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diff --git a/src/Coxeter_triangulation/include/gudhi/Functions/Constant_function.h b/src/Coxeter_triangulation/include/gudhi/Functions/Constant_function.h
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+/*    This file is part of the Gudhi Library - https://gudhi.inria.fr/ - which is released under MIT.
+ *    See file LICENSE or go to https://gudhi.inria.fr/licensing/ for full license details.
+ *    Author(s):       Siargey Kachanovich
+ *
+ *    Copyright (C) 2019 Inria
+ *
+ *    Modification(s):
+ *      - YYYY/MM Author: Description of the modification
+ */
+
+#ifndef FUNCTIONS_CONSTANT_FUNCTION_H_
+#define FUNCTIONS_CONSTANT_FUNCTION_H_
+
+#include <cstdlib>  // for std::size_t
+
+#include <Eigen/Dense>
+
+namespace Gudhi {
+
+namespace coxeter_triangulation {
+
+/**
+ * \class Constant_function
+ * \brief A class that encodes a constant function from R^d to R^k.
+ * This class does not have any implicit manifold in correspondence.
+ */
+struct Constant_function {
+  /** \brief Value of the function at a specified point. The value is constant.
+   * @param[in] p The input point. The dimension needs to coincide with the ambient dimension.
+   */
+  Eigen::VectorXd operator()(const Eigen::VectorXd& p) const {
+    return value_;
+  }
+
+  /** \brief Returns the domain dimension. Same as the ambient dimension of the sphere. */
+  std::size_t amb_d() const { return d_; };
+
+  /** \brief Returns the codomain dimension. Same as the codimension of the sphere. */
+  std::size_t cod_d() const { return k_; };
+
+  /** \brief No seed point is available. Throws an exception on evocation. */
+  Eigen::VectorXd seed() const { throw "Seed invoked on a constant function.\n"; }
+
+  Constant_function() {}
+
+  /**
+   * \brief Constructor of a constant function from R^d to R^m.
+   *
+   * @param[in] d The domain dimension.
+   * @param[in] k The codomain dimension.
+   * @param[in] value The constant value of the function.
+   */
+  Constant_function(std::size_t d, std::size_t k, const Eigen::VectorXd& value) : d_(d), k_(k), value_(value) {}
+
+ private:
+  std::size_t d_, k_;
+  Eigen::VectorXd value_;
+};
+
+}  // namespace coxeter_triangulation
+
+}  // namespace Gudhi
+
+#endif