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- /*
- * Copyright (C) 2020 Christopher J. Howard
- *
- * This file is part of Antkeeper source code.
- *
- * Antkeeper source code 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.
- *
- * Antkeeper source code 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 Antkeeper source code. If not, see <http://www.gnu.org/licenses/>.
- */
-
- #ifndef ANTKEEPER_DNA_CROSSOVER_HPP
- #define ANTKEEPER_DNA_CROSSOVER_HPP
-
- #include <algorithm>
- #include <iterator>
- #include <random>
-
- namespace dna {
-
- /**
- * Exchanges elements between two ranges, starting at a random offset.
- *
- * @param first1,last1 First range of elements to crossover.
- * @param first2 Beginning of the second range of elements to crossover.
- * @param g Uniform random bit generator.
- * @return Iterator to the start of the crossover in the second range.
- */
- template <class ForwardIt1, class ForwardIt2, class URBG>
- ForwardIt2 crossover(ForwardIt1 first1, ForwardIt1 last1, ForwardIt2 first2, URBG&& g);
-
- /**
- * Exchanges elements between two ranges multiple times, starting at a random offset each time.
- *
- * @param first1,last1 First range of elements to crossover.
- * @param first2 Beginning of the second range of elements to crossover.
- * @param count Number of times to crossover.
- * @param g Uniform random bit generator.
- */
- template <class ForwardIt1, class ForwardIt2, class Size, class URBG>
- void crossover_n(ForwardIt1 first1, ForwardIt1 last1, ForwardIt2 first2, Size count, URBG&& g);
-
- template <class ForwardIt1, class ForwardIt2, class URBG>
- ForwardIt2 crossover(ForwardIt1 first1, ForwardIt1 last1, ForwardIt2 first2, URBG&& g)
- {
- typedef typename std::iterator_traits<ForwardIt1>::difference_type difference_t;
- std::uniform_int_distribution<difference_t> distribution(0, std::distance(first1, last1) - 1);
- difference_t pos = distribution(g);
- std::advance(first1, pos);
- std::advance(first2, pos);
- std::swap_ranges(first1, last1, first2);
- return first2;
- }
-
- template <class ForwardIt1, class ForwardIt2, class Size, class URBG>
- void crossover_n(ForwardIt1 first1, ForwardIt1 last1, ForwardIt2 first2, Size count, URBG&& g)
- {
- typedef typename std::iterator_traits<ForwardIt1>::difference_type difference_t;
-
- std::uniform_int_distribution<difference_t> distribution(0, std::distance(first1, last1) - 1);
- ForwardIt1 crossover1, crossover2;
-
- while (count)
- {
- crossover1 = first1;
- crossover2 = first2;
-
- difference_t pos = distribution(g);
- std::advance(crossover1, pos);
- std::advance(crossover2, pos);
- std::swap_ranges(crossover1, last1, crossover2);
-
- --count;
- }
- }
-
- } // namespace dna
-
- #endif // ANTKEEPER_DNA_CROSSOVER_HPP
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