][MQ1*MD1];
-      MFEM_SHARED real_t XYZ[SDIM][NBZ][MD1*MD1];
-      MFEM_SHARED real_t DQ[2*SDIM][NBZ][MD1*MQ1];
-
-      kernels::internal::LoadBG<MD1,MQ1>(D1D,Q1D,B,G,BG);
-
-      // Load XYZ components
-      MFEM_FOREACH_THREAD(dy,y,D1D)
-      {
-         MFEM_FOREACH_THREAD(dx,x,D1D)
-         {
-            for (int d = 0; d < SDIM; ++d)
-            {
-               XYZ[d][tidz][dx + dy*D1D] = X(dx,dy,d,e);
-            }
-         }
-      }
-      MFEM_SYNC_THREAD;
-
-      ConstDeviceMatrix B_mat(BG[0], D1D, Q1D);
-      ConstDeviceMatrix G_mat(BG[1], D1D, Q1D);
-
-      // x contraction
-      MFEM_FOREACH_THREAD(dy,y,D1D)
-      {
-         MFEM_FOREACH_THREAD(qx,x,Q1D)
-         {
-            for (int d = 0; d < SDIM; ++d)
-            {
-               real_t u = 0.0;
-               real_t v = 0.0;
-               for (int dx = 0; dx < D1D; ++dx)
-               {
-                  const real_t xval = XYZ[d][tidz][dx + dy*D1D];
-                  u += xval * G_mat(dx,qx);
-                  v += xval * B_mat(dx,qx);
-               }
-               DQ[d][tidz][dy + qx*D1D] = u;
-               DQ[3 + d][tidz][dy + qx*D1D] = v;
-            }
-         }
-      }
-      MFEM_SYNC_THREAD;
-      // y contraction and determinant computation
-      MFEM_FOREACH_THREAD(qy,y,Q1D)
-      {
-         MFEM_FOREACH_THREAD(qx,x,Q1D)
-         {
-            real_t J_[6] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
-            for (int d = 0; d < SDIM; ++d)
-            {
-               for (int dy = 0; dy < D1D; ++dy)
-               {
-                  J_[d] += DQ[d][tidz][dy + qx*D1D] * B_mat(dy,qy);
-                  J_[3 + d] += DQ[3 + d][tidz][dy + qx*D1D] * G_mat(dy,qy);
-               }
-            }
-            DeviceTensor<2> J(J_, 3, 2);
-            const real_t E = J(0,0)*J(0,0) + J(1,0)*J(1,0) + J(2,0)*J(2,0);
-            const real_t F = J(0,0)*J(0,1) + J(1,0)*J(1,1) + J(2,0)*J(2,1);
-            const real_t G = J(0,1)*J(0,1) + J(1,1)*J(1,1) + J(2,1)*J(2,1);
-            Y(qx,qy,e) = std::sqrt(E*G - F*F);
-         }
-      }
-   });
-}
-
-template<int T_D1D = 0, int T_Q1D = 0, bool SMEM = true>
-static void Det3D(const int NE,
-                  const real_t *b,
-                  const real_t *g,
-                  const real_t *x,
-                  real_t *y,
-                  const int d1d = 0,
-                  const int q1d = 0,
-                  Vector *d_buff = nullptr) // used only with SMEM = false
-{
-   constexpr int DIM = 3;
-   static constexpr int GRID = SMEM ? 0 : 128;
-
-   const int D1D = T_D1D ? T_D1D : d1d;
-   const int Q1D = T_Q1D ? T_Q1D : q1d;
-
-   const auto B = Reshape(b, Q1D, D1D);
-   const auto G = Reshape(g, Q1D, D1D);
-   const auto X = Reshape(x, D1D, D1D, D1D, DIM, NE);
-   auto Y = Reshape(y, Q1D, Q1D, Q1D, NE);
-
-   real_t *GM = nullptr;
-   if (!SMEM)
-   {
-      const DeviceDofQuadLimits &limits = DeviceDofQuadLimits::Get();
-      const int max_q1d = T_Q1D ? T_Q1D : limits.MAX_Q1D;
-      const int max_d1d = T_D1D ? T_D1D : limits.MAX_D1D;
-      const int max_qd = std::max(max_q1d, max_d1d);
-      const int mem_size = max_qd * max_qd * max_qd * 9;
-      d_buff->SetSize(2*mem_size*GRID);
-      GM = d_buff->Write();
-   }
-
-   mfem::forall_3D_grid(NE, Q1D, Q1D, Q1D, GRID, [=] MFEM_HOST_DEVICE (int e)
-   {
-      static constexpr int MQ1 = T_Q1D ? T_Q1D :
-                                 (SMEM ? DofQuadLimits::MAX_DET_1D : DofQuadLimits::MAX_Q1D);
-      static constexpr int MD1 = T_D1D ? T_D1D :
-                                 (SMEM ? DofQuadLimits::MAX_DET_1D : DofQuadLimits::MAX_D1D);
-      static constexpr int MDQ = MQ1 > MD1 ? MQ1 : MD1;
-      static constexpr int MSZ = MDQ * MDQ * MDQ * 9;
-
-      const int bid = MFEM_BLOCK_ID(x);
-      MFEM_SHARED real_t BG[2][MQ1*MD1];
-      MFEM_SHARED real_t SM0[SMEM?MSZ:1];
-      MFEM_SHARED real_t SM1[SMEM?MSZ:1];
-      real_t *lm0 = SMEM ? SM0 : GM + MSZ*bid;
-      real_t *lm1 = SMEM ? SM1 : GM + MSZ*(GRID+bid);
-      real_t (*DDD)[MD1*MD1*MD1] = (real_t (*)[MD1*MD1*MD1]) (lm0);
-      real_t (*DDQ)[MD1*MD1*MQ1] = (real_t (*)[MD1*MD1*MQ1]) (lm1);
-      real_t (*DQQ)[MD1*MQ1*MQ1] = (real_t (*)[MD1*MQ1*MQ1]) (lm0);
-      real_t (*QQQ)[MQ1*MQ1*MQ1] = (real_t (*)[MQ1*MQ1*MQ1]) (lm1);
-
-      kernels::internal::LoadX<MD1>(e,D1D,X,DDD);
-      kernels::internal::LoadBG<MD1,MQ1>(D1D,Q1D,B,G,BG);
-
-      kernels::internal::GradX<MD1,MQ1>(D1D,Q1D,BG,DDD,DDQ);
-      kernels::internal::GradY<MD1,MQ1>(D1D,Q1D,BG,DDQ,DQQ);
-      kernels::internal::GradZ<MD1,MQ1>(D1D,Q1D,BG,DQQ,QQQ);
-
-      MFEM_FOREACH_THREAD(qz,z,Q1D)
-      {
-         MFEM_FOREACH_THREAD(qy,y,Q1D)
-         {
-            MFEM_FOREACH_THREAD(qx,x,Q1D)
-            {
-               real_t J[9];
-               kernels::internal::PullGrad<MQ1>(Q1D, qx,qy,qz, QQQ, J);
-               Y(qx,qy,qz,e) = kernels::Det<3>(J);
-            }
-         }
-      }
-   });
-}
-
 void InitDetKernels()
 {
    using k = QuadratureInterpolator::DetKernels;
@@ -302,27 +40,12 @@ void InitDetKernels()
 }
 
 } // namespace quadrature_interpolator
-
 } // namespace internal
 
 /// @cond Suppress_Doxygen_warnings
 
-namespace
-{
-using DetKernel = QuadratureInterpolator::DetKernelType;
-}
-
-template<int DIM, int SDIM, int D1D, int Q1D>
-DetKernel QuadratureInterpolator::DetKernels::Kernel()
-{
-   if (DIM == 1) { return internal::quadrature_interpolator::Det1D; }
-   else if (DIM == 2 && SDIM == 2) { return internal::quadrature_interpolator::Det2D<D1D, Q1D>; }
-   else if (DIM == 2 && SDIM == 3) { return internal::quadrature_interpolator::Det2DSurface<D1D, Q1D>; }
-   else if (DIM == 3) { return internal::quadrature_interpolator::Det3D<D1D, Q1D>; }
-   else { MFEM_ABORT(""); }
-}
-
-DetKernel QuadratureInterpolator::DetKernels::Fallback(
+QuadratureInterpolator::DetKernelType
+QuadratureInterpolator::DetKernels::Fallback(
    int DIM, int SDIM, int D1D, int Q1D)
 {
    if (DIM == 1) { return internal::quadrature_interpolator::Det1D; }

fem/qinterp/det.hpp

@@ -0,0 +1,304 @@
+// 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_QUADINTERP_DET_HPP
+#define MFEM_QUADINTERP_DET_HPP
+
+#include "../quadinterpolator.hpp"
+#include "../../general/forall.hpp"
+#include "../../linalg/dtensor.hpp"
+#include "../../fem/kernels.hpp"
+#include "../../linalg/kernels.hpp"
+
+namespace mfem
+{
+
+namespace internal
+{
+namespace quadrature_interpolator
+{
+
+inline void Det1D(const int NE,
+                  const real_t *b,
+                  const real_t *g,
+                  const real_t *x,
+                  real_t *y,
+                  const int d1d,
+                  const int q1d,
+                  Vector *d_buff = nullptr)
+{
+   MFEM_CONTRACT_VAR(b);
+   MFEM_CONTRACT_VAR(d_buff);
+   const auto G = Reshape(g, q1d, d1d);
+   const auto X = Reshape(x, d1d, NE);
+
+   auto Y = Reshape(y, q1d, NE);
+
+   mfem::forall(NE, [=] MFEM_HOST_DEVICE (int e)
+   {
+      for (int q = 0; q < q1d; q++)
+      {
+         real_t u = 0.0;
+         for (int d = 0; d < d1d; d++)
+         {
+            u += G(q, d) * X(d, e);
+         }
+         Y(q, e) = u;
+      }
+   });
+}
+
+template<int T_D1D = 0, int T_Q1D = 0>
+inline void Det2D(const int NE,
+                  const real_t *b,
+                  const real_t *g,
+                  const real_t *x,
+                  real_t *y,
+                  const int d1d = 0,
+                  const int q1d = 0,
+                  Vector *d_buff = nullptr)
+{
+   MFEM_CONTRACT_VAR(d_buff);
+   static constexpr int SDIM = 2;
+   static constexpr int NBZ = 1;
+
+   const int D1D = T_D1D ? T_D1D : d1d;
+   const int Q1D = T_Q1D ? T_Q1D : q1d;
+
+   const auto B = Reshape(b, Q1D, D1D);
+   const auto G = Reshape(g, Q1D, D1D);
+   const auto X = Reshape(x,  D1D, D1D, SDIM, NE);
+   auto Y = Reshape(y, Q1D, Q1D, NE);
+
+   mfem::forall_2D_batch(NE, Q1D, Q1D, NBZ, [=] MFEM_HOST_DEVICE (int e)
+   {
+      constexpr int MQ1 = T_Q1D ? T_Q1D : DofQuadLimits::MAX_Q1D;
+      constexpr int MD1 = T_D1D ? T_D1D : DofQuadLimits::MAX_D1D;
+      const int D1D = T_D1D ? T_D1D : d1d;
+      const int Q1D = T_Q1D ? T_Q1D : q1d;
+
+      MFEM_SHARED real_t BG[2][MQ1*MD1];
+      MFEM_SHARED real_t XY[SDIM][NBZ][MD1*MD1];
+      MFEM_SHARED real_t DQ[2*SDIM][NBZ][MD1*MQ1];
+      MFEM_SHARED real_t QQ[2*SDIM][NBZ][MQ1*MQ1];
+
+      kernels::internal::LoadX<MD1,NBZ>(e,D1D,X,XY);
+      kernels::internal::LoadBG<MD1,MQ1>(D1D,Q1D,B,G,BG);
+
+      kernels::internal::GradX<MD1,MQ1,NBZ>(D1D,Q1D,BG,XY,DQ);
+      kernels::internal::GradY<MD1,MQ1,NBZ>(D1D,Q1D,BG,DQ,QQ);
+
+      MFEM_FOREACH_THREAD(qy,y,Q1D)
+      {
+         MFEM_FOREACH_THREAD(qx,x,Q1D)
+         {
+            real_t J[4];
+            kernels::internal::PullGrad<MQ1,NBZ>(Q1D,qx,qy,QQ,J);
+            Y(qx,qy,e) = kernels::Det<2>(J);
+         }
+      }
+   });
+}
+
+template<int T_D1D = 0, int T_Q1D = 0>
+inline void Det2DSurface(const int NE,
+                         const real_t *b,
+                         const real_t *g,
+                         const real_t *x,
+                         real_t *y,
+                         const int d1d = 0,
+                         const int q1d = 0,
+                         Vector *d_buff = nullptr)
+{
+   MFEM_CONTRACT_VAR(d_buff);
+
+   static constexpr int SDIM = 3;
+   static constexpr int NBZ = 1;
+
+   const int D1D = T_D1D ? T_D1D : d1d;
+   const int Q1D = T_Q1D ? T_Q1D : q1d;
+
+   const auto B = Reshape(b, Q1D, D1D);
+   const auto G = Reshape(g, Q1D, D1D);
+   const auto X = Reshape(x,  D1D, D1D, SDIM, NE);
+   auto Y = Reshape(y, Q1D, Q1D, NE);
+
+   mfem::forall_2D_batch(NE, Q1D, Q1D, NBZ, [=] MFEM_HOST_DEVICE (int e)
+   {
+      constexpr int MQ1 = T_Q1D ? T_Q1D : DofQuadLimits::MAX_Q1D;
+      constexpr int MD1 = T_D1D ? T_D1D : DofQuadLimits::MAX_D1D;
+      const int D1D = T_D1D ? T_D1D : d1d;
+      const int Q1D = T_Q1D ? T_Q1D : q1d;
+      const int tidz = MFEM_THREAD_ID(z);
+
+      MFEM_SHARED real_t BG[2][MQ1*MD1];
+      MFEM_SHARED real_t XYZ[SDIM][NBZ][MD1*MD1];
+      MFEM_SHARED real_t DQ[2*SDIM][NBZ][MD1*MQ1];
+
+      kernels::internal::LoadBG<MD1,MQ1>(D1D,Q1D,B,G,BG);
+
+      // Load XYZ components
+      MFEM_FOREACH_THREAD(dy,y,D1D)
+      {
+         MFEM_FOREACH_THREAD(dx,x,D1D)
+         {
+            for (int d = 0; d < SDIM; ++d)
+            {
+               XYZ[d][tidz][dx + dy*D1D] = X(dx,dy,d,e);
+            }
+         }
+      }
+      MFEM_SYNC_THREAD;
+
+      ConstDeviceMatrix B_mat(BG[0], D1D, Q1D);
+      ConstDeviceMatrix G_mat(BG[1], D1D, Q1D);
+
+      // x contraction
+      MFEM_FOREACH_THREAD(dy,y,D1D)
+      {
+         MFEM_FOREACH_THREAD(qx,x,Q1D)
+         {
+            for (int d = 0; d < SDIM; ++d)
+            {
+               real_t u = 0.0;
+               real_t v = 0.0;
+               for (int dx = 0; dx < D1D; ++dx)
+               {
+                  const real_t xval = XYZ[d][tidz][dx + dy*D1D];
+                  u += xval * G_mat(dx,qx);
+                  v += xval * B_mat(dx,qx);
+               }
+               DQ[d][tidz][dy + qx*D1D] = u;
+               DQ[3 + d][tidz][dy + qx*D1D] = v;
+            }
+         }
+      }
+      MFEM_SYNC_THREAD;
+      // y contraction and determinant computation
+      MFEM_FOREACH_THREAD(qy,y,Q1D)
+      {
+         MFEM_FOREACH_THREAD(qx,x,Q1D)
+         {
+            real_t J_[6] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0};
+            for (int d = 0; d < SDIM; ++d)
+            {
+               for (int dy = 0; dy < D1D; ++dy)
+               {
+                  J_[d] += DQ[d][tidz][dy + qx*D1D] * B_mat(dy,qy);
+                  J_[3 + d] += DQ[3 + d][tidz][dy + qx*D1D] * G_mat(dy,qy);
+               }
+            }
+            DeviceTensor<2> J(J_, 3, 2);
+            const real_t E = J(0,0)*J(0,0) + J(1,0)*J(1,0) + J(2,0)*J(2,0);
+            const real_t F = J(0,0)*J(0,1) + J(1,0)*J(1,1) + J(2,0)*J(2,1);
+            const real_t G = J(0,1)*J(0,1) + J(1,1)*J(1,1) + J(2,1)*J(2,1);
+            Y(qx,qy,e) = std::sqrt(E*G - F*F);
+         }
+      }
+   });
+}
+
+template<int T_D1D = 0, int T_Q1D = 0, bool SMEM = true>
+inline void Det3D(const int NE,
+                  const real_t *b,
+                  const real_t *g,
+                  const real_t *x,
+                  real_t *y,
+                  const int d1d = 0,
+                  const int q1d = 0,
+                  Vector *d_buff = nullptr) // used only with SMEM = false
+{
+   constexpr int DIM = 3;
+   static constexpr int GRID = SMEM ? 0 : 128;
+
+   const int D1D = T_D1D ? T_D1D : d1d;
+   const int Q1D = T_Q1D ? T_Q1D : q1d;
+
+   const auto B = Reshape(b, Q1D, D1D);
+   const auto G = Reshape(g, Q1D, D1D);
+   const auto X = Reshape(x, D1D, D1D, D1D, DIM, NE);
+   auto Y = Reshape(y, Q1D, Q1D, Q1D, NE);
+
+   real_t *GM = nullptr;
+   if (!SMEM)
+   {
+      const DeviceDofQuadLimits &limits = DeviceDofQuadLimits::Get();
+      const int max_q1d = T_Q1D ? T_Q1D : limits.MAX_Q1D;
+      const int max_d1d = T_D1D ? T_D1D : limits.MAX_D1D;
+      const int max_qd = std::max(max_q1d, max_d1d);
+      const int mem_size = max_qd * max_qd * max_qd * 9;
+      d_buff->SetSize(2*mem_size*GRID);
+      GM = d_buff->Write();
+   }
+
+   mfem::forall_3D_grid(NE, Q1D, Q1D, Q1D, GRID, [=] MFEM_HOST_DEVICE (int e)
+   {
+      static constexpr int MQ1 = T_Q1D ? T_Q1D :
+                                 (SMEM ? DofQuadLimits::MAX_DET_1D : DofQuadLimits::MAX_Q1D);
+      static constexpr int MD1 = T_D1D ? T_D1D :
+                                 (SMEM ? DofQuadLimits::MAX_DET_1D : DofQuadLimits::MAX_D1D);
+      static constexpr int MDQ = MQ1 > MD1 ? MQ1 : MD1;
+      static constexpr int MSZ = MDQ * MDQ * MDQ * 9;
+
+      const int bid = MFEM_BLOCK_ID(x);
+      MFEM_SHARED real_t BG[2][MQ1*MD1];
+      MFEM_SHARED real_t SM0[SMEM?MSZ:1];
+      MFEM_SHARED real_t SM1[SMEM?MSZ:1];
+      real_t *lm0 = SMEM ? SM0 : GM + MSZ*bid;
+      real_t *lm1 = SMEM ? SM1 : GM + MSZ*(GRID+bid);
+      real_t (*DDD)[MD1*MD1*MD1] = (real_t (*)[MD1*MD1*MD1]) (lm0);
+      real_t (*DDQ)[MD1*MD1*MQ1] = (real_t (*)[MD1*MD1*MQ1]) (lm1);
+      real_t (*DQQ)[MD1*MQ1*MQ1] = (real_t (*)[MD1*MQ1*MQ1]) (lm0);
+      real_t (*QQQ)[MQ1*MQ1*MQ1] = (real_t (*)[MQ1*MQ1*MQ1]) (lm1);
+
+      kernels::internal::LoadX<MD1>(e,D1D,X,DDD);
+      kernels::internal::LoadBG<MD1,MQ1>(D1D,Q1D,B,G,BG);
+
+      kernels::internal::GradX<MD1,MQ1>(D1D,Q1D,BG,DDD,DDQ);
+      kernels::internal::GradY<MD1,MQ1>(D1D,Q1D,BG,DDQ,DQQ);
+      kernels::internal::GradZ<MD1,MQ1>(D1D,Q1D,BG,DQQ,QQQ);
+
+      MFEM_FOREACH_THREAD(qz,z,Q1D)
+      {
+         MFEM_FOREACH_THREAD(qy,y,Q1D)
+         {
+            MFEM_FOREACH_THREAD(qx,x,Q1D)
+            {
+               real_t J[9];
+               kernels::internal::PullGrad<MQ1>(Q1D, qx,qy,qz, QQQ, J);
+               Y(qx,qy,qz,e) = kernels::Det<3>(J);
+            }
+         }
+      }
+   });
+}
+
+} // namespace quadrature_interpolator
+} // namespace internal
+
+/// @cond Suppress_Doxygen_warnings
+
+template<int DIM, int SDIM, int D1D, int Q1D>
+QuadratureInterpolator::DetKernelType
+QuadratureInterpolator::DetKernels::Kernel()
+{
+   if (DIM == 1) { return internal::quadrature_interpolator::Det1D; }
+   else if (DIM == 2 && SDIM == 2) { return internal::quadrature_interpolator::Det2D<D1D, Q1D>; }
+   else if (DIM == 2 && SDIM == 3) { return internal::quadrature_interpolator::Det2DSurface<D1D, Q1D>; }
+   else if (DIM == 3) { return internal::quadrature_interpolator::Det3D<D1D, Q1D>; }
+   else { MFEM_ABORT(""); }
+}
+
+/// @endcond
+
+} // namespace mfem
+
+#endif // MFEM_QUADINTERP_DET_HPP

fem/tmop.cpp

@@ -5122,33 +5122,32 @@ real_t TMOP_Integrator::GetSurfaceFittingWeight()
 
 void TMOP_Integrator::EnableNormalization(const GridFunction &x)
 {
-   ComputeNormalizationEnergies(x, metric_normal, lim_normal, surf_fit_normal);
+   ComputeNormalizationEnergies(x, metric_normal, lim_normal);
    metric_normal = 1.0 / metric_normal;
    lim_normal = 1.0 / lim_normal;
-   //if (surf_fit_gf) { surf_fit_normal = 1.0 / surf_fit_normal; }
    if (surf_fit_gf || surf_fit_pos) { surf_fit_normal = lim_normal; }
 }
 
 #ifdef MFEM_USE_MPI
 void TMOP_Integrator::ParEnableNormalization(const ParGridFunction &x)
 {
-   real_t loc[3];
-   ComputeNormalizationEnergies(x, loc[0], loc[1], loc[2]);
-   real_t rdc[3];
-   MPI_Allreduce(loc, rdc, 3, MPITypeMap<real_t>::mpi_type, MPI_SUM,
+   real_t loc[2];
+   ComputeNormalizationEnergies(x, loc[0], loc[1]);
+   real_t rdc[2];
+   MPI_Allreduce(loc, rdc, 2, MPITypeMap<real_t>::mpi_type, MPI_SUM,
                  x.ParFESpace()->GetComm());
    metric_normal = 1.0 / rdc[0];
    lim_normal    = 1.0 / rdc[1];
-   // if (surf_fit_gf) { surf_fit_normal = 1.0 / rdc[2]; }
    if (surf_fit_gf || surf_fit_pos) { surf_fit_normal = lim_normal; }
 }
 #endif
 
 void TMOP_Integrator::ComputeNormalizationEnergies(const GridFunction &x,
                                                    real_t &metric_energy,
-                                                   real_t &lim_energy,
-                                                   real_t &surf_fit_gf_energy)
+                                                   real_t &lim_energy)
 {
+   metric_energy = 0.0;
+   lim_energy = 0.0;
    if (PA.enabled)
    {
       MFEM_VERIFY(PA.E.Size() > 0, "Must be called after AssemblePA!");
@@ -5191,9 +5190,6 @@ void TMOP_Integrator::ComputeNormalizationEnergies(const GridFunction &x,
    Jpr.SetSize(dim);
    Jpt.SetSize(dim);
 
-   metric_energy = 0.0;
-   lim_energy = 0.0;
-   surf_fit_gf_energy = 0.0;
    for (int i = 0; i < fes->GetNE(); i++)
    {
       const FiniteElement *fe = fes->GetFE(i);
@@ -5225,21 +5221,7 @@ void TMOP_Integrator::ComputeNormalizationEnergies(const GridFunction &x,
          lim_energy += weight;
       }
 
-      // Normalization of the surface fitting term.
-      if (surf_fit_gf)
-      {
-         Array<int> dofs;
-         Vector sigma_e;
-         surf_fit_gf->FESpace()->GetElementDofs(i, dofs);
-         surf_fit_gf->GetSubVector(dofs, sigma_e);
-         for (int s = 0; s < dofs.Size(); s++)
-         {
-            if ((*surf_fit_marker)[dofs[s]] == true)
-            {
-               surf_fit_gf_energy += sigma_e(s) * sigma_e(s);
-            }
-         }
-      }
+      // TODO: Normalization of the surface fitting term.
    }
 
    // Cases when integration is not over the target element, or when the

fem/tmop.hpp

@@ -2038,8 +2038,7 @@ protected:
    } PA;
 
    void ComputeNormalizationEnergies(const GridFunction &x,
-                                     real_t &metric_energy, real_t &lim_energy,
-                                     real_t &surf_fit_gf_energy);
+                                     real_t &metric_energy, real_t &lim_energy);
 
    void AssembleElementVectorExact(const FiniteElement &el,
                                    ElementTransformation &T,

general/array.hpp

@@ -190,6 +190,12 @@ public:
    /// Prepend an 'el' to the array, resize if necessary.
    inline int Prepend(const T &el);
 
+   /// Insert @a els into the array at index @a i
+   inline int Insert(int i, const Array<T> &els);
+
+   /// Insert @a el into the array at index @a i
+   inline int Insert(int i, const T &el) { return Insert(i, Array<T>({el})); }
+
    /// Return the last element in the array.
    inline T &Last();
 
