49 implement step 40 of dealii guide

.gitignore

@@ -1,6 +1,8 @@
 doc/html
 doc/latex
 
+experiments/
+
 .aider*
 .vscode
 

backends/dealii/include/register_types.h

@@ -18,6 +18,7 @@
 
 #include "coral.h"
 #include "coral_network.h"
+#include "laplace.h"
 #include "poisson.h"
 
 /** \cond INTERNAL */
@@ -164,6 +165,13 @@ namespace coral
       &PoissonSolver<dim, spacedim>::solve,
       {"PoissonSolver::solve<" + Utilities::dim_string(dim, spacedim) + ">",
        "poisson_solver"});
+
+    NodeObject::register_type<LaplaceProblem<dim>, bool>("mpi_initialize");
+    NodeObject::register_method<LaplaceProblem<dim>, void, const std::string &>(
+      &LaplaceProblem<dim>::run,
+      {"LaplaceProblem::run<" + Utilities::dim_string(dim, spacedim) + ">",
+       "laplace_problem",
+       "output_dir"});
   }
 
 

backends/dealii/tests/CMakeLists.txt

@@ -1,4 +1,5 @@
 find_package(GTest)
+find_package(MPI)
 if(NOT GTest_FOUND)
   message(WARNING "GTest not found; skipping deal.II backend tests")
   return()
@@ -11,7 +12,10 @@ include(GoogleTest)
 # Keep plugin smoke test in its own executable so it doesn't get "help" from
 # backend tests that register types directly.
 set(_plugin_test_file ${CMAKE_CURRENT_LIST_DIR}/plugin_smoke_test.cc)
-list(REMOVE_ITEM _test_files ${_plugin_test_file})
+set(_mpi_test_file ${CMAKE_CURRENT_LIST_DIR}/dealii_mpi.cc)
+list(REMOVE_ITEM _test_files ${_plugin_test_file} ${_mpi_test_file})
+
+# BACKEND TESTS
 
 add_executable(dealii_backend_tests ${_test_files})
 
@@ -47,6 +51,70 @@ gtest_discover_tests(dealii_backend_tests
   WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
   PROPERTIES LABELS "dealii;backend")
 
+# MPI TESTS
+
+add_executable(dealii_mpi_tests ${_mpi_test_file})
+
+target_include_directories(dealii_mpi_tests
+  PRIVATE
+    ${CMAKE_CURRENT_LIST_DIR}/../include)
+
+target_link_libraries(dealii_mpi_tests
+  coral_core
+  ${GTEST_LIBRARIES}
+  ${GTEST_MAIN_LIBRARIES})
+
+if(GTEST_INCLUDE_DIRS)
+  target_include_directories(dealii_mpi_tests SYSTEM PRIVATE ${GTEST_INCLUDE_DIRS})
+endif()
+
+deal_ii_setup_target(dealii_mpi_tests)
+
+if(MSVC)
+  target_compile_options(dealii_mpi_tests PRIVATE /W0)
+else()
+  target_compile_options(dealii_mpi_tests PRIVATE -w)
+endif()
+
+# Prefer running the gtest binary directly (faster iteration than ctest).
+add_custom_target(run_mpi_backend_tests
+  COMMAND ${MPIEXEC_EXECUTABLE} ${MPIEXEC_NUMPROC_FLAG} 4 "$<TARGET_FILE:dealii_mpi_tests>"
+  DEPENDS dealii_mpi_tests
+  USES_TERMINAL)
+
+# Register MPI tests with CTest.
+# gtest_discover_tests(EXECUTOR) requires CMake >= 3.29. For 3.28 we set the
+# CROSSCOMPILING_EMULATOR target property, which gtest_discover_tests respects.
+# A wrapper script is used so discovery (--gtest_list_tests) runs with -n 1
+# (single clean output) while actual test execution uses -n 4.
+if(MPI_FOUND)
+  set(_mpi_wrapper ${CMAKE_CURRENT_BINARY_DIR}/mpi_gtest_wrapper.sh)
+  file(WRITE ${_mpi_wrapper}
+"#!/bin/bash
+if [[ \"$*\" == *\"--gtest_list_tests\"* ]]; then
+  exec \"$@\"
+else
+  exec ${MPIEXEC_EXECUTABLE} ${MPIEXEC_NUMPROC_FLAG} 4 \"$@\"
+fi
+")
+  file(CHMOD ${_mpi_wrapper}
+    PERMISSIONS OWNER_READ OWNER_WRITE OWNER_EXECUTE
+                GROUP_READ GROUP_EXECUTE WORLD_READ WORLD_EXECUTE)
+
+  set_target_properties(dealii_mpi_tests PROPERTIES
+    CROSSCOMPILING_EMULATOR ${_mpi_wrapper})
+
+  gtest_discover_tests(dealii_mpi_tests
+    WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+    PROPERTIES
+      LABELS "dealii;mpi"
+      SKIP_REGULAR_EXPRESSION "\\[  SKIPPED")
+else()
+  message(WARNING "MPI not found; skipping MPI tests registration with ctest")
+endif()
+
+# PLUGIN TESTS
+
 add_executable(dealii_plugin_tests ${_plugin_test_file})
 target_link_libraries(dealii_plugin_tests coral_core dl ${GTEST_LIBRARIES} ${GTEST_MAIN_LIBRARIES})
 if(GTEST_INCLUDE_DIRS)

