From 34207229b3ab2936aecd953997286a0daab88a83 Mon Sep 17 00:00:00 2001
From: Marc Glisse <marc.glisse@inria.fr>
Date: Fri, 29 May 2020 17:56:45 +0200
Subject: convert matrix to SimplexTree

---
 src/python/include/Simplex_tree_interface.h | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

(limited to 'src/python/include/Simplex_tree_interface.h')

diff --git a/src/python/include/Simplex_tree_interface.h b/src/python/include/Simplex_tree_interface.h
index 56d7c41d..295b1b7f 100644
--- a/src/python/include/Simplex_tree_interface.h
+++ b/src/python/include/Simplex_tree_interface.h
@@ -36,6 +36,8 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
   using Skeleton_simplex_iterator = typename Base::Skeleton_simplex_iterator;
   using Complex_simplex_iterator = typename Base::Complex_simplex_iterator;
   using Extended_filtration_data = typename Base::Extended_filtration_data;
+  using Siblings = typename Base::Siblings;
+  using Node = typename Base::Node;
 
  public:
 
@@ -57,6 +59,30 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
     return (result.second);
   }
 
+  void insert_matrix(double* filtrations, int n, int stride0, int stride1, double max_filtration) {
+    // We could delegate to insert_graph, but wrapping the matrix in a graph interface is too much work
+    assert(this->num_simplices() == 0);
+    auto& rm = this->root()->members_;
+    for(int i=0; i<n; ++i) {
+      char* p = (char*)filtrations + i * stride0;
+      double fv = *(double*)(p + i * stride1);
+      if(fv > max_filtration) continue;
+      auto sh = rm.emplace_hint(rm.end(), i, Node(this->root(), fv));
+      Siblings* children = nullptr;
+      // Should we make a first pass to count the number of edges so we can reserve the right space?
+      for(int j=i+1; j<n; ++j) {
+        double fe = *(double*)(p + j * stride1);
+        if(fe > max_filtration) continue;
+        if(!children) {
+          children = new Siblings(this->root(), i);
+          sh->second.assign_children(children);
+        }
+        children->members().emplace_hint(children->members().end(), j, Node(children, fe));
+      }
+    }
+
+  }
+
   // Do not interface this function, only used in alpha complex interface for complex creation
   bool insert_simplex(const Simplex& simplex, Filtration_value filtration = 0) {
     Insertion_result result = Base::insert_simplex(simplex, filtration);
-- 
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