1 files changed, 16 insertions, 0 deletions
diff --git a/src/python/include/Simplex_tree_interface.h b/src/python/include/Simplex_tree_interface.h
index e288a8cf..629f6083 100644
--- a/src/python/include/Simplex_tree_interface.h
+++ b/src/python/include/Simplex_tree_interface.h
@@ -15,7 +15,9 @@
 #include <gudhi/distance_functions.h>
 #include <gudhi/Simplex_tree.h>
 #include <gudhi/Points_off_io.h>
+#ifdef GUDHI_USE_EIGEN3
 #include <gudhi/Flag_complex_edge_collapser.h>
+#endif
 
 #include <iostream>
 #include <vector>
@@ -39,6 +41,7 @@ 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 Boundary_simplex_iterator = typename Base::Boundary_simplex_iterator;
 
  public:
 
@@ -161,6 +164,7 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
   }
 
   Simplex_tree_interface* collapse_edges(int nb_collapse_iteration) {
+#ifdef GUDHI_USE_EIGEN3
     using Filtered_edge = std::tuple<Vertex_handle, Vertex_handle, Filtration_value>;
     std::vector<Filtered_edge> edges;
     for (Simplex_handle sh : Base::skeleton_simplex_range(1)) {
@@ -186,6 +190,9 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
       collapsed_stree_ptr->insert({std::get<0>(remaining_edge), std::get<1>(remaining_edge)}, std::get<2>(remaining_edge));
     }
     return collapsed_stree_ptr;
+#else
+    throw std::runtime_error("Unable to collapse edges as it requires Eigen3 >= 3.1.0.");
+#endif
   }
 
   // Iterator over the simplex tree
@@ -219,6 +226,15 @@ class Simplex_tree_interface : public Simplex_tree<SimplexTreeOptions> {
     // this specific case works because the range is just a pair of iterators - won't work if range was a vector
     return Base::skeleton_simplex_range(dimension).end();
   }
+
+  std::pair<Boundary_simplex_iterator, Boundary_simplex_iterator> get_boundary_iterators(const Simplex& simplex) {
+    auto bd_sh = Base::find(simplex);
+    if (bd_sh == Base::null_simplex())
+      throw std::runtime_error("simplex not found - cannot find boundaries");
+    // this specific case works because the range is just a pair of iterators - won't work if range was a vector
+    auto boundary_srange = Base::boundary_simplex_range(bd_sh);
+    return std::make_pair(boundary_srange.begin(), boundary_srange.end());
+  }
 };
 
 }  // namespace Gudhi