1 files changed, 119 insertions, 0 deletions
diff --git a/src/Bottleneck/include/gudhi/Planar_neighbors_finder.h b/src/Bottleneck/include/gudhi/Planar_neighbors_finder.h
new file mode 100644
index 00000000..4af672e4
--- /dev/null
+++ b/src/Bottleneck/include/gudhi/Planar_neighbors_finder.h
@@ -0,0 +1,119 @@
+/*    This file is part of the Gudhi Library. The Gudhi library
+ *    (Geometric Understanding in Higher Dimensions) is a generic C++
+ *    library for computational topology.
+ *
+ *    Author(s):       Francois Godi
+ *
+ *    Copyright (C) 2015  INRIA Saclay (France)
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SRC_BOTTLENECK_INCLUDE_GUDHI_PLANAR_NEIGHBORS_FINDER_H_
+#define SRC_BOTTLENECK_INCLUDE_GUDHI_PLANAR_NEIGHBORS_FINDER_H_
+
+#include <list>
+#include <iostream>
+#include <set>
+
+#include "Persistence_diagrams_graph.h"
+
+namespace Gudhi {
+
+namespace bottleneck {
+
+// Planar_neighbors_finder is a data structure used to find if a query point from U has planar neighbors in V with the
+// planar distance.
+// V's points have to be added manually using their index. A neighbor returned is automatically removed but we can also
+// remove points manually using their index.
+
+class Abstract_planar_neighbors_finder {
+ public:
+  Abstract_planar_neighbors_finder(const Persistence_diagrams_graph& g, double r);
+  virtual ~Abstract_planar_neighbors_finder() = 0;
+  virtual void add(int v_point_index) = 0;
+  virtual void remove(int v_point_index) = 0;
+  virtual bool contains(int v_point_index) const = 0;
+  virtual int pull_near(int u_point_index) = 0;
+  virtual std::list<int>* pull_all_near(int u_point_index);
+
+ protected:
+  const Persistence_diagrams_graph& g;
+  const double r;
+};
+
+
+// Naive_pnf is a nave implementation of Abstract_planar_neighbors_finder
+
+class Naive_pnf : public Abstract_planar_neighbors_finder {
+ public:
+  Naive_pnf(const Persistence_diagrams_graph& g, double r);
+  void add(int v_point_index);
+  void remove(int v_point_index);
+  bool contains(int v_point_index) const;
+  int pull_near(int u_point_index);
+
+ private:
+  std::set<int> candidates;
+};
+
+
+// Planar_neighbors_finder is the used Abstract_planar_neighbors_finder's implementation
+typedef Naive_pnf Planar_neighbors_finder;
+
+Abstract_planar_neighbors_finder::Abstract_planar_neighbors_finder(const Persistence_diagrams_graph& g, double r) :
+    g(g), r(r) { }
+
+inline Abstract_planar_neighbors_finder::~Abstract_planar_neighbors_finder() { }
+
+inline std::list<int>* Abstract_planar_neighbors_finder::pull_all_near(int u_point_index) {
+  std::list<int>* all_pull = new std::list<int>();
+  int last_pull = pull_near(u_point_index);
+  while (last_pull != null_point_index()) {
+    all_pull->emplace_back(last_pull);
+    last_pull = pull_near(u_point_index);
+  }
+  return all_pull;
+}
+
+Naive_pnf::Naive_pnf(const Persistence_diagrams_graph& g, double r) :
+    Abstract_planar_neighbors_finder(g, r), candidates() { }
+
+inline void Naive_pnf::add(int v_point_index) {
+  candidates.emplace(v_point_index);
+}
+
+inline void Naive_pnf::remove(int v_point_index) {
+  candidates.erase(v_point_index);
+}
+
+inline bool Naive_pnf::contains(int v_point_index) const {
+  return (candidates.count(v_point_index) > 0);
+}
+
+inline int Naive_pnf::pull_near(int u_point_index) {
+  for (auto it = candidates.begin(); it != candidates.end(); ++it)
+    if (g.distance(u_point_index, *it) <= r) {
+      int tmp = *it;
+      candidates.erase(it);
+      return tmp;
+    }
+  return null_point_index();
+}
+
+}  // namespace bottleneck
+
+}  // namespace Gudhi
+
+#endif  // SRC_BOTTLENECK_INCLUDE_GUDHI_PLANAR_NEIGHBORS_FINDER_H_