1 files changed, 56 insertions, 0 deletions
diff --git a/src/GudhUI/utils/Rips_builder.h b/src/GudhUI/utils/Rips_builder.h
new file mode 100644
index 00000000..aba1a8e4
--- /dev/null
+++ b/src/GudhUI/utils/Rips_builder.h
@@ -0,0 +1,56 @@
+/*    This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
+ *    See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
+ *    Author(s):       David Salinas
+ *
+ *    Copyright (C) 2014 Inria
+ *
+ *    Modification(s):
+ *      - YYYY/MM Author: Description of the modification
+ */
+
+#ifndef UTILS_RIPS_BUILDER_H_
+#define UTILS_RIPS_BUILDER_H_
+
+#include <boost/iterator/iterator_facade.hpp>
+
+#include <CGAL/Euclidean_distance.h>
+#include <CGAL/Orthogonal_k_neighbor_search.h>
+#include <CGAL/Search_traits_d.h>
+
+#include "utils/UI_utils.h"
+#include "model/Complex_typedefs.h"
+
+template<typename SkBlComplex> class Rips_builder {
+ private:
+  SkBlComplex& complex_;
+
+ public:
+  /**
+   * @brief Modify complex to be the Rips complex
+   * of its points with offset alpha.
+   */
+  Rips_builder(SkBlComplex& complex, double alpha) : complex_(complex) {
+    complex.keep_only_vertices();
+    if (alpha <= 0) return;
+    compute_edges(alpha);
+  }
+
+ private:
+  double squared_eucl_distance(const Point& p1, const Point& p2) const {
+    return Geometry_trait::Squared_distance_d()(p1, p2);
+  }
+
+  void compute_edges(double alpha) {
+    auto vertices = complex_.vertex_range();
+    for (auto p = vertices.begin(); p != vertices.end(); ++p) {
+      std::cout << *p << " ";
+      std::cout.flush();
+      for (auto q = p; ++q != vertices.end(); /**/)
+        if (squared_eucl_distance(complex_.point(*p), complex_.point(*q)) < 4 * alpha * alpha)
+          complex_.add_edge_without_blockers(*p, *q);
+    }
+    std::cout << std::endl;
+  }
+};
+
+#endif  // UTILS_RIPS_BUILDER_H_