From bf4b4eeda9762ed9e99c2b24f19331fa0111fcfe Mon Sep 17 00:00:00 2001
From: ROUVREAU Vincent <vincent.rouvreau@inria.fr>
Date: Mon, 27 Jan 2020 10:43:16 +0100
Subject: Code review: Use std::clog instead of std::cout

---
 .../average_persistence_heat_maps.cpp                      |  6 +++---
 .../compute_distance_of_persistence_heat_maps.cpp          | 10 +++++-----
 .../compute_scalar_product_of_persistence_heat_maps.cpp    | 10 +++++-----
 ...reate_p_h_m_weighted_by_arctan_of_their_persistence.cpp |  6 +++---
 .../create_p_h_m_weighted_by_distance_from_diagonal.cpp    |  6 +++---
 .../create_p_h_m_weighted_by_squared_diag_distance.cpp     |  6 +++---
 .../persistence_heat_maps/create_persistence_heat_maps.cpp |  6 +++---
 .../utilities/persistence_heat_maps/create_pssk.cpp        |  6 +++---
 .../persistence_heat_maps/plot_persistence_heat_map.cpp    |  4 ++--
 .../compute_birth_death_range_in_persistence_diagram.cpp   |  8 ++++----
 .../persistence_intervals/compute_bottleneck_distance.cpp  | 10 +++++-----
 .../compute_number_of_dominant_intervals.cpp               |  8 ++++----
 .../plot_histogram_of_intervals_lengths.cpp                |  6 +++---
 .../plot_persistence_Betti_numbers.cpp                     |  4 ++--
 .../persistence_intervals/plot_persistence_intervals.cpp   |  2 +-
 .../persistence_landscapes/average_landscapes.cpp          |  6 +++---
 .../compute_distance_of_landscapes.cpp                     | 10 +++++-----
 .../compute_scalar_product_of_landscapes.cpp               | 10 +++++-----
 .../utilities/persistence_landscapes/create_landscapes.cpp |  6 +++---
 .../utilities/persistence_landscapes/plot_landscapes.cpp   |  4 ++--
 .../average_landscapes_on_grid.cpp                         |  6 +++---
 .../compute_distance_of_landscapes_on_grid.cpp             | 10 +++++-----
 .../compute_scalar_product_of_landscapes_on_grid.cpp       | 10 +++++-----
 .../create_landscapes_on_grid.cpp                          |  6 +++---
 .../plot_landscapes_on_grid.cpp                            |  4 ++--
 .../persistence_vectors/average_persistence_vectors.cpp    |  6 +++---
 .../compute_distance_of_persistence_vectors.cpp            | 14 +++++++-------
 .../compute_scalar_product_of_persistence_vectors.cpp      | 10 +++++-----
 .../persistence_vectors/create_persistence_vectors.cpp     |  6 +++---
 .../persistence_vectors/plot_persistence_vectors.cpp       |  4 ++--
 30 files changed, 105 insertions(+), 105 deletions(-)

(limited to 'src/Persistence_representations/utilities')

diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/average_persistence_heat_maps.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/average_persistence_heat_maps.cpp
index 3d088b58..54b1f77d 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/average_persistence_heat_maps.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/average_persistence_heat_maps.cpp
@@ -17,12 +17,12 @@ using constant_scaling_function = Gudhi::Persistence_representations::constant_s
 using Persistence_heat_maps = Gudhi::Persistence_representations::Persistence_heat_maps<constant_scaling_function>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes average of persistence heat maps stored in files (the files needs to be "
+  std::clog << "This program computes average of persistence heat maps stored in files (the files needs to be "
             << "created beforehand).\n"
             << "The parameters of this programs are names of files with persistence heat maps.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -46,6 +46,6 @@ int main(int argc, char** argv) {
     delete maps[i];
   }
 
