When 3d points are on a 2d plane case - Fixes also default_filtration_value=True in 3d

3 files changed, 42 insertions, 26 deletions

diff --git a/src/Alpha_complex/include/gudhi/Alpha_complex_3d.h b/src/Alpha_complex/include/gudhi/Alpha_complex_3d.h
index c19ebb79..c29905f4 100644
--- a/src/Alpha_complex/include/gudhi/Alpha_complex_3d.h
+++ b/src/Alpha_complex/include/gudhi/Alpha_complex_3d.h
@@ -471,6 +471,10 @@ Weighted_alpha_complex_3d::Weighted_point_3 wp0(Weighted_alpha_complex_3d::Bare_
 #ifdef DEBUG_TRACES
     std::clog << "filtration_with_alpha_values returns : " << objects.size() << " objects" << std::endl;
 #endif  // DEBUG_TRACES
+    if (objects.size() == 0) {
+      std::cerr << "Alpha_complex_3d create_complex - no triangulation as points are on a 2d plane\n";
+      return false;  // ----- >>
+    }
 
     using Alpha_value_iterator = typename std::vector<FT>::const_iterator;
     Alpha_value_iterator alpha_value_iterator = alpha_values.begin();
diff --git a/src/python/include/Alpha_complex_factory.h b/src/python/include/Alpha_complex_factory.h
index 69b584c5..7d98f454 100644
--- a/src/python/include/Alpha_complex_factory.h
+++ b/src/python/include/Alpha_complex_factory.h
@@ -48,7 +48,7 @@ static CgalPointType pt_cython_to_cgal(std::vector<double> const& vec) {
 class Abstract_alpha_complex {
  public:
   virtual std::vector<double> get_point(int vh) = 0;
-  virtual void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
+  virtual bool create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
                                    bool default_filtration_value) = 0;
 };
 
@@ -68,9 +68,9 @@ class Exact_Alphacomplex_dD : public Abstract_alpha_complex {
     return pt_cgal_to_cython(point);
   }
 
-  void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
+  bool create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
                            bool default_filtration_value){
-    alpha_complex_.create_complex(*simplex_tree, max_alpha_square, exact_version_, default_filtration_value);
+    return alpha_complex_.create_complex(*simplex_tree, max_alpha_square, exact_version_, default_filtration_value);
   }
 
  private:
@@ -93,9 +93,9 @@ class Inexact_Alphacomplex_dD : public Abstract_alpha_complex {
     Point const& point = alpha_complex_.get_point(vh);
     return pt_cgal_to_cython(point);
   }
-  void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
+  bool create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
                            bool default_filtration_value){
-    alpha_complex_.create_complex(*simplex_tree, max_alpha_square, exact_version_, default_filtration_value);
+    return alpha_complex_.create_complex(*simplex_tree, max_alpha_square, exact_version_, default_filtration_value);
   }
 
  private:
@@ -122,12 +122,9 @@ class Alphacomplex_3D : public Abstract_alpha_complex {
     return pt_cgal_to_cython(point);
   }
 
-  void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
+  bool create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
                            bool default_filtration_value){
-    alpha_complex_.create_complex(*simplex_tree, max_alpha_square);
-    if (default_filtration_value) {
-      // TODO
-    }
+    return alpha_complex_.create_complex(*simplex_tree, max_alpha_square);
   }
 
  private:
diff --git a/src/python/include/Alpha_complex_interface.h b/src/python/include/Alpha_complex_interface.h
index 0b946f8e..604ff85e 100644
--- a/src/python/include/Alpha_complex_interface.h
+++ b/src/python/include/Alpha_complex_interface.h
@@ -27,21 +27,10 @@ namespace alpha_complex {
 
 class Alpha_complex_interface {
  public:
-  Alpha_complex_interface(const std::vector<std::vector<double>>& points, bool fast_version, bool exact_version) {
-    if (points.size() > 0 && points[0].size() == 3) {
-      if (fast_version)
-        alpha_ptr_ = std::make_unique<Alphacomplex_3D<Gudhi::alpha_complex::complexity::FAST>>(points);
-      else if (exact_version)
-        alpha_ptr_ = std::make_unique<Alphacomplex_3D<Gudhi::alpha_complex::complexity::EXACT>>(points);
-      else
-        alpha_ptr_ = std::make_unique<Alphacomplex_3D<Gudhi::alpha_complex::complexity::SAFE>>(points);
-    } else {
-      if (fast_version) {
-        alpha_ptr_ = std::make_unique<Inexact_Alphacomplex_dD>(points, exact_version);
-      } else {
-        alpha_ptr_ = std::make_unique<Exact_Alphacomplex_dD>(points, exact_version);
-      }
-    }
+  Alpha_complex_interface(const std::vector<std::vector<double>>& points, bool fast_version, bool exact_version)
+  : points_(points.begin(), points.end()),
+    fast_version_(fast_version),
+    exact_version_(exact_version) {
   }
 
   std::vector<double> get_point(int vh) {
@@ -50,11 +39,37 @@ class Alpha_complex_interface {
 
   void create_simplex_tree(Simplex_tree_interface<>* simplex_tree, double max_alpha_square,
                            bool default_filtration_value) {
-      alpha_ptr_->create_simplex_tree(simplex_tree, max_alpha_square, default_filtration_value);
+    if (points_.size() > 0) {
+      std::size_t dimension = points_[0].size();
+      if (dimension == 3 && !default_filtration_value) {
+        if (fast_version_)
+          alpha_ptr_ = std::make_unique<Alphacomplex_3D<Gudhi::alpha_complex::complexity::FAST>>(points_);
+        else if (exact_version_)
+          alpha_ptr_ = std::make_unique<Alphacomplex_3D<Gudhi::alpha_complex::complexity::EXACT>>(points_);
+        else
+          alpha_ptr_ = std::make_unique<Alphacomplex_3D<Gudhi::alpha_complex::complexity::SAFE>>(points_);
+        if (!alpha_ptr_->create_simplex_tree(simplex_tree, max_alpha_square, default_filtration_value)) {
+          // create_simplex_tree will fail if all points are on a 2d plane - Retry with dimension 2
+          dimension--;
+        }
+      }
+      // Not ** else ** because we have to take into account if 3d fails
+      if (dimension != 3 || default_filtration_value) {
+        if (fast_version_) {
+          alpha_ptr_ = std::make_unique<Inexact_Alphacomplex_dD>(points_, exact_version_);
+        } else {
+          alpha_ptr_ = std::make_unique<Exact_Alphacomplex_dD>(points_, exact_version_);
+        }
+        alpha_ptr_->create_simplex_tree(simplex_tree, max_alpha_square, default_filtration_value);
+      }
+    }
   }
 
  private:
   std::unique_ptr<Abstract_alpha_complex> alpha_ptr_;
+  std::vector<std::vector<double>> points_;
+  bool fast_version_;
+  bool exact_version_;
 };
 
 }  // namespace alpha_complex