From 07a692ac61324398c3c0b859307e855db8205a4b Mon Sep 17 00:00:00 2001 From: Lena Ploetzke Date: Wed, 21 Jan 2026 16:06:30 +0100 Subject: [PATCH 1/7] add partition and balance functionality --- mesh_handle/mesh.hxx | 51 +++++++++++++++++++++++++++++++++++++++----- 1 file changed, 46 insertions(+), 5 deletions(-) diff --git a/mesh_handle/mesh.hxx b/mesh_handle/mesh.hxx index 4f4cc879fc..ff1a1d65b5 100644 --- a/mesh_handle/mesh.hxx +++ b/mesh_handle/mesh.hxx @@ -277,12 +277,53 @@ class mesh { t8_forest_set_adapt (m_uncommitted_forest.value (), m_forest, detail::mesh_adapt_callback_wrapper, recursive); } + /** If this function is called, the mesh will be partitioned on committing. + * The partitioning is done according to the SFC and each rank is assigned + * the same (maybe +1) number of elements. + * \note The partition is carried out only when \ref commit is called. + * \note This setting can be combined with \ref set_adapt and \ref set_balance. The order in which + * these operations are executed is always 1) Adapt 2) Partition 3) Balance. + * \param [in] set_for_coarsening If true, the partitions are choose such that coarsening + * an element once is a process local operation. Default is false. + */ + void + set_partition (bool set_for_coarsening = false) + { + if (!m_uncommitted_forest.has_value ()) { + t8_forest_t new_forest; + t8_forest_init (&new_forest); + m_uncommitted_forest = new_forest; + } + t8_forest_set_partition (m_uncommitted_forest.value (), m_forest, set_for_coarsening); + } + + /** If this function is called, the mesh will be balanced on committing. + * The mesh is said to be balanced if each element has face neighbors of level + * at most +1 or -1 of the element's level. + * \note The balance is carried out only when \ref commit is called. + * \note This setting can be combined with \ref set_adapt and \ref set_partition. The order in which + * these operations are executed is always 1) Adapt 2) Partition 3) Balance. + * \note The balanced mesh is not repartitioned per default to maintain a balanced load. + * Call \ref set_partition if you want to repartition the balanced mesh. + */ + void + set_balance () + { + if (!m_uncommitted_forest.has_value ()) { + t8_forest_t new_forest; + t8_forest_init (&new_forest); + m_uncommitted_forest = new_forest; + } + // Disable repartitioning and let the user call set_partition if desired. + t8_forest_set_balance (tm_uncommitted_forest.value (), m_forest, true); + } + /** Enable or disable the creation of a layer of ghost elements. - * \param [in] do_ghost If true a ghost layer will be created. - * \param [in] ghost_type Controls which neighbors count as ghost elements, - * currently only T8_GHOST_FACES is supported. This value - * is ignored if \a do_ghost = false. - */ + * \param [in] do_ghost If true a ghost layer will be created. + * \param [in] ghost_type Controls which neighbors count as ghost elements, + * currently only T8_GHOST_FACES is supported. This value + * is ignored if \a do_ghost = false. + */ void set_ghost (bool do_ghost = true, t8_ghost_type_t ghost_type = T8_GHOST_FACES) { From cb6a8e0323a0d274736ed11001a9c10f97bb063b Mon Sep 17 00:00:00 2001 From: Lena Ploetzke Date: Wed, 21 Jan 2026 16:55:48 +0100 Subject: [PATCH 2/7] begin test --- mesh_handle/mesh.hxx | 15 ++++++++++++++- test/mesh_handle/t8_gtest_adapt.cxx | 10 ++++++++++ 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/mesh_handle/mesh.hxx b/mesh_handle/mesh.hxx index ff1a1d65b5..f94087f5d9 100644 --- a/mesh_handle/mesh.hxx +++ b/mesh_handle/mesh.hxx @@ -30,6 +30,8 @@ #include "element.hxx" #include "competence_pack.hxx" #include "adapt.hxx" +#include "t8_forest/t8_forest_balance.h" +#include "t8_forest/t8_forest_types.h" #include #include #include @@ -162,6 +164,17 @@ class mesh { return m_forest; } + /** Check if the local elements of the mesh are balanced. + * The mesh is said to be balanced if each element has face neighbors of level + * at most +1 or -1 of the element's level. + * \return true if the local elements are balanced, false otherwise. + */ + bool + is_balanced () + { + return t8_forest_is_balanced (m_forest); + } + // --- Methods to access elements. --- /** * Returns a constant iterator to the first (local) mesh element. @@ -315,7 +328,7 @@ class mesh { m_uncommitted_forest = new_forest; } // Disable repartitioning and let the user call set_partition if desired. - t8_forest_set_balance (tm_uncommitted_forest.value (), m_forest, true); + t8_forest_set_balance (m_uncommitted_forest.value (), m_forest, true); } /** Enable or disable the creation of a layer of ghost elements. diff --git a/test/mesh_handle/t8_gtest_adapt.cxx b/test/mesh_handle/t8_gtest_adapt.cxx index 5739c790a1..3b909782e1 100644 --- a/test/mesh_handle/t8_gtest_adapt.cxx +++ b/test/mesh_handle/t8_gtest_adapt.cxx @@ -129,6 +129,16 @@ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) // Compare results. EXPECT_TRUE (t8_forest_is_equal (mesh_handle.get_forest (), forest)); + // Adapt the mesh handle again and check that it is unbalanced afterwards. + mesh_handle.set_adapt ( + mesh_class::mesh_adapt_callback_wrapper (adapt_callback_test, user_data), false); + mesh_handle.commit (); + EXPECT_FALSE (mesh_handle.is_balanced ()); + mesh_handle.set_balance (); + mesh_handle.set_partition (); + mesh_handle.commit (); + // TODO have a look at t8_gtest_forest_commit for a better structure + EXPECT_TRUE (mesh_handle.is_balanced ()); // Clean up. t8_forest_unref (&forest); } From d0990b29d20d27c84d3734928f4b280fdea7e2ec Mon Sep 17 00:00:00 2001 From: Lena Ploetzke Date: Thu, 22 Jan 2026 16:04:39 +0100 Subject: [PATCH 3/7] adapt test to check also partition and balance --- test/mesh_handle/t8_gtest_adapt.cxx | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/test/mesh_handle/t8_gtest_adapt.cxx b/test/mesh_handle/t8_gtest_adapt.cxx index 3b909782e1..218ff40589 100644 --- a/test/mesh_handle/t8_gtest_adapt.cxx +++ b/test/mesh_handle/t8_gtest_adapt.cxx @@ -21,7 +21,7 @@ along with t8code; if not, write to the Free Software Foundation, Inc., */ /** - * \file t8_gtest_adapt.cxx + * \file t8_gtest_adapt_balance_partition.cxx * Tests for the adapt routines of mesh handles. * This tests uses the callback and user data of tutorial step 3 as example. * The adaptation criterion is to look at the midpoint coordinates of the current element and if @@ -100,6 +100,8 @@ forest_adapt_callback_example (t8_forest_t forest, t8_forest_t forest_from, t8_l /** Test the adapt routine of a mesh handle. * We compare the result to a classically adapted forest with similar callback. + * Therefore we ensure that the functionality for the mesh handle works based on the assumption that the forest functionality is correct. + * Forest functionality is tested elsewhere. */ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) { @@ -137,8 +139,18 @@ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) mesh_handle.set_balance (); mesh_handle.set_partition (); mesh_handle.commit (); - // TODO have a look at t8_gtest_forest_commit for a better structure EXPECT_TRUE (mesh_handle.is_balanced ()); + + // Compare the results again to an appropriate forest. + t8_forest_t forest_compare; + t8_forest_init (&forest_compare); + t8_forest_set_user_data (forest_compare, &user_data); + t8_forest_set_adapt (forest_compare, forest, forest_adapt_callback_example, false); + t8_forest_set_partition (forest_compare, NULL, 0); + t8_forest_set_balance (forest_compare, NULL, 0); + t8_forest_commit (forest_compare); + // Compare results. + EXPECT_TRUE (t8_forest_is_equal (mesh_handle.get_forest (), forest_compare)); // Clean up. - t8_forest_unref (&forest); + t8_forest_unref (&forest_compare); } From 72287c871e4c02b65f416421e42049f1aecf5e46 Mon Sep 17 00:00:00 2001 From: Lena Ploetzke Date: Thu, 22 Jan 2026 16:05:39 +0100 Subject: [PATCH 4/7] rename adapt test --- .../{t8_gtest_adapt.cxx => t8_gtest_adapt_partition_balance.cxx} | 0 1 file changed, 0 insertions(+), 0 deletions(-) rename test/mesh_handle/{t8_gtest_adapt.cxx => t8_gtest_adapt_partition_balance.cxx} (100%) diff --git a/test/mesh_handle/t8_gtest_adapt.cxx b/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx similarity index 100% rename from test/mesh_handle/t8_gtest_adapt.cxx rename to test/mesh_handle/t8_gtest_adapt_partition_balance.cxx From e782a56bc97052d0e366724d129c2b3595460f96 Mon Sep 17 00:00:00 2001 From: Lena Ploetzke Date: Mon, 26 Jan 2026 10:33:16 +0100 Subject: [PATCH 5/7] WIP: add balance,partition --- test/CMakeLists.txt | 14 +++++++------- .../t8_gtest_adapt_partition_balance.cxx | 17 +++++++++-------- 2 files changed, 16 insertions(+), 15 deletions(-) diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt index 77b3c56d99..44bf59d4bd 100644 --- a/test/CMakeLists.txt +++ b/test/CMakeLists.txt @@ -211,13 +211,13 @@ endif() add_t8_cpp_test( NAME t8_gtest_vector_split_serial SOURCES t8_helper_functions/t8_gtest_vector_split.cxx ) if( T8CODE_BUILD_MESH_HANDLE ) - add_t8_cpp_test( NAME t8_gtest_mesh_handle_parallel SOURCES mesh_handle/t8_gtest_mesh_handle.cxx ) - add_t8_cpp_test( NAME t8_gtest_compare_handle_to_forest_serial SOURCES mesh_handle/t8_gtest_compare_handle_to_forest.cxx ) - add_t8_cpp_test( NAME t8_gtest_handle_ghost_parallel SOURCES mesh_handle/t8_gtest_ghost.cxx ) - add_t8_cpp_test( NAME t8_gtest_custom_competence_serial SOURCES mesh_handle/t8_gtest_custom_competence.cxx ) - add_t8_cpp_test( NAME t8_gtest_cache_competence_serial SOURCES mesh_handle/t8_gtest_cache_competence.cxx ) - add_t8_cpp_test( NAME t8_gtest_handle_data_parallel SOURCES mesh_handle/t8_gtest_handle_data.cxx ) - add_t8_cpp_test( NAME t8_gtest_handle_adapt_serial SOURCES mesh_handle/t8_gtest_adapt.cxx ) + add_t8_cpp_test( NAME t8_gtest_mesh_handle_parallel SOURCES mesh_handle/t8_gtest_mesh_handle.cxx ) + add_t8_cpp_test( NAME t8_gtest_compare_handle_to_forest_serial SOURCES mesh_handle/t8_gtest_compare_handle_to_forest.cxx ) + add_t8_cpp_test( NAME t8_gtest_handle_ghost_parallel SOURCES mesh_handle/t8_gtest_ghost.cxx ) + add_t8_cpp_test( NAME t8_gtest_custom_competence_serial SOURCES mesh_handle/t8_gtest_custom_competence.cxx ) + add_t8_cpp_test( NAME t8_gtest_cache_competence_serial SOURCES mesh_handle/t8_gtest_cache_competence.cxx ) + add_t8_cpp_test( NAME t8_gtest_handle_data_parallel SOURCES mesh_handle/t8_gtest_handle_data.cxx ) + add_t8_cpp_test( NAME t8_gtest_adapt_partition_balance_parallel SOURCES mesh_handle/t8_gtest_adapt_partition_balance.cxx ) endif() copy_test_file( test_cube_unstructured_1.inp ) diff --git a/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx b/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx index 218ff40589..abf50cee51 100644 --- a/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx +++ b/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx @@ -21,11 +21,13 @@ along