-  std::cout << "Average can be found in 'average.mps' file\n";
+  std::clog << "Average can be found in 'average.mps' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/compute_distance_of_persistence_heat_maps.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/compute_distance_of_persistence_heat_maps.cpp
index 48000bb1..757a97fc 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/compute_distance_of_persistence_heat_maps.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/compute_distance_of_persistence_heat_maps.cpp
@@ -19,14 +19,14 @@ using constant_scaling_function = Gudhi::Persistence_representations::constant_s
 using Persistence_heat_maps = Gudhi::Persistence_representations::Persistence_heat_maps<constant_scaling_function>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes distance of persistence heat maps stored in files (the files needs to be "
+  std::clog << "This program computes distance of persistence heat maps stored in files (the files needs to be "
             << "created beforehand).\n"
             << "The first parameter of a program is an integer p. The program compute L^p distance of the two heat "
             << "maps. For L^infty distance choose p = -1. \n"
             << "The remaining parameters of this program are names of files with persistence heat maps.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -69,14 +69,14 @@ int main(int argc, char** argv) {
   out.open("distance.mps");
   for (size_t i = 0; i != distance.size(); ++i) {
     for (size_t j = 0; j != distance.size(); ++j) {
-      std::cout << distance[i][j] << " ";
+      std::clog << distance[i][j] << " ";
       out << distance[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'distance.mps' file\n";
+  std::clog << "Distance can be found in 'distance.mps' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/compute_scalar_product_of_persistence_heat_maps.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/compute_scalar_product_of_persistence_heat_maps.cpp
index 8a96f1b0..e7f18ce1 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/compute_scalar_product_of_persistence_heat_maps.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/compute_scalar_product_of_persistence_heat_maps.cpp
@@ -18,12 +18,12 @@ using constant_scaling_function = Gudhi::Persistence_representations::constant_s
 using Persistence_heat_maps = Gudhi::Persistence_representations::Persistence_heat_maps<constant_scaling_function>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes scalar product of persistence heat maps stored in a file (the file needs to be "
+  std::clog << "This program computes scalar product of persistence heat maps stored in a file (the file needs to be "
             << "created beforehand). \n"
             << "The parameters of this programs are names of files with persistence heat maps.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -60,14 +60,14 @@ int main(int argc, char** argv) {
   out.open("scalar_product.mps");
   for (size_t i = 0; i != scalar_product.size(); ++i) {
     for (size_t j = 0; j != scalar_product.size(); ++j) {
-      std::cout << scalar_product[i][j] << " ";
+      std::clog << scalar_product[i][j] << " ";
       out << scalar_product[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'scalar_product.mps' file\n";
+  std::clog << "Distance can be found in 'scalar_product.mps' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_arctan_of_their_persistence.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_arctan_of_their_persistence.cpp
index f82a39b0..6b38b930 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_arctan_of_their_persistence.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_arctan_of_their_persistence.cpp
@@ -20,7 +20,7 @@ using Persistence_heat_maps =
     Gudhi::Persistence_representations::Persistence_heat_maps<arc_tan_of_persistence_of_point>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
+  std::clog << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
             << "provided as an input.The Gaussian kernels are weighted by the arc tangential of their persistence.\n"
             << "The first parameter of a program is an integer, a size of a grid.\n"
             << "The second and third parameters are min and max of the grid. If you want those numbers to be computed "
@@ -36,7 +36,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 7) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
@@ -58,7 +58,7 @@ int main(int argc, char** argv) {
 
   std::vector<std::vector<double> > filter = Gudhi::Persistence_representations::create_Gaussian_filter(stdiv, 1);
   for (size_t i = 0; i != filenames.size(); ++i) {
-    std::cout << "Creating a heat map based on a file : " << filenames[i] << std::endl;
+    std::clog << "Creating a heat map based on a file : " << filenames[i] << std::endl;
     Persistence_heat_maps l(filenames[i], filter, false, size_of_grid, min_, max_, dimension);
 
     std::stringstream ss;
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_distance_from_diagonal.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_distance_from_diagonal.cpp
index 5a657b13..fece2e36 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_distance_from_diagonal.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_distance_from_diagonal.cpp
@@ -19,7 +19,7 @@ using distance_from_diagonal_scaling = Gudhi::Persistence_representations::dista
 using Persistence_heat_maps = Gudhi::Persistence_representations::Persistence_heat_maps<distance_from_diagonal_scaling>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
+  std::clog << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
             << "provided as an input.The Gaussian kernels are weighted by the distance of a center from the "
             << "diagonal.\n"
             << "The first parameter of a program is an integer, a size of a grid.\n"
@@ -36,7 +36,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 7) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
@@ -58,7 +58,7 @@ int main(int argc, char** argv) {
 
   std::vector<std::vector<double> > filter = Gudhi::Persistence_representations::create_Gaussian_filter(stdiv, 1);
   for (size_t i = 0; i != filenames.size(); ++i) {
-    std::cout << "Creating a heat map based on a file : " << filenames[i] << std::endl;
+    std::clog << "Creating a heat map based on a file : " << filenames[i] << std::endl;
     Persistence_heat_maps l(filenames[i], filter, false, size_of_grid, min_, max_, dimension);
 
     std::stringstream ss;
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_squared_diag_distance.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_squared_diag_distance.cpp
index 8d67a54d..86e6fc19 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_squared_diag_distance.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/create_p_h_m_weighted_by_squared_diag_distance.cpp
@@ -21,7 +21,7 @@ using Persistence_heat_maps =
     Gudhi::Persistence_representations::Persistence_heat_maps<squared_distance_from_diagonal_scaling>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
+  std::clog << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
             << "provided as an input.The Gaussian kernels are weighted by the square of distance of a center from the "
             << "diagonal.\n"
             << "The first parameter of a program is an integer, a size of a grid.\n"
@@ -38,7 +38,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 7) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
@@ -60,7 +60,7 @@ int main(int argc, char** argv) {
 
   std::vector<std::vector<double> > filter = Gudhi::Persistence_representations::create_Gaussian_filter(stdiv, 1);
   for (size_t i = 0; i != filenames.size(); ++i) {
-    std::cout << "Creating a heat map based on a file : " << filenames[i] << std::endl;
+    std::clog << "Creating a heat map based on a file : " << filenames[i] << std::endl;
     Persistence_heat_maps l(filenames[i], filter, false, size_of_grid, min_, max_, dimension);
 
