Allowing storing custom data in simplices

mglisse · Jul 4, 2024 · 6543043 · 6543043
1 parent 18a842d
commit 6543043
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Showing 5 changed files with 40 additions and 1 deletion.
diff --git a/src/Simplex_tree/concept/SimplexTreeOptions.h b/src/Simplex_tree/concept/SimplexTreeOptions.h
@@ -23,6 +23,8 @@ struct SimplexTreeOptions {
   typedef FiltrationValue Filtration_value;
   /** @brief Must be an integer type. */
   typedef SimplexKey Simplex_key;
+  /** @brief Optional, can be omitted. */
+  typedef SimplexData Simplex_data;
   /** @brief If true, each simplex has extra storage for one `Simplex_key`. Necessary for `Persistent_cohomology`. */
   static const bool store_key;
   /** @brief If true, each simplex has extra storage for one `Filtration_value`, and this value is propagated by

diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree.h b/src/Simplex_tree/include/gudhi/Simplex_tree.h
@@ -104,6 +104,8 @@ class Simplex_tree {
    *
    * Must be an integer type. */
   typedef typename Options::Simplex_key Simplex_key;
+  /** \bried Extra data stored in each simplex. */
+  typedef typename Get_simplex_data_type<Options>::type Simplex_data;
   /** \brief Type for the vertex handle.
    *
    * Must be a signed integer type. It admits a total order <. */
@@ -641,6 +643,13 @@ class Simplex_tree {
     return -1;
   }
 
+  /** \brief Returns the extra data stored in a simplex. */
+  static Simplex_data& simplex_data(Simplex_handle sh) {
+    GUDHI_CHECK(sh != null_simplex(),
+                std::invalid_argument("Simplex_tree::simplex_data - no data associated to null_simplex"));
+    return sh->second.data();
+  }
+
   /** \brief Returns a Vertex_handle different from all Vertex_handles associated
    * to the vertices of the simplicial complex. */
   Vertex_handle null_vertex() const {

diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_node_explicit_storage.h b/src/Simplex_tree/include/gudhi/Simplex_tree/Simplex_tree_node_explicit_storage.h
@@ -19,6 +19,7 @@
 #endif
 
 #include <vector>
+#include <boost/core/empty_value.hpp>
 
 namespace Gudhi {
 
@@ -35,10 +36,12 @@ namespace Gudhi {
 template<class SimplexTree>
 struct GUDHI_EMPTY_BASE_CLASS_OPTIMIZATION Simplex_tree_node_explicit_storage : SimplexTree::Filtration_simplex_base,
                                                                           SimplexTree::Key_simplex_base,
-                                                                          SimplexTree::Hooks_simplex_base {
+                                                                          SimplexTree::Hooks_simplex_base,
+                                                                          boost::empty_value<typename SimplexTree::Simplex_data> {
   typedef typename SimplexTree::Siblings Siblings;
   typedef typename SimplexTree::Filtration_value Filtration_value;
   typedef typename SimplexTree::Simplex_key Simplex_key;
+  typedef typename SimplexTree::Simplex_data Simplex_data;
 
   Simplex_tree_node_explicit_storage(Siblings * sib = nullptr,
                                      Filtration_value filtration = 0)
@@ -58,6 +61,8 @@ struct GUDHI_EMPTY_BASE_CLASS_OPTIMIZATION Simplex_tree_node_explicit_storage :
     return children_;
   }
 
+  Simplex_data& data() { return boost::empty_value<Simplex_data>::get(); }
+
  private:
   Siblings * children_;
 };

diff --git a/src/Simplex_tree/include/gudhi/Simplex_tree/simplex_tree_options.h b/src/Simplex_tree/include/gudhi/Simplex_tree/simplex_tree_options.h
@@ -14,6 +14,7 @@
 #include <gudhi/Simplex_tree/indexing_tag.h>
 
 #include <cstdint>
+#include <type_traits> // void_t
 
 namespace Gudhi {
 
@@ -91,6 +92,13 @@ struct Simplex_tree_options_fast_persistence {
 
 /** @}*/  // end addtogroup simplex_tree
 
+struct No_simplex_data {};
+
+// Nested `type` is O::Simplex_data if that exists, No_simplex_data otherwise
+template <class, class=void> struct Get_simplex_data_type { typedef No_simplex_data type; };
+template <class O>
+struct Get_simplex_data_type<O, std::void_t<typename O::Simplex_data>> { typedef typename O::Simplex_data type; };
+
 }  // namespace Gudhi
 
 #endif  // SIMPLEX_TREE_SIMPLEX_TREE_OPTIONS_H_
diff --git a/src/Simplex_tree/test/simplex_tree_unit_test.cpp b/src/Simplex_tree/test/simplex_tree_unit_test.cpp
@@ -1241,3 +1241,18 @@ BOOST_AUTO_TEST_CASE_TEMPLATE(for_each_simplex_skip_iteration, typeST, list_of_t
   BOOST_CHECK(num_simplices_by_dim_until_two[0] == num_simplices_by_dim[0]);
   BOOST_CHECK(num_simplices_by_dim_until_two[1] == num_simplices_by_dim[1]);
 }
+
+struct Options_with_int_data : Simplex_tree_options_minimal {
+  typedef int Simplex_data;
+};
+
+BOOST_AUTO_TEST_CASE(simplex_data) {
+  Simplex_tree<Options_with_int_data> st;
+  st.insert_simplex_and_subfaces({0, 1});
+  st.insert_simplex_and_subfaces({2, 1});
+  st.insert_simplex_and_subfaces({0, 2});
+  st.simplex_data(st.find({0, 1})) = 5;
+  st.expansion(3);
+  st.simplex_data(st.find({0, 1, 2})) = 4;
+  BOOST_CHECK(st.simplex_data(st.find({0, 1})) == 5);
+}