@@ -211,6 +217,9 @@ public:
    /// Delete the first entry with value == 'el'.
    inline void DeleteFirst(const T &el);
 
+   /// Delete entries at @a indices, and resize
+   inline void DeleteAt(const Array<int> &indices);
+
    /// Delete the whole array.
    inline void DeleteAll();
 
@@ -249,6 +258,9 @@ public:
    /// Copy sub array starting from @a offset out to the provided @a sa.
    inline void GetSubArray(int offset, int sa_size, Array<T> &sa) const;
 
+   /// Set from sub array @sa at @a offset
+   inline void SetSubArray(int offset, const Array<T> &sa);
+
    /// Prints array to stream with width elements per row.
    void Print(std::ostream &out = mfem::out, int width = 4) const;
 
@@ -326,7 +338,11 @@ public:
        the Size to match this Capacity after this.*/
    template <typename U>
    inline void CopyFrom(const U *src)
-   { std::memcpy(begin(), src, MemoryUsage()); }
+   {
+      if (!begin() || size == 0) { return; }
+      MFEM_ASSERT(begin() && src, "Error in Array::CopyFrom");
+      std::memcpy(begin(), src, MemoryUsage());
+   }
 
    /// STL-like begin.  Returns pointer to the first element of the array.
    inline T* begin() { return data; }
@@ -869,6 +885,22 @@ inline int Array<T>::Prepend(const T &el)
    return size;
 }
 
+template<class T>
+inline int Array<T>::Insert(int i, const Array<T> &els)
+{
+   MFEM_ASSERT(i < size, "Insert index is out-of-bounds.");
+
+   const int old_size = size;
+
+   SetSize(size + els.Size());
+   for (int j = old_size-1; j >= i; j--)
+   {
+      data[j+els.Size()] = data[j];
+   }
+   SetSubArray(i, els);
+   return size;
+}
+
 template <class T>
 inline T &Array<T>::Last()
 {
@@ -931,6 +963,30 @@ inline void Array<T>::DeleteFirst(const T &el)
    }
 }
 
+template <class T>
+inline void Array<T>::DeleteAt(const Array<int> &indices)
+{
+   // Make a copy of the indices, sorted.
+   Array<int> sorted_indices(indices);
+   sorted_indices.Sort();
+
+   int rm_count = 0;
+   for (int i = 0; i < size; i++)
+   {
+      if (rm_count < sorted_indices.Size() && i == sorted_indices[rm_count])
+      {
+         rm_count++;
+      }
+      else
+      {
+         data[i-rm_count] = data[i]; // shift data rm_count
+      }
+   }
+
+   // Resize to remove tail
+   SetSize(size - rm_count);
+}
+
 template <class T>
 inline void Array<T>::DeleteAll()
 {
@@ -983,6 +1039,18 @@ inline void Array<T>::GetSubArray(int offset, int sa_size, Array<T> &sa) const
    }
 }
 
+template<class T>
+inline void Array<T>::SetSubArray(int offset, const Array<T> &sa)
+{
+   MFEM_ASSERT(offset + sa.Size() < size,
+               "Sub-array with size " << sa.Size() << " is too large to set at offset " <<
+               offset << ", given array size " << size);
+   for (int i = 0; i < sa.Size(); i++)
+   {
+      data[offset + i] = sa[i];
+   }
+}
+
 template <class T>
 inline void Array<T>::operator=(const T &a)
 {

general/backends.hpp

@@ -14,7 +14,7 @@
 
 #include "../config/config.hpp"
 
-#ifdef MFEM_USE_CUDA
+#if defined(MFEM_USE_CUDA) && defined(__CUDACC__)
 #include <cusparse.h>
 #include <library_types.h>
 #include <cuda_runtime.h>
@@ -22,7 +22,7 @@
 #endif
 #include "cuda.hpp"
 
-#ifdef MFEM_USE_HIP
+#if defined(MFEM_USE_HIP) && defined(__HIP__)
 #include <hip/hip_runtime.h>
 #endif
 #include "hip.hpp"
@@ -43,7 +43,7 @@
 #endif
 #endif
 
-#if !(defined(MFEM_USE_CUDA) || defined(MFEM_USE_HIP))
+#if !defined(MFEM_USE_CUDA_OR_HIP)
 #define MFEM_DEVICE
 #define MFEM_HOST
 #define MFEM_LAMBDA
@@ -55,17 +55,18 @@
 #endif
 
 #if !((defined(MFEM_USE_CUDA) && defined(__CUDA_ARCH__)) || \
-      (defined(MFEM_USE_HIP)  && defined(__HIP_DEVICE_COMPILE__)))
+      (defined(MFEM_USE_HIP) && defined(__HIP_DEVICE_COMPILE__)))
 #define MFEM_SHARED
 #define MFEM_SYNC_THREAD
 #define MFEM_BLOCK_ID(k) 0
 #define MFEM_THREAD_ID(k) 0
 #define MFEM_THREAD_SIZE(k) 1
 #define MFEM_FOREACH_THREAD(i,k,N) for(int i=0; i<N; i++)
+#define MFEM_FOREACH_THREAD_DIRECT(i,k,N) MFEM_FOREACH_THREAD(i,k,N)
 #endif
 
 // 'double' and 'float' atomicAdd implementation for previous versions of CUDA
-#if defined(MFEM_USE_CUDA) && defined(__CUDA_ARCH__) && __CUDA_ARCH__ < 600
+#if defined(MFEM_USE_CUDA) && defined(__CUDA_ARCH__) && (__CUDA_ARCH__ < 600)
 MFEM_DEVICE inline mfem::real_t atomicAdd(mfem::real_t *add, mfem::real_t val)
 {
    unsigned long long int *ptr = (unsigned long long int *) add;
@@ -93,7 +94,7 @@ template <typename T>
 MFEM_HOST_DEVICE T AtomicAdd(T &add, const T val)
 {
 #if ((defined(MFEM_USE_CUDA) && defined(__CUDA_ARCH__)) || \
-     (defined(MFEM_USE_HIP)  && defined(__HIP_DEVICE_COMPILE__)))
+     (defined(MFEM_USE_HIP) && defined(__HIP_DEVICE_COMPILE__)))
    return atomicAdd(&add,val);
 #else
    T old = add;

general/communication.hpp

@@ -425,16 +425,24 @@ public:
    ~GroupCommunicator();
 };
 
+/// General MPI message tags used by MFEM
+enum MessageTag
+{
+   DEREFINEMENT_MATRIX_CONSTRUCTION_DATA =
+      291, /// ParFiniteElementSpace ParallelDerefinementMatrix and
+   /// ParDerefineMatrixOp
+};
+
 enum VarMessageTag
 {
-   NEIGHBOR_ELEMENT_RANK_VM,  ///< NeighborElementRankMessage
-   NEIGHBOR_ORDER_VM,         ///< NeighborOrderMessage
-   NEIGHBOR_DEREFINEMENT_VM,  ///< NeighborDerefinementMessage
-   NEIGHBOR_REFINEMENT_VM,    ///< NeighborRefinementMessage
-   NEIGHBOR_PREFINEMENT_VM,   ///< NeighborPRefinementMessage
-   NEIGHBOR_ROW_VM,           ///< NeighborRowMessage
-   REBALANCE_VM,              ///< RebalanceMessage
-   REBALANCE_DOF_VM           ///< RebalanceDofMessage
+   NEIGHBOR_ELEMENT_RANK_VM, ///< NeighborElementRankMessage
+   NEIGHBOR_ORDER_VM,        ///< NeighborOrderMessage
+   NEIGHBOR_DEREFINEMENT_VM, ///< NeighborDerefinementMessage
+   NEIGHBOR_REFINEMENT_VM,   ///< NeighborRefinementMessage
+   NEIGHBOR_PREFINEMENT_VM,  ///< NeighborPRefinementMessage
+   NEIGHBOR_ROW_VM,          ///< NeighborRowMessage
+   REBALANCE_VM,             ///< RebalanceMessage
+   REBALANCE_DOF_VM,         ///< RebalanceDofMessage
 };
 
 /// \brief Variable-length MPI message containing unspecific binary data.

general/cuda.cpp

@@ -24,7 +24,7 @@ void mfem_cuda_error(cudaError_t err, const char *expr, const char *func,
                      const char *file, int line)
 {
    mfem::err << "\n\nCUDA error: (" << expr << ") failed with error:\n --> "
-             << cudaGetErrorString(err)
+             << cudaGetErrorString(err) << " [code: " << (int)err << ']'
              << "\n ... in function: " << func
              << "\n ... in file: " << file << ':' << line << '\n';
    mfem_error();

general/cuda.hpp

@@ -18,7 +18,7 @@
 // CUDA block size used by MFEM.
 #define MFEM_CUDA_BLOCKS 256
 
-#ifdef MFEM_USE_CUDA
+#if defined(MFEM_USE_CUDA) && defined(__CUDACC__)
 #define MFEM_USE_CUDA_OR_HIP
 #define MFEM_DEVICE __device__
 #define MFEM_HOST __host__
@@ -37,22 +37,23 @@
                               __FILE__, __LINE__);                             \
     }                                                                          \
   } while (0)
-#endif // MFEM_USE_CUDA
 
 // Define the MFEM inner threading macros
-#if defined(MFEM_USE_CUDA) && defined(__CUDA_ARCH__)
+#if defined(__CUDA_ARCH__)
 #define MFEM_SHARED __shared__
 #define MFEM_SYNC_THREAD __syncthreads()
 #define MFEM_BLOCK_ID(k) blockIdx.k
 #define MFEM_THREAD_ID(k) threadIdx.k
 #define MFEM_THREAD_SIZE(k) blockDim.k
 #define MFEM_FOREACH_THREAD(i,k,N) for(int i=threadIdx.k; i<N; i+=blockDim.k)
-#endif
+#define MFEM_FOREACH_THREAD_DIRECT(i,k,N) if(const int i=threadIdx.k; i<N)
+#endif // defined(__CUDA_ARCH__)
+#endif // defined(MFEM_USE_CUDA) && defined(__CUDACC__)
 
 namespace mfem
 {
 
-#ifdef MFEM_USE_CUDA
+#if defined(MFEM_USE_CUDA) && defined(__CUDACC__)
 // Function used by the macro MFEM_GPU_CHECK.
 void mfem_cuda_error(cudaError_t err, const char *expr, const char *func,
                      const char *file, int line);

general/device.cpp

@@ -16,6 +16,7 @@
 #include "../fem/ceed/interface/util.hpp"
 #endif
 #ifdef MFEM_USE_MPI
+#include "communication.hpp"
 #include "../linalg/hypre.hpp"
 #endif
 
@@ -145,6 +146,11 @@ Device::Device()
       Configure(device);
       device_env = true;
    }
+
+   if (GetEnv("MFEM_GPU_AWARE_MPI"))
+   {
+      SetGPUAwareMPI(true);
+   }
 }
 
 Device::~Device()
@@ -196,6 +202,29 @@ void Device::Configure(const std::string &device, const int device_id)
    {
       bmap[internal::backend_name[i]] = internal::backend_list[i];
    }
+   // auto-detect GPU configurations
+   // assumes only one of HIP or CUDA are available
+#ifdef MFEM_USE_HIP
+   bmap["gpu"] = Backend::HIP;
+#ifdef MFEM_USE_RAJA
+   bmap["raja-gpu"] = Backend::RAJA_HIP;
+#endif
+#ifdef MFEM_USE_CEED
+   bmap["ceed-gpu"] = Backend::CEED_HIP;
+#endif
+   // no OCCA+HIP?
+#elif defined(MFEM_USE_CUDA)
+   bmap["gpu"] = Backend::CUDA;
+#ifdef MFEM_USE_RAJA
+   bmap["raja-gpu"] = Backend::RAJA_CUDA;
+#endif
+#ifdef MFEM_USE_CEED
+   bmap["ceed-gpu"] = Backend::CEED_CUDA;
+#endif
+#ifdef MFEM_USE_OCCA
+   bmap["occa-gpu"] = Backend::OCCA_CUDA;
+#endif
+#endif
    std::string device_option;
    std::string::size_type beg = 0, end;
    while (1)
@@ -313,6 +342,13 @@ void Device::Print(std::ostream &os)
    {
       os << ',' << MemoryTypeName[static_cast<int>(device_mem_type)];
    }
+#ifdef MFEM_USE_MPI
+   if (Allows(Backend::DEVICE_MASK) &&
+       Mpi::IsInitialized() && !Mpi::IsFinalized())
+   {
+      os << "\nUse GPU-aware MPI:    " << (GetGPUAwareMPI() ? "yes" : "no");
+   }
+#endif
    os << std::endl;
 }
 
@@ -579,7 +615,7 @@ void Device::Setup(const std::string &device_option, const int device_id)
    if (Allows(Backend::DEBUG_DEVICE)) { ngpu = 1; }
 }
 
-MemoryType Device::QueryMemoryType(void *ptr)
+MemoryType Device::QueryMemoryType(const void* ptr)
 {
    // from HYPRE's hypre_GetPointerLocation
    MemoryType res = MemoryType::HOST;

general/device.hpp

@@ -198,6 +198,10 @@ public:
          'ceed-hip', 'hip', 'debug',
          'occa-omp', 'raja-omp', 'omp',
          'ceed-cpu', 'occa-cpu', 'raja-cpu', 'cpu'.
+       - The following backend aliases are also available: 'ceed-gpu',
+         'occa-gpu', 'raja-gpu', and 'gpu' where they alias their respective
+         '*-cuda' or '*-hip' backends depending on the MFEM build-time
+         configuration.
        - Multiple backends can be configured at the same time.
        - Only one 'occa-*' backend can be configured at a time.
        - The backend 'occa-cuda' enables the 'cuda' backend unless 'raja-cuda'
@@ -293,9 +297,9 @@ public:
    /// Get the status of GPU-aware MPI flag.
    static bool GetGPUAwareMPI() { return Get().mpi_gpu_aware; }
 
-   /** @brief Query the device driver for what memory type a given @a ptr is
-       allocated with. */
-   static MemoryType QueryMemoryType(void *ptr);
+   /** Query the device driver for what memory type a given @a ptr is allocated
+    * with. */
+   static MemoryType QueryMemoryType(const void* ptr);
 
    /** @brief The number of hardware compute units/streaming multiprocessors
        available on a given compute device @a device_id. */

general/error.hpp

@@ -176,7 +176,7 @@ __device__ void abort_msg(T & msg)
       printf(__VA_ARGS__);     \
       asm("trap;");            \
    }
-#elif defined(MFEM_USE_HIP)
+#elif defined(__HIP_DEVICE_COMPILE__)
 #define MFEM_ABORT_KERNEL(...) \
    {                           \
       printf(__VA_ARGS__);     \

general/forall.hpp

@@ -158,8 +158,8 @@ private:
 #define MFEM_PRAGMA(X) _Pragma(#X)
 
 // MFEM_UNROLL pragma macro that can be used inside MFEM_FORALL macros.
-#if defined(MFEM_USE_CUDA) && defined(__CUDA_ARCH__)
-#ifdef __NVCC__
+#if defined(MFEM_USE_CUDA) && defined(__CUDA_ARCH__) // Clang cuda or nvcc
+#ifdef __NVCC__ // nvcc specifically
 #define MFEM_UNROLL(N) MFEM_PRAGMA(unroll(N))
 #else // Assuming Clang CUDA
 #define MFEM_UNROLL(N) MFEM_PRAGMA(unroll N)
@@ -169,12 +169,12 @@ private:
 #endif
 
 // MFEM_GPU_FORALL: "parallel for" executed with CUDA or HIP based on the MFEM
-// build-time configuration (MFEM_USE_CUDA or MFEM_USE_HIP). If neither CUDA nor
-// HIP is enabled, this macro is a no-op.
-#if defined(MFEM_USE_CUDA)
+// build-time configuration (MFEM_USE_CUDA or MFEM_USE_HIP), and if compiling
+// with CUDA/HIP language. Otherwise, this macro is a no-op.
+#if defined(MFEM_USE_CUDA) && defined(__CUDACC__)
 #define MFEM_GPU_FORALL(i, N,...) CuWrap1D(N, [=] MFEM_DEVICE      \
                                        (int i) {__VA_ARGS__})
-#elif defined(MFEM_USE_HIP)
+#elif defined(MFEM_USE_HIP) && defined(__HIP__)
 #define MFEM_GPU_FORALL(i, N,...) HipWrap1D(N, [=] MFEM_DEVICE     \
                                         (int i) {__VA_ARGS__})
 #else
@@ -481,7 +481,7 @@ void RajaSeqWrap(const int N, HBODY &&h_body)
 
 
 /// CUDA backend
-#ifdef MFEM_USE_CUDA
+#if defined(MFEM_USE_CUDA) && defined(__CUDACC__)
 
 template <typename BODY> __global__ static
 void CuKernel1D(const int N, BODY body)
@@ -573,11 +573,11 @@ struct CuWrap<3>
    }
 };
 
-#endif // MFEM_USE_CUDA
+#endif // defined(MFEM_USE_CUDA) && defined(__CUDACC__)
 
 
 /// HIP backend
-#ifdef MFEM_USE_HIP
+#if defined(MFEM_USE_HIP) && defined(__HIP__)
 
 template <typename BODY> __global__ static
 void HipKernel1D(const int N, BODY body)
@@ -668,7 +668,7 @@ struct HipWrap<3>
    }
 };
 
-#endif // MFEM_USE_HIP
+#endif // defined(MFEM_USE_HIP) && defined(__HIP__)
 
 
 /// The forall kernel body wrapper
@@ -701,7 +701,7 @@ inline void ForallWrap(const bool use_dev, const int N,
    }
 #endif
 
-#ifdef MFEM_USE_CUDA
+#if defined(MFEM_USE_CUDA) && defined(__CUDACC__)
    // If Backend::CUDA is allowed, use it
    if (Device::Allows(Backend::CUDA))
    {
@@ -709,7 +709,7 @@ inline void ForallWrap(const bool use_dev, const int N,
    }
 #endif
 
-#ifdef MFEM_USE_HIP
+#if defined(MFEM_USE_HIP) && defined(__HIP__)
    // If Backend::HIP is allowed, use it
    if (Device::Allows(Backend::HIP))
    {

general/hip.cpp

@@ -24,7 +24,7 @@ void mfem_hip_error(hipError_t err, const char *expr, const char *func,
                     const char *file, int line)
 {
    mfem::err << "\n\nHIP error: (" << expr << ") failed with error:\n --> "
-             << hipGetErrorString(err)
+             << hipGetErrorString(err) << " [code: " << (int)err << ']'
              << "\n ... in function: " << func
              << "\n ... in file: " << file << ':' << line << '\n';
    mfem_error();

general/hip.hpp

@@ -18,7 +18,7 @@
 // HIP block size used by MFEM.
 #define MFEM_HIP_BLOCKS 256
 
-#ifdef MFEM_USE_HIP
+#if defined(MFEM_USE_HIP) && defined(__HIP__)
 #define MFEM_USE_CUDA_OR_HIP
 #define MFEM_DEVICE __device__
 #define MFEM_HOST __host__
@@ -37,18 +37,20 @@
                              __FILE__, __LINE__);                              \
     }                                                                          \
   } while (0)
-#endif // MFEM_USE_HIP
 
 // Define the MFEM inner threading macros
-#if defined(MFEM_USE_HIP) && defined(__HIP_DEVICE_COMPILE__)
+#if defined(__HIP_DEVICE_COMPILE__)
 #define MFEM_SHARED __shared__
 #define MFEM_SYNC_THREAD __syncthreads()
 #define MFEM_BLOCK_ID(k) hipBlockIdx_ ##k
 #define MFEM_THREAD_ID(k) hipThreadIdx_ ##k
 #define MFEM_THREAD_SIZE(k) hipBlockDim_ ##k
 #define MFEM_FOREACH_THREAD(i,k,N) \
-    for(int i=hipThreadIdx_ ##k; i<N; i+=hipBlockDim_ ##k)
-#endif
+   for(int i=hipThreadIdx_ ##k; i<N; i+=hipBlockDim_ ##k)
+#define MFEM_FOREACH_THREAD_DIRECT(i,k,N) \
+   if(const int i=hipThreadIdx_ ##k; i<N)
+#endif // defined(__HIP_DEVICE_COMPILE__)
+#endif // defined(MFEM_USE_HIP) && defined(__HIP__)
 
 namespace mfem
 {

general/mem_manager.cpp

@@ -513,10 +513,7 @@ public:
    void *HtoD(void *dst, const void *src, size_t bytes) override
    { return HipMemcpyHtoD(dst, src, bytes); }
    void *DtoD(void* dst, const void* src, size_t bytes) override
-   // Unlike cudaMemcpy(DtoD), hipMemcpy(DtoD) causes a host-side synchronization so
-   // instead we use hipMemcpyAsync to get similar behavior.
-   // for more info see: https://github.com/mfem/mfem/pull/2780
-   { return HipMemcpyDtoDAsync(dst, src, bytes); }
+   { return HipMemcpyDtoD(dst, src, bytes); }
    void *DtoH(void *dst, const void *src, size_t bytes) override
    { return HipMemcpyDtoH(dst, src, bytes); }
 };
@@ -658,10 +655,7 @@ public:
       return CuMemcpyDtoD(dst, src, bytes);
 #endif
 #ifdef MFEM_USE_HIP
-      // Unlike cudaMemcpy(DtoD), hipMemcpy(DtoD) causes a host-side synchronization so
-      // instead we use hipMemcpyAsync to get similar behavior.
-      // for more info see: https://github.com/mfem/mfem/pull/2780
-      return HipMemcpyDtoDAsync(dst, src, bytes);
+      return HipMemcpyDtoD(dst, src, bytes);
 #endif
       // rm.copy(dst, const_cast<void*>(src), bytes); return dst;
    }

general/mem_manager.hpp

@@ -896,6 +896,7 @@ inline HYPRE_MemoryLocation GetHypreMemoryLocation()
 #elif MFEM_HYPRE_VERSION < 23100
    return HYPRE_MEMORY_DEVICE;
 #else // HYPRE_USING_GPU is defined and MFEM_HYPRE_VERSION >= 23100
+   if (!HYPRE_Initialized()) { return HYPRE_MEMORY_HOST; }
    HYPRE_MemoryLocation loc;
    HYPRE_GetMemoryLocation(&loc);
    return loc;
@@ -1057,7 +1058,8 @@ inline void Memory<T>::MakeAlias(const Memory &base, int offset, int size)
          // register the 'base' if the MemoryManager::Exists():
          MemoryManager::Exists()
 #else // HYPRE_USING_GPU is defined and MFEM_HYPRE_VERSION >= 23100
-         MemoryManager::Exists() && HypreUsingGPU()
+         IsDeviceMemory(MemoryManager::GetDeviceMemoryType()) ||
+         (MemoryManager::Exists() && HypreUsingGPU())
 #endif
       )
       {

general/reducers.hpp

@@ -537,7 +537,7 @@ void reduce(int N, T &res, B &&body, const R &reducer, bool use_dev,
       return;
    }
 
-#if defined(MFEM_USE_HIP) || defined(MFEM_USE_CUDA)
+#if defined(MFEM_USE_CUDA_OR_HIP)
    if (use_dev &&
        mfem::Device::Allows(Backend::CUDA | Backend::HIP | Backend::RAJA_CUDA |
                             Backend::RAJA_HIP))

linalg/densemat.cpp

@@ -4405,4 +4405,32 @@ void BatchLUSolve(const DenseTensor &Mlu, const Array<int> &P, Vector &X)
    BatchedLinAlg::LUSolve(Mlu, P, X);
 }
 
+#ifdef MFEM_USE_LAPACK
+void BandedSolve(int KL, int KU, DenseMatrix &AB, DenseMatrix &B,
+                 Array<int> &ipiv)
+{
+   int LDAB = (2*KL) + KU + 1;
+   int N = AB.NumCols();
+   int NRHS = B.NumCols();
+   int info;
+   ipiv.SetSize(N);
+   MFEM_LAPACK_PREFIX(gbsv_)(&N, &KL, &KU, &NRHS, AB.GetData(), &LDAB,
+                             ipiv.GetData(), B.GetData(), &N, &info);
+   MFEM_ASSERT(info == 0, "BandedSolve failed in LAPACK");
+}
+
+void BandedFactorizedSolve(int KL, int KU, DenseMatrix &AB, DenseMatrix &B,
+                           bool transpose, Array<int> &ipiv)
+{
+   int LDAB = (2*KL) + KU + 1;
+   int N = AB.NumCols();
+   int NRHS = B.NumCols();
+   char trans = transpose ? 'T' : 'N';
+   int info;
+   MFEM_LAPACK_PREFIX(gbtrs_)(&trans, &N, &KL, &KU, &NRHS, AB.GetData(), &LDAB,
+                              ipiv.GetData(), B.GetData(), &N, &info);
+   MFEM_ASSERT(info == 0, "BandedFactorizedSolve failed in LAPACK");
+}
+#endif
+
 } // namespace mfem

linalg/densemat.hpp

@@ -1329,6 +1329,13 @@ void BatchLUFactor(DenseTensor &Mlu, Array<int> &P, const real_t TOL = 0.0);
     dimension m x n. */
 void BatchLUSolve(const DenseTensor &Mlu, const Array<int> &P, Vector &X);
 