     std::stringstream ss;
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/create_persistence_heat_maps.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/create_persistence_heat_maps.cpp
index 29170c32..ca27f8e3 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/create_persistence_heat_maps.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/create_persistence_heat_maps.cpp
@@ -19,7 +19,7 @@ using constant_scaling_function = Gudhi::Persistence_representations::constant_s
 using Persistence_heat_maps = Gudhi::Persistence_representations::Persistence_heat_maps<constant_scaling_function>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
+  std::clog << "This program creates persistence heat map files (*.mps) of persistence diagrams files (*.pers) "
             << "provided as an input.\n"
             << "The first parameter of a program is an integer, a size of a grid.\n"
             << "The second and third parameters are min and max of the grid. If you want those numbers to be computed "
@@ -35,7 +35,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 7) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
   size_t size_of_grid = (size_t)atoi(argv[1]);
@@ -55,7 +55,7 @@ int main(int argc, char** argv) {
 
   std::vector<std::vector<double> > filter = Gudhi::Persistence_representations::create_Gaussian_filter(stdiv, 1);
   for (size_t i = 0; i != filenames.size(); ++i) {
-    std::cout << "Creating a heat map based on file : " << filenames[i] << std::endl;
+    std::clog << "Creating a heat map based on file : " << filenames[i] << std::endl;
     Persistence_heat_maps l(filenames[i], filter, false, size_of_grid, min_, max_, dimension);
 
     std::stringstream ss;
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/create_pssk.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/create_pssk.cpp
index 995771b9..d2ebcc7e 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/create_pssk.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/create_pssk.cpp
@@ -18,7 +18,7 @@
 using PSSK = Gudhi::Persistence_representations::PSSK;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates PSSK files (*.pssk) of persistence diagrams files (*.pers) "
+  std::clog << "This program creates PSSK files (*.pssk) of persistence diagrams files (*.pers) "
             << "provided as an input.\n"
             << "The first parameter of a program is an integer, a size of a grid.\n"
             << "The second and third parameters are min and max of the grid. If you want those numbers to be computed "
@@ -34,7 +34,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 7) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
@@ -56,7 +56,7 @@ int main(int argc, char** argv) {
 
   std::vector<std::vector<double> > filter = Gudhi::Persistence_representations::create_Gaussian_filter(stdiv, 1);
   for (size_t i = 0; i != filenames.size(); ++i) {
-    std::cout << "Creating a PSSK based on a file : " << filenames[i] << std::endl;
+    std::clog << "Creating a PSSK based on a file : " << filenames[i] << std::endl;
     PSSK l(filenames[i], filter, size_of_grid, min_, max_, dimension);
 
     std::stringstream ss;
diff --git a/src/Persistence_representations/utilities/persistence_heat_maps/plot_persistence_heat_map.cpp b/src/Persistence_representations/utilities/persistence_heat_maps/plot_persistence_heat_map.cpp
index cf6e07cb..87cc97d1 100644
--- a/src/Persistence_representations/utilities/persistence_heat_maps/plot_persistence_heat_map.cpp
+++ b/src/Persistence_representations/utilities/persistence_heat_maps/plot_persistence_heat_map.cpp
@@ -17,10 +17,10 @@ using constant_scaling_function = Gudhi::Persistence_representations::constant_s
 using Persistence_heat_maps = Gudhi::Persistence_representations::Persistence_heat_maps<constant_scaling_function>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates a gnuplot script from a persistence heat maps stored in a file (the file needs "
+  std::clog << "This program creates a gnuplot script from a persistence heat maps stored in a file (the file needs "
             << "to be created beforehand). Please call the code with the name of a single heat maps file \n";
   if (argc != 2) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
   Persistence_heat_maps l;
diff --git a/src/Persistence_representations/utilities/persistence_intervals/compute_birth_death_range_in_persistence_diagram.cpp b/src/Persistence_representations/utilities/persistence_intervals/compute_birth_death_range_in_persistence_diagram.cpp
index 519cc47d..72325cad 100644
--- a/src/Persistence_representations/utilities/persistence_intervals/compute_birth_death_range_in_persistence_diagram.cpp
+++ b/src/Persistence_representations/utilities/persistence_intervals/compute_birth_death_range_in_persistence_diagram.cpp
@@ -18,7 +18,7 @@
 using Persistence_intervals = Gudhi::Persistence_representations::Persistence_intervals;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes the range of birth and death times of persistence pairs in diagrams provided as "
+  std::clog << "This program computes the range of birth and death times of persistence pairs in diagrams provided as "
             << "an input.\n"
             << "The first parameter is the dimension of persistence to be used to create persistence intervals. "
             << "If your file contains the information about dimension of persistence pairs, please provide here the "
@@ -27,7 +27,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters of the program are the names of files with persistence diagrams.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
@@ -45,12 +45,12 @@ int main(int argc, char** argv) {
   double max_ = -std::numeric_limits<double>::max();
 
