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Diffstat (limited to 'src/Coxeter_triangulation/include/gudhi/Functions/Negation.h')
-rw-r--r-- | src/Coxeter_triangulation/include/gudhi/Functions/Negation.h | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/src/Coxeter_triangulation/include/gudhi/Functions/Negation.h b/src/Coxeter_triangulation/include/gudhi/Functions/Negation.h new file mode 100644 index 00000000..6b7feff5 --- /dev/null +++ b/src/Coxeter_triangulation/include/gudhi/Functions/Negation.h @@ -0,0 +1,92 @@ +/* This file is part of the Gudhi Library. The Gudhi library + * (Geometric Understanding in Higher Dimensions) is a generic C++ + * library for computational topology. + * + * Author(s): Siargey Kachanovich + * + * Copyright (C) 2019 Inria + * + * Modification(s): + * - YYYY/MM Author: Description of the modification + */ + +#ifndef FUNCTIONS_NEGATION_H_ +#define FUNCTIONS_NEGATION_H_ + +#include <cstdlib> + +#include <gudhi/Functions/Function.h> +#include <Eigen/Dense> + +namespace Gudhi { + +namespace coxeter_triangulation { + +/** + *\class Negation + * \brief Constructs the "minus" function. The zero-set is the same, but + * the values at other points are the negative of their original value. + * + * \tparam Function_ The function template parameter. Should be a model of + * the concept FunctionForImplicitManifold. + * + * \ingroup coxeter_triangulation + */ +template <class Function_> +struct Negation : public Function { + + /** + * \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 = -fun_(p); + return result; + } + + /** \brief Returns the domain (ambient) dimension. */ + std::size_t amb_d() const {return fun_.amb_d();} + + /** \brief Returns the codomain dimension. */ + std::size_t cod_d() const {return fun_.cod_d();} + + /** \brief Returns a point on the zero-set. */ + Eigen::VectorXd seed() const { + Eigen::VectorXd result = fun_.seed(); + return result; + } + + /** + * \brief Constructor of the negative function. + * + * @param[in] function The function to be negated. + */ + Negation(const Function_& function) : + fun_(function) { + } + Function_ fun_; +}; + + +/** + * \brief Static constructor of the negative function. + * + * @param[in] function The function to be translated. + * @param[in] off The offset vector. The dimension should correspond to the + * domain (ambient) dimension of 'function'. + * + * \tparam Function_ The function template parameter. Should be a model of + * the concept FunctionForImplicitManifold. + * + * \ingroup coxeter_triangulation + */ +template <class Function_> +Negation<Function_> negation(const Function_& function) { + return Negation<Function_>(function); +} + +} // namespace coxeter_triangulation + +} // namespace Gudhi + +#endif |