+#ifdef MFEM_USE_LAPACK
+void BandedSolve(int KL, int KU, DenseMatrix &AB, DenseMatrix &B,
+                 Array<int> &ipiv);
+void BandedFactorizedSolve(int KL, int KU, DenseMatrix &AB, DenseMatrix &B,
+                           bool transpose, Array<int> &ipiv);
+#endif
+
 // Inline methods
 
 inline real_t &DenseMatrix::operator()(int i, int j)

linalg/hypre.cpp

@@ -2574,6 +2574,18 @@ void HypreParMatrix::EliminateBC(const Array<int> &ess_dofs,
 #if defined(HYPRE_USING_GPU)
       if (HypreUsingGPU())
       {
+#if defined(HYPRE_WITH_GPU_AWARE_MPI) || defined(HYPRE_USING_GPU_AWARE_MPI)
+         // hypre_GetGpuAwareMPI() was introduced in v2.31.0, however, its value
+         // is not checked in hypre_ParCSRCommHandleCreate_v2() before v2.33.0,
+         // instead only HYPRE_WITH_GPU_AWARE_MPI is checked.
+#if MFEM_HYPRE_VERSION >= 23300
+         if (hypre_GetGpuAwareMPI())
+#endif
+         {
+            // ensure int_buf_data has been computed before sending it
+            MFEM_STREAM_SYNC;
+         }
+#endif
          // Try to use device-aware MPI for the communication if available
          comm_handle = hypre_ParCSRCommHandleCreate_v2(
                           11, comm_pkg, HYPRE_MEMORY_DEVICE, int_buf_data,

linalg/lapack.hpp

@@ -42,6 +42,13 @@ extern "C" void
 MFEM_LAPACK_PREFIX(getri_)(int *N, real_t *A, int *LDA, int *IPIV, real_t *WORK,
                            int *LWORK, int *INFO);
 extern "C" void
+MFEM_LAPACK_PREFIX(gbsv_)(int *, int *, int *, int *, real_t *, int *, int *,
+                          real_t *, int *, int *);
+extern "C" void
+MFEM_LAPACK_PREFIX(gbtrs_)(char *, int *, int *, int *, int *, real_t *, int *,
+                           int *, real_t *, int *, int *);
+
+extern "C" void
 MFEM_LAPACK_PREFIX(syevr_)(char *JOBZ, char *RANGE, char *UPLO, int *N,
                            real_t *A, int *LDA, real_t *VL, real_t *VU, int *IL,
                            int *IU, real_t *ABSTOL, int *M, real_t *W,

linalg/vector.cpp

@@ -668,6 +668,28 @@ void Vector::median(const Vector &lo, const Vector &hi)
    });
 }
 
+void Vector::Insert(int offset, const Vector &sv)
+{
+   const int old_size = size;
+
+   if (sv.Size() + old_size > Capacity())
+   {
+      Vector copy = *this;
+      SetSize(size + sv.Size());
+      SetVector(copy, 0);
+   }
+   else
+   {
+      SetSize(size + sv.Size());
+   }
+
+   for (int j = old_size-1; j >= offset; j--)
+   {
+      data[j+sv.Size()] = data[j];
+   }
+   SetVector(sv, offset);
+}
+
 void Vector::GetSubVector(const Array<int> &dofs, Vector &elemvect) const
 {
    const int n = dofs.Size();

linalg/vector.hpp

@@ -171,6 +171,9 @@ public:
    /// Resize the vector to size @a s using the MemoryType of @a v.
    void SetSize(int s, const Vector &v) { SetSize(s, v.GetMemory().GetMemoryType()); }
 
+   /// Delete elements at @a indices and resize vector accordingly
+   void DeleteAt(const Array<int> &indices);
+
    /// Set the Vector data.
    /// @warning This method should be called only when OwnsData() is false.
    void SetData(real_t *d) { data.Wrap(d, data.Capacity(), false); }
@@ -396,6 +399,12 @@ public:
    /// v = median(v,lo,hi) entrywise.  Implementation assumes lo <= hi.
    void median(const Vector &lo, const Vector &hi);
 
+   /// Insert sub Vector @a sv at @a offset and resize
+   void Insert(int offset, const Vector &sv);
+
+   /// Insert @a value at @a offset and resize
+   void Insert(int offset, const real_t value) { Insert(offset, Vector({value})); }
+
    /// Extract entries listed in @a dofs to the output Vector @a elemvect.
    /** Negative dof values cause the -dof-1 position in @a elemvect to receive
        the -val in from this Vector. */
@@ -621,6 +630,29 @@ inline void Vector::SetSize(int s, MemoryType mt)
    data.UseDevice(use_dev);
 }
 
+inline void Vector::DeleteAt(const Array<int> &indices)
+{
+   // Make copy of the indices, sorted.
+   Array<int> sorted_indices(indices);
+   sorted_indices.Sort();
+
+   int rm_count = 0;
+   for (int i = 0; i < size; i++)
+   {
+      if (rm_count < sorted_indices.Size() && i == sorted_indices[rm_count])
+      {
+         rm_count++;
+      }
+      else
+      {
+         data[i-rm_count] = data[i]; // shift data rm_count
+      }
+   }
+
+   // Resize to remove tail
+   SetSize(size - rm_count);
+}
+
 inline void Vector::NewMemoryAndSize(const Memory<real_t> &mem, int s,
                                      bool own_mem)
 {

mesh/exodus_writer.cpp

@@ -26,6 +26,12 @@
    }\
 }
 
+#if defined(MFEM_USE_DOUBLE)
+#define MFEM_NETCDF_REAL_T NC_DOUBLE
+#elif defined(MFEM_USE_SINGLE)
+#define MFEM_NETCDF_REAL_T NC_FLOAT
+#endif
+
 namespace mfem
 {
 
@@ -135,18 +141,18 @@ public:
    /// @brief Writes the mesh to an ExodusII file.
    /// @param fpath The path to the file.
    /// @param flags NC_CLOBBER will overwrite existing file.
-   void PrintExodusII(std::string fpath, int flags = NC_CLOBBER);
+   void PrintExodusII(const std::string &fpath, int flags = NC_CLOBBER);
 
    /// @brief Static method for writing a mesh to an ExodusII file.
    /// @param mesh The mesh to write to the file.
    /// @param fpath The path to the file.
    /// @param flags NetCDF file flags.
-   static void PrintExodusII(Mesh & mesh, std::string fpath,
+   static void PrintExodusII(Mesh & mesh, const std::string &fpath,
                              int flags = NC_CLOBBER);
 
 protected:
    /// @brief Closes any open file and creates a NetCDF file using selected flags.
-   void OpenExodusII(std::string fpath, int flags);
+   void OpenExodusII(const std::string &fpath, int flags);
 
    /// @brief Closes any open file.
    void CloseExodusII();
@@ -167,9 +173,9 @@ protected:
    std::unordered_set<int> GenerateUniqueNodeIDs();
 
    /// @brief Populates vectors with x, y, z coordinates from mesh.
-   void ExtractVertexCoordinates(std::vector<double> & coordx,
-                                 std::vector<double> & coordy,
-                                 std::vector<double> & coordz);
+   void ExtractVertexCoordinates(std::vector<real_t> &coordx,
+                                 std::vector<real_t> &coordy,
+                                 std::vector<real_t> &coordz);
 
    /// @brief Writes node connectivity for a particular block.
    /// @param block_id The block to write to the file.
@@ -187,7 +193,7 @@ protected:
    /// @brief Writes the number of elements in the mesh.
    void WriteNumOfElements();
 
-   /// @brief Writes the floating-point word size (4 == float; 8 == double).
+   /// @brief Writes the floating-point word size (sizeof(real_t)).
    void WriteFloatingPointWordSize();
 
    /// @brief Writes the API version.
@@ -291,7 +297,7 @@ private:
    std::map<int, std::vector<int>> exodusII_side_ids_for_boundary_id;
 };
 
-void Mesh::PrintExodusII(const std::string fpath)
+void Mesh::PrintExodusII(const std::string &fpath)
 {
    ExodusIIWriter::PrintExodusII(*this, fpath);
 }
@@ -362,7 +368,7 @@ void ExodusIIWriter::WriteExodusIIMeshInformation()
    WriteNodeSets();
 }
 
-void ExodusIIWriter::PrintExodusII(std::string fpath, int flags)
+void ExodusIIWriter::PrintExodusII(const std::string &fpath, int flags)
 {
    OpenExodusII(fpath, flags);
 
@@ -374,7 +380,7 @@ void ExodusIIWriter::PrintExodusII(std::string fpath, int flags)
    mfem::out << "Mesh successfully written to Exodus II file" << std::endl;
 }
 
-void ExodusIIWriter::PrintExodusII(Mesh & mesh, std::string fpath,
+void ExodusIIWriter::PrintExodusII(Mesh &mesh, const std::string &fpath,
                                    int flags)
 {
    ExodusIIWriter writer(mesh);
@@ -382,7 +388,7 @@ void ExodusIIWriter::PrintExodusII(Mesh & mesh, std::string fpath,
    writer.PrintExodusII(fpath, flags);
 }
 
-void ExodusIIWriter::OpenExodusII(std::string fpath, int flags)
+void ExodusIIWriter::OpenExodusII(const std::string &fpath, int flags)
 {
    CloseExodusII();  // Close any open files.
 
@@ -422,7 +428,7 @@ void ExodusIIWriter::WriteNumOfElements()
 
 void ExodusIIWriter::WriteFloatingPointWordSize()
 {
-   const int word_size = 8;
+   const int word_size = sizeof(real_t);
    PutAtt(NC_GLOBAL, ExodusIILabels::EXODUS_FLOATING_POINT_WORD_SIZE_LABEL,
           NC_INT, 1,
           &word_size);
@@ -430,13 +436,15 @@ void ExodusIIWriter::WriteFloatingPointWordSize()
 
 void ExodusIIWriter::WriteAPIVersion()
 {
-   PutAtt(NC_GLOBAL, ExodusIILabels::EXODUS_API_VERSION_LABEL, NC_FLOAT, 1,
+   PutAtt(NC_GLOBAL, ExodusIILabels::EXODUS_API_VERSION_LABEL, MFEM_NETCDF_REAL_T,
+          1,
           &ExodusIILabels::EXODUS_API_VERSION);
 }
 
 void ExodusIIWriter::WriteDatabaseVersion()
 {
-   PutAtt(NC_GLOBAL, ExodusIILabels::EXODUS_DATABASE_VERSION_LABEL, NC_FLOAT, 1,
+   PutAtt(NC_GLOBAL, ExodusIILabels::EXODUS_DATABASE_VERSION_LABEL,
+          MFEM_NETCDF_REAL_T, 1,
           &ExodusIILabels::EXODUS_DATABASE_VERSION);
 }
 
@@ -607,25 +615,25 @@ void ExodusIIWriter::WriteNodalCoordinates()
    DefineDimension("num_nodes", num_nodes, &num_nodes_id);
 
    // 3. Extract the nodal coordinates.
-   // NB: assume doubles (could be floats!); ndims = 1 (vector).
+   // NB: writes in format real_t (double or float); ndims = 1 (vector).
    // https://docs.unidata.ucar.edu/netcdf-c/current/group__variables.html#gac7e8662c51f3bb07d1fc6d6c6d9052c8
-   std::vector<double> coordx(num_nodes);
-   std::vector<double> coordy(num_nodes);
-   std::vector<double> coordz(mesh.Dimension() == 3 ? num_nodes : 0);
+   std::vector<real_t> coordx(num_nodes);
+   std::vector<real_t> coordy(num_nodes);
+   std::vector<real_t> coordz(mesh.Dimension() == 3 ? num_nodes : 0);
 
    ExtractVertexCoordinates(coordx, coordy, coordz);
 
    // 4. Define and put the nodal coordinates.
-   DefineAndPutVar(ExodusIILabels::EXODUS_COORDX_LABEL, NC_DOUBLE, 1,
+   DefineAndPutVar(ExodusIILabels::EXODUS_COORDX_LABEL, MFEM_NETCDF_REAL_T, 1,
                    &num_nodes_id,
                    coordx.data());
-   DefineAndPutVar(ExodusIILabels::EXODUS_COORDY_LABEL, NC_DOUBLE, 1,
+   DefineAndPutVar(ExodusIILabels::EXODUS_COORDY_LABEL, MFEM_NETCDF_REAL_T, 1,
                    &num_nodes_id,
                    coordy.data());
 
    if (mesh.Dimension() == 3)
    {
-      DefineAndPutVar(ExodusIILabels::EXODUS_COORDZ_LABEL, NC_DOUBLE, 1,
+      DefineAndPutVar(ExodusIILabels::EXODUS_COORDZ_LABEL, MFEM_NETCDF_REAL_T, 1,
                       &num_nodes_id,
                       coordz.data());
    }
@@ -770,9 +778,9 @@ void ExodusIIWriter::WriteNodeConnectivityForBlock(const int block_id)
 }
 
 
-void ExodusIIWriter::ExtractVertexCoordinates(std::vector<double> & coordx,
-                                              std::vector<double> & coordy,
-                                              std::vector<double> & coordz)
+void ExodusIIWriter::ExtractVertexCoordinates(std::vector<real_t> & coordx,
+                                              std::vector<real_t> & coordy,
+                                              std::vector<real_t> & coordz)
 {
    if (mesh.GetNodes()) // Higher-order.
    {
@@ -782,7 +790,7 @@ void ExodusIIWriter::ExtractVertexCoordinates(std::vector<double> & coordx,
       sorted_node_ids.assign(unordered_node_ids.begin(), unordered_node_ids.end());
       std::sort(sorted_node_ids.begin(), sorted_node_ids.end());
 
-      double coordinates[3];
+      real_t coordinates[3];
       for (size_t i = 0; i < sorted_node_ids.size(); i++)
       {
          int node_id = sorted_node_ids[i];
@@ -802,7 +810,7 @@ void ExodusIIWriter::ExtractVertexCoordinates(std::vector<double> & coordx,
    {
       for (int ivertex = 0; ivertex < mesh.GetNV(); ivertex++)
       {
-         double * coordinates = mesh.GetVertex(ivertex);
+         real_t *coordinates = mesh.GetVertex(ivertex);
 
          coordx[ivertex] = coordinates[0];
          coordy[ivertex] = coordinates[1];
@@ -1080,4 +1088,4 @@ void ExodusIIWriter::CheckNodalFESpaceIsSecondOrderH1() const
 
 #endif
 
-}
+}

mesh/mesh.cpp

@@ -2994,6 +2994,7 @@ void Mesh::DoNodeReorder(DSTable *old_v_to_v, Table *old_elem_vert)
    const int num_edge_dofs = old_dofs.Size();
 
    // Save the original nodes
+   Nodes->HostReadWrite(); // for "(*Nodes)() = "
    const Vector onodes = *Nodes;
 
    // vertex dofs do not need to be moved
@@ -13256,7 +13257,7 @@ void Mesh::ScaleElements(real_t sf)
    delete [] vn;
 }
 
-void Mesh::Transform(void (*f)(const Vector&, Vector&))
+void Mesh::Transform(std::function<void(const Vector &, Vector&)> f)
 {
    // TODO: support for different new spaceDim.
    if (Nodes == NULL)
@@ -13269,7 +13270,7 @@ void Mesh::Transform(void (*f)(const Vector&, Vector&))
             vold(j) = vertices[i](j);
          }
          vnew.SetData(vertices[i]());
-         (*f)(vold, vnew);
+         f(vold, vnew);
       }
    }
    else

mesh/mesh.hpp

@@ -588,9 +588,10 @@ protected:
    void Loader(std::istream &input, int generate_edges = 0,
                std::string parse_tag = "");
 
-   /** If NURBS mesh, write NURBS format. If NCMesh, write mfem v1.1 format.
-       If section_delimiter is empty, write mfem v1.0 format. Otherwise, write
-       mfem v1.2 format with the given section_delimiter at the end.
+   /** @brief If NURBS mesh, write NURBS format. If NCMesh, write mfem v1.1
+       format. If section_delimiter is empty, write mfem v1.0 format. Otherwise,
+       write mfem v1.2 format with the given section_delimiter at the end.
+
        If @a comments is non-empty, it will be printed after the first line of
        the file, and each line should begin with '#'. */
    void Printer(std::ostream &os = mfem::out,
@@ -2253,7 +2254,7 @@ public:
    void ScaleSubdomains (real_t sf);
    void ScaleElements (real_t sf);
 
-   void Transform(void (*f)(const Vector&, Vector&));
+   void Transform(std::function<void(const Vector &, Vector&)> f);
    void Transform(VectorCoefficient &deformation);
 
    /** @brief This function should be called after the mesh node coordinates
@@ -2482,10 +2483,12 @@ public:
    /// Print the mesh to the given stream using Netgen/Truegrid format.
    virtual void PrintXG(std::ostream &os = mfem::out) const;
 
-   /// Print the mesh to the given stream using the default MFEM mesh format.
-   /// \see mfem::ofgzstream() for on-the-fly compression of ascii outputs. If
-   /// @a comments is non-empty, it will be printed after the first line of the
-   /// file, and each line should begin with '#'.
+   /** @brief Print the mesh to the given stream using the default MFEM mesh
+       format.
+
+       \see mfem::ofgzstream() for on-the-fly compression of ascii outputs. If
+       @a comments is non-empty, it will be printed after the first line of the
+       file, and each line should begin with '#'. */
    virtual void Print(std::ostream &os = mfem::out,
                       const std::string &comments = "") const
    { Printer(os, "", comments); }
@@ -2537,7 +2540,7 @@ public:
 
 #ifdef MFEM_USE_NETCDF
    /// @brief Export a mesh to an Exodus II file.
-   void PrintExodusII(const std::string fpath);
+   void PrintExodusII(const std::string &fpath);
 #endif
 
    /** @brief Prints the mesh with boundary elements given by the boundary of

mesh/mesh_readers.cpp

@@ -802,21 +802,11 @@ struct BufferReader : BufferReaderBase
       {
          // Each "data block" is preceded by a header that is either UInt32 or
          // UInt64. The rest of the data follows.
-         uint64_t data_size;
-         if (header_type == UINT32_HEADER)
-         {
-            uint32_t *data_size_32 = (uint32_t *)header_buf;
-            data_size = *data_size_32;
-         }
-         else
-         {
-            uint64_t *data_size_64 = (uint64_t *)header_buf;
-            data_size = *data_size_64;
-         }
-         MFEM_VERIFY(sizeof(F)*n == data_size, "AppendedData: wrong data size");
+         MFEM_VERIFY(sizeof(F)*n == ReadHeaderEntry(header_buf),
+                     "AppendedData: wrong data size");
       }
 
-      if (std::is_same<T, F>::value)
+      if (std::is_same_v<T, F>)
       {
          // Special case: no type conversions necessary, so can just memcpy
          memcpy(dest, buf, sizeof(T)*n);

mesh/nurbs.cpp

@@ -9,8 +9,13 @@
 // terms of the BSD-3 license. We welcome feedback and contributions, see file
 // CONTRIBUTING.md for details.
 
-#include "mesh_headers.hpp"
-#include "../fem/fem.hpp"
+#include "nurbs.hpp"
+
+#include "point.hpp"
+#include "segment.hpp"
+#include "quadrilateral.hpp"
+#include "hexahedron.hpp"
+#include "../fem/gridfunc.hpp"
 #include "../general/text.hpp"
 
 #include <fstream>
@@ -33,6 +38,7 @@ KnotVector::KnotVector(istream &input)
 
    knot.Load(input, NumOfControlPoints + Order + 1);
    GetElements();
+   coarse = false;
 }
 
 KnotVector::KnotVector(int order, int NCP)
@@ -41,12 +47,13 @@ KnotVector::KnotVector(int order, int NCP)
    NumOfControlPoints = NCP;
    knot.SetSize(NumOfControlPoints + Order + 1);
    NumOfElements = 0;
+   coarse = false;
 
    knot = -1.;
 }
 
 KnotVector::KnotVector(int order, const Vector& intervals,
-                       const Array<int>& continuity )
+                       const Array<int>& continuity)
 {
    // NOTE: This may need to be generalized to support periodicity
    // in the future.
@@ -86,6 +93,7 @@ KnotVector::KnotVector(int order, const Vector& intervals,
          ++NumOfElements;
       }
    }
+   coarse = false;
 }
 
 KnotVector &KnotVector::operator=(const KnotVector &kv)
@@ -143,7 +151,7 @@ void KnotVector::UniformRefinement(Vector &newknots, int rf) const
       {
          for (int m = 1; m < rf; ++m)
          {
-            newknots(j) = m * h * (knot(i) + knot(i+1));
+            newknots(j) = ((1.0 - (m * h)) * knot(i)) + (m * h * knot(i+1));
             j++;
          }
       }
@@ -332,7 +340,7 @@ void KnotVector::PrintFunctions(std::ostream &os, int samples) const
    }
 }
 
-// Routine from "The NURBS book" - 2nd ed - Piegl and Tiller
+// Routine from "The NURBS Book" - 2nd ed - Piegl and Tiller
 // Algorithm A2.2 p. 70
 void KnotVector::CalcShape(Vector &shape, int i, real_t xi) const
 {
@@ -359,7 +367,7 @@ void KnotVector::CalcShape(Vector &shape, int i, real_t xi) const
    }
 }
 
-// Routine from "The NURBS book" - 2nd ed - Piegl and Tiller
+// Routine from "The NURBS Book" - 2nd ed - Piegl and Tiller
 // Algorithm A2.3 p. 72
 void KnotVector::CalcDShape(Vector &grad, int i, real_t xi) const
 {
@@ -417,7 +425,7 @@ void KnotVector::CalcDShape(Vector &grad, int i, real_t xi) const
    }
 }
 
-// Routine from "The NURBS book" - 2nd ed - Piegl and Tiller
+// Routine from "The NURBS Book" - 2nd ed - Piegl and Tiller
 // Algorithm A2.3 p. 72
 void KnotVector::CalcDnShape(Vector &gradn, int n, int i, real_t xi) const
 {
@@ -537,11 +545,11 @@ void KnotVector::FindMaxima(Array<int> &ks, Vector &xi, Vector &u) const
          int i = j - d;
          if (isElement(i))
          {
-            arg1 = 1e-16;
+            arg1 = std::numeric_limits<real_t>::epsilon() / 2_r;
             CalcShape(shape, i, arg1);
             max1 = shape[d];
 
-            arg2 = 1-(1e-16);
+            arg2 = 1_r - arg1;
             CalcShape(shape, i, arg2);
             max2 = shape[d];
 
@@ -579,9 +587,9 @@ void KnotVector::FindMaxima(Array<int> &ks, Vector &xi, Vector &u) const
    }
 }
 
-// Routine from "The NURBS book" - 2nd ed - Piegl and Tiller
+// Routine from "The NURBS Book" - 2nd ed - Piegl and Tiller
 // Algorithm A9.1 p. 369
-void KnotVector::FindInterpolant(Array<Vector*> &x)
+void KnotVector::FindInterpolant(Array<Vector*> &x, bool reuse_inverse)
 {
    int order = GetOrder();
    int ncp = GetNCP();
@@ -589,29 +597,93 @@ void KnotVector::FindInterpolant(Array<Vector*> &x)
    // Find interpolation points
    Vector xi_args, u_args;
    Array<int> i_args;
-   FindMaxima(i_args,xi_args, u_args);
+   FindMaxima(i_args, xi_args, u_args);
 
    // Assemble collocation matrix
-   Vector shape(order+1);
-   DenseMatrix A(ncp,ncp);
-   A = 0.0;
+#ifdef MFEM_USE_LAPACK
+   // If using LAPACK, we use banded matrix storage (order + 1 nonzeros per row).
+   // Find banded structure of matrix.
+   int KL = 0; // Number of subdiagonals
+   int KU = 0; // Number of superdiagonals
    for (int i = 0; i < ncp; i++)
    {
-      CalcShape(shape, i_args[i], xi_args[i]);
       for (int p = 0; p < order+1; p++)
       {
-         A(i,i_args[i] + p) =  shape[p];
+         const int col = i_args[i] + p;
+         if (col < i)
+         {
+            KL = std::max(KL, i - col);
+         }
+         else if (i < col)
+         {
+            KU = std::max(KU, col - i);
+         }
       }
    }
 
-   // Solve problems
-   A.Invert();
+   const int LDAB = (2*KL) + KU + 1;
+   const int N = ncp;
+
+   fact_AB.SetSize(LDAB, N);
+#else
+   // Without LAPACK, we store and invert a DenseMatrix (inefficient).
+   if (!reuse_inverse)
+   {
+      A_coll_inv.SetSize(ncp, ncp);
+      A_coll_inv = 0.0;
+   }
+#endif
+
+   Vector shape(order+1);
+
+   if (!reuse_inverse) // Set collocation matrix entries
+   {
+      for (int i = 0; i < ncp; i++)
+      {
+         CalcShape(shape, i_args[i], xi_args[i]);
+         for (int p = 0; p < order+1; p++)
+         {
+            const int j = i_args[i] + p;
+#ifdef MFEM_USE_LAPACK
+            fact_AB(KL+KU+i-j,j) = shape[p];
+#else
+            A_coll_inv(i,j) = shape[p];
+#endif
+         }
+      }
+   }
+
+   // Solve the system
+#ifdef MFEM_USE_LAPACK
+   const int NRHS = x.Size();
+   DenseMatrix B(N, NRHS);
+   for (int j=0; j<NRHS; ++j)
+   {
+      for (int i=0; i<N; ++i) { B(i, j) = (*x[j])[i]; }
+   }
+
+   if (reuse_inverse)
+   {
+      BandedFactorizedSolve(KL, KU, fact_AB, B, false, fact_ipiv);
+   }
+   else
+   {
+      BandedSolve(KL, KU, fact_AB, B, fact_ipiv);
+   }
+
+   for (int j=0; j<NRHS; ++j)
+   {
+      for (int i=0; i<N; ++i) { (*x[j])[i] = B(i, j); }
+   }
+#else
+   if (!reuse_inverse) { A_coll_inv.Invert(); }
    Vector tmp;
-   for (int i= 0; i < x.Size(); i++)
+   for (int i = 0; i < x.Size(); i++)
    {
       tmp = *x[i];
-      A.Mult(tmp,*x[i]);
+      A_coll_inv.Mult(tmp, *x[i]);
    }
+#endif
 }
 
 int KnotVector::findKnotSpan(real_t u) const
@@ -1413,7 +1485,7 @@ void NURBSPatch::DegreeElevate(int t)
    }
 }
 
-// Routine from "The NURBS book" - 2nd ed - Piegl and Tiller
+// Routine from "The NURBS Book" - 2nd ed - Piegl and Tiller
 void NURBSPatch::DegreeElevate(int dir, int t)
 {
    if (dir >= kv.Size() || dir < 0)
@@ -1431,8 +1503,8 @@ void NURBSPatch::DegreeElevate(int dir, int t)
    KnotVector &oldkv = *kv[dir];
    oldkv.GetElements();
 