   for (size_t file_no = 0; file_no != filenames.size(); ++file_no) {
-    std::cout << "Creating diagram based on a file : " << filenames[file_no] << std::endl;
+    std::clog << "Creating diagram based on a file : " << filenames[file_no] << std::endl;
     Persistence_intervals p(filenames[file_no], dimension);
     std::pair<double, double> min_max_ = p.get_x_range();
     if (min_max_.first < min_) min_ = min_max_.first;
     if (min_max_.second > max_) max_ = min_max_.second;
   }
-  std::cout << "Birth-death range : min: " << min_ << ", max: " << max_ << std::endl;
+  std::clog << "Birth-death range : min: " << min_ << ", max: " << max_ << std::endl;
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_intervals/compute_bottleneck_distance.cpp b/src/Persistence_representations/utilities/persistence_intervals/compute_bottleneck_distance.cpp
index 6155727a..465bf72e 100644
--- a/src/Persistence_representations/utilities/persistence_intervals/compute_bottleneck_distance.cpp
+++ b/src/Persistence_representations/utilities/persistence_intervals/compute_bottleneck_distance.cpp
@@ -18,7 +18,7 @@
 using Persistence_intervals_with_distances = Gudhi::Persistence_representations::Persistence_intervals_with_distances;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes the bottleneck distance of persistence pairs in diagrams provided as "
+  std::clog << "This program computes the bottleneck distance of persistence pairs in diagrams provided as "
             << "an input.\n"
             << "The first parameter is the dimension of persistence to be used to create persistence intervals. "
             << "If your file contains the information about dimension of persistence pairs, please provide here the "
@@ -27,7 +27,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters of the program are the names of files with persistence diagrams.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -70,14 +70,14 @@ int main(int argc, char** argv) {
   out.open("distance.itv");
   for (size_t i = 0; i != distance.size(); ++i) {
     for (size_t j = 0; j != distance.size(); ++j) {
-      std::cout << distance[i][j] << " ";
+      std::clog << distance[i][j] << " ";
       out << distance[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'distance.itv' file\n";
+  std::clog << "Distance can be found in 'distance.itv' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_intervals/compute_number_of_dominant_intervals.cpp b/src/Persistence_representations/utilities/persistence_intervals/compute_number_of_dominant_intervals.cpp
index dd6e1a5b..ea1fe717 100644
--- a/src/Persistence_representations/utilities/persistence_intervals/compute_number_of_dominant_intervals.cpp
+++ b/src/Persistence_representations/utilities/persistence_intervals/compute_number_of_dominant_intervals.cpp
@@ -18,10 +18,10 @@
 using Persistence_intervals = Gudhi::Persistence_representations::Persistence_intervals;
 
 int main(int argc, char** argv) {
-  std::cout << "This program compute the dominant intervals. A number of intervals to be displayed is a parameter of "
+  std::clog << "This program compute the dominant intervals. A number of intervals to be displayed is a parameter of "
                "this program. \n";
   if (argc != 4) {
-    std::cout << "To run this program, please provide the name of a file with persistence diagram, dimension of "
+    std::clog << "To run this program, please provide the name of a file with persistence diagram, dimension of "
                  "intervals that should be taken into account (if your file contains only persistence pairs in a "
                  "single dimension, set it up to -1) and number of dominant intervals you would like to get \n";
     return 1;
@@ -33,9 +33,9 @@ int main(int argc, char** argv) {
   }
   Persistence_intervals p(argv[1], dimension);
   std::vector<std::pair<double, double> > dominant_intervals = p.dominant_intervals(atoi(argv[3]));
-  std::cout << "Here are the dominant intervals : " << std::endl;
+  std::clog << "Here are the dominant intervals : " << std::endl;
   for (size_t i = 0; i != dominant_intervals.size(); ++i) {
-    std::cout << " " << dominant_intervals[i].first << "," << dominant_intervals[i].second << " " << std::endl;
+    std::clog << " " << dominant_intervals[i].first << "," << dominant_intervals[i].second << " " << std::endl;
   }
 
   return 0;
diff --git a/src/Persistence_representations/utilities/persistence_intervals/plot_histogram_of_intervals_lengths.cpp b/src/Persistence_representations/utilities/persistence_intervals/plot_histogram_of_intervals_lengths.cpp
index 13d2133f..e5eec3f5 100644
--- a/src/Persistence_representations/utilities/persistence_intervals/plot_histogram_of_intervals_lengths.cpp
+++ b/src/Persistence_representations/utilities/persistence_intervals/plot_histogram_of_intervals_lengths.cpp
@@ -18,10 +18,10 @@
 using Persistence_intervals = Gudhi::Persistence_representations::Persistence_intervals;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes a histogram of barcode's length. A number of bins in the histogram is a "
+  std::clog << "This program computes a histogram of barcode's length. A number of bins in the histogram is a "
             << "parameter of this program. \n";
   if ((argc != 3) && (argc != 4)) {
-    std::cout << "To run this program, please provide the name of a file with persistence diagram and number of "
+    std::clog << "To run this program, please provide the name of a file with persistence diagram and number of "
               << "dominant intervals you would like to get. Set a negative number dominant intervals value "
               << "If your file contains only birth-death pairs.\n"
               << "The third parameter is the dimension of the persistence that is to be used. If your "
@@ -59,7 +59,7 @@ int main(int argc, char** argv) {
   out << std::endl;
   out.close();
 
