1 files changed, 87 insertions, 0 deletions
diff --git a/utilities/Persistence_representations/persistence_intervals/plot_persistence_Betti_numbers.cpp b/utilities/Persistence_representations/persistence_intervals/plot_persistence_Betti_numbers.cpp
new file mode 100644
index 00000000..b433c2b3
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+++ b/utilities/Persistence_representations/persistence_intervals/plot_persistence_Betti_numbers.cpp
@@ -0,0 +1,87 @@
+/*    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):       Pawel Dlotko
+ *
+ *    Copyright (C) 2016  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/>.
+ */
+
+#include <gudhi/Persistence_intervals.h>
+
+#include <iostream>
+#include <vector>
+#include <limits>
+#include <utility>
+
+using Persistence_intervals = Gudhi::Persistence_representations::Persistence_intervals;
+
+int main(int argc, char** argv) {
+  if ((argc != 3) && (argc != 2)) {
+    std::cout << "This program creates a gnuplot script of Betti numbers from a single persistence diagram file"
+              << "(*.pers).\n"
+              << "To run this program, please provide the name of a file with persistence diagram.\n"
+              << "The second optional parameter of a program is the dimension of the persistence that is to be used. "
+              << "If your file contains only birth-death pairs, you can skip this parameter.\n";
+    return 1;
+  }
+
+  unsigned dimension = std::numeric_limits<unsigned>::max();
+  int dim = -1;
+  if (argc == 3) {
+    dim = atoi(argv[2]);
+  }
+  if (dim >= 0) {
+    dimension = (unsigned)dim;
+  }
+
+  Persistence_intervals p(argv[1], dimension);
+  std::vector<std::pair<double, size_t> > pbns = p.compute_persistent_betti_numbers();
+
+  // set up the ranges so that we see the image well.
+  double xRangeBegin = pbns[0].first;
+  double xRangeEnd = pbns[pbns.size() - 1].first;
+  double yRangeBegin = 0;
+  double yRangeEnd = 0;
+  for (size_t i = 0; i != pbns.size(); ++i) {
+    if (pbns[i].second > yRangeEnd) yRangeEnd = pbns[i].second;
+  }
+  xRangeBegin -= (xRangeEnd - xRangeBegin) / 100.0;
+  xRangeEnd += (xRangeEnd - xRangeBegin) / 100.0;
+  yRangeEnd += yRangeEnd / 100;
+
+  std::stringstream gnuplot_script;
+  gnuplot_script << argv[1] << "_GnuplotScript";
+  std::ofstream out;
+  out.open(gnuplot_script.str().c_str());
+
+  out << "set xrange [" << xRangeBegin << " : " << xRangeEnd << "]" << std::endl;
+  out << "set yrange [" << yRangeBegin << " : " << yRangeEnd << "]" << std::endl;
+  out << "plot '-' using 1:2 notitle with lp " << std::endl;
+  double previous_y = 0;
+  for (size_t i = 0; i != pbns.size(); ++i) {
+    out << pbns[i].first << " " << previous_y << std::endl;
+    out << pbns[i].first << " " << pbns[i].second << std::endl;
+    previous_y = pbns[i].second;
+  }
+  out << std::endl;
+  out.close();
+
+  std::cout << "To visualize, install gnuplot and type the command: gnuplot -persist -e \"load \'"
+            << gnuplot_script.str().c_str() << "\'\"" << std::endl;
+
+  return 0;
+}