1 files changed, 75 insertions, 0 deletions
diff --git a/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_Betti_numbers.cpp b/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_Betti_numbers.cpp
new file mode 100644
index 00000000..451be77f
--- /dev/null
+++ b/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_Betti_numbers.cpp
@@ -0,0 +1,75 @@
+/*    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):       Pawel Dlotko
+ *
+ *    Copyright (C) 2016 Inria
+ *
+ *    Modification(s):
+ *      - YYYY/MM Author: Description of the modification
+ */
+
+#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;
+}