-  std::cout << "To visualize, install gnuplot and type the command: gnuplot -persist -e \"load \'"
+  std::clog << "To visualize, install gnuplot and type the command: gnuplot -persist -e \"load \'"
             << gnuplot_script.str().c_str() << "\'\"" << std::endl;
   return 0;
 }
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
index 451be77f..27c69e07 100644
--- a/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_Betti_numbers.cpp
+++ b/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_Betti_numbers.cpp
@@ -19,7 +19,7 @@ using Persistence_intervals = Gudhi::Persistence_representations::Persistence_in
 
 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"
+    std::clog << "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. "
@@ -68,7 +68,7 @@ int main(int argc, char** argv) {
   out << std::endl;
   out.close();
 
-  std::cout << "To visualize, install gnuplot and type the command: gnuplot -persist -e \"load \'"
+  std::clog << "To visualize, install gnuplot and type the command: gnuplot -persist -e \"load \'"
             << gnuplot_script.str().c_str() << "\'\"" << std::endl;
 
   return 0;
diff --git a/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_intervals.cpp b/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_intervals.cpp
index 09a56869..199a3266 100644
--- a/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_intervals.cpp
+++ b/src/Persistence_representations/utilities/persistence_intervals/plot_persistence_intervals.cpp
@@ -19,7 +19,7 @@ using Persistence_intervals = Gudhi::Persistence_representations::Persistence_in
 
 int main(int argc, char** argv) {
   if ((argc != 3) && (argc != 2)) {
-    std::cout << "This program creates a gnuplot script from a single persistence diagram file (*.pers).\n"
+    std::clog << "This program creates a gnuplot script 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";
diff --git a/src/Persistence_representations/utilities/persistence_landscapes/average_landscapes.cpp b/src/Persistence_representations/utilities/persistence_landscapes/average_landscapes.cpp
index 04a0ada4..612e9700 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes/average_landscapes.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes/average_landscapes.cpp
@@ -16,13 +16,13 @@
 using Persistence_landscape = Gudhi::Persistence_representations::Persistence_landscape;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes average of persistence landscapes stored in files (the files needs to be "
+  std::clog << "This program computes average of persistence landscapes stored in files (the files needs to be "
             << "created beforehand).\n"
             << "The parameters of this programs are names of files with persistence landscapes.\n";
   std::vector<const char*> filenames;
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -46,6 +46,6 @@ int main(int argc, char** argv) {
     delete lands[i];
   }
 
-  std::cout << "Average can be found in 'average.land' file\n";
+  std::clog << "Average can be found in 'average.land' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_landscapes/compute_distance_of_landscapes.cpp b/src/Persistence_representations/utilities/persistence_landscapes/compute_distance_of_landscapes.cpp
index 1093c1aa..2246a37d 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes/compute_distance_of_landscapes.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes/compute_distance_of_landscapes.cpp
@@ -18,14 +18,14 @@
 using Persistence_landscape = Gudhi::Persistence_representations::Persistence_landscape;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes distance of persistence landscapes stored in files (the files needs to be "
+  std::clog << "This program computes distance of persistence landscapes stored in files (the files needs to be "
             << "created beforehand).\n"
             << "The first parameter of a program is an integer p. The program compute L^p distance of the two heat "
             << "maps. For L^infty distance choose p = -1. \n"
             << "The remaining parameters of this program are names of files with persistence landscapes.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -68,14 +68,14 @@ int main(int argc, char** argv) {
   out.open("distance.land");
   for (size_t i = 0; i != distance.size(); ++i) {
     for (size_t j = 0; j != distance.size(); ++j) {
-      std::cout << distance[i][j] << " ";
+      std::clog << distance[i][j] << " ";
       out << distance[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'distance.land' file\n";
+  std::clog << "Distance can be found in 'distance.land' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_landscapes/compute_scalar_product_of_landscapes.cpp b/src/Persistence_representations/utilities/persistence_landscapes/compute_scalar_product_of_landscapes.cpp
index 16b76497..44f50543 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes/compute_scalar_product_of_landscapes.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes/compute_scalar_product_of_landscapes.cpp
@@ -17,12 +17,12 @@
 using Persistence_landscape = Gudhi::Persistence_representations::Persistence_landscape;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes scalar product of persistence landscapes stored in a file (the file needs to be "
+  std::clog << "This program computes scalar product of persistence landscapes stored in a file (the file needs to be "
             << "created beforehand). \n"
             << "The parameters of this programs are names of files with persistence landscapes.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -59,14 +59,14 @@ int main(int argc, char** argv) {
   out.open("scalar_product.land");
   for (size_t i = 0; i != scalar_product.size(); ++i) {
     for (size_t j = 0; j != scalar_product.size(); ++j) {
-      std::cout << scalar_product[i][j] << " ";
+      std::clog << scalar_product[i][j] << " ";
       out << scalar_product[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'scalar_product.land' file\n";
+  std::clog << "Distance can be found in 'scalar_product.land' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_landscapes/create_landscapes.cpp b/src/Persistence_representations/utilities/persistence_landscapes/create_landscapes.cpp
index 4d772086..fab5c75f 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes/create_landscapes.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes/create_landscapes.cpp
@@ -18,7 +18,7 @@
 using Persistence_landscape = Gudhi::Persistence_representations::Persistence_landscape;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates persistence landscapes files (*.land) of persistence diagrams files (*.pers) "
+  std::clog << "This program creates persistence landscapes files (*.land) of persistence diagrams files (*.pers) "
             << "provided as an input.\n"
             << "The first parameter of this program is a dimension of persistence that will be used in creation of "
             << "the persistence heat maps."
@@ -29,7 +29,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 3) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
   std::vector<const char*> filenames;
@@ -43,7 +43,7 @@ int main(int argc, char** argv) {
   }
 
