Add min and max filtration values for the sparse Rips

2 files changed, 5 insertions, 12 deletions

diff --git a/src/cython/doc/rips_complex_user.rst b/src/cython/doc/rips_complex_user.rst
index e814b4c3..1d340dbe 100644
--- a/src/cython/doc/rips_complex_user.rst
+++ b/src/cython/doc/rips_complex_user.rst
@@ -50,8 +50,8 @@ by more than the length used to define "too close".
 A more general technique is to use a sparse approximation of the Rips
 introduced by Don Sheehy :cite:`sheehy13linear`. We are using the version
 described in :cite:`buchet16efficient` (except that we multiply all filtration
-values by 2, to match the usual Rips complex), which proves a
-:math:`\frac{1+\varepsilon}{1-\varepsilon}`-interleaving, although in practice the
+values by 2, to match the usual Rips complex). :cite:`cavanna15geometric` proves
+a :math:`\frac{1}{1-\varepsilon}`-interleaving, although in practice the
 error is usually smaller.  A more intuitive presentation of the idea is
 available in :cite:`cavanna15geometric`, and in a video
 :cite:`cavanna15visualizing`. Passing an extra argument `sparse=0.3` at the
diff --git a/src/cython/include/Rips_complex_interface.h b/src/cython/include/Rips_complex_interface.h
index 1a6e2477..40aff299 100644
--- a/src/cython/include/Rips_complex_interface.h
+++ b/src/cython/include/Rips_complex_interface.h
@@ -54,23 +54,17 @@ class Rips_complex_interface {
   }
 
   void init_points_sparse(const std::vector<std::vector<double>>& points, double threshold, double epsilon) {
-    sparse_rips_complex_.emplace(points, Gudhi::Euclidean_distance(), epsilon);
-    threshold_ = threshold;
+    sparse_rips_complex_.emplace(points, Gudhi::Euclidean_distance(), epsilon, -std::numeric_limits<double>::infinity(), threshold);
   }
   void init_matrix_sparse(const std::vector<std::vector<double>>& matrix, double threshold, double epsilon) {
-    sparse_rips_complex_.emplace(matrix, epsilon);
-    threshold_ = threshold;
+    sparse_rips_complex_.emplace(matrix, epsilon, -std::numeric_limits<double>::infinity(), threshold);
   }
 
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, int dim_max) {
     if (rips_complex_)
       rips_complex_->create_complex(*simplex_tree, dim_max);
-    else {
+    else
       sparse_rips_complex_->create_complex(*simplex_tree, dim_max);
-      // This pruning should be done much earlier! It isn't that useful for sparse Rips,
-      // but it would be inconsistent not to do it.
-      simplex_tree->prune_above_filtration(threshold_);
-    }
     simplex_tree->initialize_filtration();
   }
 
@@ -79,7 +73,6 @@ class Rips_complex_interface {
   // Anyway, storing a graph would make more sense. Or changing the interface completely so there is no such storage.
   boost::optional<Rips_complex<Simplex_tree_interface<>::Filtration_value>> rips_complex_;
   boost::optional<Sparse_rips_complex<Simplex_tree_interface<>::Filtration_value>> sparse_rips_complex_;
-  double threshold_;
 };
 
 }  // namespace rips_complex