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diff --git a/src/Coxeter_triangulation/include/gudhi/Functions/Function_affine_plane_in_Rd.h b/src/Coxeter_triangulation/include/gudhi/Functions/Function_affine_plane_in_Rd.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_FUNCTION_AFFINE_PLANE_IN_RD_H_
+#define FUNCTIONS_FUNCTION_AFFINE_PLANE_IN_RD_H_
+
+#include <cstdlib>  // for std::size_t
+
+#include <Eigen/Dense>
+
+namespace Gudhi {
+
+namespace coxeter_triangulation {
+
+/**
+ * \class Function_affine_plane_in_Rd
+ * \brief A class for the function that defines an m-dimensional implicit affine plane
+ * embedded in d-dimensional Euclidean space.
+ */
+struct Function_affine_plane_in_Rd {
+  /**
+   * \brief Value of the function at a specified point.
+   * @param[in] p The input point. The dimension needs to coincide with the ambient dimension.
+   */
+  Eigen::VectorXd operator()(const Eigen::VectorXd& p) const {
+    Eigen::VectorXd result = normal_matrix_.transpose() * (p - off_);
+    return result;
+  }
+
+  /** \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 Returns a point on the affine plane. */
+  Eigen::VectorXd seed() const {
+    Eigen::VectorXd result = off_;
+    return result;
+  }
+
+  /**
+   * \brief Constructor of the function that defines an m-dimensional implicit affine
+   * plane in the d-dimensional Euclidean space.
+   *
+   * @param[in] normal_matrix A normal matrix of the affine plane. The number of rows should
+   * correspond to the ambient dimension, the number of columns should corespond to
+   * the size of the normal basis (codimension).
+   * @param[in] offset The offset vector of the affine plane.
+   * The dimension of the vector should be the ambient dimension of the manifold.
+   */
+  Function_affine_plane_in_Rd(const Eigen::MatrixXd& normal_matrix, const Eigen::VectorXd& offset)
+      : normal_matrix_(normal_matrix), d_(normal_matrix.rows()), k_(normal_matrix.cols()), m_(d_ - k_), off_(offset) {
+    normal_matrix_.colwise().normalize();
+  }
+
+  /**
+   * \brief Constructor of the function that defines an m-dimensional implicit affine
+   * plane in the d-dimensional Euclidean space that passes through origin.
+   *
+   * @param[in] normal_matrix A normal matrix of the affine plane. The number of rows should
+   * correspond to the ambient dimension, the number of columns should corespond to
+   * the size of the normal basis (codimension).
+   */
+  Function_affine_plane_in_Rd(const Eigen::MatrixXd& normal_matrix)
+      : normal_matrix_(normal_matrix),
+        d_(normal_matrix.rows()),
+        k_(normal_matrix.cols()),
+        m_(d_ - k_),
+        off_(Eigen::VectorXd::Zero(d_)) {
+    normal_matrix_.colwise().normalize();
+  }
+
+ private:
+  Eigen::MatrixXd normal_matrix_;
+  std::size_t d_, k_, m_;
+  Eigen::VectorXd off_;
+};
+
+}  // namespace coxeter_triangulation
+
+}  // namespace Gudhi
+
+#endif