Add exact option for exact cech variant

3 files changed, 32 insertions, 17 deletions

diff --git a/src/Cech_complex/benchmark/cech_complex_benchmark.cpp b/src/Cech_complex/benchmark/cech_complex_benchmark.cpp
index d2a71879..19142780 100644
--- a/src/Cech_complex/benchmark/cech_complex_benchmark.cpp
+++ b/src/Cech_complex/benchmark/cech_complex_benchmark.cpp
@@ -31,7 +31,7 @@ using Points_off_reader = Gudhi::Points_off_reader<Point>;
 using Rips_complex = Gudhi::rips_complex::Rips_complex<Filtration_value>;
 
 template<typename Kernel>
-Simplex_tree benchmark_cech(const std::string& off_file_points, const Filtration_value& radius, const int& dim_max) {
+Simplex_tree benchmark_cech(const std::string& off_file_points, const Filtration_value& radius, const int& dim_max, const bool exact) {
     using Point_cgal = typename Kernel::Point_d;
     using Points_off_reader_cgal = Gudhi::Points_off_reader<Point_cgal>;
     using Cech_complex = Gudhi::cech_complex::Cech_complex<Kernel, Simplex_tree>;
@@ -42,7 +42,7 @@ Simplex_tree benchmark_cech(const std::string& off_file_points, const Filtration
     Gudhi::Clock cech_clock("Cech computation");
     Cech_complex cech_complex_from_points(off_reader_cgal.get_point_cloud(), radius);
     Simplex_tree cech_stree;
-    cech_complex_from_points.create_complex(cech_stree, dim_max);
+    cech_complex_from_points.create_complex(cech_stree, dim_max, exact);
 
     // ------------------------------------------
     // Display information about the Cech complex
@@ -56,8 +56,9 @@ int main(int argc, char* argv[]) {
     boost::filesystem::path full_path(boost::filesystem::current_path());
     std::clog << "Current path is : " << full_path << std::endl;
 
-    std::clog << "File name ; Radius ; Rips time ; Dim-3 Epick Cech time ; Dynamic_dim Epick Cech time ; "
-                 "Dim-3 Epeck Cech time ; Dynamic_dim Epeck Cech time ; Cech nb simplices ; Rips nb simplices;"
+    std::clog << "File name ; Radius ; Rips time ; Dim-3 Fast Cech time ; Dynamic_dim Fast Cech time ; "
+                 "Dim-3 Safe Cech time ; Dynamic_dim Safe Cech time ; Dim-3 Exact Cech time ; Dynamic_dim Exact Cech time ; "
+                 "Cech nb simplices ; Rips nb simplices;"
               << std::endl;
     boost::filesystem::directory_iterator end_itr;  // default construction yields past-the-end
     for (boost::filesystem::directory_iterator itr(boost::filesystem::current_path()); itr != end_itr; ++itr) {
@@ -83,10 +84,15 @@ int main(int argc, char* argv[]) {
                     // --------------
                     // Cech complex
                     // --------------
-                    benchmark_cech<CGAL::Epick_d<CGAL::Dimension_tag<3>>>(itr->path().string(), radius, p0.size() - 1);
-                    benchmark_cech<CGAL::Epick_d<CGAL::Dynamic_dimension_tag>>(itr->path().string(), radius, p0.size() - 1);
-                    benchmark_cech<CGAL::Epeck_d<CGAL::Dimension_tag<3>>>(itr->path().string(), radius, p0.size() - 1);
-                    auto cech_stree = benchmark_cech<CGAL::Epeck_d<CGAL::Dynamic_dimension_tag>>(itr->path().string(), radius, p0.size() - 1);
+                    // Fast
+                    benchmark_cech<CGAL::Epick_d<CGAL::Dimension_tag<3>>>(itr->path().string(), radius, p0.size() - 1, false);
+                    benchmark_cech<CGAL::Epick_d<CGAL::Dynamic_dimension_tag>>(itr->path().string(), radius, p0.size() - 1, false);
+                    // Safe
+                    benchmark_cech<CGAL::Epeck_d<CGAL::Dimension_tag<3>>>(itr->path().string(), radius, p0.size() - 1, false);
+                    benchmark_cech<CGAL::Epeck_d<CGAL::Dynamic_dimension_tag>>(itr->path().string(), radius, p0.size() - 1, false);
+                    // Exact
+                    benchmark_cech<CGAL::Epeck_d<CGAL::Dimension_tag<3>>>(itr->path().string(), radius, p0.size() - 1, true);
+                    auto cech_stree = benchmark_cech<CGAL::Epeck_d<CGAL::Dynamic_dimension_tag>>(itr->path().string(), radius, p0.size() - 1, true);
 
