added weight_functions.h

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/branches/kernels@3388 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: 71f741e7ca2fcacc877d44e4d6b633f283526f2f

1 files changed, 81 insertions, 0 deletions

diff --git a/src/Persistence_representations/include/gudhi/Weight_functions.h b/src/Persistence_representations/include/gudhi/Weight_functions.h
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+++ b/src/Persistence_representations/include/gudhi/Weight_functions.h
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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):       Mathieu Carriere
+ *
+ *    Copyright (C) 2018  INRIA (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 WEIGHT_FUNCTIONS_H_
+#define WEIGHT_FUNCTIONS_H_
+
+// gudhi include
+#include <gudhi/read_persistence_from_file.h>
+#include <gudhi/common_persistence_representations.h>
+
+// standard include
+#include <cmath>
+#include <iostream>
+#include <vector>
+#include <limits>
+#include <fstream>
+#include <sstream>
+#include <algorithm>
+#include <string>
+#include <utility>
+#include <functional>
+
+namespace Gudhi {
+namespace Persistence_representations {
+
+/** \fn  static double pss_weight(std::pair<double,double> p)
+ * \brief Persistence Scale Space kernel weight function.
+ * \ingroup Persistence_representations
+ *
+ * @param[in] p point in 2D.
+ */
+static double pss_weight(std::pair<double,double> p)     {if(p.second > p.first)  return 1; else return -1;}
+
+/** \fn static double linear_weight(std::pair<double,double> p)
+ * \brief Linear weight function.
+ * \ingroup Persistence_representations
+ *
+ * @param[in] p point in 2D.
+ */
+static double linear_weight(std::pair<double,double> p)  {return std::abs(p.second - p.first);}
+
+/** \fn static double const_weight(std::pair<double,double> p)
+ * \brief Constant weight function.
+ * \ingroup Persistence_representations
+ *
+ * @param[in] p point in 2D.
+ */
+static double const_weight(std::pair<double,double> p)   {return 1;}
+
+/** \fn static std::function<double (std::pair<double,double>) > arctan_weight(double C, double alpha)
+ * \brief Returns the arctan weight function with parameters C and alpha.
+ * \ingroup Persistence_representations
+ *
+ * @param[in] C     positive constant.
+ * @param[in] alpha positive power.
+ */
+static std::function<double (std::pair<double,double>) > arctan_weight(double C, double alpha)  {return [=](std::pair<double,double> p){return C * atan(std::pow(std::abs(p.second - p.first), alpha));};}
+
+}  // namespace Persistence_representations
+}  // namespace Gudhi
+
+#endif  // WEIGHT_FUNCTIONS_H_