backends/dealii/tests/dealii_mpi.cc

@@ -0,0 +1,162 @@
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <memory>
+
+#include "coral.h"
+#include "coral_network.h"
+#include "register_types.h"
+#include "test_utils.h"
+
+using namespace dealii;
+using namespace coral;
+using coral_test::ScopedTestOutputDir;
+
+/**
+ * MPI-aware wrapper around ScopedTestOutputDir.
+ *
+ * Only the master rank (rank 0) constructs and destructs the underlying
+ * ScopedTestOutputDir, so all filesystem operations (create/delete) happen
+ * exactly once. MPI barriers ensure:
+ *  - the directory exists before non-master ranks proceed after construction,
+ *  - all ranks have finished writing before master rank deletes on destruction.
+ */
+class MPIScopedTestOutputDir
+{
+public:
+  MPIScopedTestOutputDir(
+    const std::string           &test_name,
+    const std::filesystem::path &base_dir = "./test_output")
+    : path_(base_dir / test_name)
+  {
+    int rank;
+    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
+    if (rank == 0)
+      scoped_dir_ = std::make_unique<ScopedTestOutputDir>(test_name, base_dir);
+    MPI_Barrier(MPI_COMM_WORLD); // ensure dir exists before all ranks proceed
+  }
+
+  ~MPIScopedTestOutputDir()
+  {
+    MPI_Barrier(MPI_COMM_WORLD); // wait for all ranks to finish writing
+    // scoped_dir_ destructs only on rank 0; other ranks hold nullptr
+  }
+
+  const std::filesystem::path &
+  path() const
+  {
+    return path_;
+  }
+
+  operator const std::filesystem::path &() const
+  {
+    return path_;
+  }
+
+private:
+  std::filesystem::path                path_;
+  std::unique_ptr<ScopedTestOutputDir> scoped_dir_;
+};
+
+class DealiiMPITest : public ::testing::Test
+{
+private:
+  using MPI_Session = Utilities::MPI::MPI_InitFinalize;
+
+  inline static std::unique_ptr<MPI_Session> m_mpi_session = nullptr;
+
+protected:
+  void static SetUpTestSuite()
+  {
+    int    argc   = 0;
+    char **argv   = nullptr;
+    m_mpi_session = std::make_unique<MPI_Session>(argc, argv, 1);
+
+    if (Utilities::MPI::n_mpi_processes(MPI_COMM_WORLD) == 1)
+      GTEST_SKIP() << "Please run MPI test with non trivial world size.";
+  }
+
+  void static TearDownTestSuite()
+  {
+    m_mpi_session.reset();
+  }
+};
+
+TEST_F(DealiiMPITest, Setup)
+{
+  int size;
+  ASSERT_EQ(MPI_Comm_size(MPI_COMM_WORLD, &size), MPI_SUCCESS);
+  ASSERT_GE(size, 0);
+
+  int rank;
+  ASSERT_EQ(MPI_Comm_rank(MPI_COMM_WORLD, &rank), MPI_SUCCESS);
+  ASSERT_GE(rank, 0);
+}
+
+TEST_F(DealiiMPITest, LaplaceProblem)
+{
+  MARK_LONG_TEST();
+
+  MPIScopedTestOutputDir output_dir("DealiiMPITest_PoissonSolver");
+
+  register_non_dimensional_types();
+  register_dimensional_types<2, 2>();
+
+  auto laplace  = make_node<LaplaceProblem<2>>();
+  auto mpi_init = make_node(false);
+  laplace->set_arguments({mpi_init});
+  ASSERT_TRUE((*laplace)());
+  ASSERT_TRUE(laplace->ready());
+
+  auto run_method        = make_node("LaplaceProblem::run<2>");
+  auto output_dir_string = make_node(std::string(output_dir.path()));
+  run_method->set_arguments({laplace, output_dir_string});
+  (*run_method)();
+}
+
+TEST_F(DealiiMPITest, LaplaceProblemNetwork)
+{
+  MARK_LONG_TEST();
+
+  MPIScopedTestOutputDir output_dir("dealiiMPITest_LaplaceTransformNetwork");
+
+  register_non_dimensional_types();
+  register_dimensional_types<2, 2>();
+
+  Network network;
+  network.set_touch_file_base_path(output_dir);
+  network.clear_network();
+
+  std::ifstream file(SOURCE_DIR "/test_files/laplace.json");
+  ASSERT_TRUE(file.is_open()) << "Failed to open laplace.json file.";
+
+  nlohmann::json json_data;
+  file >> json_data;
+  file.close();
+
+  ASSERT_FALSE(json_data.empty()) << "JSON data is empty.";
+
+  // Update the initialize constant
+  // Node 5 contains the bool value
+  if (json_data["workflow"]["nodes"].contains("5") &&
+      json_data["workflow"]["nodes"]["5"].contains("value"))
+    {
+      json_data["workflow"]["nodes"]["5"]["value"] = "false";
+    }
+
+  // Update the output file path to use the test output directory
+  // Node 2 contains the output filename
+  if (json_data["workflow"]["nodes"].contains("2") &&
+      json_data["workflow"]["nodes"]["2"].contains("value"))
+    {
+      json_data["workflow"]["nodes"]["2"]["value"] = output_dir.path().string();
+    }
+
+  network.from_json(json_data);
+
+  slog_debug("Network has %u nodes and %u connections",
+             network.n_nodes(),
+             network.n_connections());
+
+  network.run();
+}