-   NURBSPatch *newpatch = new NURBSPatch(this, dir, oldkv.GetOrder() + t,
-                                         oldkv.GetNCP() + oldkv.GetNE()*t);
+   auto *newpatch = new NURBSPatch(this, dir, oldkv.GetOrder() + t,
+                                   oldkv.GetNCP() + oldkv.GetNE()*t);
    NURBSPatch &newp  = *newpatch;
    KnotVector &newkv = *newp.GetKV(dir);
 
@@ -2377,7 +2449,7 @@ NURBSExtension::NURBSExtension(Mesh *mesh_array[], int num_pieces)
 }
 
 NURBSExtension::NURBSExtension(const Mesh *patch_topology,
-                               const Array<const NURBSPatch*> patches_)
+                               const Array<const NURBSPatch*> &patches_)
 {
    // Basic topology checks
    MFEM_VERIFY(patches_.Size() > 0, "Must have at least one patch");
@@ -4587,7 +4659,7 @@ void NURBSExtension::KnotInsert(Array<Vector *> &kv)
 
             // Flip vector
             int size = pkvc[d]->Size();
-            int ns = ceil(size/2.0);
+            int ns = static_cast<int>(ceil(size/2.0));
             for (int j = 0; j < ns; j++)
             {
                real_t tmp = apb - pkvc[d]->Elem(j);
@@ -4647,7 +4719,7 @@ void NURBSExtension::KnotRemove(Array<Vector *> &kv, real_t tol)
 
             // Flip vector
             int size = pkvc[d]->Size();
-            int ns = ceil(size/2.0);
+            int ns = static_cast<int>(ceil(size/2.0));
             for (int j = 0; j < ns; j++)
             {
                real_t tmp = apb - pkvc[d]->Elem(j);

mesh/nurbs.hpp

@@ -22,7 +22,6 @@
 #include "../general/communication.hpp"
 #endif
 #include <iostream>
-#include <set>
 
 namespace mfem
 {
@@ -55,7 +54,7 @@ protected:
 
 public:
    /// Create an empty KnotVector.
-   KnotVector() { }
+   KnotVector() = default;
 
    /** @brief Create a KnotVector by reading data from stream @a input. Two
        integers are read, for order and number of control points. */
@@ -74,7 +73,7 @@ public:
        polynomial degree). Periodicity is not supported.
    */
    KnotVector(int order, const Vector& intervals,
-              const Array<int>& continuity );
+              const Array<int>& continuity);
 
    /// Copy constructor.
    KnotVector(const KnotVector &kv) { (*this) = kv; }
@@ -144,8 +143,13 @@ public:
    /** @brief Global curve interpolation through the points @a x (overwritten).
        @a x is an array with the length of the spatial dimension containing
        vectors with spatial coordinates. The control points of the interpolated
-       curve are returned in @a x in the same form. */
-   void FindInterpolant(Array<Vector*> &x);
+       curve are returned in @a x in the same form.
+
+       The inverse of the collocation matrix, used in the interpolation, is
+       stored for repeated calls and used if @a reuse_inverse is true. Reuse is
+       valid only if this KnotVector has not changed since the initial call with
+       @a reuse_inverse false. */
+   void FindInterpolant(Array<Vector*> &x, bool reuse_inverse = false);
 
    /** Set @a diff, comprised of knots in @a kv not contained in this KnotVector.
        @a kv must be of the same order as this KnotVector. The current
@@ -203,6 +207,14 @@ public:
    /** Flag to indicate whether the KnotVector has been coarsened, which means
        it is ready for non-nested refinement. */
    bool coarse;
+
+#ifdef MFEM_USE_LAPACK
+   // Data for reusing banded matrix factorization in FindInterpolant().
+   DenseMatrix fact_AB; /// Banded matrix factorization
+   Array<int> fact_ipiv; /// Row pivot indices
+#else
+   DenseMatrix A_coll_inv; /// Collocation matrix inverse
+#endif
 };
 
 
@@ -286,7 +298,7 @@ public:
        includes the weight. The array of control point coordinates stores each
        point's coordinates contiguously, and points are ordered in a standard
        ijk grid ordering. */
-   NURBSPatch(Array<const KnotVector *> &kv_,  int dim_,
+   NURBSPatch(Array<const KnotVector *> &kv_, int dim_,
               const real_t* control_points);
 
    /// Constructor for a patch of dimension equal to the size of @a kv.
@@ -701,7 +713,8 @@ public:
 
    NURBSExtension(Mesh *mesh_array[], int num_pieces);
 
-   NURBSExtension(const Mesh *patch_topology, const Array<const NURBSPatch*> p);
+   NURBSExtension(const Mesh *patch_topology,
+                  const Array<const NURBSPatch*> &patches_);
 
    /// Copy assignment not supported.
    NURBSExtension& operator=(const NURBSExtension&) = delete;

mesh/pmesh.cpp

@@ -3132,11 +3132,12 @@ void ParMesh::GetFaceNbrElementTransformation(
          pNodes->ParFESpace()->GetFaceNbrElementVDofs(FaceNo, vdofs);
          int n = vdofs.Size()/spaceDim;
          pointmat.SetSize(spaceDim, n);
+         pNodes->FaceNbrData().HostRead();
          for (int k = 0; k < spaceDim; k++)
          {
             for (int j = 0; j < n; j++)
             {
-               pointmat(k,j) = (pNodes->FaceNbrData())(vdofs[n*k+j]);
+               pointmat(k,j) = AsConst(pNodes->FaceNbrData())(vdofs[n*k+j]);
             }
          }
 

mesh/submesh/submesh_utils.cpp

@@ -257,15 +257,7 @@ template <typename SubMeshT>
 void AddBoundaryElements(SubMeshT &mesh,
                          const std::unordered_map<int,int> &lface_to_boundary_attribute)
 {
-   mesh.Dimension();
-   const int num_codim_1 = [&mesh]()
-   {
-      auto Dim = mesh.Dimension();
-      if (Dim == 1) { return mesh.GetNV(); }
-      else if (Dim == 2) { return mesh.GetNEdges(); }
-      else if (Dim == 3) { return mesh.GetNFaces(); }
-      else { MFEM_ABORT("Invalid dimension."); return -1; }
-   }();
+   const int num_codim_1 = mesh.GetNumFaces();
 
    if (mesh.Dimension() == 3)
    {

mesh/vtkhdf.cpp

@@ -84,7 +84,7 @@ void VTKHDF::EnsureSteps()
 }
 
 hid_t VTKHDF::EnsureDataset(hid_t f, const std::string &name, hid_t type,
-                            int ndims)
+                            Dims &dims)
 {
    const char *name_c = name.c_str();
 
@@ -94,20 +94,23 @@ hid_t VTKHDF::EnsureDataset(hid_t f, const std::string &name, hid_t type,
    if (status == 0)
    {
       // Dataset does not exist, create it.
-      Dims dims(ndims);
-      Dims maxdims(ndims, H5S_UNLIMITED);
-      const hid_t fspace = H5Screate_simple(ndims, dims, maxdims);
+      const int ndims = dims.ndims;
+      // The dataset is allowed to grow in the first dimension, but is fixed
+      // in size in all other dimesions; the maximum dataset size is same as
+      // dims, but unlimited in first dimension.
+      Dims max_dims = dims;
+      max_dims[0] = H5S_UNLIMITED;
+      const hid_t fspace = H5Screate_simple(ndims, dims, max_dims);
 
       Dims chunk(ndims);
       size_t chunk_size_bytes = 1024 * 1024 / 2; // 0.5 MB
       const size_t t_bytes = H5Tget_size(type);
       for (int i = 1; i < ndims; ++i)
       {
-         chunk[i] = 16;
-         chunk_size_bytes /= 16;
+         chunk[i] = dims[i];
+         chunk_size_bytes /= dims[i];
       }
       chunk[0] = chunk_size_bytes / t_bytes;
-      for (int i = 1; i < ndims; ++i) { chunk[i] = 16; }
       const hid_t dcpl = H5Pcreate(H5P_DATASET_CREATE);
       H5Pset_chunk(dcpl, ndims, chunk);
       if (compression_level >= 0)
@@ -124,7 +127,19 @@ hid_t VTKHDF::EnsureDataset(hid_t f, const std::string &name, hid_t type,
    else if (status > 0)
    {
       // Dataset exists, open it.
-      return H5Dopen2(f, name_c, H5P_DEFAULT);
+      const hid_t d = H5Dopen2(f, name_c, H5P_DEFAULT);
+
+      // Resize the dataset, set dims to its new size.
+      Dims old_dims(dims.ndims);
+      const hid_t dspace = H5Dget_space(d);
+      const int ndims_dset = H5Sget_simple_extent_ndims(dspace);
+      MFEM_VERIFY(ndims_dset == dims.ndims, "");
+      H5Sget_simple_extent_dims(dspace, old_dims, NULL);
+      H5Sclose(dspace);
+      dims[0] += old_dims[0];
+      H5Dset_extent(d, dims);
+
+      return d;
    }
    else
    {
@@ -160,27 +175,13 @@ void VTKHDF::AppendParData(hid_t f, const std::string &name, hsize_t locsize,
                            hsize_t offset, Dims globsize, T *data)
 {
    const int ndims = globsize.ndims;
-   const hid_t d = EnsureDataset(f, name, GetTypeID<T>(), ndims);
-
-   // Resize the dataset, set dims to its new size.
-   hsize_t old_size;
-   Dims dims(ndims);
-   {
-      const hid_t dspace = H5Dget_space(d);
-      const int ndims_dset = H5Sget_simple_extent_ndims(dspace);
-      MFEM_VERIFY(ndims_dset == ndims, "");
-      H5Sget_simple_extent_dims(dspace, dims, NULL);
-      H5Sclose(dspace);
-      old_size = dims[0];
-      dims[0] += globsize[0];
-      for (int i = 1; i < ndims; ++i) { dims[i] = globsize[i]; }
-      H5Dset_extent(d, dims);
-   }
+   Dims dims = globsize;
+   const hid_t d = EnsureDataset(f, name, GetTypeID<T>(), dims);
 
    // Write the new entry.
    const hid_t dspace = H5Dget_space(d);
    Dims start(ndims);
-   start[0] = old_size + offset;
+   start[0] = dims[0] - globsize[0] + offset;
    Dims count(ndims);
    count[0] = locsize;
    for (int i = 1; i < ndims; ++i) { count[i] = globsize[i]; }
@@ -334,14 +335,14 @@ void VTKHDF::Truncate(const real_t t)
    }
 
    // Index of found time index (may be 'one-past-the-end' if not found)
-   const int i = std::distance(tvals.begin(), it);
+   const ptrdiff_t i = std::distance(tvals.begin(), it);
 
    // Only truncate if needed
    const bool truncate = it != tvals.end();
 
    // Number of steps we are keeping
    nsteps = i;
-   H5LTset_attribute_int(vtk, "Steps", "NSteps", &nsteps, 1);
+   H5LTset_attribute_ulong(vtk, "Steps", "NSteps", &nsteps, 1);
 
    // We want to continue writing immediately after step 'i - 1'. If i = 0,
    // then this is at the beginning of the file, and the offsets do not need
@@ -509,7 +510,7 @@ void VTKHDF::UpdateSteps(real_t t)
 
    // Set the NSteps attribute
    ++nsteps;
-   H5LTset_attribute_int(steps, ".", "NSteps", &nsteps, 1);
+   H5LTset_attribute_ulong(steps, ".", "NSteps", &nsteps, 1);
 
    AppendValue(steps, "Values", t);
    AppendValue(steps, "PartOffsets", part_offset);
@@ -618,16 +619,16 @@ void VTKHDF::SaveMesh(const Mesh &mesh, bool high_order, int ref)
 
          for (int i = 0; i < pmat.Width(); i++)
          {
-            points.push_back(pmat(0,i));
-            if (pmat.Height() > 1) { points.push_back(pmat(1,i)); }
+            points.push_back(FP_T(pmat(0,i)));
+            if (pmat.Height() > 1) { points.push_back(FP_T(pmat(1,i))); }
             else { points.push_back(0.0); }
-            if (pmat.Height() > 2) { points.push_back(pmat(2,i)); }
+            if (pmat.Height() > 2) { points.push_back(FP_T(pmat(2,i))); }
             else { points.push_back(0.0); }
          }
       }
    }
 
-   const hsize_t ne_0 = mesh.GetNE();
+   const int ne_0 = mesh.GetNE();
    const hsize_t ne = high_order ? ne_0 : ne_ref;
 
    AppendParData(vtk, "NumberOfPoints", 1, mpi_rank, mpi_dims, &np);
@@ -657,7 +658,7 @@ void VTKHDF::SaveMesh(const Mesh &mesh, bool high_order, int ref)
          if (high_order)
          {
             Array<int> local_connectivity;
-            for (size_t e = 0; e < ne; ++e)
+            for (int e = 0; e < int(ne); ++e)
             {
                offsets[e] = off;
                const Geometry::Type geom = mesh.GetElementGeometry(e);
@@ -675,7 +676,7 @@ void VTKHDF::SaveMesh(const Mesh &mesh, bool high_order, int ref)
          {
             int off_0 = 0;
             int e_ref = 0;
-            for (hsize_t e = 0; e < ne_0; ++e)
+            for (int e = 0; e < ne_0; ++e)
             {
                const Geometry::Type geom = mesh.GetElementGeometry(e);
                const int nv = get_nv(e);
@@ -714,12 +715,13 @@ void VTKHDF::SaveMesh(const Mesh &mesh, bool high_order, int ref)
          const int *vtk_geom_map =
             high_order ? VTKGeometry::HighOrderMap : VTKGeometry::Map;
          int e_ref = 0;
-         for (hsize_t e = 0; e < ne_0; ++e)
+         for (int e = 0; e < ne_0; ++e)
          {
-            const int ne_ref = get_ne_ref(e, ref_0);
-            for (int i = 0; i < ne_ref; ++i, ++e_ref)
+            const int ne_ref_e = get_ne_ref(e, ref_0);
+            for (int i = 0; i < ne_ref_e; ++i, ++e_ref)
             {
-               cell_types[e_ref] = vtk_geom_map[mesh.GetElementGeometry(e)];
+               cell_types[e_ref] = static_cast<unsigned char>(
+                                      vtk_geom_map[mesh.GetElementGeometry(e)]);
             }
          }
          AppendParData(vtk, "Types", ne, e_offset, Dims({ne_total}),
@@ -732,11 +734,11 @@ void VTKHDF::SaveMesh(const Mesh &mesh, bool high_order, int ref)
          EnsureGroup("CellData", cell_data);
          std::vector<int> attributes(ne);
          hsize_t e_ref = 0;
-         for (hsize_t e = 0; e < ne_0; ++e)
+         for (int e = 0; e < ne_0; ++e)
          {
             const int attr = mesh.GetAttribute(e);
-            const int ne_ref = get_ne_ref(e, ref_0);
-            for (int i = 0; i < ne_ref; ++i, ++e_ref)
+            const int ne_ref_e = get_ne_ref(e, ref_0);
+            for (int i = 0; i < ne_ref_e; ++i, ++e_ref)
             {
                attributes[e_ref] = attr;
             }
@@ -772,7 +774,7 @@ void VTKHDF::SaveGridFunction(const GridFunction &gf, const std::string &name)
       {
          for (int vd = 0; vd < vdim; ++vd)
          {
-            point_values[off] = vec_val(vd, i);
+            point_values[off] = FP_T(vec_val(vd, i));
             ++off;
          }
       }

mesh/vtkhdf.hpp

@@ -76,14 +76,14 @@ private:
    /// Wrapper for storing dataset dimensions (max ndims is 2D in VTKHDF).
    struct Dims
    {
-      static constexpr int MAX_NDIMS = 2;
+      static constexpr size_t MAX_NDIMS = 2;
       std::array<hsize_t, MAX_NDIMS> data = { }; // Zero initialized
       int ndims = 0;
       Dims() = default;
       Dims(int ndims_) : ndims(ndims_) { MFEM_ASSERT(ndims <= MAX_NDIMS, ""); }
       Dims(int ndims_, hsize_t val) : Dims(ndims_) { data.fill(val); }
       template <typename T>
-      Dims(std::initializer_list<T> data_) : Dims(data_.size())
+      Dims(std::initializer_list<T> data_) : Dims(int(data_.size()))
       { std::copy(data_.begin(), data_.end(), data.begin()); }
       operator hsize_t*() { return data.data(); }
       hsize_t &operator[](int i) { return data[i]; }
@@ -97,7 +97,7 @@ private:
    hid_t steps = H5I_INVALID_HID;
 
    /// Number of time steps saved.
-   int nsteps = 0;
+   unsigned long nsteps = 0;
 
    /// Keep track of the offsets into the data arrays at each time step.
    struct Offsets
@@ -123,8 +123,8 @@ private:
    class MeshId
    {
       const Mesh *mesh_ptr = nullptr;
-      int sequence = -1;
-      int nodes_sequence = -1;
+      long sequence = -1;
+      long nodes_sequence = -1;
       bool high_order = true;
       int ref = -1;
    public:
@@ -187,8 +187,10 @@ private:
    /// The rank (number of dimensions) of the dataset is given by @a ndims and
    /// its data type is given by @a type.
    ///
-   /// The dataset will initially have zero size and unlimited maximum size.
-   hid_t EnsureDataset(hid_t f, const std::string &name, hid_t type, int ndims);
+   /// If the dataset does not exist, it will initially have size @a dims.
+   /// Otherwise, it will be resized to append data of size @a dims, and @a dims
+   /// will be set to the new total size.
+   hid_t EnsureDataset(hid_t f, const std::string &name, hid_t type, Dims &dims);
 
    /// @brief Ensure the named group is open, creating it if needed. Set @a
    /// group to the ID.

miniapps/meshing/fit-node-position.cpp

@@ -224,5 +224,6 @@ int main (int argc, char *argv[])
    }
 
    delete metric;
+   delete fec_mesh;
    return 0;
 }

miniapps/nurbs/CMakeLists.txt

@@ -80,6 +80,10 @@ add_mfem_miniapp(nurbs_solenoidal
   LIBRARIES mfem)
   add_dependencies(nurbs_solenoidal copy_miniapps_nurbs_data)
 
+add_mfem_miniapp(nurbs_surface
+  MAIN nurbs_surface.cpp
+  LIBRARIES mfem)
+
 if (MFEM_ENABLE_TESTING)
   add_test(NAME nurbs_ex1_1d_r1_o2_ser
     COMMAND $<TARGET_FILE:nurbs_ex1> -no-vis
@@ -247,6 +251,14 @@ if (MFEM_ENABLE_TESTING)
     COMMAND $<TARGET_FILE:nurbs_solenoidal> -no-vis
         -m ${PROJECT_SOURCE_DIR}/data/cube-nurbs.mesh -r 1 -o 2)
 
+  add_test(NAME nurbs_surface_10_10_10_10_ex1_o3_ser
+    COMMAND $<TARGET_FILE:nurbs_surface> -no-vis
+        -o 3 -nx 10 -ny 10 -fnx 10 -fny 10 -ex 1 -orig)
+
+  add_test(NAME nurbs_surface_10_10_40_40_ex1_o3_ser
+    COMMAND $<TARGET_FILE:nurbs_surface> -no-vis
+        -o 3 -nx 10 -ny 10 -fnx 40 -fny 14 -ex 1)
+
 endif()
 
 if (MFEM_USE_MPI)

miniapps/nurbs/makefile

@@ -21,7 +21,7 @@ MFEM_LIB_FILE = mfem_is_not_built
 -include $(CONFIG_MK)
 
 SEQ_MINIAPPS = nurbs_ex1 nurbs_patch_ex1 nurbs_ex3 nurbs_ex5 nurbs_ex24 \
-   nurbs_curveint nurbs_printfunc nurbs_solenoidal nurbs_naca_cmesh
+   nurbs_curveint nurbs_printfunc nurbs_solenoidal nurbs_naca_cmesh nurbs_surface
 PAR_MINIAPPS = nurbs_ex1p nurbs_ex11p
 ifeq ($(MFEM_USE_MPI),NO)
    MINIAPPS = $(SEQ_MINIAPPS)
@@ -158,6 +158,13 @@ nurbs_naca_cmesh-test-seq: nurbs_naca_cmesh
 nurbs_printfunc-test-seq: nurbs_printfunc
 	@$(call mfem-test,$<,, NURBS miniapp)
 
+SURF_ARGS_1 := -o 3 -nx 10 -ny 10 -fnx 10 -fny 10 -ex 1 -orig
+SURF_ARGS_2 := -o 3 -nx 10 -ny 10 -fnx 40 -fny 40 -ex 1
+
+nurbs_surface-test-seq: nurbs_surface
+	@$(call mfem-test,$<,, NURBS miniapp,$(SURF_ARGS_1))
+	@$(call mfem-test,$<,, NURBS miniapp,$(SURF_ARGS_2))
+
 EX1P_ARGS_1 :=
 EX1P_ARGS_2 := -m ../../data/pipe-nurbs-2d.mesh -o 2 -no-ibp
 EX1P_ARGS_3 := -m ../../data/ball-nurbs.mesh -o 2 --weak-bc -r 0
@@ -192,6 +199,6 @@ clean-build:
 
 clean-exec:
 	@rm -f refined.mesh sin-fit.mesh ex5.mesh exsol.mesh mesh.* sol.* mode_*
-	@rm -f naca-cmesh.mesh sol_?.gf
+	@rm -f naca-cmesh.mesh sol_?.gf *-Surface.mesh
 	@rm -rf Example1* Example3* Example5* Solenoidal_* ParaView
 	@rm -rf CurveInt Naca_cmesh glvis_naca-cmesh.mesh solution.dat

