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+/* 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): Siargey Kachanovich
+ *
+ * Copyright (C) 2016 INRIA Sophia Antipolis-Méditerranée (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 LANDMARK_CHOICE_BY_RANDOM_POINT_H_
+#define LANDMARK_CHOICE_BY_RANDOM_POINT_H_
+
+#include <boost/range/size.hpp>
+
+#include <random> // random_device, mt19937
+#include <algorithm> // shuffle
+#include <numeric> // iota
+#include <iterator>
+#include <gudhi/Clock.h>
+
+
+namespace Gudhi {
+
+ /**
+ * \ingroup witness_complex
+ * \brief Landmark choice strategy by taking random vertices for landmarks.
+ *
+ * \details It chooses nbL distinct landmarks from a random access range `points`
+ * and outputs them to an output iterator.
+ * Point_container::iterator should be ValueSwappable and RandomAccessIterator.
+ */
+
+ template <typename Point_container,
+ typename OutputIterator>
+ void landmark_choice_by_random_point(Point_container const &points,
+ unsigned nbL,
+ OutputIterator output_it) {
+#ifdef GUDHI_LM_PROFILING
+ Gudhi::Clock t;
+#endif
+
+ unsigned nbP = boost::size(points);
+ assert(nbP >= nbL);
+ std::vector<int> landmarks(nbP);
+ std::iota(landmarks.begin(), landmarks.end(), 0);
+
+ std::random_device rd;
+ std::mt19937 g(rd());
+
+ std::shuffle(landmarks.begin(), landmarks.end(), g);
+ landmarks.resize(nbL);
+
+ for (int l: landmarks)
+ *output_it++ = points[l];
+
+#ifdef GUDHI_LM_PROFILING
+ t.end();
+ std::cerr << "Random landmark choice took " << t.num_seconds()
+ << " seconds." << std::endl;
+#endif
+
+
+ }
+
+} // namespace Gudhi
+
+#endif // LANDMARK_CHOICE_BY_RANDOM_POINT_H_