   for (size_t i = 0; i != filenames.size(); ++i) {
-    std::cout << "Creating a landscape based on file : " << filenames[i] << std::endl;
+    std::clog << "Creating a landscape based on file : " << filenames[i] << std::endl;
     Persistence_landscape l(filenames[i], dimension);
     std::stringstream ss;
     ss << filenames[i] << ".land";
diff --git a/src/Persistence_representations/utilities/persistence_landscapes/plot_landscapes.cpp b/src/Persistence_representations/utilities/persistence_landscapes/plot_landscapes.cpp
index 1fe03640..da9b9bba 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes/plot_landscapes.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes/plot_landscapes.cpp
@@ -16,10 +16,10 @@
 using Persistence_landscape = Gudhi::Persistence_representations::Persistence_landscape;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates a gnuplot script from a persistence landscape stored in a file (the file needs "
+  std::clog << "This program creates a gnuplot script from a persistence landscape stored in a file (the file needs "
             << "to be created beforehand). Please call the code with the name of a single landscape file.\n";
   if (argc != 2) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
diff --git a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/average_landscapes_on_grid.cpp b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/average_landscapes_on_grid.cpp
index f92cde72..39f7a67f 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/average_landscapes_on_grid.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/average_landscapes_on_grid.cpp
@@ -16,12 +16,12 @@
 using Persistence_landscape_on_grid = Gudhi::Persistence_representations::Persistence_landscape_on_grid;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes average of persistence landscapes on grid stored in files (the files needs to "
+  std::clog << "This program computes average of persistence landscapes on grid stored in files (the files needs to "
             << "be created beforehand).\n"
             << "The parameters of this programs are names of files with persistence landscapes on grid.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -46,6 +46,6 @@ int main(int argc, char** argv) {
     delete lands[i];
   }
 
-  std::cout << "Average can be found in 'average.g_land' file\n";
+  std::clog << "Average can be found in 'average.g_land' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_distance_of_landscapes_on_grid.cpp b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_distance_of_landscapes_on_grid.cpp
index baec6aeb..01fd09d8 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_distance_of_landscapes_on_grid.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_distance_of_landscapes_on_grid.cpp
@@ -18,14 +18,14 @@
 using Persistence_landscape_on_grid = Gudhi::Persistence_representations::Persistence_landscape_on_grid;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes distance of persistence landscapes on grid stored in files (the files needs to "
+  std::clog << "This program computes distance of persistence landscapes on grid stored in files (the files needs to "
             << "be created beforehand).\n"
             << "The first parameter of a program is an integer p. The program compute L^p distance of the two heat "
             << "maps. For L^infty distance choose p = -1. \n"
             << "The remaining parameters of this program are names of files with persistence landscapes on grid.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -68,14 +68,14 @@ int main(int argc, char** argv) {
   out.open("distance.g_land");
   for (size_t i = 0; i != distance.size(); ++i) {
     for (size_t j = 0; j != distance.size(); ++j) {
-      std::cout << distance[i][j] << " ";
+      std::clog << distance[i][j] << " ";
       out << distance[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'distance.g_land' file\n";
+  std::clog << "Distance can be found in 'distance.g_land' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_scalar_product_of_landscapes_on_grid.cpp b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_scalar_product_of_landscapes_on_grid.cpp
index e94dacdb..71c2f419 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_scalar_product_of_landscapes_on_grid.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/compute_scalar_product_of_landscapes_on_grid.cpp
@@ -17,13 +17,13 @@
 using Persistence_landscape_on_grid = Gudhi::Persistence_representations::Persistence_landscape_on_grid;
 
