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diff --git a/src/Coxeter_triangulation/include/gudhi/Permutahedral_representation/Size_range.h b/src/Coxeter_triangulation/include/gudhi/Permutahedral_representation/Size_range.h
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+++ b/src/Coxeter_triangulation/include/gudhi/Permutahedral_representation/Size_range.h
@@ -0,0 +1,89 @@
+/*    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):       Siargey Kachanovich
+ *
+ *    Copyright (C) 2019 Inria
+ *
+ *    Modification(s):
+ *      - YYYY/MM Author: Description of the modification
+ */
+
+#ifndef PERMUTAHEDRAL_REPRESENTATION_SIZE_RANGE_H_
+#define PERMUTAHEDRAL_REPRESENTATION_SIZE_RANGE_H_
+
+#include <boost/range/iterator_range.hpp>
+#include <cstdlib>         // std::size_t
+
+namespace Gudhi {
+
+namespace coxeter_triangulation {
+
+/** \brief Auxillary iterator class for sizes of parts in an ordered set partition.
+ */
+template <class T_it>
+class Size_iterator : public boost::iterator_facade< Size_iterator<T_it>,
+						     std::size_t const,
+						     boost::forward_traversal_tag> {
+  friend class boost::iterator_core_access;
+
+protected:
+  bool equal(Size_iterator const& other) const {
+    return (is_end_ && other.is_end_);
+  }
+
+  std::size_t const& dereference() const {
+    return value_;
+  }
+
+  void increment() {
+    if (++t_it_ == t_end_) {
+      is_end_ = true;
+      return;
+    }
+    value_ = t_it_->size()-1;
+  }
+
+public:
+
+  Size_iterator(const T_it& t_begin, const T_it& t_end)
+    : t_it_(t_begin), t_end_(t_end), is_end_(t_begin == t_end) {
+    if (!is_end_)
+      value_ = t_it_->size()-1;
+  }
+
+protected:
+  T_it t_it_, t_end_;
+  bool is_end_;
+  std::size_t value_;
+};
+
+template <class T>
+class Size_range {
+  const T& t_;
+
+public:
+  typedef Size_iterator<typename T::const_iterator> iterator;
+  
+  Size_range(const T& t) : t_(t) {}
+  
+  std::size_t operator[](std::size_t i) const {
+    return t_[i].size()-1;
+  }
+
+  iterator begin() const {
+    return iterator(t_.begin(), t_.end());
+  }
+
+  iterator end() const {
+    return iterator(t_.end(), t_.end());
+  }
+
+};
+
+} // namespace coxeter_triangulation
+
+} // namespace Gudhi
+
+#endif