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Diffstat (limited to 'src/Coxeter_triangulation/include/gudhi/Functions/Function_iron_in_R3.h')
-rw-r--r-- | src/Coxeter_triangulation/include/gudhi/Functions/Function_iron_in_R3.h | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/src/Coxeter_triangulation/include/gudhi/Functions/Function_iron_in_R3.h b/src/Coxeter_triangulation/include/gudhi/Functions/Function_iron_in_R3.h new file mode 100644 index 00000000..f73c4280 --- /dev/null +++ b/src/Coxeter_triangulation/include/gudhi/Functions/Function_iron_in_R3.h @@ -0,0 +1,69 @@ +/* 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_IRON_IN_R3_H_ +#define FUNCTIONS_FUNCTION_IRON_IN_R3_H_ + +#include <cstdlib> // for std::size_t +#include <cmath> // for std::pow + +#include <Eigen/Dense> + +namespace Gudhi { + +namespace coxeter_triangulation { + +/** + * \class Function_iron_in_R3 + * \brief A class that encodes the function, the zero-set of which is a surface + * embedded in R^3 that ressembles an iron. + */ +struct Function_iron_in_R3 { + /** + * \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 { + double x = p(0), y = p(1), z = p(2); + Eigen::VectorXd result(cod_d()); + result(0) = -std::pow(x, 6) / 300. - std::pow(y, 6) / 300. - std::pow(z, 6) / 300. + x * y * y * z / 2.1 + y * y + + std::pow(z - 2, 4) - 1; + return result; + } + + /** \brief Returns the domain (ambient) dimension. */ + std::size_t amb_d() const { return 3; }; + + /** \brief Returns the codomain dimension. */ + std::size_t cod_d() const { return 1; }; + + /** \brief Returns a point on the surface. */ + Eigen::VectorXd seed() const { + Eigen::Vector3d result(std::pow(4500, 1. / 6), 0, 0); + return result; + } + + /** + * \brief Constructor of the function that defines a surface embedded in R^3 + * that ressembles an iron. + * + * @param[in] off Offset vector. + */ + Function_iron_in_R3(Eigen::Vector3d off = Eigen::Vector3d::Zero()) : off_(off) {} + + private: + Eigen::Vector3d off_; +}; + +} // namespace coxeter_triangulation + +} // namespace Gudhi + +#endif |