 int main(int argc, char** argv) {
-  std::cout
+  std::clog
       << "This program computes scalar product of persistence landscapes on grid stored in a file (the file needs to "
       << "be created beforehand). \n"
       << "The parameters of this programs are names of files with persistence landscapes on grid.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -60,14 +60,14 @@ int main(int argc, char** argv) {
   out.open("scalar_product.g_land");
   for (size_t i = 0; i != scalar_product.size(); ++i) {
     for (size_t j = 0; j != scalar_product.size(); ++j) {
-      std::cout << scalar_product[i][j] << " ";
+      std::clog << scalar_product[i][j] << " ";
       out << scalar_product[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'scalar_product.g_land' file\n";
+  std::clog << "Distance can be found in 'scalar_product.g_land' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/create_landscapes_on_grid.cpp b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/create_landscapes_on_grid.cpp
index d510c3df..788313c4 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/create_landscapes_on_grid.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/create_landscapes_on_grid.cpp
@@ -18,7 +18,7 @@
 using Persistence_landscape_on_grid = Gudhi::Persistence_representations::Persistence_landscape_on_grid;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates persistence landscapes on grid files (*.g_land) of persistence diagrams files "
+  std::clog << "This program creates persistence landscapes on grid files (*.g_land) of persistence diagrams files "
             << "(*.pers) provided as an input.\n"
             << "The first parameter of a program is an integer, a size of a grid.\n"
             << "The second and third parameters are min and max of the grid. If you want those numbers to be computed "
@@ -32,7 +32,7 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 6) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
@@ -51,7 +51,7 @@ int main(int argc, char** argv) {
   }
 
   for (size_t i = 0; i != filenames.size(); ++i) {
-    std::cout << "Creating persistence landscape on a grid based on a file : " << filenames[i] << std::endl;
+    std::clog << "Creating persistence landscape on a grid based on a file : " << filenames[i] << std::endl;
     Persistence_landscape_on_grid l;
     if ((min_ != -1) || (max_ != -1)) {
       l = Persistence_landscape_on_grid(filenames[i], min_, max_, size_of_grid, dimension);
diff --git a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/plot_landscapes_on_grid.cpp b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/plot_landscapes_on_grid.cpp
index 4e20f37f..ec6112b5 100644
--- a/src/Persistence_representations/utilities/persistence_landscapes_on_grid/plot_landscapes_on_grid.cpp
+++ b/src/Persistence_representations/utilities/persistence_landscapes_on_grid/plot_landscapes_on_grid.cpp
@@ -16,11 +16,11 @@
 using Persistence_landscape_on_grid = Gudhi::Persistence_representations::Persistence_landscape_on_grid;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates a gnuplot script from a persistence landscape on grid stored in a file (the file "
+  std::clog << "This program creates a gnuplot script from a persistence landscape on grid stored in a file (the file "
             << "needs to be created beforehand). Please call the code with the name of a single landscape on grid file"
             << ".\n";
   if (argc != 2) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
diff --git a/src/Persistence_representations/utilities/persistence_vectors/average_persistence_vectors.cpp b/src/Persistence_representations/utilities/persistence_vectors/average_persistence_vectors.cpp
index 89e42f0f..4eb32eb3 100644
--- a/src/Persistence_representations/utilities/persistence_vectors/average_persistence_vectors.cpp
+++ b/src/Persistence_representations/utilities/persistence_vectors/average_persistence_vectors.cpp
@@ -17,12 +17,12 @@ using Euclidean_distance = Gudhi::Euclidean_distance;
 using Vector_distances_in_diagram = Gudhi::Persistence_representations::Vector_distances_in_diagram<Euclidean_distance>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes average of persistence vectors stored in files (the files needs to "
+  std::clog << "This program computes average of persistence vectors stored in files (the files needs to "
             << "be created beforehand).\n"
             << "The parameters of this programs are names of files with persistence vectors.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -47,7 +47,7 @@ int main(int argc, char** argv) {
     delete lands[i];
   }
 
-  std::cout << "Done \n";
+  std::clog << "Done \n";
 
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_vectors/compute_distance_of_persistence_vectors.cpp b/src/Persistence_representations/utilities/persistence_vectors/compute_distance_of_persistence_vectors.cpp
index 541dd25f..236981a3 100644
--- a/src/Persistence_representations/utilities/persistence_vectors/compute_distance_of_persistence_vectors.cpp
+++ b/src/Persistence_representations/utilities/persistence_vectors/compute_distance_of_persistence_vectors.cpp
@@ -19,14 +19,14 @@ using Euclidean_distance = Gudhi::Euclidean_distance;
 using Vector_distances_in_diagram = Gudhi::Persistence_representations::Vector_distances_in_diagram<Euclidean_distance>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program compute distance of persistence vectors stored in a file (the file needs to be created "
+  std::clog << "This program compute distance of persistence vectors stored in a file (the file needs to be created "
                "beforehand). \n";
-  std::cout << "The first parameter of a program is an integer p. The program compute l^p distance of the vectors. For "
+  std::clog << "The first parameter of a program is an integer p. The program compute l^p distance of the vectors. For "
                "l^infty distance choose p = -1. \n";
-  std::cout << "The remaining parameters of this programs are names of files with persistence vectors.\n";
+  std::clog << "The remaining parameters of this programs are names of files with persistence vectors.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -69,14 +69,14 @@ int main(int argc, char** argv) {
   out.open("distance.vect");
   for (size_t i = 0; i != distance.size(); ++i) {
     for (size_t j = 0; j != distance.size(); ++j) {
-      std::cout << distance[i][j] << " ";
+      std::clog << distance[i][j] << " ";
       out << distance[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'distance.vect' file\n";
+  std::clog << "Distance can be found in 'distance.vect' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_vectors/compute_scalar_product_of_persistence_vectors.cpp b/src/Persistence_representations/utilities/persistence_vectors/compute_scalar_product_of_persistence_vectors.cpp
index bbc50c98..c6ea0e1c 100644
--- a/src/Persistence_representations/utilities/persistence_vectors/compute_scalar_product_of_persistence_vectors.cpp
+++ b/src/Persistence_representations/utilities/persistence_vectors/compute_scalar_product_of_persistence_vectors.cpp
@@ -19,12 +19,12 @@ using Euclidean_distance = Gudhi::Euclidean_distance;
 using Vector_distances_in_diagram = Gudhi::Persistence_representations::Vector_distances_in_diagram<Euclidean_distance>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program computes scalar product of persistence vectors stored in a file (the file needs to "
+  std::clog << "This program computes scalar product of persistence vectors stored in a file (the file needs to "
             << "be created beforehand). \n"
             << "The parameters of this programs are names of files with persistence vectors.\n";
 