miniapps/nurbs/nurbs_surface.cpp

@@ -0,0 +1,655 @@
+// 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.
+//
+//          --------------------------------------------------------
+//          NURBS Surface: Interpolate a 3D Surface in a NURBS Patch
+//          --------------------------------------------------------
+//
+// Compile with: make nurbs_surface
+//
+// Sample runs:  nurbs_surface -o 3 -nx 10 -ny 10 -fnx 10 -fny 10 -ex 1 -orig
+//               nurbs_surface -o 3 -nx 10 -ny 10 -fnx 40 -fny 40 -ex 1
+//               nurbs_surface -o 3 -nx 20 -ny 20 -fnx 10 -fny 10 -ex 1
+//               nurbs_surface -o 3 -nx 20 -ny 20 -fnx 40 -fny 40 -ex 1 -j 0.5
+//               nurbs_surface -o 3 -nx 10 -ny 10 -fnx 10 -fny 10 -ex 2 -orig
+//               nurbs_surface -o 3 -nx 10 -ny 10 -fnx 40 -fny 40 -ex 2
+//               nurbs_surface -o 3 -nx 20 -ny 20 -fnx 10 -fny 10 -ex 2
+//               nurbs_surface -o 3 -nx 10 -ny 10 -fnx 10 -fny 10 -ex 3 -orig
+//               nurbs_surface -o 3 -nx 10 -ny 10 -fnx 40 -fny 40 -ex 3
+//               nurbs_surface -o 3 -nx 20 -ny 20 -fnx 10 -fny 10 -ex 3
+//               nurbs_surface -o 3 -nx 20 -ny 10 -fnx 20 -fny 10 -ex 4 -orig
+//             * nurbs_surface -o 3 -nx 20 -ny 10 -fnx 80 -fny 40 -ex 4
+//             * nurbs_surface -o 3 -nx 40 -ny 20 -fnx 20 -fny 10 -ex 4
+//             * nurbs_surface -o 3 -nx 100 -ny 100 -fnx 100 -fny 100 -ex 5 -orig
+//             * nurbs_surface -o 3 -nx 100 -ny 100 -fnx 400 -fny 400 -ex 5
+//             * nurbs_surface -o 3 -nx 200 -ny 200 -fnx 100 -fny 100 -ex 5
+//
+// Description:  This example demonstrates the use of MFEM to interpolate an
+//               input surface point grid in 3D using a NURBS surface. The NURBS
+//               surface can then be sampled to generate an output mesh of
+//               arbitrary resolution while staying close to the input geometry.
+
+#include "mfem.hpp"
+#include <fstream>
+#include <iostream>
+
+using namespace std;
+using namespace mfem;
+
+// Example data for 3D point grid on surface, given by an analytic function.
+void SurfaceGridExample(int example, int nx, int ny, Array3D<real_t> &vertices,
+                        real_t jitter);
+
+// Write a linear surface mesh with given vertex positions in v.
+void WriteLinearMesh(int nx, int ny, const Array3D<real_t> &v,
+                     const std::string &basename, bool visualization = false,
+                     int x = 0, int y = 0, int w = 500, int h = 500);
+
+// Given an input grid of 3D points on a surface, this class computes a NURBS
+// surface of given order that interpolates the vertices of the input grid.
+class SurfaceInterpolator
+{
+public:
+   /// Constructor for a given 2D point grid size and NURBS order.
+   SurfaceInterpolator(int num_elem_x, int num_elem_y, int order);
+
+   /// Create a surface interpolating the 2D grid of 3D points in @a input3D.
+   void CreateSurface(const Array3D<real_t> &input3D);
+
+   /// Sample the surface with the given grid size, storing points in
+   /// @a output3D.
+   void SampleSurface(int num_elem_x, int num_elem_y, bool compareOriginal,
+                      Array3D<real_t> &output3D);
+
+   /** @brief Write the NURBS surface mesh to file, defined coordinate-wise by
+       the entries of @a cmesh. */
+   void WriteNURBSMesh(const std::string &basename, bool visualization = false,
+                       int x = 0, int y = 0, int w = 500, int h = 500);
+
+protected:
+   /** @brief Compute the NURBS mesh interpolating the given coordinate of the
+       grid of 3D points in @a input3D. */
+   void ComputeNURBS(int coordinate, const Array3D<real_t> &input3D);
+
+private:
+   int nx, ny; // Number of elements in two directions of the surface grid
+   int orderNURBS; // NURBS degree
+   real_t hx, hy, hz; // Grid size in reference space
+
+   Array3D<real_t> initial3D; // Initial grid of points
+
+   static constexpr int dim = 3;
+   Array<int> ncp; // Number of control points in each direction
+   Array<int> nks; // Number of knot-spans in each direction
+
+   std::vector<Vector> ugrid; // Parameter space [0,1]^2 grid point coordinates
+
+   std::vector<KnotVector> kv; // KnotVectors in each direction
+
+   std::unique_ptr<NURBSPatch> patch; // Pointer to the only patch in the mesh
+
+   Mesh mesh; // NURBS mesh representing the surface
+   std::vector<Mesh> cmesh; // NURBS meshes representing point components
+};
+
+
+int main(int argc, char *argv[])
+{
+   // Parse command-line options
+   int nx = 4;
+   int ny = 4;
+   int fnx = 40;
+   int fny = 40;
+   int order = 3;
+   int example = 1;
+   bool visualization = true;
+   bool compareOriginal = false;
+   real_t jitter = 0.0;
+
+   OptionsParser args(argc, argv);
+   args.AddOption(&example, "-ex", "--example",
+                  "Example data");
+   args.AddOption(&nx, "-nx", "--nx",
+                  "Number of elements in x");
+   args.AddOption(&ny, "-ny", "--ny",
+                  "Number of elements in y");
+   args.AddOption(&fnx, "-fnx", "--fnx",
+                  "Number of resampled elements in x");
+   args.AddOption(&fny, "-fny", "--fny",
+                  "Number of resampled elements in y");
+   args.AddOption(&order, "-o", "--order",
+                  "NURBS finite element order (polynomial degree)");
+   args.AddOption(&visualization, "-vis", "--visualization", "-no-vis",
+                  "--no-visualization",
+                  "Enable or disable GLVis visualization.");
+   args.AddOption(&compareOriginal, "-orig", "--compare-original", "-no-orig",
+                  "--no-compare-original",
+                  "Compare to the original mesh?");
+   args.AddOption(&jitter, "-j", "--jitter",
+                  "Relative jittering in (0,1) to add to the input point "
+                  "coordinates on a uniform nx x ny grid (0 by default)");
+   args.Parse();
+   if (!args.Good())
+   {
+      args.PrintUsage(cout);
+      return 1;
+   }
+   args.PrintOptions(cout);
+
+   if (compareOriginal && (fnx != nx || fny != ny))
+   {
+      cout << "Comparing to the original mesh requires the same number of "
+           << "samples!\n";
+      return 1;
+   }
+
+   // Dimensions of the 3 surfaces (Input, NURBS, Output)
+   cout << "Input Surface:  " << nx << " x " << ny << " linear elements\n";
+   cout << "NURBS Surface:  " << nx + 1 - order << " x " << ny + 1 - order
+        << " knot elements of order " << order << "\n";
+   cout << "Output Surface: " << fnx << " x " << fny << " linear elements\n";
+
+   // Set the vertex coordinates of the initial linear mesh
+   constexpr int dim = 3;
+   Array3D<real_t> input3D(nx + 1, ny + 1, dim);
+   SurfaceGridExample(example, nx, ny, input3D, jitter);
+
+   // Create a NURBS surface for the given nx, ny and order parameters that
+   // interpolates the input vertex coordinates
+   SurfaceInterpolator surf(nx, ny, order);
+   surf.CreateSurface(input3D);
+
+   // Compute the vertex coordinates of the output linear mesh by sampling the
+   // values from the NURBS surface
+   Array3D<real_t> output3D(fnx + 1, fny + 1, dim);
+   surf.SampleSurface(fnx, fny, compareOriginal, output3D);
+
+   // Save and optionally visualize the 3 surfaces (Input, NURBS, Output)
+   WriteLinearMesh(nx, ny, input3D, "Input-Surface", visualization, 0, 0);
+   surf.WriteNURBSMesh("NURBS-Surface", visualization, 502, 0);
+   WriteLinearMesh(fnx, fny, output3D, "Output-Surface", visualization, 1004, 0);
+
+   return 0;
+}
+
+// f(x,y) = sin(2 * pi * x) * sin(2 * pi * y)
+void Function1(real_t u, real_t v, real_t &x, real_t &y, real_t &z)
+{
+   x = u;
+   y = v;
+   z = sin(2.0 * M_PI * u) * sin(2.0 * M_PI * v);
+}
+
+// Part of the parametric surface of a sphere, using spherical coordinates.
+void Function2(real_t u, real_t v, real_t &x, real_t &y, real_t &z)
+{
+   constexpr real_t r = 1.0;
+   constexpr real_t pi_4 = M_PI * 0.25;
+   constexpr real_t phi0 = -3*pi_4;
+   constexpr real_t phi1 = 3*pi_4;
+   constexpr real_t theta0 = pi_4;
+   constexpr real_t theta1 = 3 * pi_4;
+
+   const real_t phi = (phi0 * (1.0 - v)) + (phi1 * v);
+   const real_t theta = (theta0 * (1.0 - u)) + (theta1 * u);
+   x = r * sin(theta) * cos(phi);
+   y = r * sin(theta) * sin(phi);
+   z = r * cos(theta);
+}
+
+// Helicoid surface
+void Function3(real_t u, real_t v, real_t &x, real_t &y, real_t &z)
+{
+   x = u * cos(2.0 * M_PI * v);
+   y = u * sin(2.0 * M_PI * v);
+   z = v;
+}
+
+// Mobius strip
+void Function4(real_t u, real_t v, real_t &x, real_t &y, real_t &z)
+{
+   constexpr int twists = 1;
+   const real_t a = 1.0 + 0.5 * ((2.0 * v) - 1.0) * cos(2.0 * M_PI * twists * u);
+   x = a * cos(2.0 * M_PI * u);
+   y = a * sin(2.0 * M_PI * u);
+   z = 0.5 * (2.0 * v - 1.0) * sin(2.0 * M_PI * twists * u);
+}
+
+// Breather surface
+void Function5(real_t u, real_t v, real_t &x, real_t &y, real_t &z)
+{
+   const real_t m = 13.2 * ((2.0 * u) - 1.0);
+   const real_t n = 37.4 * ((2.0 * v) - 1.0);
+   constexpr real_t b = 0.4;
+   constexpr real_t r = 1.0 - (b*b);
+   const real_t w = sqrt(r);
+   const real_t denom = b * (pow(w*cosh(b*m),2) + pow(b*sin(w*n),2));
+   x = -m + (2*r*cosh(b*m)*sinh(b*m)) / denom;
+   y = (2*w*cosh(b*m)*(-(w*cos(n)*cos(w*n)) - sin(n)*sin(w*n))) / denom;
+   z = (2*w*cosh(b*m)*(-(w*sin(n)*cos(w*n)) + cos(n)*sin(w*n))) / denom;
+}
+
+void SurfaceFunction(int example, real_t u, real_t v,
+                     real_t &x, real_t &y, real_t &z)
+{
+   switch (example)
+   {
+      case 1:
+         Function1(u, v, x, y, z);
+         break;
+      case 2:
+         Function2(u, v, x, y, z);
+         break;
+      case 3:
+         Function3(u, v, x, y, z);
+         break;
+      case 4:
+         Function4(u, v, x, y, z);
+         break;
+      default:
+         Function5(u, v, x, y, z);
+   };
+}
+
+// Example data for 3D point grid on surface, given by an analytic function.
+void SurfaceExample(int example, const std::vector<Vector> &grid,
+                    Array3D<real_t> &v3D, real_t jitter)
+{
+   int seed = (int)time(0);
+   srand((unsigned)seed);
+
+   real_t h0 = grid[0][1]-grid[0][0], h1 = grid[1][1]-grid[1][0];
+   for (int i = 0; i < grid[0].Size(); i++)
+   {
+      for (int j = 0; j < grid[1].Size(); j++)
+      {
+         if (i != 0 && i != grid[0].Size()-1 && j != 0 && j != grid[1].Size()-1)
+         {
+            SurfaceFunction(example, grid[0][i] + rand_real()*h0*jitter,
+                            grid[1][j] + rand_real()*h1*jitter,
+                            v3D(i, j, 0), v3D(i, j, 1), v3D(i, j, 2));
+         }
+         else
+         {
+            SurfaceFunction(example, grid[0][i], grid[1][j],
+                            v3D(i, j, 0), v3D(i, j, 1), v3D(i, j, 2));
+         }
+      }
+   }
+}
+
+void SurfaceGridExample(int example, int nx, int ny, Array3D<real_t> &vertices,
+                        real_t jitter = 0)
+{
+   // Define a uniform grid of the reference parameter space [0,1]^2
+   std::vector<Vector> uniformGrid(2);
+   for (int i = 0; i < 2; ++i)
+   {
+      const int n = (i == 0) ? nx : ny;
+      const real_t h = 1.0 / n;
+      uniformGrid[i].SetSize(n + 1);
+      for (int j = 0; j <= n; ++j) { uniformGrid[i][j] = j * h; }
+   }
+
+   SurfaceExample(example, uniformGrid, vertices, jitter);
+}
+
+// Write a linear surface mesh with given vertex positions in v.
+void WriteLinearMesh(int nx, int ny, const Array3D<real_t> &v,
+                     const std::string &basename, bool visualization,
+                     int x, int y, int w, int h)
+{
+   const int nv = (nx + 1) * (ny + 1);
+   const int nelem = nx * ny;
+   constexpr int dim = 3; // Spatial dimension
+
+   Mesh lmesh(2, nv, nelem, 0, dim);
+   Vector vertex(dim);
+
+   for (int i = 0; i <= nx; ++i)
+   {
+      for (int j = 0; j <= ny; ++j)
+      {
+         for (int k = 0; k < dim; ++k) { vertex[k] = v(i, j, k); }
+         lmesh.AddVertex(vertex);
+      }
+   }
+
+   Array<int> verts(4);
+
+   auto vID = [&](int i, int j)
+   {
+      return j + (i * (ny + 1));
+   };
+
+   for (int i = 0; i < nx; ++i)
+   {
+      for (int j = 0; j < ny; ++j)
+      {
+         verts[0] = vID(i, j);
+         verts[1] = vID(i+1, j);
+         verts[2] = vID(i+1, j+1);
+         verts[3] = vID(i, j+1);
+
+         Element* el = lmesh.NewElement(Element::QUADRILATERAL);
+         el->SetVertices(verts);
+         lmesh.AddElement(el);
+      }
+   }
+
+   lmesh.FinalizeTopology();
+
+   ofstream mesh_ofs(basename + ".mesh");
+   mesh_ofs.precision(8);
+   lmesh.Print(mesh_ofs);
+
+   if (visualization)
+   {
+      char vishost[] = "localhost";
+      constexpr int visport = 19916;
+      socketstream sol_sock(vishost, visport);
+      sol_sock.precision(8);
+      sol_sock << "mesh\n" << lmesh
+               << "window_title '" << basename << "'"
+               << "window_geometry "
+               << x << " " << y << " " << w << " " << h << "\n"
+               << "keys PPPPPPPPAattttt******\n"
+               << flush;
+   }
+}
+
+
+// Compute error of interpolation with respect to an input grid of point data.
+void CheckError(const Array3D<real_t> &a, const Array3D<real_t> &b, int c,
+                int nx, int ny)
+{
+   real_t maxErr = 0.0;
+   for (int i = 0; i <= nx; ++i)
+   {
+      for (int j = 0; j <= ny; ++j)
+      {
+         const real_t err_ij = std::abs(a(i, j, c) - b(i, j, 2));
+         maxErr = std::max(maxErr, err_ij);
+      }
+   }
+
+   cout << "Max error: " << maxErr << " for coordinate " << c << endl;
+}
+
+
+// Sample a NURBS mesh to generate a first-order mesh.
+void SampleNURBS(bool uniform, int nx, int ny, const Mesh &mesh,
+                 const Array<int> &nks, const std::vector<Vector> &ugrid,
+                 Array3D<real_t> &vpos)
+{
+   const GridFunction *nodes = mesh.GetNodes();
+
+   const real_t hx = 1.0 / (real_t) nx;
+   const real_t hy = 1.0 / (real_t) ny;
+
+   const real_t hxks = 1.0 / (real_t) nks[0];
+   const real_t hyks = 1.0 / (real_t) nks[1];
+
+   Vector vertex;
+   IntegrationPoint ip;
+
+   ip.z = 1.0;
+   for (int i = 0; i <= nx; ++i)
+   {
+      const real_t xref = uniform ? i * hx : ugrid[0][i];
+      const int nurbsElem0 = std::min((int) (xref / hxks), nks[0] - 1);
+      const real_t ipx = (xref - (nurbsElem0 * hxks)) / hxks;
+      ip.x = ipx;
+
+      for (int j = 0; j <= ny; ++j)
+      {
+         const real_t yref = uniform ? j * hy : ugrid[1][j];
+         const int nurbsElem1 = std::min((int) (yref / hyks), nks[1] - 1);
+         const real_t ipy = (yref - (nurbsElem1 * hyks)) / hyks;
+         ip.y = ipy;
+
+         const int nurbsElem = nurbsElem0 + (nurbsElem1 * nks[0]);
+         nodes->GetVectorValue(nurbsElem, ip, vertex);
+
+         for (int k = 0; k < 3; ++k)
+         {
+            vpos(i, j, k) = vertex[k];
+         }
+      }
+   }
+}
+
+
+SurfaceInterpolator::SurfaceInterpolator(int num_elem_x, int num_elem_y,
+                                         int order) :
+   nx(num_elem_x), ny(num_elem_y), orderNURBS(order),
+   ncp(dim), nks(dim), ugrid(dim - 1)
+{
+   ncp[0] = nx + 1;
+   ncp[1] = ny + 1;
+   ncp[2] = order + 1;
+
+   for (int i = 0; i < dim; ++i)
+   {
+      nks[i] = ncp[i] - order;
+
+      Vector intervals(nks[i]);
+      Array<int> continuity(nks[i] + 1);
+
+      intervals = 1.0 / (real_t) nks[i];
+      continuity = order - 1;
+      continuity[0] = -1;
+      continuity[nks[i]] = -1;
+
+      kv.emplace_back(order, intervals, continuity);
+   }
+
+   patch.reset(new NURBSPatch(&kv[0], &kv[1], &kv[2], dim + 1));
+
+   hx = 1.0 / (real_t) (ncp[0] - 1);
+   hy = 1.0 / (real_t) (ncp[1] - 1);
+   hz = 1.0 / (real_t) (ncp[2] - 1);
+
+   Vector xi_args;
+   Array<int> i_args;
+   for (int i = 0; i < 2; ++i)
+   {
+      kv[i].FindMaxima(i_args, xi_args, ugrid[i]);
+   }
+}
+
+void SurfaceInterpolator::CreateSurface(const Array3D<real_t> &input3D)
+{
+   cmesh.clear();
+   for (int c = 0; c < dim; ++c) // Loop over coordinates
+   {
+      ComputeNURBS(c, input3D);
+      cmesh.emplace_back(mesh);
+   }
+
+   initial3D = input3D;
+}
+
+void SurfaceInterpolator::SampleSurface(int num_elem_x, int num_elem_y,
+                                        bool compareOriginal,
+                                        Array3D<real_t> &output3D)
+{
+   Array3D<real_t> vpos(num_elem_x + 1, num_elem_y + 1, dim);
+   for (int c = 0; c < dim; ++c) // Loop over coordinates
+   {
+      SampleNURBS(true, num_elem_x, num_elem_y, cmesh[c], nks, ugrid, vpos);
+
+      if (compareOriginal)
+      {
+         SampleNURBS(false, num_elem_x, num_elem_y, cmesh[c], nks, ugrid, vpos);
+         CheckError(initial3D, vpos, c, nx, ny);
+      }
+
+      for (int i = 0; i <= num_elem_x; ++i)
+      {
+         for (int j = 0; j <= num_elem_y; ++j)
+         {
+            output3D(i,j,c) = vpos(i,j,2);
+         }
+      }
+   }
+}
+
+void SurfaceInterpolator::ComputeNURBS(int coordinate,
+                                       const Array3D<real_t> &input3D)
+{
+   Array<Vector*> x;
+   for (int i = 0; i < dim; ++i) { x.Append(new Vector(ncp[0])); }
+
+   for (int k = 0; k < ncp[2]; ++k)
+   {
+      const real_t z = k * hz;
+
+      // For each horizontal slice (fixed k), interpolate a 2D surface by
+      // sweeping curve interpolations in each direction. See Algorithm A9.4 of
+      // "The NURBS Book" - 2nd ed - Piegl and Tiller.
+
+      // Resize for sweep in first direction
+      for (int i = 0; i < dim; ++i) { x[i]->SetSize(ncp[0]); }
+
+      // Sweep in the first direction
+      for (int j = 0; j < ncp[1]; ++j)
+      {
+         for (int i = 0; i < ncp[0]; i++)
+         {
+            (*x[0])[i] = ugrid[0][i];
+            (*x[1])[i] = ugrid[1][j];
+
+            const real_t s_ij = input3D(i, j, coordinate);
+            (*x[2])[i] = -1.0 + z + s_ij;
+         }
+
+         const bool reuse_factorization = j > 0;
+         kv[0].FindInterpolant(x, reuse_factorization);
+
+         for (int i = 0; i < ncp[0]; i++)
+         {
+            (*patch)(i,j,k,0) = (*x[0])[i];
+            (*patch)(i,j,k,1) = (*x[1])[i];
+            (*patch)(i,j,k,2) = (*x[2])[i];
+            (*patch)(i,j,k,3) = 1.0; // weight
+         }
+      }
+
+      // Resize for sweep in second direction
+      for (int i = 0; i < dim; ++i) { x[i]->SetSize(ncp[1]); }
+
+      // Do another sweep in the second direction
+      for (int i = 0; i < ncp[0]; i++)
+      {
+         for (int j = 0; j < ncp[1]; ++j)
+         {
+            (*x[0])[j] = (*patch)(i,j,k,0);
+            (*x[1])[j] = (*patch)(i,j,k,1);
+            (*x[2])[j] = (*patch)(i,j,k,2);
+         }
+
+         const bool reuse_factorization = i > 0;
+         kv[1].FindInterpolant(x, reuse_factorization);
+
+         for (int j = 0; j < ncp[1]; ++j)
+         {
+            (*patch)(i,j,k,0) = (*x[0])[j];
+            (*patch)(i,j,k,1) = (*x[1])[j];
+            (*patch)(i,j,k,2) = (*x[2])[j];
+         }
+      }
+   }
+
+   for (auto p : x) { delete p; }
+
+   Array<const NURBSPatch*> patches(1);
+   patches[0] = patch.get();
+   Mesh patch_topology = Mesh::MakeCartesian3D(1, 1, 1, Element::HEXAHEDRON);
+   NURBSExtension nurbsExt(&patch_topology, patches);
+
+   mesh = Mesh(nurbsExt);
+}
+
+void SurfaceInterpolator::WriteNURBSMesh(const std::string &basename,
+                                         bool visualization,
+                                         int x, int y, int w, int h)
+{
+   GridFunction *nodes = cmesh[0].GetNodes();
+   NURBSPatch patch2D(&kv[0], &kv[1], dim);
+   Array<const NURBSPatch*> patches(1);
+   patches[0] = &patch2D;
+   Mesh patch_topology = Mesh::MakeCartesian2D(1, 1, Element::QUADRILATERAL);
+   Array<int> dofs;
+   cmesh[0].NURBSext->GetPatchDofs(0, dofs);
+
+   MFEM_VERIFY(dofs.Size() == (nx + 1) * (ny + 1) * (orderNURBS + 1), "");
+
+   for (int j = 0; j < ncp[1]; ++j)
+   {
+      for (int i = 0; i < ncp[0]; i++)
+      {
+         const int dof = dofs[i + (ncp[0] * (j + (ncp[1] * orderNURBS)))];
+         for (int k = 0; k < 2; ++k) { patch2D(i,j,k) = (*nodes)[dim*dof + k]; }
+         patch2D(i,j,2) = 1.0; // weight
+      }
+   }
+
+   NURBSExtension nurbsExt(&patch_topology, patches);
+   Mesh mesh2D(nurbsExt);
+
+   FiniteElementCollection *fec = nodes->OwnFEC();
+   FiniteElementSpace fespace(&mesh2D, fec, dim, Ordering::byVDIM);
+   GridFunction nodes2D(&fespace);
+
+   const int n = mesh2D.GetNodes()->Size() / (dim - 1);
+   MFEM_VERIFY((dim - 1) * n == mesh2D.GetNodes()->Size(), "");
+   MFEM_VERIFY(dim * n == nodes2D.Size(), "");
+
+   Array<int> dofs2D;
+   mesh2D.NURBSext->GetPatchDofs(0, dofs2D);
+
+   for (int k = 0; k < dim; ++k)
+   {
+      const GridFunction &nodes_k = *cmesh[k].GetNodes();
+
+      for (int j = 0; j < ncp[1]; ++j)
+      {
+         for (int i = 0; i < ncp[0]; i++)
+         {
+            const int dof = dofs[i + (ncp[0] * (j + (ncp[1] * orderNURBS)))];
+            const int dof2D = dofs2D[i + (ncp[0] * j)];
+            nodes2D[(dim*dof2D) + k] = nodes_k[dim*dof + 2];
+         }
+      }
+   }
+
+   // Make mesh2D into a surface mesh with nodes given by nodes2D
+   mesh2D.NewNodes(nodes2D);
+
+   ofstream mesh_ofs(basename + ".mesh");
+   mesh_ofs.precision(8);
+   mesh2D.Print(mesh_ofs);
+
+   if (visualization)
+   {
+      char vishost[] = "localhost";
+      constexpr int visport = 19916;
+      socketstream sol_sock(vishost, visport);
+      sol_sock.precision(8);
+      sol_sock << "mesh\n" << mesh2D
+               << "window_title '" << basename << "'"
+               << "window_geometry "
+               << x << " " << y << " " << w << " " << h << "\n"
+               << "keys PPPPPPPPAattttt******\n"
+               << flush;
+   }
+}

miniapps/performance/makefile

@@ -105,8 +105,11 @@ MFEM_PERF_CXXFLAGS_xlc = -mcpu=native
 # - Clang extra options:
 ifeq ($(MFEM_MACHINE),riscv64)
   MFEM_PERF_CXXFLAGS_clang += -march=rv64gc
-else ifneq ($(MFEM_MACHINE),arm64)
-  # -march=native is unavailable on clang/ARM64 as of 05/2021: support could be added later.
+else ifneq (,$(findstring ppc,$(MFEM_MACHINE)))
+  MFEM_PERF_CXXFLAGS_clang += -mcpu=native -mtune=native
+else ifeq ($(MFEM_MACHINE),arm64)
+  MFEM_PERF_CXXFLAGS_clang += -mcpu=native -mtune=native
+else
   MFEM_PERF_CXXFLAGS_clang += -march=native
 endif
 MFEM_PERF_CXXFLAGS_clang += $(PEDANTIC_FLAG) -Wall

miniapps/solvers/block-solvers.cpp

@@ -52,12 +52,13 @@
 //        (respectively 0), essential (respectively natural) boundary condition
 //        will be imposed on boundary with the i-th attribute.
 
