3 files changed, 36 insertions, 13 deletions
diff --git a/src/Bitmap_cubical_complex/doc/Gudhi_Cubical_Complex_doc.h b/src/Bitmap_cubical_complex/doc/Gudhi_Cubical_Complex_doc.h
index d1836ef0..9e14455e 100644
--- a/src/Bitmap_cubical_complex/doc/Gudhi_Cubical_Complex_doc.h
+++ b/src/Bitmap_cubical_complex/doc/Gudhi_Cubical_Complex_doc.h
@@ -90,8 +90,12 @@ namespace cubical_complex {
  * In the current implantation, filtration is given at the maximal cubes, and it is then extended by the lower star
  * filtration to all cubes. There are a number of constructors that can be used to construct cubical complex by users
  * who want to use the code directly. They can be found in the \a Bitmap_cubical_complex class.
- * Currently one input from a text file is used. It uses a format used already in Perseus software
- * (http://www.sas.upenn.edu/~vnanda/perseus/) by Vidit Nanda. The file format is described here: \ref FileFormatsPerseus.
+ * Currently one input from a text file is used. It uses a format nspired from the Perseus software
+ * (http://www.sas.upenn.edu/~vnanda/perseus/) by Vidit Nanda. Note however an important difference: while Perseus
+ * assume the filtration of all maximal cubes to be non-negative, over here we do not enforce this and we allow any
+ * filtration values.
+ * As a consequence one cannot use -1's to indicate missing cubes. If you have missing cubes in your complex, please
+ * set their filtration to +Inf. The file format is described in details in here: \ref FileFormatsPerseus.
  *
  * \section PeriodicBoundaryConditions Periodic boundary conditions
  * Often one would like to impose periodic boundary conditions to the cubical complex. Let \f$ I_1\times ... \times
diff --git a/src/Bitmap_cubical_complex/include/gudhi/Bitmap_cubical_complex_base.h b/src/Bitmap_cubical_complex/include/gudhi/Bitmap_cubical_complex_base.h
index 9b74e267..f5e005b2 100644
--- a/src/Bitmap_cubical_complex/include/gudhi/Bitmap_cubical_complex_base.h
+++ b/src/Bitmap_cubical_complex/include/gudhi/Bitmap_cubical_complex_base.h
@@ -650,18 +650,33 @@ void Bitmap_cubical_complex_base<T>::read_perseus_style_file(const char* perseus
   Bitmap_cubical_complex_base<T>::Top_dimensional_cells_iterator it(*this);
   it = this->top_dimensional_cells_iterator_begin();
 
-  T filtrationLevel;
-  for (std::size_t i = 0; i < dimensions; ++i) {
-    if (!(inFiltration >> filtrationLevel) || (inFiltration.eof())) {
-      throw std::ios_base::failure("Bad Perseus file format.");
-    }
-    if (dbg) {
-      std::cerr << "Cell of an index : " << it.compute_index_in_bitmap()
-                << " and dimension: " << this->get_dimension_of_a_cell(it.compute_index_in_bitmap())
-                << " get the value : " << filtrationLevel << std::endl;
+  T filtrationLevel = 0.;
+  std::size_t filtration_counter = 0;
+  while (!inFiltration.eof()) {
+    std::string line;
+    getline(inFiltration, line);
+    if (line.length() != 0) {
+      int n = sscanf(line.c_str(), "%lf", &filtrationLevel);
+      if (n != 1) {
+        std::string perseus_error("Bad Perseus file format. This line is incorrect : " + line);
+        throw std::ios_base::failure(perseus_error.c_str());
+      }
+
+      if (dbg) {
+        std::cerr << "Cell of an index : " << it.compute_index_in_bitmap()
+                  << " and dimension: " << this->get_dimension_of_a_cell(it.compute_index_in_bitmap())
+                  << " get the value : " << filtrationLevel << std::endl;
+      }
+      this->get_cell_data(*it) = filtrationLevel;
+      ++it;
+      ++filtration_counter;
     }
-    this->get_cell_data(*it) = filtrationLevel;
-    ++it;
+  }
+
+  if (filtration_counter != dimensions) {
+    std::string perseus_error("Bad Perseus file format. Read " + std::to_string(filtration_counter) + " expected " + \
+      std::to_string(dimensions) + " values");
+    throw std::ios_base::failure(perseus_error.c_str());
   }
 
   inFiltration.close();
diff --git a/src/common/doc/file_formats.h b/src/common/doc/file_formats.h
index 523153b8..d38d90e0 100644
--- a/src/common/doc/file_formats.h
+++ b/src/common/doc/file_formats.h
@@ -118,6 +118,10 @@ namespace Gudhi {
  Indicate that we have imposed periodic boundary conditions in the direction x, but not in the direction y.
 
  Other sample files can be found in the `data/bitmap` folder.
+ 
+ Please note that unlike in Perseus format the filtration on the maximal cubes can be any double precision number.
+ Consequently one cannot mark the cubes that are not present with -1's. To do that please set their filtration value to
+ +Inf.
 
 */
 }  // namespace Gudhi