with t8code; if not, write to the Free Software Foundation, Inc., */ /** - * \file t8_gtest_adapt_balance_partition.cxx - * Tests for the adapt routines of mesh handles. - * This tests uses the callback and user data of tutorial step 3 as example. + * \file t8_gtest_adapt_partition_balance.cxx + * Tests for the adapt, partition and balance routines of mesh handles. + * For the adapt routine, we use the callback and user data of tutorial step 3 as example. * The adaptation criterion is to look at the midpoint coordinates of the current element and if * they are inside a sphere around a given midpoint we refine, if they are outside, we coarsen. + * The test compares the results of the mesh handle to a forest adapted with the same criterion and balanced and partitioned similarly. + * Therefore, the check is based on the assumption that the forest functionality works as intended and is tested elsewhere. */ #include #include @@ -98,10 +100,9 @@ forest_adapt_callback_example (t8_forest_t forest, t8_forest_t forest_from, t8_l return 0; } -/** Test the adapt routine of a mesh handle. - * We compare the result to a classically adapted forest with similar callback. - * Therefore we ensure that the functionality for the mesh handle works based on the assumption that the forest functionality is correct. - * Forest functionality is tested elsewhere. +/** Test the adapt partition and balance routine of a mesh handle. + * The test compares the results of the mesh handle to a forest adapted with the same criterion and balanced and partitioned similarly. + * Therefore, the check is based on the assumption that the forest functionality works as intended and is tested elsewhere. */ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) { @@ -136,6 +137,7 @@ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) mesh_class::mesh_adapt_callback_wrapper (adapt_callback_test, user_data), false); mesh_handle.commit (); EXPECT_FALSE (mesh_handle.is_balanced ()); + // Now apply partition and balance. mesh_handle.set_balance (); mesh_handle.set_partition (); mesh_handle.commit (); @@ -149,7 +151,6 @@ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) t8_forest_set_partition (forest_compare, NULL, 0); t8_forest_set_balance (forest_compare, NULL, 0); t8_forest_commit (forest_compare); - // Compare results. EXPECT_TRUE (t8_forest_is_equal (mesh_handle.get_forest (), forest_compare)); // Clean up. t8_forest_unref (&forest_compare); From a869748e75623b38202285b10d9cb973c2ed1f1b Mon Sep 17 00:00:00 2001 From: Lena Ploetzke Date: Tue, 27 Jan 2026 11:24:17 +0100 Subject: [PATCH 6/7] add flag and correct test --- mesh_handle/adapt.hxx | 10 +++++----- mesh_handle/mesh.hxx | 18 +++++++++++------- .../t8_gtest_adapt_partition_balance.cxx | 12 +++++------- 3 files changed, 21 insertions(+), 19 deletions(-) diff --git a/mesh_handle/adapt.hxx b/mesh_handle/adapt.hxx index 9bf787c917..cf962b0b62 100644 --- a/mesh_handle/adapt.hxx +++ b/mesh_handle/adapt.hxx @@ -120,8 +120,8 @@ class AdaptRegistry { public: /** Static function to register \a context using \a forest as identifier. * This makes the context publicly available using the Registry. - * \param [in] forest The forest identifier. In our case, this is the forest to be adapted - * and not the forest from which we adapt. + * \param [in] forest The forest identifier. In our case, this is the forest from which we adapt the mesh because + * we do not change this forest during adaptation such that it is valid unique identifier. * \param [in] context The context to register. Use unique pointer to ensure proper memory management and