+#include <fstream>
+#include <iostream>
+#include <functional>
+
 #include "mfem.hpp"
 #include "bramble_pasciak.hpp"
 #include "div_free_solver.hpp"
-#include <fstream>
-#include <iostream>
-#include <memory>
 
 using namespace std;
 using namespace mfem;
@@ -83,48 +84,54 @@ real_t natural_bc(const Vector & x);
        D: subset of the boundary where natural boundary condition is imposed. */
 class DarcyProblem
 {
-   OperatorPtr M_;
-   OperatorPtr B_;
-   Vector rhs_;
-   Vector ess_data_;
-   ParGridFunction u_;
-   ParGridFunction p_;
+   OperatorPtr M_, B_;
+   Vector rhs_, ess_data_;
+   ParGridFunction u_, p_;
    ParMesh mesh_;
-   ParBilinearForm *mVarf_;
-   ParMixedBilinearForm *bVarf_;
+   DFSSpaces dfs_spaces_;
+   std::function<bool (int)> refine_fn = [&](int num_refs)
+   {
+      for (int l = 0; l < num_refs; l++)
+      {
+         mesh_.UniformRefinement();
+         dfs_spaces_.CollectDFSData();
+      }
+      return true;
+   };
+   const bool dfs_refine_;
+   ParBilinearForm mVarf_;
+   ParMixedBilinearForm bVarf_;
    VectorFunctionCoefficient ucoeff_;
    FunctionCoefficient pcoeff_;
-   DFSSpaces dfs_spaces_;
    PWConstCoefficient mass_coeff;
    const IntegrationRule *irs_[Geometry::NumGeom];
 public:
    DarcyProblem(Mesh &mesh, int num_refines, int order, const char *coef_file,
                 Array<int> &ess_bdr, DFSParameters param);
 
-   HypreParMatrix& GetM() { return *M_.As<HypreParMatrix>(); }
-   HypreParMatrix& GetB() { return *B_.As<HypreParMatrix>(); }
+   const HypreParMatrix& GetM() const { return *M_.As<HypreParMatrix>(); }
+   const HypreParMatrix& GetB() const { return *B_.As<HypreParMatrix>(); }
    const Vector& GetRHS() { return rhs_; }
    const Vector& GetEssentialBC() { return ess_data_; }
    const DFSData& GetDFSData() const { return dfs_spaces_.GetDFSData(); }
    void ShowError(const Vector &sol, bool verbose);
    void VisualizeSolution(const Vector &sol, std::string tag, int visport = 19916);
-   ParBilinearForm* GetMform() const { return mVarf_; }
-   ParMixedBilinearForm* GetBform() const { return bVarf_; }
+   ParBilinearForm& GetMform() { return mVarf_; }
+   ParMixedBilinearForm& GetBform() { return bVarf_; }
 };
 
 DarcyProblem::DarcyProblem(Mesh &mesh, int num_refs, int order,
                            const char *coef_file, Array<int> &ess_bdr,
                            DFSParameters dfs_param)
-   : mesh_(MPI_COMM_WORLD, mesh), ucoeff_(mesh.Dimension(), u_exact),
-     pcoeff_(p_exact), dfs_spaces_(order, num_refs, &mesh_, ess_bdr, dfs_param),
+   : mesh_(MPI_COMM_WORLD, mesh),
+     dfs_spaces_(order, num_refs, &mesh_, ess_bdr, dfs_param),
+     dfs_refine_(refine_fn(num_refs)),
+     mVarf_(dfs_spaces_.GetHdivFES()),
+     bVarf_(dfs_spaces_.GetHdivFES(), dfs_spaces_.GetL2FES()),
+     ucoeff_(mesh.Dimension(), u_exact),
+     pcoeff_(p_exact),
      mass_coeff()
 {
-   for (int l = 0; l < num_refs; l++)
-   {
-      mesh_.UniformRefinement();
-      dfs_spaces_.CollectDFSData();
-   }
-
    Vector coef_vector(mesh.GetNE());
    coef_vector = 1.0;
    if (std::strcmp(coef_file, ""))
@@ -153,24 +160,20 @@ DarcyProblem::DarcyProblem(Mesh &mesh, int num_refs, int order,
    gform.AddDomainIntegrator(new DomainLFIntegrator(gcoeff));
    gform.Assemble();
 
-   mVarf_ = new ParBilinearForm(dfs_spaces_.GetHdivFES());
-   bVarf_ = new ParMixedBilinearForm(dfs_spaces_.GetHdivFES(),
-                                     dfs_spaces_.GetL2FES());
+   mVarf_.AddDomainIntegrator(new VectorFEMassIntegrator(mass_coeff));
+   mVarf_.ComputeElementMatrices();
+   mVarf_.Assemble();
+   mVarf_.EliminateEssentialBC(ess_bdr, u_, fform);
 
-   mVarf_->AddDomainIntegrator(new VectorFEMassIntegrator(mass_coeff));
-   mVarf_->ComputeElementMatrices();
-   mVarf_->Assemble();
-   mVarf_->EliminateEssentialBC(ess_bdr, u_, fform);
+   mVarf_.Finalize();
+   M_.Reset(mVarf_.ParallelAssemble());
 
-   mVarf_->Finalize();
-   M_.Reset(mVarf_->ParallelAssemble());
-
-   bVarf_->AddDomainIntegrator(new VectorFEDivergenceIntegrator);
-   bVarf_->Assemble();
-   bVarf_->SpMat() *= -1.0;
-   bVarf_->EliminateTrialEssentialBC(ess_bdr, u_, gform);
-   bVarf_->Finalize();
-   B_.Reset(bVarf_->ParallelAssemble());
+   bVarf_.AddDomainIntegrator(new VectorFEDivergenceIntegrator);
+   bVarf_.Assemble();
+   bVarf_.SpMat() *= -1.0;
+   bVarf_.EliminateTrialEssentialBC(ess_bdr, u_, gform);
+   bVarf_.Finalize();
+   B_.Reset(bVarf_.ParallelAssemble());
 
    rhs_.SetSize(M_->NumRows() + B_->NumRows());
    Vector rhs_block0(rhs_.GetData(), M_->NumRows());
@@ -341,8 +344,8 @@ int main(int argc, char *argv[])
 
    // Generate components of the saddle point problem
    DarcyProblem darcy(*mesh, par_ref_levels, order, coef_file, ess_bdr, param);
-   HypreParMatrix& M = darcy.GetM();
-   HypreParMatrix& B = darcy.GetB();
+   const HypreParMatrix &M = darcy.GetM();
+   const HypreParMatrix &B = darcy.GetB();
    const DFSData& DFS_data = darcy.GetDFSData();
    delete mesh;
 

miniapps/solvers/block_fespace_operator.cpp

@@ -14,29 +14,27 @@
 namespace mfem
 {
 
-BlockFESpaceOperator::BlockFESpaceOperator(const
-                                           std::vector<const FiniteElementSpace*> &fespaces):
+BlockFESpaceOperator::BlockFESpaceOperator(const FESVector &fespaces):
    Operator(GetHeight(fespaces)),
    offsets(GetBlockOffsets(fespaces)),
    prolongColOffsets(GetProColBlockOffsets(fespaces)),
    restrictRowOffsets(GetResRowBlockOffsets(fespaces)),
    A(offsets),
-   prolongation(offsets,prolongColOffsets),
+   prolongation(offsets, prolongColOffsets),
    restriction(restrictRowOffsets, offsets)
 {
    for (size_t i = 0; i <fespaces.size(); i++)
    {
       // Since const_cast is required here, be sure to avoid using
       // BlockOperator::GetBlock on restriction or prolongation.
-      prolongation.SetDiagonalBlock(i,
-                                    const_cast<Operator *>(fespaces[i]->GetProlongationMatrix()));
-      restriction.SetDiagonalBlock(i,
-                                   const_cast<Operator *>(fespaces[i]->GetRestrictionOperator()));
+      auto prolongation_matrix = fespaces[i]->GetProlongationMatrix();
+      auto restriction_matrix = fespaces[i]->GetRestrictionOperator();
+      prolongation.SetDiagonalBlock(i, const_cast<Operator *>(prolongation_matrix));
+      restriction.SetDiagonalBlock(i, const_cast<Operator *>(restriction_matrix));
    }
 }
 
-int BlockFESpaceOperator::GetHeight(const std::vector<const FiniteElementSpace*>
-                                    &fespaces)
+int BlockFESpaceOperator::GetHeight(const FESVector &fespaces)
 {
    int height = 0;
    for (size_t i = 0; i < fespaces.size(); i++)
@@ -46,8 +44,7 @@ int BlockFESpaceOperator::GetHeight(const std::vector<const FiniteElementSpace*>
    return height;
 }
 
-Array<int> BlockFESpaceOperator::GetBlockOffsets(const
-                                                 std::vector<const FiniteElementSpace*> &fespaces)
+Array<int> BlockFESpaceOperator::GetBlockOffsets(const FESVector &fespaces)
 {
    Array<int> offsets(fespaces.size()+1);
    offsets[0] = 0;
@@ -60,8 +57,8 @@ Array<int> BlockFESpaceOperator::GetBlockOffsets(const
    return offsets;
 }
 
-Array<int> BlockFESpaceOperator::GetProColBlockOffsets(const
-                                                       std::vector<const FiniteElementSpace*> &fespaces)
+Array<int> BlockFESpaceOperator::GetProColBlockOffsets(const FESVector
+                                                       &fespaces)
 {
    Array<int> offsets(fespaces.size()+1);
    offsets[0] = 0;
@@ -83,8 +80,8 @@ Array<int> BlockFESpaceOperator::GetProColBlockOffsets(const
    return offsets;
 }
 
-Array<int> BlockFESpaceOperator::GetResRowBlockOffsets(const
-                                                       std::vector<const FiniteElementSpace*> &fespaces)
+Array<int> BlockFESpaceOperator::GetResRowBlockOffsets(const FESVector
+                                                       &fespaces)
 {
    Array<int> offsets(fespaces.size()+1);
    std::cout << "fespaces.size() = " << fespaces.size() << std::endl;

miniapps/solvers/block_fespace_operator.hpp

@@ -25,7 +25,8 @@ namespace mfem
 ///        L-Vectors. For example, a block may be a BilinearForm.
 class BlockFESpaceOperator : public Operator
 {
-private:
+   using FESVector = std::vector<const FiniteElementSpace*>;
+
    /// Offsets for the square "A" operator.
    Array<int> offsets;
    /// Column offsets for the prolongation operator.
@@ -39,33 +40,27 @@ private:
    /// Maps true dofs of each block to local dofs.
    BlockOperator restriction;
    /// Computes height for parent operator.
-   static int GetHeight(const std::vector<const FiniteElementSpace*>
-                        &fespaces);
+   static int GetHeight(const FESVector &fespaces);
    /// Computes offsets for A BlockOperator.
-   static Array<int> GetBlockOffsets(const std::vector<const FiniteElementSpace*>
-                                     &fespaces);
+   static Array<int> GetBlockOffsets(const FESVector &fespaces);
    /// Computes col_offsets for prolongation operator.
-   static Array<int> GetProColBlockOffsets(const
-                                           std::vector<const FiniteElementSpace*> &fespaces);
+   static Array<int> GetProColBlockOffsets(const FESVector &fespaces);
    /// Computes row_offsets for restriction operator.
-   static Array<int> GetResRowBlockOffsets(const
-                                           std::vector<const FiniteElementSpace*> &fespaces);
+   static Array<int> GetResRowBlockOffsets(const FESVector &fespaces);
+
 public:
    /// @brief Constructor for BlockFESpaceOperator.
    /// @param[in] fespaces Finite element spaces for diagonal blocks. Spaces are not owned.
-   BlockFESpaceOperator(const std::vector<const FiniteElementSpace*> &fespaces);
+   BlockFESpaceOperator(const FESVector &fespaces);
    const Operator* GetProlongation () const override;
    const Operator* GetRestriction () const override;
    void Mult(const Vector &x, Vector &y) const override {A.Mult(x,y);};
    /// @brief Wraps BlockOperator::SetBlock. Eventually would like this class to inherit
    /// from BlockOperator instead, but can't easily due to ownership of offset data
    /// in BlockOperator being by reference.
-   void SetBlock( int   iRow,
-                  int   iCol,
-                  Operator *  op,
-                  real_t   c = 1.0) {A.SetBlock(iRow, iCol, op, c);};
+   void SetBlock(int iRow, int iCol, Operator *op, real_t c = 1.0) { A.SetBlock(iRow, iCol, op, c); };
 };
 
 } // namespace mfem
 
-#endif
+#endif // MFEM_BLOCK_FESPACE_OPERATOR

miniapps/solvers/bramble_pasciak.cpp

@@ -9,70 +9,65 @@
 // terms of the BSD-3 license. We welcome feedback and contributions, see file
 // CONTRIBUTING.md for details.
 
-
 #include "bramble_pasciak.hpp"
 
 using namespace std;
 
-namespace mfem
-{
-namespace blocksolvers
+namespace mfem::blocksolvers
 {
+
 /// Bramble-Pasciak Solver
-BramblePasciakSolver::BramblePasciakSolver(
-   ParBilinearForm *mVarf,
-   ParMixedBilinearForm *bVarf,
-   const BPSParameters &param)
-   : DarcySolver(mVarf->ParFESpace()->GetTrueVSize(),
-                 bVarf->TestFESpace()->GetTrueVSize())
+BramblePasciakSolver::BramblePasciakSolver(ParBilinearForm &mVarf,
+                                           ParMixedBilinearForm &bVarf,
+                                           const BPSParameters &param)
+   : DarcySolver(mVarf.ParFESpace()->GetTrueVSize(),
+                 bVarf.TestFESpace()->GetTrueVSize())
 {
-   M_.reset(mVarf->ParallelAssemble());
-   B_.reset(bVarf->ParallelAssemble());
-   Q_.reset(ConstructMassPreconditioner(*mVarf, param.q_scaling));
+   M_.reset(mVarf.ParallelAssemble());
+   B_.reset(bVarf.ParallelAssemble());
+   Q_.reset(ConstructMassPreconditioner(mVarf, param.q_scaling));
 
    Vector diagM;
    M_->GetDiag(diagM);
-   auto BT = B_->Transpose();
-   auto invDBt = new HypreParMatrix(*BT);
+   std::unique_ptr<HypreParMatrix> invDBt(B_->Transpose());
    invDBt->InvScaleRows(diagM);
-   auto S = ParMult(B_.get(), invDBt);
+   S_.reset(ParMult(B_.get(), invDBt.get(), true));
    M0_.Reset(new HypreDiagScale(*M_));
-   M1_.Reset(new HypreBoomerAMG(*S));
+   M1_.Reset(new HypreBoomerAMG(*S_));
    M1_.As<HypreBoomerAMG>()->SetPrintLevel(0);
 
    Init(*M_, *B_, *Q_, *M0_.As<Solver>(), *M1_.As<Solver>(), param);
 }
 
-BramblePasciakSolver::BramblePasciakSolver(
-   HypreParMatrix &M, HypreParMatrix &B, HypreParMatrix &Q,
-   Solver &M0, Solver &M1,
-   const BPSParameters &param)
+BramblePasciakSolver::BramblePasciakSolver(HypreParMatrix &M,
+                                           HypreParMatrix &B,
+                                           HypreParMatrix &Q,
+                                           Solver &M0, Solver &M1,
+                                           const BPSParameters &param)
    : DarcySolver(M.NumRows(), B.NumRows())
 {
    Init(M, B, Q, M0, M1, param);
 }
 
-void BramblePasciakSolver::Init(
-   HypreParMatrix &M, HypreParMatrix &B, HypreParMatrix &Q,
-   Solver &M0, Solver &M1,
-   const BPSParameters &param)
+void BramblePasciakSolver::Init(HypreParMatrix &M,
+                                HypreParMatrix &B,
+                                HypreParMatrix &Q,
+                                Solver &M0, Solver &M1,
+                                const BPSParameters &param)
 {
-   auto Bt = new TransposeOperator(&B);
+   Bt_ = std::make_unique<TransposeOperator>(&B);
    auto invQ = new HypreDiagScale(Q);
 
    use_bpcg = param.use_bpcg;
 
    if (use_bpcg)
    {
-      oop_ = new BlockOperator(offsets_);
-      oop_->owns_blocks = false;
+      oop_ = std::make_unique<BlockOperator>(offsets_);
       oop_->SetBlock(0, 0, &M);
-      oop_->SetBlock(0, 1, Bt);
+      oop_->SetBlock(0, 1, Bt_.get());
       oop_->SetBlock(1, 0, &B);
-
       // cpc_ unused in bpcg
       auto temp_cpc = new BlockDiagonalPreconditioner(offsets_);
-      temp_cpc->owns_blocks = true;
       temp_cpc->SetDiagonalBlock(0, invQ);
       temp_cpc->SetDiagonalBlock(1, &M1);
       // tri(1,0) = B M0 = B invQ
@@ -81,51 +76,48 @@ void BramblePasciakSolver::Init(
       auto BinvQ = new ProductOperator(&B, invQ, false, false);
       // tri
       auto temp_tri = new BlockOperator(offsets_);
-      temp_tri->owns_blocks = true;
       temp_tri->SetBlock(0, 0, id_m);
       temp_tri->SetBlock(1, 1, id_b, -1.0);
       temp_tri->SetBlock(1, 0, BinvQ);
+      temp_tri->owns_blocks = 1;
 
-      ppc_ = new ProductOperator(temp_cpc, temp_tri, true, true);
+      ppc_ = std::make_unique<ProductOperator>(temp_cpc, temp_tri, true, true);
 
-      ipc_ = new BlockOperator(offsets_);
-      ipc_->owns_blocks = false;
+      ipc_ = std::make_unique<BlockOperator>(offsets_);
       ipc_->SetDiagonalBlock(0, invQ);
+      ipc_->owns_blocks = 1;
 
       // bpcg
-      solver_.reset(new BPCGSolver(M.GetComm(), *ipc_, *ppc_));
+      solver_ = std::make_unique<BPCGSolver>(M.GetComm(), ipc_.get(), ppc_.get());
       solver_->SetOperator(*oop_);
    }
    else
    {
       // oop_ unused in cg
       auto temp_oop = new BlockOperator(offsets_);
-      temp_oop->owns_blocks = false;
       temp_oop->SetBlock(0, 0, &M);
-      temp_oop->SetBlock(0, 1, Bt);
+      temp_oop->SetBlock(0, 1, Bt_.get());
       temp_oop->SetBlock(1, 0, &B);
 
       // ipc_ unused in cg
       auto temp_ipc = new BlockOperator(offsets_);
-      temp_ipc->owns_blocks = false;
       temp_ipc->SetDiagonalBlock(0, invQ);
+      temp_ipc->owns_blocks = 1;
 
       // temp_AN = temp_oop * temp_ipc
       auto temp_AN = new ProductOperator(temp_oop, temp_ipc, true, true);
 
       // Required for updating the RHS
       auto id = new IdentityOperator(M.NumRows()+B.NumRows());
-      map_ = new SumOperator(temp_AN, 1.0, id, -1.0, true, true);
+      map_ = std::make_unique<SumOperator>(temp_AN, 1.0, id, -1.0, true, true);
+      mop_ = std::make_unique<ProductOperator>(map_.get(), temp_oop, false, false);
 
-      mop_ = new ProductOperator(map_, temp_oop, false, true);
-
-      cpc_ = new BlockDiagonalPreconditioner(offsets_);
-      cpc_->owns_blocks = true;
+      cpc_ = std::make_unique<BlockDiagonalPreconditioner>(offsets_);
       cpc_->SetDiagonalBlock(0, &M0);
       cpc_->SetDiagonalBlock(1, &M1);
 
       // (P)CG
-      solver_.reset(new CGSolver(M.GetComm()));
+      solver_ = std::make_unique<CGSolver>(M.GetComm());
       solver_->SetOperator(*mop_);
       solver_->SetPreconditioner(*cpc_);
    }
@@ -133,7 +125,7 @@ void BramblePasciakSolver::Init(
 }
 
 HypreParMatrix *BramblePasciakSolver::ConstructMassPreconditioner(
-   ParBilinearForm &mVarf, real_t q_scaling)
+   const ParBilinearForm &mVarf, real_t q_scaling)
 {
    MFEM_ASSERT((q_scaling > 0.0) && (q_scaling < 1.0),
                "Invalid Q-scaling factor: q_scaling = " << q_scaling );
@@ -167,7 +159,7 @@ HypreParMatrix *BramblePasciakSolver::ConstructMassPreconditioner(
       Vector x(M_i.Height()), Mx(M_i.Height()), diff(M_i.Height());
       real_t eval_prev = 0.0;
       int iter = 0;
-      x.Randomize(696383552+779345*i);
+      x.Randomize(static_cast<int>(696383552LL+779345LL*i));
 #if defined(MFEM_USE_DOUBLE)
       const real_t rel_tol = 1e-12;
 #elif defined(MFEM_USE_SINGLE)
@@ -400,5 +392,5 @@ void BPCGSolver::Mult(const Vector &b, Vector &x) const
    final_norm = sqrt(delta);
    Monitor(final_iter, final_norm, r, x, true);
 }
-} // namespace blocksolvers
-} // namespace mfem
+
+} // namespace mfem::blocksolvers

miniapps/solvers/bramble_pasciak.hpp

@@ -49,9 +49,7 @@
 #include "darcy_solver.hpp"
 #include <memory>
 
-namespace mfem
-{
-namespace blocksolvers
+namespace mfem::blocksolvers
 {
 
 /// Parameters for the BramblePasciakSolver method
@@ -70,11 +68,11 @@ protected:
    void UpdateVectors();
 
 public:
-   BPCGSolver(const Operator &ipc, const Operator &ppc) { pprec = &ppc; iprec = &ipc; }
+   BPCGSolver(const Operator *ipc, const Operator *ppc): iprec(ipc), pprec(ppc) {}
 
 #ifdef MFEM_USE_MPI
-   BPCGSolver(MPI_Comm comm_, const Operator &ipc, const Operator &ppc)
-      : IterativeSolver(comm_) { pprec = &ppc; iprec = &ipc; }
+   BPCGSolver(MPI_Comm comm_, const Operator *ipc, const Operator *ppc)
+      : IterativeSolver(comm_), iprec(ipc), pprec(ppc) { }
 #endif
 
    void SetOperator(const Operator &op) override
@@ -83,11 +81,9 @@ public:
    void SetPreconditioner(Solver &pc) override
    { if (Mpi::Root()) { MFEM_WARNING("SetPreconditioner has no effect on BPCGSolver.\n"); } }
 
-   virtual void SetIncompletePreconditioner(const Operator &ipc)
-   { iprec = &ipc; }
+   virtual void SetIncompletePreconditioner(const Operator *ipc) { iprec = ipc; }
 
-   virtual void SetParticularPreconditioner(const Operator &ppc)
-   { pprec = &ppc; }
+   virtual void SetParticularPreconditioner(const Operator *ppc) { pprec = ppc; }
 
    void Mult(const Vector &b, Vector &x) const override;
 };
@@ -116,23 +112,20 @@ public:
     1. P. Vassilevski, Multilevel Block Factorization Preconditioners (Appendix
        F.3), Springer, 2008.
 
-    2. J. Bramble and J. Pasciak.  A Preconditioning Technique for Indefinite
+    2. J. Bramble and J. Pasciak. A Preconditioning Technique for Indefinite
        Systems Resulting From Mixed Approximations of Elliptic Problems,
        Mathematics of Computation, 50:1-17, 1988. */
 class BramblePasciakSolver : public DarcySolver
 {
    mutable bool use_bpcg;
    std::unique_ptr<IterativeSolver> solver_;
-   BlockOperator *oop_, *ipc_;
-   ProductOperator *mop_;
-   SumOperator *map_;
-   ProductOperator *ppc_;
-   BlockDiagonalPreconditioner *cpc_;
-   std::unique_ptr<HypreParMatrix> M_;
-   std::unique_ptr<HypreParMatrix> B_;
-   std::unique_ptr<HypreParMatrix> Q_;
-   OperatorPtr M0_;
-   OperatorPtr M1_;
+   std::unique_ptr<BlockOperator> oop_, ipc_;
+   std::unique_ptr<ProductOperator> mop_, ppc_;
+   std::unique_ptr<SumOperator> map_;
+   std::unique_ptr<BlockDiagonalPreconditioner> cpc_;
+   std::unique_ptr<HypreParMatrix> M_, B_, Q_, S_;
+   std::unique_ptr<TransposeOperator> Bt_;
+   OperatorPtr M0_, M1_;
    Array<int> ess_zero_dofs_;
 
    void Init(HypreParMatrix &M, HypreParMatrix &B,
@@ -142,8 +135,8 @@ class BramblePasciakSolver : public DarcySolver
 public:
    /// System and mass preconditioner are constructed from bilinear forms
    BramblePasciakSolver(
-      ParBilinearForm *mVarf,
-      ParMixedBilinearForm *bVarf,
+      ParBilinearForm &mVarf,
+      ParMixedBilinearForm &bVarf,
       const BPSParameters &param);
 
    /// System and mass preconditioner are user-provided
@@ -158,8 +151,8 @@ public:
        element T:
                                 M_T x_T = lambda_T diag(M_T) x_T.
        We set Q_T = alpha * min(lambda_T) * diag(M_T), 0 < alpha < 1. */
-   static HypreParMatrix *ConstructMassPreconditioner(ParBilinearForm &mVarf,
-                                                      real_t alpha = 0.5);
+   static HypreParMatrix *ConstructMassPreconditioner(const ParBilinearForm &mVarf,
+                                                      const real_t alpha = 0.5);
 
    void Mult(const Vector &x, Vector &y) const override;
    void SetOperator(const Operator &op) override { }
@@ -167,7 +160,6 @@ public:
    int GetNumIterations() const override { return solver_->GetNumIterations(); }
 };
 
-} // namespace blocksolvers
-} // namespace mfem
+} // namespace mfem::blocksolvers
 
 #endif // MFEM_BP_SOLVER_HPP

miniapps/solvers/darcy_solver.cpp

@@ -13,10 +13,9 @@
 
 using namespace std;
 
-namespace mfem
-{
-namespace blocksolvers
+namespace mfem::blocksolvers
 {
+
 void SetOptions(IterativeSolver& solver, const IterSolveParameters& param)
 {
    solver.SetPrintLevel(param.print_level);
@@ -49,7 +48,7 @@ BDPMinresSolver::BDPMinresSolver(const HypreParMatrix& M,
    prec_.SetDiagonalBlock(0, new HypreDiagScale(M));
    prec_.SetDiagonalBlock(1, new HypreBoomerAMG(*S_.As<HypreParMatrix>()));
    static_cast<HypreBoomerAMG&>(prec_.GetDiagonalBlock(1)).SetPrintLevel(0);
-   prec_.owns_blocks = true;
+   prec_.owns_blocks = 1;
 
    SetOptions(solver_, param);
    solver_.SetOperator(op_);
@@ -61,5 +60,5 @@ void BDPMinresSolver::Mult(const Vector & x, Vector & y) const
    solver_.Mult(x, y);
    for (int dof : ess_zero_dofs_) { y[dof] = 0.0; }
 }
-} // namespace blocksolvers
-} // namespace mfem
+
+} // namespace mfem::blocksolvers

miniapps/solvers/darcy_solver.hpp

@@ -13,13 +13,10 @@
 #define MFEM_DARCY_SOLVER_HPP
 
 #include "mfem.hpp"
-#include <memory>
-#include <vector>
 
-namespace mfem
-{
-namespace blocksolvers
+namespace mfem::blocksolvers
 {
+
 struct IterSolveParameters
 {
    int print_level = 0;
@@ -32,8 +29,6 @@ struct IterSolveParameters
    real_t rel_tol = 1e-5;
 #else
 #error "Only single and double precision are supported!"
-   real_t abs_tol = 1e-12;
-   real_t rel_tol = 1e-9;
 #endif
 };
 
@@ -68,7 +63,7 @@ public:
    void SetEssZeroDofs(const Array<int>& dofs) { dofs.Copy(ess_zero_dofs_); }
    int GetNumIterations() const override { return solver_.GetNumIterations(); }
 };
-} // namespace blocksolvers
-} // namespace mfem
+
+} // namespace mfem::blocksolvers
 
 #endif // MFEM_DARCY_SOLVER_HPP

miniapps/solvers/div_free_solver.cpp

@@ -13,16 +13,16 @@
 
 using namespace std;
 