   if (argc < 3) {
-    std::cout << "Wrong number of parameters, the program will now terminate \n";
+    std::clog << "Wrong number of parameters, the program will now terminate \n";
     return 1;
   }
 
@@ -61,14 +61,14 @@ int main(int argc, char** argv) {
   out.open("scalar_product.vect");
   for (size_t i = 0; i != scalar_product.size(); ++i) {
     for (size_t j = 0; j != scalar_product.size(); ++j) {
-      std::cout << scalar_product[i][j] << " ";
+      std::clog << scalar_product[i][j] << " ";
       out << scalar_product[i][j] << " ";
     }
-    std::cout << std::endl;
+    std::clog << std::endl;
     out << std::endl;
   }
   out.close();
 
-  std::cout << "Distance can be found in 'scalar_product.vect' file\n";
+  std::clog << "Distance can be found in 'scalar_product.vect' file\n";
   return 0;
 }
diff --git a/src/Persistence_representations/utilities/persistence_vectors/create_persistence_vectors.cpp b/src/Persistence_representations/utilities/persistence_vectors/create_persistence_vectors.cpp
index f974c3d3..608e04e5 100644
--- a/src/Persistence_representations/utilities/persistence_vectors/create_persistence_vectors.cpp
+++ b/src/Persistence_representations/utilities/persistence_vectors/create_persistence_vectors.cpp
@@ -19,7 +19,7 @@ using Euclidean_distance = Gudhi::Euclidean_distance;
 using Vector_distances_in_diagram = Gudhi::Persistence_representations::Vector_distances_in_diagram<Euclidean_distance>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program creates persistence vectors files (*.vect) of persistence diagrams files (*.pers) "
+  std::clog << "This program creates persistence vectors files (*.vect) of persistence diagrams files (*.pers) "
             << "provided as an input.\n"
             << "The first parameter of this program is a dimension of persistence that will be used in creation of "
             << "the persistence heat maps."
@@ -30,11 +30,11 @@ int main(int argc, char** argv) {
             << "The remaining parameters are the names of files with persistence diagrams. \n";
 
   if (argc < 3) {
-    std::cout << "Wrong parameter list, the program will now terminate \n";
+    std::clog << "Wrong parameter list, the program will now terminate \n";
     return 1;
   }
 
-  std::cout << "The remaining parameters are the names of files with persistence diagrams. \n";
+  std::clog << "The remaining parameters are the names of files with persistence diagrams. \n";
   int dim = atoi(argv[1]);
   unsigned dimension = std::numeric_limits<unsigned>::max();
   if (dim >= 0) {
diff --git a/src/Persistence_representations/utilities/persistence_vectors/plot_persistence_vectors.cpp b/src/Persistence_representations/utilities/persistence_vectors/plot_persistence_vectors.cpp
index de08fcfe..2decb134 100644
--- a/src/Persistence_representations/utilities/persistence_vectors/plot_persistence_vectors.cpp
+++ b/src/Persistence_representations/utilities/persistence_vectors/plot_persistence_vectors.cpp
@@ -17,10 +17,10 @@ using Euclidean_distance = Gudhi::Euclidean_distance;
 using Vector_distances_in_diagram = Gudhi::Persistence_representations::Vector_distances_in_diagram<Euclidean_distance>;
 
 int main(int argc, char** argv) {
-  std::cout << "This program create a Gnuplot script to plot persistence vector. Please call this program with the "
+  std::clog << "This program create a Gnuplot script to plot persistence vector. Please call this program with the "
                "name of file with persistence vector. \n";
   if (argc != 2) {
-    std::cout << "Wrong number of parameters, the program will now terminate. \n";
+    std::clog << "Wrong number of parameters, the program will now terminate. \n";
     return 1;
   }
   Vector_distances_in_diagram l;
-- 
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