print errors to stderr

1 files changed, 5 insertions, 3 deletions

diff --git a/src/python/gudhi/periodic_cubical_complex.pyx b/src/python/gudhi/periodic_cubical_complex.pyx
index b5dece10..4ec06524 100644
--- a/src/python/gudhi/periodic_cubical_complex.pyx
+++ b/src/python/gudhi/periodic_cubical_complex.pyx
@@ -7,11 +7,13 @@
 # Modification(s):
 #   - YYYY/MM Author: Description of the modification
 
+from __future__ import print_function
 from cython cimport numeric
 from libcpp.vector cimport vector
 from libcpp.utility cimport pair
 from libcpp.string cimport string
 from libcpp cimport bool
+import sys
 import os
 
 import numpy as np
@@ -95,12 +97,12 @@ cdef class PeriodicCubicalComplex:
             if os.path.isfile(perseus_file):
                 self.thisptr = new Periodic_cubical_complex_base_interface(str.encode(perseus_file))
             else:
-                print("file " + perseus_file + " not found.")
+                print("file " + perseus_file + " not found.", file=sys.stderr)
         else:
             print("CubicalComplex can be constructed from dimensions, "
               "top_dimensional_cells and periodic_dimensions, or from "
               "top_dimensional_cells and periodic_dimensions or from "
-              "a Perseus-style file name.")
+              "a Perseus-style file name.", file=sys.stderr)
 
     def __dealloc__(self):
         if self.thisptr != NULL:
@@ -209,5 +211,5 @@ cdef class PeriodicCubicalComplex:
             intervals_result = self.pcohptr.intervals_in_dimension(dimension)
         else:
             print("intervals_in_dim function requires persistence function"
-                  " to be launched first.")
+                  " to be launched first.", file=sys.stderr)
         return np.array(intervals_result)