Interpolation between different meshes

cpp/demo/hyperelasticity/CMakeLists.txt

@@ -26,7 +26,7 @@ else()
     VERBATIM DEPENDS hyperelasticity.py COMMENT "Compile hyperelasticity.py using FFCx")
 
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
-
+  
   add_executable(${PROJECT_NAME} main.cpp ${CMAKE_CURRENT_BINARY_DIR}/hyperelasticity.c)
   target_link_libraries(${PROJECT_NAME} dolfinx)
 

cpp/demo/interpolation-io/CMakeLists.txt

@@ -16,6 +16,8 @@ if (NOT TARGET dolfinx)
   find_package(DOLFINX REQUIRED)
 endif()
 
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
 add_executable(${PROJECT_NAME} main.cpp)
 target_link_libraries(${PROJECT_NAME} dolfinx)
 

cpp/demo/interpolation/CMakeLists.txt

@@ -0,0 +1,35 @@
+# This file was generated by running
+#
+#     python cmake/scripts/generate-cmakefiles from dolfinx/cpp
+#
+cmake_minimum_required(VERSION 3.16)
+
+set(PROJECT_NAME demo_interpolation)
+project(${PROJECT_NAME} LANGUAGES C CXX)
+
+# Set C++17 standard
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+if (NOT TARGET dolfinx)
+  find_package(DOLFINX REQUIRED)
+endif()
+
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
+add_executable(${PROJECT_NAME} main.cpp)
+target_link_libraries(${PROJECT_NAME} dolfinx)
+
+# Do not throw error for 'multi-line comments' (these are typical in
+# rst which includes LaTeX)
+include(CheckCXXCompilerFlag)
+CHECK_CXX_COMPILER_FLAG("-Wno-comment" HAVE_NO_MULTLINE)
+set_source_files_properties(main.cpp PROPERTIES COMPILE_FLAGS "$<$<BOOL:${HAVE_NO_MULTLINE}>:-Wno-comment -Wall -Wextra -pedantic -Werror>")
+
+# Test targets (used by DOLFINx testing system)
+set(TEST_PARAMETERS2 -np 2 ${MPIEXEC_PARAMS} "./${PROJECT_NAME}")
+set(TEST_PARAMETERS3 -np 3 ${MPIEXEC_PARAMS} "./${PROJECT_NAME}")
+add_test(NAME ${PROJECT_NAME}_mpi_2 COMMAND "mpirun" ${TEST_PARAMETERS2})
+add_test(NAME ${PROJECT_NAME}_mpi_3 COMMAND "mpirun" ${TEST_PARAMETERS3})
+add_test(NAME ${PROJECT_NAME}_serial COMMAND ${PROJECT_NAME})

cpp/demo/interpolation/main.cpp

@@ -0,0 +1,80 @@
+#include <basix/e-lagrange.h>
+#include <cmath>
+#include <dolfinx/common/timing.h>
+#include <dolfinx/fem/utils.h>
+#include <dolfinx/io/ADIOS2Writers.h>
+#include <dolfinx/mesh/generation.h>
+#include <memory>
+
+using namespace dolfinx;
+
+using T = double;
+
+void interpolation_different_meshes()
+{
+  const std::array<std::size_t, 3> subdivisions = {50, 50, 50};
+
+  auto meshL = std::make_shared<mesh::Mesh>(mesh::create_box(
+      MPI_COMM_WORLD, {{{0, 0, 0}, {1, 1, 1}}}, subdivisions,
+      mesh::CellType::tetrahedron, mesh::GhostMode::shared_facet));
+
+auto meshR = std::make_shared<mesh::Mesh>(mesh::create_box(
+      MPI_COMM_WORLD, {{{0, 0, 0}, {1, 1, 1}}}, {47, 49, 33},
+      mesh::CellType::hexahedron, mesh::GhostMode::shared_facet));
+
+  basix::FiniteElement eL = basix::element::create_lagrange(
+      mesh::cell_type_to_basix_type(meshL->topology().cell_type()), 1,
+      basix::element::lagrange_variant::equispaced, false);
+  auto VL = std::make_shared<fem::FunctionSpace>(
+      fem::create_functionspace(meshL, eL, 3));
+
+  basix::FiniteElement eR = basix::element::create_lagrange(
+      mesh::cell_type_to_basix_type(meshR->topology().cell_type()), 2,
+      basix::element::lagrange_variant::equispaced, false);
+  auto VR = std::make_shared<fem::FunctionSpace>(
+      fem::create_functionspace(meshR, eR, 3));
+
+  auto uL = std::make_shared<fem::Function<T>>(VL);
+  auto uR = std::make_shared<fem::Function<T>>(VR);
+
+  auto fun = [](auto& x)
+  {
+    auto r = xt::zeros_like(x);
+    for (std::size_t i = 0; i < x.shape(1); ++i)
+    {
+      r(0, i) = std::cos(10 * x(0, i)) * std::sin(10 * x(2, i));
+      r(1, i) = std::sin(10 * x(0, i)) * std::sin(10 * x(2, i));
+      r(2, i) = std::cos(10 * x(0, i)) * std::cos(10 * x(2, i));
+    }
+    return r;
+  };
+
+  uL->interpolate(fun);
+
+  uR->interpolate(*uL);
+
+  io::VTXWriter writeruL(meshL->comm(), "uL.bp", {uL});
+  writeruL.write(0.0);
+
+  io::VTXWriter writeruR(meshR->comm(), "uR.bp", {uR});
+  writeruR.write(0.0);
+}
+
+int main(int argc, char* argv[])
+{
+  dolfinx::init_logging(argc, argv);
+  MPI_Init(&argc, &argv);
+
+  int mpi_rank;
+  MPI_Comm_rank(MPI_COMM_WORLD, &mpi_rank);
+
+  interpolation_different_meshes();
+  dolfinx::list_timings(MPI_COMM_WORLD, {dolfinx::TimingType::wall},
+                        dolfinx::Table::Reduction::max);
+
+  dolfinx::list_timings(MPI_COMM_WORLD, {dolfinx::TimingType::wall},
+                        dolfinx::Table::Reduction::min);
+  MPI_Finalize();
+
+  return 0;
+}

cpp/demo/poisson_matrix_free/CMakeLists.txt

@@ -25,6 +25,8 @@ add_custom_command(
   COMMAND ffcx ${CMAKE_CURRENT_SOURCE_DIR}/poisson.py ${SCALAR_TYPE}
   VERBATIM DEPENDS poisson.py COMMENT "Compile poisson.py using FFCx")
 
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
 add_executable(${PROJECT_NAME} main.cpp ${CMAKE_CURRENT_BINARY_DIR}/poisson.c)
 target_link_libraries(${PROJECT_NAME} dolfinx)