-namespace mfem
+namespace mfem::blocksolvers
 {
-namespace blocksolvers
+
+static HypreParMatrix* TwoStepsRAP(const HypreParMatrix *Rt,
+                                   const HypreParMatrix *A,
+                                   const HypreParMatrix *P)
 {
-HypreParMatrix* TwoStepsRAP(const HypreParMatrix& Rt, const HypreParMatrix& A,
-                            const HypreParMatrix& P)
-{
-   OperatorPtr R(Rt.Transpose());
-   OperatorPtr RA(ParMult(R.As<HypreParMatrix>(), &A));
-   return ParMult(RA.As<HypreParMatrix>(), &P, true);
+   OperatorPtr R(Rt->Transpose());
+   OperatorPtr RA(ParMult(R.As<HypreParMatrix>(), A));
+   return ParMult(RA.As<HypreParMatrix>(), P, true);
 }
 
 void GetRowColumnsRef(const SparseMatrix& A, int row, Array<int>& cols)
@@ -59,34 +59,36 @@ DFSSpaces::DFSSpaces(int order, int num_refine, ParMesh *mesh,
 
    if (mesh->Dimension() == 3)
    {
-      hcurl_fec_.reset(new ND_FECollection(order+1, mesh->Dimension()));
+      hcurl_fec_ = std::make_unique<ND_FECollection>(order+1, mesh->Dimension());
    }
    else
    {
-      hcurl_fec_.reset(new H1_FECollection(order+1, mesh->Dimension()));
+      hcurl_fec_ = std::make_unique<H1_FECollection>(order+1, mesh->Dimension());
    }
 
    all_bdr_attr_.SetSize(ess_attr.Size(), 1);
-   hdiv_fes_.reset(new ParFiniteElementSpace(mesh, &hdiv_fec_));
-   l2_fes_.reset(new ParFiniteElementSpace(mesh, &l2_fec_));
-   coarse_hdiv_fes_.reset(new ParFiniteElementSpace(*hdiv_fes_));
-   coarse_l2_fes_.reset(new ParFiniteElementSpace(*l2_fes_));
-   l2_0_fes_.reset(new ParFiniteElementSpace(mesh, &l2_0_fec_));
+   hdiv_fes_ = std::make_unique<ParFiniteElementSpace>(mesh, &hdiv_fec_);
+   l2_fes_ = std::make_unique<ParFiniteElementSpace>(mesh, &l2_fec_);
+   coarse_hdiv_fes_ = std::make_unique<ParFiniteElementSpace>(*hdiv_fes_);
+   coarse_l2_fes_ = std::make_unique<ParFiniteElementSpace>(*l2_fes_);
+   l2_0_fes_ = std::make_unique<ParFiniteElementSpace>(mesh, &l2_0_fec_);
    l2_0_fes_->SetUpdateOperatorType(Operator::MFEM_SPARSEMAT);
    el_l2dof_.reserve(num_refine+1);
    el_l2dof_.push_back(ElemToDof(*coarse_l2_fes_));
 
    data_.agg_hdivdof.resize(num_refine);
    data_.agg_l2dof.resize(num_refine);
-   data_.P_hdiv.resize(num_refine, OperatorPtr(Operator::Hypre_ParCSR));
-   data_.P_l2.resize(num_refine, OperatorPtr(Operator::Hypre_ParCSR));
+   data_.P_hdiv.resize(num_refine);
+   data_.P_l2.resize(num_refine);
+
    data_.Q_l2.resize(num_refine);
    hdiv_fes_->GetEssentialTrueDofs(ess_attr, data_.coarsest_ess_hdivdofs);
    data_.C.resize(num_refine+1);
+   data_.Ae.resize(num_refine+1);
 
-   hcurl_fes_.reset(new ParFiniteElementSpace(mesh, hcurl_fec_.get()));
-   coarse_hcurl_fes_.reset(new ParFiniteElementSpace(*hcurl_fes_));
-   data_.P_hcurl.resize(num_refine, OperatorPtr(Operator::Hypre_ParCSR));
+   hcurl_fes_ = std::make_unique<ParFiniteElementSpace>(mesh, hcurl_fec_.get());
+   coarse_hcurl_fes_ = std::make_unique<ParFiniteElementSpace>(*hcurl_fes_);
+   data_.P_hcurl.resize(num_refine);
 }
 
 SparseMatrix* AggToInteriorDof(const Array<int>& bdr_truedofs,
@@ -104,8 +106,8 @@ SparseMatrix* AggToInteriorDof(const Array<int>& bdr_truedofs,
    agg_tdof_T.As<HypreParMatrix>()->GetDiag(tdof_agg);
    agg_tdof_T.As<HypreParMatrix>()->GetOffd(is_shared, trash);
 
-   int * I = new int [tdof_agg.NumRows()+1]();
-   int * J = new int[tdof_agg.NumNonZeroElems()];
+   int *I = new int[tdof_agg.NumRows()+1]();
+   int *J = new int[tdof_agg.NumNonZeroElems()];
 
    Array<int> is_bdr;
    FiniteElementSpace::ListToMarker(bdr_truedofs, tdof_agg.NumRows(), is_bdr);
@@ -119,7 +121,7 @@ SparseMatrix* AggToInteriorDof(const Array<int>& bdr_truedofs,
       J[counter++] = tdof_agg.GetRowColumns(i)[0];
    }
 
-   real_t * D = new real_t[I[tdof_agg.NumRows()]];
+   auto *D = new real_t[I[tdof_agg.NumRows()]];
    std::fill_n(D, I[tdof_agg.NumRows()], 1.0);
 
    SparseMatrix intdof_agg(I, J, D, tdof_agg.NumRows(), tdof_agg.NumCols());
@@ -146,20 +148,21 @@ void DFSSpaces::MakeDofRelationTables(int level)
 
 void DFSSpaces::CollectDFSData()
 {
-   auto GetP = [this](OperatorPtr& P, unique_ptr<ParFiniteElementSpace>& cfes,
-                      ParFiniteElementSpace& fes, bool remove_zero)
+   auto GetP = [&](std::unique_ptr<OperatorPtr> &P,
+                   std::unique_ptr<ParFiniteElementSpace> &cfes,
+                   ParFiniteElementSpace& fes, const bool remove_zero)
    {
       fes.Update();
-      fes.GetTrueTransferOperator(*cfes, P);
-      if (remove_zero)
-      {
-         P.As<HypreParMatrix>()->DropSmallEntries(1e-16);
-      }
+      auto T = new OperatorHandle(Operator::Hypre_ParCSR);
+      fes.GetTrueTransferOperator(*cfes, *T);
+      P.reset(T);
+      if (remove_zero) { P->As<HypreParMatrix>()->DropSmallEntries(1e-16); }
       (level_ < (int)data_.P_l2.size()-1) ? cfes->Update() : cfes.reset();
    };
 
    GetP(data_.P_hdiv[level_], coarse_hdiv_fes_, *hdiv_fes_, true);
    GetP(data_.P_l2[level_], coarse_l2_fes_, *l2_fes_, false);
+
    MakeDofRelationTables(level_);
 
    GetP(data_.P_hcurl[level_], coarse_hcurl_fes_, *hcurl_fes_, true);
@@ -171,7 +174,9 @@ void DFSSpaces::CollectDFSData()
    data_.C[level_+1].Reset(curl.ParallelAssemble());
    mfem::Array<int> ess_hcurl_tdof;
    hcurl_fes_->GetEssentialTrueDofs(ess_bdr_attr_, ess_hcurl_tdof);
-   data_.C[level_+1].As<HypreParMatrix>()->EliminateCols(ess_hcurl_tdof);
+   data_.Ae[level_+1].reset(
+      data_.C[level_+1].As<HypreParMatrix>()
+      ->EliminateCols(ess_hcurl_tdof));
 
    ++level_;
 
@@ -189,7 +194,7 @@ void DFSSpaces::DataFinalize()
    SparseMatrix P_l2;
    for (int l = (int)data_.P_l2.size()-1; l >= 0; --l)
    {
-      data_.P_l2[l].As<HypreParMatrix>()->GetDiag(P_l2);
+      data_.P_l2[l]->As<HypreParMatrix>()->GetDiag(P_l2);
       OperatorPtr PT_l2(Transpose(P_l2));
       auto PTW = Mult(*PT_l2.As<SparseMatrix>(), *W.As<SparseMatrix>());
       auto cW = Mult(*PTW, P_l2);
@@ -245,7 +250,7 @@ SaddleSchwarzSmoother::SaddleSchwarzSmoother(const HypreParMatrix& M,
                                              const SparseMatrix& agg_hdivdof,
                                              const SparseMatrix& agg_l2dof,
                                              const HypreParMatrix& P_l2,
-                                             const HypreParMatrix& Q_l2)
+                                             const ProductOperator& Q_l2)
    : Solver(M.NumRows() + B.NumRows()), agg_hdivdof_(agg_hdivdof),
      agg_l2dof_(agg_l2dof), solvers_loc_(agg_l2dof.NumRows())
 {
@@ -312,23 +317,27 @@ void SaddleSchwarzSmoother::Mult(const Vector & x, Vector & y) const
    blk_y.GetBlock(1) -= coarse_l2_projection;
 }
 
-DivFreeSolver::DivFreeSolver(const HypreParMatrix &M, const HypreParMatrix& B,
+DivFreeSolver::DivFreeSolver(const HypreParMatrix &M,
+                             const HypreParMatrix &B,
                              const DFSData& data)
    : DarcySolver(M.NumRows(), B.NumRows()), data_(data), param_(data.param),
-     BT_(B.Transpose()), BBT_solver_(B, param_.BBT_solve_param),
-     ops_offsets_(data.P_l2.size()+1), ops_(ops_offsets_.size()),
-     blk_Ps_(ops_.Size()-1), smoothers_(ops_.Size())
+     BT_(B.Transpose()),
+     BBT_solver_(B, param_.BBT_solve_param),
+     ops_offsets_(data.P_l2.size()+1),
+     ops_(ops_offsets_.size()),
+     blk_Ps_(ops_.size()-1),
+     smoothers_(ops_.size())
 {
    ops_offsets_.back().MakeRef(DarcySolver::offsets_);
-   ops_.Last() = new BlockOperator(ops_offsets_.back());
-   ops_.Last()->SetBlock(0, 0, const_cast<HypreParMatrix*>(&M));
-   ops_.Last()->SetBlock(1, 0, const_cast<HypreParMatrix*>(&B));
-   ops_.Last()->SetBlock(0, 1, BT_.Ptr());
+   ops_.back() = std::make_unique<BlockOperator>(ops_offsets_.back());
+   ops_.back()->SetBlock(0, 0, const_cast<HypreParMatrix*>(&M));
+   ops_.back()->SetBlock(1, 0, const_cast<HypreParMatrix*>(&B));
+   ops_.back()->SetBlock(0, 1, BT_.Ptr());
 
    for (int l = data.P_l2.size(); l >= 0; --l)
    {
-      auto& M_f = static_cast<const HypreParMatrix&>(ops_[l]->GetBlock(0, 0));
-      auto& B_f = static_cast<const HypreParMatrix&>(ops_[l]->GetBlock(1, 0));
+      auto &M_f = static_cast<const HypreParMatrix&>(ops_[l]->GetBlock(0, 0));
+      auto &B_f = static_cast<const HypreParMatrix&>(ops_[l]->GetBlock(1, 0));
 
       if (l == 0)
       {
@@ -343,123 +352,112 @@ DivFreeSolver::DivFreeSolver(const HypreParMatrix &M, const HypreParMatrix& B,
 
          const IterSolveParameters& param = param_.coarse_solve_param;
          auto coarse_solver = new BDPMinresSolver(M_f, B_f, param);
-         if (ops_.Size() > 1)
+         if (ops_.size() > 1)
          {
             coarse_solver->SetEssZeroDofs(data.coarsest_ess_hdivdofs);
          }
-         smoothers_[l] = coarse_solver;
+         smoothers_[l].reset(coarse_solver);
          continue;
       }
 
-      HypreParMatrix& P_hdiv_l = *data.P_hdiv[l-1].As<HypreParMatrix>();
-      HypreParMatrix& P_l2_l = *data.P_l2[l-1].As<HypreParMatrix>();
+      auto P_hdiv_l = data.P_hdiv[l-1]->As<HypreParMatrix>();
+      auto P_l2_l = data.P_l2[l-1]->As<HypreParMatrix>();
       SparseMatrix& agg_hdivdof_l = *data.agg_hdivdof[l-1].As<SparseMatrix>();
       SparseMatrix& agg_l2dof_l = *data.agg_l2dof[l-1].As<SparseMatrix>();
-      HypreParMatrix& Q_l2_l = *data.Q_l2[l-1].As<HypreParMatrix>();
-      HypreParMatrix* C_l = data.C[l].As<HypreParMatrix>();
+      ProductOperator& Q_l2_l = *data.Q_l2[l-1].As<ProductOperator>();
+      auto* C_l = data.C[l].As<HypreParMatrix>();
 
       auto S0 = new SaddleSchwarzSmoother(M_f, B_f, agg_hdivdof_l,
-                                          agg_l2dof_l, P_l2_l, Q_l2_l);
+                                          agg_l2dof_l, *P_l2_l, Q_l2_l);
       if (param_.coupled_solve)
       {
          auto S1 = new BlockDiagonalPreconditioner(ops_offsets_[l]);
          S1->SetDiagonalBlock(0, new AuxSpaceSmoother(M_f, C_l));
-         S1->owns_blocks = true;
-         smoothers_[l] = new ProductSolver(ops_[l], S0, S1, false, true, true);
+         S1->owns_blocks = 1;
+         smoothers_[l] =
+            std::make_unique<ProductSolver>(ops_[l].get(), S0, S1, false, true, true);
       }
       else
       {
-         smoothers_[l] = S0;
+         smoothers_[l].reset(S0);
       }
 
-      HypreParMatrix* M_c = TwoStepsRAP(P_hdiv_l, M_f, P_hdiv_l);
-      HypreParMatrix* B_c = TwoStepsRAP(P_l2_l, B_f, P_hdiv_l);
+      HypreParMatrix* M_c = TwoStepsRAP(P_hdiv_l, &M_f, P_hdiv_l);
+      HypreParMatrix* B_c = TwoStepsRAP(P_l2_l, &B_f, P_hdiv_l);
 
       ops_offsets_[l-1].SetSize(3, 0);
       ops_offsets_[l-1][1] = M_c->NumRows();
       ops_offsets_[l-1][2] = M_c->NumRows() + B_c->NumRows();
 
-      blk_Ps_[l-1] = new BlockOperator(ops_offsets_[l], ops_offsets_[l-1]);
-      blk_Ps_[l-1]->SetBlock(0, 0, &P_hdiv_l);
-      blk_Ps_[l-1]->SetBlock(1, 1, &P_l2_l);
+      blk_Ps_[l-1] =
+         std::make_unique<BlockOperator>(ops_offsets_[l], ops_offsets_[l-1]);
+      blk_Ps_[l-1]->SetBlock(0, 0, P_hdiv_l);
+      blk_Ps_[l-1]->SetBlock(1, 1, P_l2_l);
 
-      ops_[l-1] = new BlockOperator(ops_offsets_[l-1]);
+      ops_[l-1] =
+         std::make_unique<BlockOperator>(ops_offsets_[l-1]);
       ops_[l-1]->SetBlock(0, 0, M_c);
       ops_[l-1]->SetBlock(1, 0, B_c);
       ops_[l-1]->SetBlock(0, 1, B_c->Transpose());
-      ops_[l-1]->owns_blocks = true;
+      ops_[l-1]->owns_blocks = 1;
    }
 
-   Array<bool> own_ops(ops_.Size());
-   Array<bool> own_smoothers(smoothers_.Size());
-   Array<bool> own_Ps(blk_Ps_.Size());
-   own_ops = true;
-   own_smoothers = true;
-   own_Ps = true;
-
    if (data_.P_l2.size() == 0) { return; }
 
+   Array<bool> own_ops(ops_.size());
+   Array<bool> own_smoothers(smoothers_.size());
+   Array<bool> own_blk_Ps(blk_Ps_.size());
+   own_ops = false, own_smoothers = false, own_blk_Ps = false;
+
+   Array<Solver*> smoothers(smoothers_.size());
+
    if (param_.coupled_solve)
    {
       solver_.Reset(new GMRESSolver(B.GetComm()));
-      solver_.As<GMRESSolver>()->SetOperator(*(ops_.Last()));
-      prec_.Reset(new Multigrid(ops_, smoothers_, blk_Ps_,
-                                own_ops, own_smoothers, own_Ps));
+      solver_.As<GMRESSolver>()->SetOperator(*(ops_.back()));
+      Array<BlockOperator*> ops(ops_.size()), blk_Ps(blk_Ps_.size());
+      for (size_t i = 0; i < ops_.size(); ++i) { ops[i] = ops_[i].get(); }
+      for (size_t i = 0; i < blk_Ps_.size(); ++i) { blk_Ps[i] = blk_Ps_[i].get(); }
+      for (size_t i = 0; i < smoothers_.size(); ++i) { smoothers[i] = smoothers_[i].get(); }
+      prec_.Reset(new Multigrid(ops, smoothers, blk_Ps,
+                                own_ops, own_smoothers, own_blk_Ps));
    }
    else
    {
       Array<HypreParMatrix*> ops(data_.P_hcurl.size()+1);
-      Array<Solver*> smoothers(ops.Size());
       Array<HypreParMatrix*> Ps(data_.P_hcurl.size());
-      own_Ps = false;
-
-      HypreParMatrix& C_finest = *data.C.back().As<HypreParMatrix>();
-      ops.Last() = TwoStepsRAP(C_finest, M, C_finest);
+      auto C_finest = data.C.back().As<HypreParMatrix>();
+      ops.Last() = TwoStepsRAP(C_finest, &M, C_finest);
       ops.Last()->EliminateZeroRows();
       ops.Last()->DropSmallEntries(1e-14);
-
       solver_.Reset(new CGSolver(B.GetComm()));
       solver_.As<CGSolver>()->SetOperator(*ops.Last());
       smoothers.Last() = new HypreSmoother(*ops.Last());
       static_cast<HypreSmoother*>(smoothers.Last())->SetOperatorSymmetry(true);
-
       for (int l = Ps.Size()-1; l >= 0; --l)
       {
-         Ps[l] = data_.P_hcurl[l].As<HypreParMatrix>();
-         ops[l] = TwoStepsRAP(*Ps[l], *ops[l+1], *Ps[l]);
+         Ps[l] = data_.P_hcurl[l]->As<HypreParMatrix>();
+         ops[l] = TwoStepsRAP(Ps[l], ops[l+1], Ps[l]);
          ops[l]->DropSmallEntries(1e-14);
          smoothers[l] = new HypreSmoother(*ops[l]);
          static_cast<HypreSmoother*>(smoothers[l])->SetOperatorSymmetry(true);
       }
-
-      prec_.Reset(new Multigrid(ops, smoothers, Ps, own_ops, own_smoothers, own_Ps));
+      own_ops = true, own_smoothers = true;
+      prec_.Reset(new Multigrid(ops, smoothers, Ps,
+                                own_ops, own_smoothers, own_blk_Ps));
    }
 
    solver_.As<IterativeSolver>()->SetPreconditioner(*prec_.As<Solver>());
    SetOptions(*solver_.As<IterativeSolver>(), param_);
 }
 
-DivFreeSolver::~DivFreeSolver()
-{
-   if (param_.coupled_solve) { return; }
-   for (int i = 0; i < ops_.Size(); ++i)
-   {
-      delete ops_[i];
-      delete smoothers_[i];
-      if (i == ops_.Size() - 1) { break; }
-      delete blk_Ps_[i];
-   }
-}
-
 void DivFreeSolver::SolveParticular(const Vector& rhs, Vector& sol) const
 {
-   std::vector<Vector> rhss(smoothers_.Size());
-   std::vector<Vector> sols(smoothers_.Size());
-
+   std::vector<Vector> rhss(smoothers_.size()), sols(smoothers_.size());
    rhss.back().SetDataAndSize(const_cast<real_t*>(rhs.HostRead()), rhs.Size());
    sols.back().SetDataAndSize(sol.HostWrite(), sol.Size());
 
-   for (int l = blk_Ps_.Size()-1; l >= 0; --l)
+   for (int l = blk_Ps_.size()-1; l >= 0; --l)
    {
       rhss[l].SetSize(blk_Ps_[l]->NumCols());
       sols[l].SetSize(blk_Ps_[l]->NumCols());
@@ -470,12 +468,12 @@ void DivFreeSolver::SolveParticular(const Vector& rhs, Vector& sol) const
       blk_Ps_[l]->MultTranspose(rhss[l+1], rhss[l]);
    }
 
-   for (int l = 0; l < smoothers_.Size(); ++l)
+   for (size_t l = 0; l < smoothers_.size(); ++l)
    {
       smoothers_[l]->Mult(rhss[l], sols[l]);
    }
 
-   for (int l = 0; l < blk_Ps_.Size(); ++l)
+   for (size_t l = 0; l < blk_Ps_.size(); ++l)
    {
       Vector P_sol(blk_Ps_[l]->NumRows());
       blk_Ps_[l]->Mult(sols[l], P_sol);
@@ -507,12 +505,12 @@ void DivFreeSolver::Mult(const Vector & x, Vector & y) const
    MFEM_VERIFY(x.Size() == offsets_[2], "MLDivFreeSolver: x size is invalid");
    MFEM_VERIFY(y.Size() == offsets_[2], "MLDivFreeSolver: y size is invalid");
 
-   if (ops_.Size() == 1) { smoothers_[0]->Mult(x, y); return; }
+   if (ops_.size() == 1) { smoothers_[0]->Mult(x, y); return; }
 
    BlockVector blk_y(y, offsets_);
 
    BlockVector resid(offsets_);
-   ops_.Last()->Mult(y, resid);
+   ops_.back()->Mult(y, resid);
    add(1.0, x, -1.0, resid, resid);
 
    BlockVector correction(offsets_);
@@ -539,7 +537,7 @@ void DivFreeSolver::Mult(const Vector & x, Vector & y) const
       ch.Clear();
       ch.Start();
 
-      ops_.Last()->Mult(y, resid);
+      ops_.back()->Mult(y, resid);
       add(1.0, x, -1.0, resid, resid);
 
       SolveDivFree(resid.GetBlock(0), correction.GetBlock(0));
@@ -553,7 +551,7 @@ void DivFreeSolver::Mult(const Vector & x, Vector & y) const
       ch.Clear();
       ch.Start();
 
-      auto& M = dynamic_cast<const HypreParMatrix&>(ops_.Last()->GetBlock(0, 0));
+      auto& M = dynamic_cast<const HypreParMatrix&>(ops_.back()->GetBlock(0, 0));
       M.Mult(-1.0, correction.GetBlock(0), 1.0, resid.GetBlock(0));
       SolvePotential(resid.GetBlock(0), correction.GetBlock(1));
       blk_y.GetBlock(1) += correction.GetBlock(1);
@@ -567,11 +565,12 @@ void DivFreeSolver::Mult(const Vector & x, Vector & y) const
 
 int DivFreeSolver::GetNumIterations() const
 {
-   if (ops_.Size() == 1)
+   if (ops_.size() == 1)
    {
-      return static_cast<BDPMinresSolver*>(smoothers_[0])->GetNumIterations();
+      return static_cast<BDPMinresSolver*>
+             (smoothers_.at(0).get())->GetNumIterations();
    }
    return solver_.As<IterativeSolver>()->GetNumIterations();
 }
-} // namespace blocksolvers
-} // namespace mfem
+
+} // namespace mfem::blocksolvers

miniapps/solvers/div_free_solver.hpp

@@ -13,11 +13,11 @@
 #define MFEM_DIVFREE_SOLVER_HPP
 
 #include "darcy_solver.hpp"
+#include <memory>
 
-namespace mfem
-{
-namespace blocksolvers
+namespace mfem::blocksolvers
 {
+
 /// Parameters for the divergence free solver
 struct DFSParameters : IterSolveParameters
 {
@@ -35,14 +35,18 @@ struct DFSParameters : IterSolveParameters
 /// Data for the divergence free solver
 struct DFSData
 {
-   std::vector<OperatorPtr> agg_hdivdof;  // agglomerates to H(div) dofs table
-   std::vector<OperatorPtr> agg_l2dof;    // agglomerates to L2 dofs table
-   std::vector<OperatorPtr> P_hdiv;   // Interpolation matrix for H(div) space
-   std::vector<OperatorPtr> P_l2;     // Interpolation matrix for L2 space
-   std::vector<OperatorPtr> P_hcurl;  // Interpolation for kernel space of div
-   std::vector<OperatorPtr> Q_l2;     // Q_l2[l] = (W_{l+1})^{-1} P_l2[l]^T W_l
-   Array<int> coarsest_ess_hdivdofs;  // coarsest level essential H(div) dofs
-   std::vector<OperatorPtr> C;        // discrete curl: ND -> RT, map to Null(B)
+   using UniqueOperatorPtr = std::unique_ptr<OperatorPtr>;
+   using UniqueHypreParMatrix = std::unique_ptr<HypreParMatrix>;
+
+   std::vector<OperatorPtr> agg_hdivdof; // agglomerates to H(div) dofs table
+   std::vector<OperatorPtr> agg_l2dof; // agglomerates to L2 dofs table
+   std::vector<UniqueOperatorPtr> P_hdiv; // Interpolation matrix for H(div) space
+   std::vector<UniqueOperatorPtr> P_l2; // Interpolation matrix for L2 space
+   std::vector<UniqueOperatorPtr> P_hcurl; // Interpolation for kernel space of div
+   std::vector<OperatorPtr> Q_l2; // Q_l2[l] = (W_{l+1})^{-1} P_l2[l]^T W_l
+   Array<int> coarsest_ess_hdivdofs; // coarsest level essential H(div) dofs
+   std::vector<OperatorPtr> C; // discrete curl: ND -> RT, map to Null(B)
+   std::vector<UniqueHypreParMatrix> Ae;
    DFSParameters param;
 };
 
@@ -92,8 +96,7 @@ public:
 /// Compute the product B * B^T and solve it with CG preconditioned by BoomerAMG
 class BBTSolver : public Solver
 {
-   OperatorPtr BBT_;
-   OperatorPtr BBT_prec_;
+   OperatorPtr BBT_, BBT_prec_;
    CGSolver BBT_solver_;
 public:
    BBTSolver(const HypreParMatrix &B, IterSolveParameters param);
@@ -115,14 +118,11 @@ public:
 ///                      [ B   0  ]
 class SaddleSchwarzSmoother : public Solver
 {
-   const SparseMatrix& agg_hdivdof_;
-   const SparseMatrix& agg_l2dof_;
+   const SparseMatrix &agg_hdivdof_, &agg_l2dof_;
    OperatorPtr coarse_l2_projector_;
 