                     std::clog << cech_stree.num_simplices() << "  ;  ";
                     std::clog << rips_stree.num_simplices() << ";" << std::endl;
diff --git a/src/Cech_complex/include/gudhi/Cech_complex.h b/src/Cech_complex/include/gudhi/Cech_complex.h
index fc39f75b..2c6d3df5 100644
--- a/src/Cech_complex/include/gudhi/Cech_complex.h
+++ b/src/Cech_complex/include/gudhi/Cech_complex.h
@@ -78,17 +78,19 @@ class Cech_complex {
    *
    * @param[in] complex SimplicialComplexForCech to be created.
    * @param[in] dim_max graph expansion until this given maximal dimension.
+   * @param[in] exact Exact filtration values computation. Not exact if `Kernel` is not <a target="_blank"
+   * href="https://doc.cgal.org/latest/Kernel_d/structCGAL_1_1Epeck__d.html">CGAL::Epeck_d</a>.
    * @exception std::invalid_argument In debug mode, if `complex.num_vertices()` does not return 0.
    *
    */
-  void create_complex(SimplicialComplexForCechComplex& complex, int dim_max) {
+  void create_complex(SimplicialComplexForCechComplex& complex, int dim_max, const bool exact = false) {
     GUDHI_CHECK(complex.num_vertices() == 0,
                 std::invalid_argument("Cech_complex::create_complex - simplicial complex is not empty"));
 
     // insert the proximity graph in the simplicial complex
     complex.insert_graph(cech_skeleton_graph_);
     // expand the graph until dimension dim_max
-    complex.expansion_with_blockers(dim_max, cech_blocker(&complex, this));
+    complex.expansion_with_blockers(dim_max, cech_blocker(&complex, this, exact));
   }
 
   /** @return max_radius value given at construction. */
diff --git a/src/Cech_complex/include/gudhi/Cech_complex_blocker.h b/src/Cech_complex/include/gudhi/Cech_complex_blocker.h
index 3141d27a..087390b6 100644
--- a/src/Cech_complex/include/gudhi/Cech_complex_blocker.h
+++ b/src/Cech_complex/include/gudhi/Cech_complex_blocker.h
@@ -94,9 +94,9 @@ class Cech_blocker {
             Point_cloud face_points;
             for (auto vertex : sc_ptr_->simplex_vertex_range(face)) {
                 face_points.push_back(cc_ptr_->get_point(vertex));
-                #ifdef DEBUG_TRACES
-                    std::clog << "#(" << vertex << ")#";
-                #endif  // DEBUG_TRACES
+#ifdef DEBUG_TRACES
+                std::clog << "#(" << vertex << ")#";
+#endif  // DEBUG_TRACES
             }
             sph = get_sphere(face_points.cbegin(), face_points.cend());
             // Put edge sphere in cache
@@ -107,10 +107,13 @@ class Cech_blocker {
         }
         // Check if the minimal enclosing ball of current face contains the extra point
         if (kernel_.squared_distance_d_object()(sph.first, cc_ptr_->get_point(extra)) <= sph.second) {
-            #ifdef DEBUG_TRACES
-                std::clog << "center: " << sph.first << ", radius: " <<  radius << std::endl;
-            #endif  // DEBUG_TRACES
+#ifdef DEBUG_TRACES
+            std::clog << "center: " << sph.first << ", radius: " <<  radius << std::endl;
+#endif  // DEBUG_TRACES
             is_min_enclos_ball = true;
+#if CGAL_VERSION_NR >= 1050000000
+            if(exact_) CGAL::exact(sph.second);
+#endif
             radius = std::sqrt(cast_to_fv(sph.second));
             sc_ptr_->assign_key(sh, cc_ptr_->get_cache().size());
             cc_ptr_->get_cache().push_back(sph);
@@ -124,6 +127,9 @@ class Cech_blocker {
             points.push_back(cc_ptr_->get_point(vertex));
         }
         Sphere sph = get_sphere(points.cbegin(), points.cend());
+#if CGAL_VERSION_NR >= 1050000000
+        if(exact_) CGAL::exact(sph.second);
+#endif
         radius = std::sqrt(cast_to_fv(sph.second));
 
         sc_ptr_->assign_key(sh, cc_ptr_->get_cache().size());
@@ -138,12 +144,13 @@ class Cech_blocker {
   }
 
   /** \internal \brief Čech complex blocker constructor. */
-  Cech_blocker(SimplicialComplexForCech* sc_ptr, Cech_complex* cc_ptr) : sc_ptr_(sc_ptr), cc_ptr_(cc_ptr) {}
+  Cech_blocker(SimplicialComplexForCech* sc_ptr, Cech_complex* cc_ptr, const bool exact) : sc_ptr_(sc_ptr), cc_ptr_(cc_ptr), exact_(exact) {}
 
  private:
   SimplicialComplexForCech* sc_ptr_;
   Cech_complex* cc_ptr_;
   Kernel kernel_;
+  const bool exact_;
 };
 
 }  // namespace cech_complex