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Diffstat (limited to 'src/Coxeter_triangulation/include/gudhi/Functions/Function_affine_plane_in_Rd.h')
-rw-r--r-- | src/Coxeter_triangulation/include/gudhi/Functions/Function_affine_plane_in_Rd.h | 91 |
1 files changed, 91 insertions, 0 deletions
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 new file mode 100644 index 00000000..b29f0906 --- /dev/null +++ b/src/Coxeter_triangulation/include/gudhi/Functions/Function_affine_plane_in_Rd.h @@ -0,0 +1,91 @@ +/* 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 |