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Diffstat (limited to 'src/Persistent_cohomology/include/gudhi/Persistent_cohomology/Field_Zp.h')
| -rw-r--r-- | src/Persistent_cohomology/include/gudhi/Persistent_cohomology/Field_Zp.h | 196 |
1 files changed, 106 insertions, 90 deletions
diff --git a/src/Persistent_cohomology/include/gudhi/Persistent_cohomology/Field_Zp.h b/src/Persistent_cohomology/include/gudhi/Persistent_cohomology/Field_Zp.h index af0d6605..8b09a800 100644 --- a/src/Persistent_cohomology/include/gudhi/Persistent_cohomology/Field_Zp.h +++ b/src/Persistent_cohomology/include/gudhi/Persistent_cohomology/Field_Zp.h @@ -1,106 +1,122 @@ - /* 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): Clément Maria - * - * Copyright (C) 2014 INRIA Sophia Antipolis-Méditerranée (France) - * - * This program is free software: you can redistribute it and/or modify - * it under the terms of the GNU General Public License as published by - * the Free Software Foundation, either version 3 of the License, or - * (at your option) any later version. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with this program. If not, see <http://www.gnu.org/licenses/>. - */ - -#ifndef GUDHI_FIELD_ZP_H -#define GUDHI_FIELD_ZP_H - -namespace Gudhi{ +/* 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): Clément Maria + * + * Copyright (C) 2014 INRIA Sophia Antipolis-Méditerranée (France) + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#ifndef SRC_PERSISTENT_COHOMOLOGY_INCLUDE_GUDHI_PERSISTENT_COHOMOLOGY_FIELD_ZP_H_ +#define SRC_PERSISTENT_COHOMOLOGY_INCLUDE_GUDHI_PERSISTENT_COHOMOLOGY_FIELD_ZP_H_ + +#include <utility> +#include <vector> + +namespace Gudhi { /** \brief Structure representing the coefficient field \f$\mathbb{Z}/p\mathbb{Z}\f$ - * - * \implements CoefficientField - * \ingroup persistent_cohomology - */ + * + * \implements CoefficientField + * \ingroup persistent_cohomology + */ class Field_Zp { -public: -typedef int Element; - -Field_Zp() -: Prime(-1) -, inverse_() {} - -void init(int charac ) { - assert(charac <= 32768); - Prime = charac; - inverse_.clear(); - inverse_.reserve(charac); - inverse_.push_back(0); - for(int i=1 ; i<Prime ; ++i) - { - int inv = 1; - while(((inv * i) % Prime) != 1) ++inv; - inverse_.push_back(inv); + public: + typedef int Element; + + Field_Zp() + : Prime(0), + inverse_(), + mult_id_all(1), + add_id_all(0) { } -} -/** Set x <- x + w * y*/ -void plus_times_equal ( Element & x, Element y, Element w ) -{ x = (x + w * y) % Prime; } - -// operator= defined on Element - -/** Returns y * w */ -Element times ( Element y, int w ) { - Element res = (y * w) % Prime; - if(res < 0) return res+Prime; - else return res; -} - -void clear_coefficient(Element x) {} + void init(uint8_t charac) { + assert(charac != 0); // division by zero + Prime = charac; + inverse_.clear(); + inverse_.reserve(charac); + inverse_.push_back(0); + for (int i = 1; i < Prime; ++i) { + int inv = 1; + while (((inv * i) % Prime) != 1) + ++inv; + inverse_.push_back(inv); + } + } -void plus_equal(Element & x, Element y) { x = ((x+y)%Prime); } + /** Set x <- x + w * y*/ + void plus_times_equal(Element & x, Element y, Element w) { + assert(Prime != 0); // division by zero + x = (x + w * y) % Prime; + } -/** \brief Returns the additive idendity \f$0_{\Bbbk}\f$ of the field.*/ -Element additive_identity () { return 0; } -/** \brief Returns the multiplicative identity \f$1_{\Bbbk}\f$ of the field.*/ -Element multiplicative_identity ( Element P = 0) { return 1; } -/** Returns the inverse in the field. Modifies P.*/ -std::pair<Element,Element> inverse ( Element x - , Element P ) -{ return std::pair<Element,Element>(inverse_[x],P); -} // <------ return the product of field characteristic for which x is invertible +// operator= defined on Element -/** Returns -x * y.*/ -Element times_minus ( Element x, Element y ) -{ - Element out = (-x * y) % Prime; - return (out < 0) ? out + Prime : out; -} + /** Returns y * w */ + Element times(Element y, int w) { + assert(Prime != 0); // division by zero + Element res = (y * w) % Prime; + if (res < 0) + return res + Prime; + else + return res; + } + void clear_coefficient(Element x) { + } -bool is_one ( Element x ) { return x == 1; } -bool is_zero ( Element x ) { return x == 0; } + void plus_equal(Element & x, Element y) { + assert(Prime != 0); // division by zero + x = ((x + y) % Prime); + } -//bool is_null() + /** \brief Returns the additive idendity \f$0_{\Bbbk}\f$ of the field.*/ + const Element& additive_identity() const { + return add_id_all; + } + /** \brief Returns the multiplicative identity \f$1_{\Bbbk}\f$ of the field.*/ + const Element& multiplicative_identity(Element P = 0) const { + return mult_id_all; + } + /** Returns the inverse in the field. Modifies P.*/ + std::pair<Element, Element> inverse(Element x, Element P) { + return std::pair<Element, Element>(inverse_[x], P); + } // <------ return the product of field characteristic for which x is invertible + + /** Returns -x * y.*/ + Element times_minus(Element x, Element y) { + assert(Prime != 0); // division by zero + Element out = (-x * y) % Prime; + return (out < 0) ? out + Prime : out; + } -/** \brief Returns the characteristic \f$p\f$ of the field.*/ -Element characteristic() { return Prime; } + /** \brief Returns the characteristic \f$p\f$ of the field.*/ + const uint8_t& characteristic() const { + return Prime; + } -private: - Element Prime; -/** Property map Element -> Element, which associate to an element its inverse in the field.*/ - std::vector< Element > inverse_; + private: + uint8_t Prime; + /** Property map Element -> Element, which associate to an element its inverse in the field.*/ + std::vector<Element> inverse_; + const Element mult_id_all; + const Element add_id_all; }; -} // namespace GUDHI +} // namespace Gudhi -#endif // GUDHI_FIELD_ZP_H +#endif // SRC_PERSISTENT_COHOMOLOGY_INCLUDE_GUDHI_PERSISTENT_COHOMOLOGY_FIELD_ZP_H_ |