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diff --git a/src/Cech_complex/include/gudhi/Cech_complex_blocker.h b/src/Cech_complex/include/gudhi/Cech_complex_blocker.h
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+/*    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):       Vincent Rouvreau
+ *
+ *    Copyright (C) 2018 Inria
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation, either version 3 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef CECH_COMPLEX_BLOCKER_H_
+#define CECH_COMPLEX_BLOCKER_H_
+
+#include <gudhi/Cech_complex.h>        // Cech_blocker is using a pointer on Gudhi::cech_complex::Cech_complex
+#include <gudhi/distance_functions.h>  // for Gudhi::Radius_distance
+
+#include <iostream>
+#include <vector>
+#include <cmath>  // for std::sqrt
+
+namespace Gudhi {
+
+namespace cech_complex {
+
+// Just declaring Cech_complex class because used and not yet defined.
+template<typename SimplicialComplexForCechComplex, typename ForwardPointRange>
+class Cech_complex;
+
+/** \internal
+ * \class Cech_blocker
+ * \brief Cech complex blocker.
+ *
+ * \ingroup cech_complex
+ *
+ * \details
+ * Cech blocker is an oracle constructed from a Cech_complex and a simplicial complex.
+ *
+ * \tparam SimplicialComplexForProximityGraph furnishes `Simplex_handle` and `Filtration_value` type definition,
+ * `simplex_vertex_range(Simplex_handle sh)`and `assign_filtration(Simplex_handle sh, Filtration_value filt)` methods.
+ *
+ * \tparam ForwardPointRange is required by the pointer on Chech_complex for type definition.
+ */
+template <typename SimplicialComplexForCech, typename ForwardPointRange>
+class Cech_blocker {
+ private:
+  using Point = std::vector<double>;
+  using Point_cloud = std::vector<Point>;
+  using Simplex_handle = typename SimplicialComplexForCech::Simplex_handle;
+  using Filtration_value = typename SimplicialComplexForCech::Filtration_value;
+  using Cech_complex = Gudhi::cech_complex::Cech_complex<SimplicialComplexForCech, ForwardPointRange>;
+
+ public:
+  /** \internal \brief Cech complex blocker operator() - the oracle - assigns the filtration value from the simplex
+   * radius and returns if the simplex expansion must be blocked.
+   *  \param[in] sh The Simplex_handle.
+   *  \return true if the simplex radius is greater than the Cech_complex max_radius*/
+  bool operator()(Simplex_handle sh) {
+    Point_cloud points;
+    for (auto vertex : simplicial_complex_.simplex_vertex_range(sh)) {
+      points.push_back(Point(cc_ptr_->point_iterator(vertex)->begin(),
+                             cc_ptr_->point_iterator(vertex)->end()));
+#ifdef DEBUG_TRACES
+      std::cout << "#(" << vertex << ")#";
+#endif  // DEBUG_TRACES
+    }
+    Filtration_value radius = Gudhi::Radius_distance()(points);
+#ifdef DEBUG_TRACES
+    if (radius > cc_ptr_->max_radius())
+      std::cout << "radius > max_radius => expansion is blocked\n";
+#endif  // DEBUG_TRACES
+    simplicial_complex_.assign_filtration(sh, radius);
+    return (radius > cc_ptr_->max_radius());
+  }
+
+  /** \internal \brief Cech complex blocker constructor. */
+  Cech_blocker(SimplicialComplexForCech& simplicial_complex, Cech_complex* cc_ptr)
+    : simplicial_complex_(simplicial_complex),
+      cc_ptr_(cc_ptr) {
+  }
+ private:
+  SimplicialComplexForCech simplicial_complex_;
+  Cech_complex* cc_ptr_;
+};
+
+}  // namespace cech_complex
+
+}  // namespace Gudhi
+
+#endif  // CECH_COMPLEX_BLOCKER_H_