backends/dealii/tests/test_utils.h

@@ -158,4 +158,17 @@ namespace coral_test
 
 } // namespace coral_test
 
+
+#define MARK_LONG_TEST()                                                \
+  do                                                                    \
+    {                                                                   \
+      if (std::getenv("CORAL_KEEP_LONG_TESTS") == nullptr)              \
+        {                                                               \
+          std::cout << "Skip On" << std::endl;                          \
+          GTEST_SKIP()                                                  \
+            << "Long test and CORAL_KEEP_LONG_TEST disable. Skipping."; \
+        }                                                               \
+    }                                                                   \
+  while (0)
+
 #endif // GTESTS_TEST_UTILS_H

test_files/laplace.json

@@ -0,0 +1,36 @@
+{
+  "workflow": {
+    "nodes": {
+      "0": {
+        "type": "LaplaceProblem::run<2>",
+        "position": { "x": 293.7562932408905, "y": 327.37380674085716 },
+        "qualified_id": "0"
+      },
+      "1": {
+        "type": "LaplaceProblem<2>",
+        "position": { "x": -183.0478681433714, "y": 226.5708997085626 },
+        "qualified_id": "1"
+      },
+      "2": {
+        "type": "std::string",
+        "position": { "x": -164.89097078018403, "y": 417.02495316403406 },
+        "value": "/app/build/output/",
+        "qualified_id": "2"
+      },
+      "5": {
+        "type": "bool",
+        "position": { "x": -515.9703517123914, "y": 221.60561502104412 },
+        "value": "true",
+        "qualified_id": "5"
+      }
+    },
+    "edges": {
+      "0": { "source": 1, "target": 0, "source_output": 0, "target_input": 0 },
+      "1": { "source": 2, "target": 0, "source_output": 0, "target_input": 1 },
+      "2": { "source": 5, "target": 1, "source_output": 0, "target_input": 0 }
+    }
+  },
+  "version": 1,
+  "author": "dealiix-platform",
+  "date_time_utc": "2026-03-11T11:35:34.762Z"
+}