Feature: SFC-Based Tree Indexing

src/CMakeLists.txt

@@ -151,6 +151,7 @@ target_sources( T8 PRIVATE
     t8_cmesh/t8_cmesh_internal/t8_cmesh_partition.cxx
     t8_cmesh/t8_cmesh_internal/t8_cmesh_stash.c
     t8_cmesh/t8_cmesh_internal/t8_cmesh_trees.cxx
+    t8_cmesh/t8_cmesh_internal/t8_cmesh_tree_reindex.cxx
     t8_cmesh/t8_cmesh_vertex_connectivity/t8_cmesh_vertex_conn_tree_to_vertex.cxx
     t8_cmesh/t8_cmesh_vertex_connectivity/t8_cmesh_vertex_conn_vertex_to_tree.cxx
     t8_cmesh/t8_cmesh_vertex_connectivity/t8_cmesh_vertex_connectivity.cxx

src/t8_cmesh/t8_cmesh.cxx

@@ -152,6 +152,12 @@ t8_cmesh_disable_negative_volume_check ([[maybe_unused]] t8_cmesh_t cmesh)
 #endif
 }
 
+void
+t8_cmesh_enable_tree_reordering (t8_cmesh_t cmesh)
+{
+  cmesh->reindex_trees = 1;
+}
+
 #if T8_ENABLE_DEBUG
 int
 t8_cmesh_validate_geometry (const t8_cmesh_t cmesh, const int check_for_negative_volume)
@@ -239,6 +245,7 @@ t8_cmesh_init (t8_cmesh_t *pcmesh)
 #if T8_ENABLE_DEBUG
   cmesh->negative_volume_check = 1;
 #endif /* T8_ENABLE_DEBUG */
+  cmesh->reindex_trees = 0;
 
   T8_ASSERT (t8_cmesh_is_initialized (cmesh));
 }
@@ -2254,8 +2261,8 @@ t8_cmesh_uniform_bounds_from_partition (const t8_cmesh_t cmesh, const t8_gloidx_
 #endif
 
       } /* End sending of end message */
-    }   /* End loop over processes */
-  }     /* if (num_pure_local_trees > 0) */
+    } /* End loop over processes */
+  } /* if (num_pure_local_trees > 0) */
 
   if (this_proc_is_empty) {
     /* If this proc is empty, we only expect a start message.

src/t8_cmesh/t8_cmesh.h

@@ -132,6 +132,13 @@ t8_cmesh_stash_is_empty (const t8_cmesh_t cmesh);
 void
 t8_cmesh_disable_negative_volume_check (t8_cmesh_t cmesh);
 
+/**
+ * Enable localitly based indexing of trees during \ref t8_cmesh_commit.
+ * \param [in, out] cmesh 
+ */
+void
+t8_cmesh_enable_tree_reordering (t8_cmesh_t cmesh);
+
 #if T8_ENABLE_DEBUG
 /** Check the geometry of the mesh for validity, this means checking if trees and their geometries
  *  are compatible and if they have negative volume.
@@ -140,7 +147,6 @@ t8_cmesh_disable_negative_volume_check (t8_cmesh_t cmesh);
  * \return                                True if the geometry of the cmesh is valid.
  */
 int
-
 t8_cmesh_validate_geometry (const t8_cmesh_t cmesh, const int check_for_negative_volume);
 #endif
 

src/t8_cmesh/t8_cmesh_internal/t8_cmesh_commit.cxx

@@ -36,6 +36,8 @@
 #include <t8_cmesh/t8_cmesh_geometry.hxx>
 #include <t8_geometry/t8_geometry_handler.hxx>
 #include <t8_cmesh/t8_cmesh_vertex_connectivity/t8_cmesh_vertex_connectivity.hxx>
+#include <t8_cmesh/t8_cmesh_internal/t8_cmesh_tree_reindex.hxx>
+#include <chrono>
 
 /**
  * A struct to hold the information about a ghost facejoin.
@@ -148,6 +150,16 @@ t8_cmesh_commit_replicated_new (t8_cmesh_t cmesh)
     t8_stash_class_struct_t *entry;
     t8_locidx_t num_trees = class_entries->elem_count, ltree;
 
+    if (cmesh->reindex_trees) {
+      auto start = std::chrono::high_resolution_clock::now ();
+      std::map<t8_gloidx_t, t8_gloidx_t> reindexing_map = t8_cmesh_reindex_tree (cmesh);
+
+      t8_cmesh_tree_perform_reindex_inplace (stash, reindexing_map);
+      auto stop = std::chrono::high_resolution_clock::now ();
+      auto duration = duration_cast<std::chrono::microseconds> (stop - start);
+      t8_productionf ("Time taken: %lims\n", duration.count ());
+    }
+
     t8_cmesh_trees_init (&cmesh->trees, 1, num_trees, 0);
     t8_cmesh_trees_start_part (cmesh->trees, 0, 0, num_trees, 0, 0, 1);
     /* set tree classes */