    Array<int> offsets_;
-   mutable Array<int> offsets_loc_;
-   mutable Array<int> hdivdofs_loc_;
-   mutable Array<int> l2dofs_loc_;
+   mutable Array<int> offsets_loc_, hdivdofs_loc_, l2dofs_loc_;
    std::vector<OperatorPtr> solvers_loc_;
 public:
    /** SaddleSchwarzSmoother solves local saddle point problems defined on a
@@ -140,7 +140,7 @@ public:
                          const SparseMatrix& agg_hdivdof,
                          const SparseMatrix& agg_l2dof,
                          const HypreParMatrix& P_l2,
-                         const HypreParMatrix& Q_l2);
+                         const ProductOperator& Q_l2);
    void Mult(const Vector &x, Vector &y) const override;
    void MultTranspose(const Vector &x, Vector &y) const override { Mult(x, y); }
    void SetOperator(const Operator &op) override { }
@@ -178,11 +178,10 @@ class DivFreeSolver : public DarcySolver
    OperatorPtr BT_;
    BBTSolver BBT_solver_;
    std::vector<Array<int>> ops_offsets_;
-   Array<BlockOperator*> ops_;
-   Array<BlockOperator*> blk_Ps_;
-   Array<Solver*> smoothers_;
-   OperatorPtr prec_;
-   OperatorPtr solver_;
+   std::vector<std::unique_ptr<BlockOperator>> ops_;
+   std::vector<std::unique_ptr<BlockOperator>> blk_Ps_;
+   std::vector<std::unique_ptr<Solver>> smoothers_;
+   OperatorPtr prec_, solver_;
 
    void SolveParticular(const Vector& rhs, Vector& sol) const;
    void SolveDivFree(const Vector& rhs, Vector& sol) const;
@@ -190,14 +189,11 @@ class DivFreeSolver : public DarcySolver
 public:
    DivFreeSolver(const HypreParMatrix& M, const HypreParMatrix &B,
                  const DFSData& data);
-   ~DivFreeSolver();
    void Mult(const Vector &x, Vector &y) const override;
    void SetOperator(const Operator &op) override { }
    int GetNumIterations() const override;
 };
 
-} // namespace blocksolvers
-
-} // namespace mfem
+} // namespace mfem::blocksolvers
 
 #endif // MFEM_DIVFREE_SOLVER_HPP

miniapps/spde/generate_random_field.cpp

@@ -33,8 +33,6 @@
 //     (2D random field with anisotropy)
 //     mpirun -np 4 generate_random_field -o 1 -r 3 -rp 3 -nu 4 -l1 0.09 -l2 0.03 -l3 0.05 -s 0.01 -t 0.08 -top 1 -no-rs -m ../../data/ref-square.mesh
 
-#include <math.h>
-#include <fstream>
 #include <iostream>
 #include <string>
 #include "mfem.hpp"
@@ -260,7 +258,8 @@ int main(int argc, char *argv[])
    // III.3 Solve the SPDE problem
    spde::SPDESolver solver(nu, bc, &fespace, l1, l2, l3, e1, e2,
                            e3);
-   const int seed = (random_seed) ? 0 : std::numeric_limits<int>::max();
+   const int seed = (random_seed) ? 0 :
+                    std::numeric_limits<int>::max() - Mpi::WorldRank();
    solver.SetupRandomFieldGenerator(seed);
    solver.GenerateRandomField(u);
 

miniapps/toys/lissajous.cpp

@@ -133,8 +133,11 @@ int main(int argc, char *argv[])
       u.Save(sol_ofs);
    }
 
-   soutv << "keys '.0" << std::string((int)b, '0') << "'\n" << flush;
-   south << "keys '.0" << std::string((int)a, '0') << "'\n" << flush;
+   if (visualization)
+   {
+      soutv << "keys '.0" << std::string((int)b, '0') << "'\n" << flush;
+      south << "keys '.0" << std::string((int)a, '0') << "'\n" << flush;
+   }
 
    cout << "Which direction(s) are the two curves spinning in?\n";
 

tests/unit/CMakeLists.txt

@@ -179,25 +179,42 @@ if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
 endif()
 
 #-----------------------------------------------------------
-# SERIAL CUDA TESTS: cunit_tests
+# SERIAL CUDA TESTS: gpu_unit_tests
 #-----------------------------------------------------------
-# Create CUDA 'cunit_tests' executable and test
+# Create CUDA executable and test
 if (MFEM_USE_CUDA)
-   set(CUNIT_TESTS_SRCS cunit_test_main.cpp)
-   set_property(SOURCE ${CUNIT_TESTS_SRCS} PROPERTY LANGUAGE CUDA)
-   mfem_add_executable(cunit_tests ${CUNIT_TESTS_SRCS} ${UNIT_TESTS_SRCS})
-   target_link_libraries(cunit_tests mfem)
-   add_dependencies(cunit_tests copy_data)
-   add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} cunit_tests)
+   # gpu_unit_tests
+   set(GPU_UNIT_TESTS_SRCS gpu_unit_test_main.cpp)
+   set_property(SOURCE ${GPU_UNIT_TESTS_SRCS} PROPERTY LANGUAGE CUDA)
+   mfem_add_executable(gpu_unit_tests ${GPU_UNIT_TESTS_SRCS} ${UNIT_TESTS_SRCS})
+   target_link_libraries(gpu_unit_tests mfem)
+   add_dependencies(gpu_unit_tests copy_data)
+   add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} gpu_unit_tests)
    if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
-      add_test(NAME cunit_tests COMMAND cunit_tests)
+      add_test(NAME gpu_unit_tests COMMAND gpu_unit_tests)
+   endif()
+endif()
+
+#-----------------------------------------------------------
+# SERIAL HIP TESTS: gpu_unit_tests
+#-----------------------------------------------------------
+# Create HIP 'gpu_unit_tests' executable and test
+if (MFEM_USE_HIP)
+   # gpu_unit_tests
+   set(GPU_UNIT_TESTS_SRCS gpu_unit_test_main.cpp)
+   mfem_add_executable(gpu_unit_tests ${GPU_UNIT_TESTS_SRCS} ${UNIT_TESTS_SRCS})
+   target_link_libraries(gpu_unit_tests mfem)
+   add_dependencies(gpu_unit_tests copy_data)
+   add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} gpu_unit_tests)
+   if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
+      add_test(NAME gpu_unit_tests COMMAND gpu_unit_tests)
    endif()
 endif()
 
 #-----------------------------------------------------------
 # SERIAL SEDOV + TMOP TESTS:
-#   sedov_tests_{cpu,debug,cuda,cuda_uvm}
-#   tmop_pa_tests_{cpu,debug,cuda}
+#   sedov_tests_{cpu,debug,gpu,gpu_uvm}
+#   tmop_pa_tests_{cpu,debug,gpu}
 #-----------------------------------------------------------
 # Function to add one device serial test from the tests/unit/miniapp directory.
 # All device unit tests are built into a separate executable, in order to be
@@ -226,27 +243,27 @@ function(add_serial_miniapp_test name test_uvm)
         add_test(NAME ${name}_tests_debug COMMAND ${name}_tests_debug)
     endif()
 
-    if (MFEM_USE_CUDA)
-       mfem_add_executable(${name}_tests_cuda ${${NAME}_TESTS_SRCS})
-       target_compile_definitions(${name}_tests_cuda PUBLIC MFEM_${NAME}_DEVICE="cuda")
-       target_link_libraries(${name}_tests_cuda mfem)
-       add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} ${name}_tests_cuda)
+    if (MFEM_USE_CUDA OR MFEM_USE_HIP)
+       mfem_add_executable(${name}_tests_gpu ${${NAME}_TESTS_SRCS})
+       target_compile_definitions(${name}_tests_gpu PUBLIC MFEM_${NAME}_DEVICE="gpu")
+       target_link_libraries(${name}_tests_gpu mfem)
+       add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} ${name}_tests_gpu)
        if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
-           add_test(NAME ${name}_tests_cuda COMMAND ${name}_tests_cuda)
+           add_test(NAME ${name}_tests_gpu COMMAND ${name}_tests_gpu)
        endif()
 
        if (test_uvm)
-           mfem_add_executable(${name}_tests_cuda_uvm ${${NAME}_TESTS_SRCS})
-           target_compile_definitions(${name}_tests_cuda_uvm PUBLIC
-               MFEM_${NAME}_DEVICE="cuda:uvm")
-           target_link_libraries(${name}_tests_cuda_uvm mfem)
+           mfem_add_executable(${name}_tests_gpu_uvm ${${NAME}_TESTS_SRCS})
+           target_compile_definitions(${name}_tests_gpu_uvm PUBLIC
+               MFEM_${NAME}_DEVICE="gpu:uvm")
+           target_link_libraries(${name}_tests_gpu_uvm mfem)
            add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME}
-               ${name}_tests_cuda_uvm)
+               ${name}_tests_gpu_uvm)
            if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
-               add_test(NAME ${name}_tests_cuda_uvm COMMAND ${name}_tests_cuda_uvm)
+               add_test(NAME ${name}_tests_gpu_uvm COMMAND ${name}_tests_gpu_uvm)
            endif()
        endif()
-    endif(MFEM_USE_CUDA)
+    endif()
 endfunction(add_serial_miniapp_test)
 
 add_serial_miniapp_test(sedov ON)  # UVM ON
@@ -282,10 +299,11 @@ if (MFEM_USE_CEED)
 endif()
 
 #-----------------------------------------------------------
-# PARALLEL CPU AND CUDA TESTS: {p,pc}unit_tests
+# PARALLEL CPU AND CUDA TESTS: {p,pc}unit_tests and pgpu_unit_tests
 #-----------------------------------------------------------
-# Define executables and tests 'punit_tests' and 'pcunit_tests'
+# Define executables and tests
 if (MFEM_USE_MPI)
+   # punit_tests
    if (MFEM_USE_CUDA)
       set_property(SOURCE punit_test_main.cpp PROPERTY LANGUAGE CUDA)
    endif()
@@ -301,27 +319,44 @@ if (MFEM_USE_MPI)
       endif()
    endforeach()
    if (MFEM_USE_CUDA)
-      set(PCUNIT_TESTS_SRCS pcunit_test_main.cpp)
-      set_property(SOURCE ${PCUNIT_TESTS_SRCS} PROPERTY LANGUAGE CUDA)
-      mfem_add_executable(pcunit_tests ${PCUNIT_TESTS_SRCS} ${UNIT_TESTS_SRCS})
-      add_dependencies(pcunit_tests copy_data)
-      target_link_libraries(pcunit_tests mfem)
-      add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} pcunit_tests)
-      foreach(np 1 ${MFEM_MPI_NP})
-         if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
-            add_test(NAME pcunit_tests_np=${np}
-                     COMMAND ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${np}
-                     ${MPIEXEC_PREFLAGS} $<TARGET_FILE:pcunit_tests>
-                     ${MPIEXEC_POSTFLAGS})
-         endif()
-      endforeach()
+       # pgpu_unit_tests
+       set(PGPU_UNIT_TESTS_SRCS pgpu_unit_test_main.cpp)
+       set_property(SOURCE ${PGPU_UNIT_TESTS_SRCS} PROPERTY LANGUAGE CUDA)
+       mfem_add_executable(pgpu_unit_tests ${PGPU_UNIT_TESTS_SRCS} ${UNIT_TESTS_SRCS})
+       add_dependencies(pgpu_unit_tests copy_data)
+       target_link_libraries(pgpu_unit_tests mfem)
+       add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} pgpu_unit_tests)
+       foreach(np 1 ${MFEM_MPI_NP})
+          if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
+             add_test(NAME pgpu_unit_tests_np=${np}
+                      COMMAND ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${np}
+                      ${MPIEXEC_PREFLAGS} $<TARGET_FILE:pgpu_unit_tests>
+                      ${MPIEXEC_POSTFLAGS})
+          endif()
+       endforeach()
+    endif()
+    if (MFEM_USE_HIP)
+       # pgpu_unit_tests
+       set(PGPU_UNIT_TESTS_SRCS pgpu_unit_test_main.cpp)
+       mfem_add_executable(pgpu_unit_tests ${PGPU_UNIT_TESTS_SRCS} ${UNIT_TESTS_SRCS})
+       add_dependencies(pgpu_unit_tests copy_data)
+       target_link_libraries(pgpu_unit_tests mfem)
+       add_dependencies(${MFEM_ALL_TESTS_TARGET_NAME} pgpu_unit_tests)
+       foreach(np 1 ${MFEM_MPI_NP})
+          if (MFEM_USE_DOUBLE) # otherwise returns MFEM_SKIP_RETURN_VALUE
+             add_test(NAME pgpu_unit_tests_np=${np}
+                      COMMAND ${MPIEXEC} ${MPIEXEC_NUMPROC_FLAG} ${np}
+                      ${MPIEXEC_PREFLAGS} $<TARGET_FILE:pgpu_unit_tests>
+                      ${MPIEXEC_POSTFLAGS})
+          endif()
+       endforeach()
    endif()
 endif(MFEM_USE_MPI)
 
 #-----------------------------------------------------------
 # PARALLEL SEDOV + TMOP TESTS:
-#   psedov_tests_{cpu,debug,cuda,cuda_uvm}
-#   ptmop_pa_tests_{cpu,cuda}
+#   psedov_tests_{cpu,debug,gpu,gpu_uvm}
+#   ptmop_pa_tests_{cpu,gpu}
 #-----------------------------------------------------------
 # Function to add one MPI executable for a test.
 function(add_mpi_executable_test name dev)
@@ -371,10 +406,10 @@ function(add_parallel_miniapp_test name HYPRE_MM)
             list(APPEND backends debug)
         endif()
     endif()
-    if (MFEM_USE_CUDA)
-        list(APPEND backends cuda)
+    if (MFEM_USE_CUDA OR MFEM_USE_HIP)
+        list(APPEND backends gpu)
         if (HYPRE_MM)
-            list(APPEND backends cuda_uvm)
+            list(APPEND backends gpu_uvm)
         endif()
     endif()
 

tests/unit/README.md

@@ -8,10 +8,10 @@ This directory contains MFEM's suite of unit tests, using the
 MFEM's unit test suite includes a number of executables:
 
 * `unit_tests`
-* `cunit_tests` if MFEM is compiled with CUDA support
-* `sedov_tests_cpu`, `sedov_tests_debug` (and `sedov_tests_cuda` and
-  `sedov_tests_cuda_uvm` if CUDA is enabled), testing a Sedov hydrodynamics case
-* `tmop_pa_tests_cpu`, `tmop_pa_tests_debug` (and `tmop_pa_tests_cuda` if CUDA
+* `gpu_unit_tests` if MFEM is compiled with CUDA/HIP support
+* `sedov_tests_cpu`, `sedov_tests_debug` (and `sedov_tests_gpu` and
+  `sedov_tests_gpu_uvm` if GPU is enabled), testing a Sedov hydrodynamics case
+* `tmop_pa_tests_cpu`, `tmop_pa_tests_debug` (and `tmop_pa_tests_gpu` if GPU
   is enabled), testing TMOP with partial assembly
 
 There are also parallel versions of these executables (prefixed with `p`), which
@@ -67,11 +67,11 @@ and those are:
   serial test executables, and will only be tested with the parallel executable
   (e.g. `punit_tests`). `punit_tests` will only run tests marked with
   `[Parallel]`.
-* `[CUDA]`, which indicates that a test will be tested with the CUDA executables
-  (e.g. `cunit_tests`). These tests will still be run by the standard (CPU)
-  executables. `cunit_tests` will only run tests marked with `[CUDA]`, and its
-  parallel version `pcunit_tests` will only run tests marked with _both_
-  `[CUDA]` and `[Parallel]`.
+* `[GPU]`, which indicates that a test will be tested with the GPU executables
+  (e.g. `gpu_unit_tests`). These tests will still be run by the standard (CPU)
+  executables. `gpu_unit_tests` will only run tests marked with `[GPU]`, and its
+  parallel version `pgpu_unit_tests` will only run tests marked with _both_
+  `[GPU]` and `[Parallel]`.
 * `[MFEMData]`, which indicates that a test requires access to a clone of the
   MFEM data repository (see the `--data` flag below), in order to run tests on
   some larger mesh files. By default, tests tagged with this tag are skipped,

tests/unit/fem/test_assemblediagonalpa.cpp

@@ -185,7 +185,7 @@ TEST_CASE("Diffusion Diagonal PA", "[PartialAssembly][AssembleDiagonal]")
    {
       for (int ne = 1; ne < 3; ++ne)
       {
-         const int n_elements = pow(ne, dimension);
+         const int n_elements = static_cast<int>(pow(ne, dimension));
          CAPTURE(dimension, n_elements);
 
          for (int order = 1; order < 5; ++order)
@@ -359,7 +359,7 @@ TEST_CASE("Vector Diffusion Diagonal PA",
 }
 
 TEST_CASE("Hcurl/Hdiv diagonal PA",
-          "[CUDA][PartialAssembly][AssembleDiagonal]")
+          "[GPU][PartialAssembly][AssembleDiagonal]")
 {
    for (int dimension = 2; dimension < 4; ++dimension)
    {
@@ -404,7 +404,7 @@ TEST_CASE("Hcurl/Hdiv diagonal PA",
             {
                for (int ne = 1; ne < 3; ++ne)
                {
-                  const int n_elements = std::pow(ne, dimension);
+                  const int n_elements = static_cast<int>(std::pow(ne, dimension));
                   CAPTURE(dimension, spaceType, integrator, coeffType, n_elements);
 
                   int max_order = (dimension == 3) ? 2 : 3;

tests/unit/fem/test_assembly_levels.cpp

@@ -195,7 +195,7 @@ void test_assembly_level(const char *meshname,
    REQUIRE(y_test.Norml2() < 1.e-12);
 }
 
-TEST_CASE("H1 Assembly Levels", "[AssemblyLevel], [PartialAssembly], [CUDA]")
+TEST_CASE("H1 Assembly Levels", "[AssemblyLevel], [PartialAssembly], [GPU]")
 {
    const bool all_tests = launch_all_non_regression_tests;
 
@@ -251,7 +251,7 @@ TEST_CASE("H1 Assembly Levels", "[AssemblyLevel], [PartialAssembly], [CUDA]")
    }
 } // H1 Assembly Levels test case
 
-TEST_CASE("H(div) Element Assembly", "[AssemblyLevel][CUDA]")
+TEST_CASE("H(div) Element Assembly", "[AssemblyLevel][GPU]")
 {
    const auto fname = GENERATE(
                          "../../data/inline-quad.mesh",
@@ -316,7 +316,7 @@ TEST_CASE("H(div) Element Assembly", "[AssemblyLevel][CUDA]")
    }
 }
 
-TEST_CASE("NormalTraceJumpIntegrator Element Assembly", "[AssemblyLevel][CUDA]")
+TEST_CASE("NormalTraceJumpIntegrator Element Assembly", "[AssemblyLevel][GPU]")
 {
    const auto fname = GENERATE(
                          "../../data/inline-quad.mesh",
@@ -387,7 +387,7 @@ TEST_CASE("NormalTraceJumpIntegrator Element Assembly", "[AssemblyLevel][CUDA]")
    }
 }
 
-TEST_CASE("L2 Assembly Levels", "[AssemblyLevel], [PartialAssembly], [CUDA]")
+TEST_CASE("L2 Assembly Levels", "[AssemblyLevel], [PartialAssembly], [GPU]")
 {
    const bool dg = true;
    auto pb = GENERATE(Problem::Mass, Problem::Convection);
@@ -454,7 +454,16 @@ void CompareMatricesNonZeros(SparseMatrix &A1, const SparseMatrix &A2,
                              HYPRE_BigInt *cmap1=nullptr,
                              std::unordered_map<HYPRE_BigInt,int> *cmap2inv=nullptr)
 {
-   REQUIRE(A1.Height() == A2.Height());
+   bool A1_Heigh_equals_A2_Height = A1.Height() == A2.Height();
+#ifdef MFEM_USE_MPI
+   if (Mpi::IsInitialized() && !Mpi::IsFinalized())
+   {
+      const bool in = A1_Heigh_equals_A2_Height;
+      MPI_Allreduce(&in, &A1_Heigh_equals_A2_Height, 1, MPI_C_BOOL, MPI_LAND,
+                    MPI_COMM_WORLD);
+   }
+#endif
+   REQUIRE(A1_Heigh_equals_A2_Height);
    int n = A1.Height();
 
    const int *I1 = A1.HostReadI();
@@ -488,6 +497,14 @@ void CompareMatricesNonZeros(SparseMatrix &A1, const SparseMatrix &A2,
       }
    }
 
+#ifdef MFEM_USE_MPI
+   if (Mpi::IsInitialized() && !Mpi::IsFinalized())
+   {
+      const real_t in = error;
+      MPI_Allreduce(&in, &error, 1, MPITypeMap<real_t>::mpi_type, MPI_MAX,
+                    MPI_COMM_WORLD);
+   }
+#endif
    REQUIRE(error == MFEM_Approx(0.0, 1e-10));
 }
 
@@ -559,7 +576,7 @@ void TestH1FullAssembly(Mesh &mesh, int order)
    REQUIRE(B1.Normlinf() == MFEM_Approx(0.0));
 }
 
-TEST_CASE("Serial H1 Full Assembly", "[AssemblyLevel], [CUDA]")
+TEST_CASE("Serial H1 Full Assembly", "[AssemblyLevel], [GPU]")
 {
    auto order = GENERATE(1, 2, 3);
    auto mesh_fname = GENERATE(
@@ -570,7 +587,7 @@ TEST_CASE("Serial H1 Full Assembly", "[AssemblyLevel], [CUDA]")
    TestH1FullAssembly(mesh, order);
 }
 
-TEST_CASE("Full Assembly Connectivity", "[AssemblyLevel], [CUDA]")
+TEST_CASE("Full Assembly Connectivity", "[AssemblyLevel], [GPU]")
 {
    const int order = GENERATE(1, 2, 3);
    const int ne = GENERATE(4, 8, 16, 32);
@@ -638,7 +655,7 @@ void TestSameHypreMatrices(OperatorHandle &A1, OperatorHandle &A2)
    CompareMatricesNonZeros(*M2, *M1);
 }
 
-TEST_CASE("Parallel H1 Full Assembly", "[AssemblyLevel], [Parallel], [CUDA]")
+TEST_CASE("Parallel H1 Full Assembly", "[AssemblyLevel], [Parallel], [GPU]")
 {
    auto order = GENERATE(1, 2, 3);
    auto mesh_fname = GENERATE(
@@ -646,6 +663,8 @@ TEST_CASE("Parallel H1 Full Assembly", "[AssemblyLevel], [Parallel], [CUDA]")
                         "../../data/fichera.mesh"
                      );
 
+   // CAPTURE(order, mesh_fname);
+
    Mesh serial_mesh(mesh_fname);
    ParMesh mesh(MPI_COMM_WORLD, serial_mesh);
    serial_mesh.Clear();
@@ -675,17 +694,25 @@ TEST_CASE("Parallel H1 Full Assembly", "[AssemblyLevel], [Parallel], [CUDA]")
 
    OperatorHandle A_fa, A_legacy;
 
-   // Test that ParallelAssemble gives the same result
-   A_fa.Reset(a_fa.ParallelAssemble());
-   A_legacy.Reset(a_legacy.ParallelAssemble());
+   DYNAMIC_SECTION("[order: " << order << ", dim: " << dim
+                   << "]: (1) ParallelAssemble")
+   {
+      // Test that ParallelAssemble gives the same result
+      A_fa.Reset(a_fa.ParallelAssemble());
+      A_legacy.Reset(a_legacy.ParallelAssemble());
 
-   TestSameHypreMatrices(A_fa, A_legacy);
+      TestSameHypreMatrices(A_fa, A_legacy);
+   }
 
-   // Test that FormSystemMatrix gives the same result
-   a_fa.FormSystemMatrix(ess_tdof_list, A_fa);
-   a_legacy.FormSystemMatrix(ess_tdof_list, A_legacy);
+   DYNAMIC_SECTION("[order: " << order << ", dim: " << dim
+                   << "]: (2) FormSystemMatrix")
+   {
+      // Test that FormSystemMatrix gives the same result
+      a_fa.FormSystemMatrix(ess_tdof_list, A_fa);
+      a_legacy.FormSystemMatrix(ess_tdof_list, A_legacy);
 
-   TestSameHypreMatrices(A_fa, A_legacy);
+      TestSameHypreMatrices(A_fa, A_legacy);
+   }
 
    // Test that FormLinearSystem gives the same result
    ParGridFunction x1(&fespace);
@@ -701,13 +728,23 @@ TEST_CASE("Parallel H1 Full Assembly", "[AssemblyLevel], [Parallel], [CUDA]")
 
    a_fa.Assemble();
 
-   a_fa.FormLinearSystem(ess_tdof_list, x1, b1, A_fa, X1, B1);
-   a_legacy.FormLinearSystem(ess_tdof_list, x2, b2, A_legacy, X2, B2);
+   DYNAMIC_SECTION("[order: " << order << ", dim: " << dim
+                   << "]: (3) FormLinearSystem")
+   {
+      a_fa.FormLinearSystem(ess_tdof_list, x1, b1, A_fa, X1, B1);
+      a_legacy.FormLinearSystem(ess_tdof_list, x2, b2, A_legacy, X2, B2);
 
-   TestSameHypreMatrices(A_fa, A_legacy);
+      TestSameHypreMatrices(A_fa, A_legacy);
+   }
 
-   B1 -= B2;
-   REQUIRE(B1.Normlinf() == MFEM_Approx(0.0));
+   DYNAMIC_SECTION("[order: " << order << ", dim: " << dim
+                   << "]: (4) FormLinearSystem - RHS")
+   {
+      B1 -= B2;
+      const real_t B_err = GlobalLpNorm(infinity(), B1.Normlinf(),
+                                        MPI_COMM_WORLD);
+      REQUIRE(B_err == MFEM_Approx(0.0));
+   }
 }
 
 #endif