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Diffstat (limited to 'src/Coxeter_triangulation/include/gudhi/Functions/Function_Sm_in_Rd.h')
-rw-r--r-- | src/Coxeter_triangulation/include/gudhi/Functions/Function_Sm_in_Rd.h | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/src/Coxeter_triangulation/include/gudhi/Functions/Function_Sm_in_Rd.h b/src/Coxeter_triangulation/include/gudhi/Functions/Function_Sm_in_Rd.h new file mode 100644 index 00000000..8911f990 --- /dev/null +++ b/src/Coxeter_triangulation/include/gudhi/Functions/Function_Sm_in_Rd.h @@ -0,0 +1,110 @@ +/* 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_SM_IN_RD_H_ +#define FUNCTIONS_FUNCTION_SM_IN_RD_H_ + +#include <cstdlib> // for std::size_t + +#include <Eigen/Dense> + +namespace Gudhi { + +namespace coxeter_triangulation { + +/** + * \class Function_Sm_in_Rd + * \brief A class for the function that defines an m-dimensional implicit sphere embedded + * in the d-dimensional Euclidean space. + */ +struct Function_Sm_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 x = p; + for (std::size_t i = 0; i < d_; ++i) x(i) -= center_[i]; + Eigen::VectorXd result = Eigen::VectorXd::Zero(k_); + for (std::size_t i = 0; i < m_ + 1; ++i) result(0) += x(i) * x(i); + result(0) -= r_ * r_; + for (std::size_t j = 1; j < k_; ++j) result(j) = x(m_ + j); + 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 sphere. */ + Eigen::VectorXd seed() const { + Eigen::VectorXd result = Eigen::VectorXd::Zero(d_); + result(0) += r_; + for (std::size_t i = 0; i < d_; ++i) result(i) += center_[i]; + return result; + } + + /** + * \brief Constructor of the function that defines an m-dimensional implicit sphere embedded + * in the d-dimensional Euclidean space. + * + * @param[in] r The radius of the sphere. + * @param[in] m The dimension of the sphere. + * @param[in] d The ambient dimension of the sphere. + * @param[in] center The center of the sphere. + */ + Function_Sm_in_Rd(double r, std::size_t m, std::size_t d, Eigen::VectorXd center) + : m_(m), k_(d - m), d_(d), r_(r), center_(center) {} + + /** + * \brief Constructor of the function that defines an m-dimensional implicit sphere embedded + * in the d-dimensional Euclidean space centered at the origin. + * + * @param[in] r The radius of the sphere. + * @param[in] m The dimension of the sphere. + * @param[in] d The ambient dimension of the sphere. + */ + Function_Sm_in_Rd(double r, std::size_t m, std::size_t d) + : m_(m), k_(d - m), d_(d), r_(r), center_(Eigen::VectorXd::Zero(d_)) {} + + /** + * \brief Constructor of the function that defines an m-dimensional implicit sphere embedded + * in the (m+1)-dimensional Euclidean space. + * + * @param[in] r The radius of the sphere. + * @param[in] m The dimension of the sphere. + * @param[in] center The center of the sphere. + */ + Function_Sm_in_Rd(double r, std::size_t m, Eigen::VectorXd center) + : m_(m), k_(1), d_(m_ + 1), r_(r), center_(center) {} + + /** + * \brief Constructor of the function that defines an m-dimensional implicit sphere embedded + * in the (m+1)-dimensional Euclidean space centered at the origin. + * + * @param[in] r The radius of the sphere. + * @param[in] m The dimension of the sphere. + */ + Function_Sm_in_Rd(double r, std::size_t m) : m_(m), k_(1), d_(m_ + 1), r_(r), center_(Eigen::VectorXd::Zero(d_)) {} + + Function_Sm_in_Rd(const Function_Sm_in_Rd& rhs) : Function_Sm_in_Rd(rhs.r_, rhs.m_, rhs.d_, rhs.center_) {} + + private: + std::size_t m_, k_, d_; + double r_; + Eigen::VectorXd center_; +}; + +} // namespace coxeter_triangulation + +} // namespace Gudhi + +#endif |