ownership. */ static void @@ -135,7 +135,7 @@ class AdaptRegistry { } /** Static function to unregister a context using \a forest as identifier. - * \param [in] forest The forest identifier. In our case, this is the forest to be adapted. + * \param [in] forest The forest identifier. In our case, this is the forest from which we adapt. */ static void unregister_context (t8_forest_t forest) @@ -146,7 +146,7 @@ class AdaptRegistry { } /** Getter for a context using \a forest as identifier. - * \param [in] forest The forest identifier. In our case, this is the forest to be adapted. + * \param [in] forest The forest identifier. In our case, this is the forest from which we adapt. * \return Pointer to the context registered with the id \a forest if found, nullptr otherwise. */ static MeshAdaptContextBase* @@ -193,7 +193,7 @@ mesh_adapt_callback_wrapper ([[maybe_unused]] t8_forest_t forest, t8_forest_t fo { // Get static adapt context from the registry. // Via this, we can access the mesh handle and the user defined adapt callback that uses mesh handle functionality. - auto* context = AdaptRegistry::get (forest); + auto* context = AdaptRegistry::get (forest_from); if (!context) { t8_global_infof ( "Something went wrong while registering the adaptation callbacks. Please check your implementation."); diff --git a/mesh_handle/mesh.hxx b/mesh_handle/mesh.hxx index 6a52c477e2..c9a459367d 100644 --- a/mesh_handle/mesh.hxx +++ b/mesh_handle/mesh.hxx @@ -283,8 +283,7 @@ class mesh { } // Create and register adaptation context holding the mesh handle and the user defined callback. detail::AdaptRegistry::register_context ( - m_uncommitted_forest.value (), - std::make_unique> (*this, std::move (adapt_callback))); + m_forest, std::make_unique> (*this, std::move (adapt_callback))); // Set up the forest for adaptation using the wrapper callback. t8_forest_set_adapt (m_uncommitted_forest.value (), m_forest, detail::mesh_adapt_callback_wrapper, recursive); @@ -314,13 +313,16 @@ class mesh { * The mesh is said to be balanced if each element has face neighbors of level * at most +1 or -1 of the element's level. * \note The balance is carried out only when \ref commit is called. + * \param [in] no_repartition Balance constructs several intermediate steps that + * are refined from each other. In order to maintain a balanced load, a repartitioning is performed in each + * round and the resulting mesh is load-balanced per default. + * Set \a no_repartition to true if this behaviour is not desired. + * If \a no_repartition is false (default), an additional call of \ref set_partition is not necessary. * \note This setting can be combined with \ref set_adapt and \ref set_partition. The order in which * these operations are executed is always 1) Adapt 2) Partition 3) Balance. - * \note The balanced mesh is not repartitioned per default to maintain a balanced load. - * Call \ref set_partition if you want to repartition the balanced mesh. */ void - set_balance () + set_balance (bool no_repartition = false) { if (!m_uncommitted_forest.has_value ()) { t8_forest_t new_forest; @@ -328,7 +330,7 @@ class mesh { m_uncommitted_forest = new_forest; } // Disable repartitioning and let the user call set_partition if desired. - t8_forest_set_balance (m_uncommitted_forest.value (), m_forest, true); + t8_forest_set_balance (m_uncommitted_forest.value (), m_forest, no_repartition); } /** Enable or disable the creation of a layer of ghost elements. @@ -367,16 +369,18 @@ class mesh { if (m_uncommitted_forest.value ()->set_from == NULL) { t8_forest_set_copy (m_uncommitted_forest.value (), m_forest); } + t8_forest_ref (m_forest); t8_forest_commit (m_uncommitted_forest.value ()); // Check if we adapted and unregister the adapt context if so. if (detail::AdaptRegistry::get (m_uncommitted_forest.value ()) != nullptr) { - detail::AdaptRegistry::unregister_context (m_uncommitted_forest.value ()); + detail::AdaptRegistry::unregister_context (m_forest); if (!std::is_void::value) { t8_global_infof ( "Please note that the element data is not interpolated automatically during adaptation. Use the " "function set_element_data() to provide new adapted element data.\n"); } } + t8_forest_unref (&m_forest); // Update underlying forest of the mesh. m_forest = m_uncommitted_forest.value (); m_uncommitted_forest = std::nullopt; diff --git a/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx b/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx index abf50cee51..1afa512dbb 100644 --- a/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx +++ b/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx @@ -127,17 +127,14 @@ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) mesh_class::mesh_adapt_callback_wrapper (adapt_callback_test, user_data), false); mesh_handle.commit (); // Adapt forest classically. - forest = t8_forest_new_adapt (forest, forest_adapt_callback_example, 0, 1, &user_data); + forest = t8_forest_new_adapt (forest, forest_adapt_callback_example, 0, 0, &user_data); // Compare results. EXPECT_TRUE (t8_forest_is_equal (mesh_handle.get_forest (), forest)); - // Adapt the mesh handle again and check that it is unbalanced afterwards. + // Adapt the mesh handle again and apply partition and balance. mesh_handle.set_adapt ( mesh_class::mesh_adapt_callback_wrapper (adapt_callback_test, user_data), false); - mesh_handle.commit (); - EXPECT_FALSE (mesh_handle.is_balanced ()); - // Now apply partition and balance. mesh_handle.set_balance (); mesh_handle.set_partition (); mesh_handle.commit (); @@ -148,10 +145,11 @@ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) t8_forest_init (&forest_compare); t8_forest_set_user_data (forest_compare, &user_data); t8_forest_set_adapt (forest_compare, forest, forest_adapt_callback_example, false); - t8_forest_set_partition (forest_compare, NULL, 0); - t8_forest_set_balance (forest_compare, NULL, 0); + t8_forest_set_partition (forest_compare, NULL, false); + t8_forest_set_balance (forest_compare, NULL, false); t8_forest_commit (forest_compare); EXPECT_TRUE (t8_forest_is_equal (mesh_handle.get_forest (), forest_compare)); + // Clean up. t8_forest_unref (&forest_compare); } From 75657fac69afe3ea9232438e8ef9457d39339a0f Mon Sep 17 00:00:00 2001 From: Lena Ploetzke Date: Tue, 27 Jan 2026 13:55:50 +0100 Subject: [PATCH 7/7] change order for codecov --- test/mesh_handle/t8_gtest_adapt_partition_balance.cxx | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx b/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx index 1afa512dbb..3dde1d26cf 100644 --- a/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx +++ b/test/mesh_handle/t8_gtest_adapt_partition_balance.cxx @@ -133,10 +133,10 @@ TEST (t8_gtest_handle_adapt, compare_adapt_with_forest) EXPECT_TRUE (t8_forest_is_equal (mesh_handle.get_forest (), forest)); // Adapt the mesh handle again and apply partition and balance. - mesh_handle.set_adapt ( - mesh_class::mesh_adapt_callback_wrapper (adapt_callback_test, user_data), false); mesh_handle.set_balance (); mesh_handle.set_partition (); + mesh_handle.set_adapt ( + mesh_class::mesh_adapt_callback_wrapper (adapt_callback_test, user_data), false); mesh_handle.commit (); EXPECT_TRUE (mesh_handle.is_balanced ());