76 lines
2.9 KiB
C++
76 lines
2.9 KiB
C++
/*
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* <Short Description>
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* Copyright (C) 2024 Brett Terpstra
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <blt/gp/transformers.h>
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#include <blt/gp/program.h>
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#include <random>
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namespace blt::gp
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{
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blt::expected<crossover_t::result_t, crossover_t::error_t> crossover_t::apply(gp_program& program, const tree_t& p1, const tree_t& p2) // NOLINT
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{
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const auto& config = program.get_config();
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result_t result{p1, p2};
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auto& c1 = result.child1;
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auto& c2 = result.child2;
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auto& c1_ops = c1.get_operations();
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auto& c2_ops = c2.get_operations();
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std::uniform_int_distribution op_sel1(1ul, c1_ops.size() - 1);
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std::uniform_int_distribution op_sel2(1ul, c2_ops.size() - 1);
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blt::size_t crossover_point = op_sel1(program.get_random());
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blt::size_t attempted_point = 0;
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const auto& crossover_point_type = program.get_operator_info(c1_ops[crossover_point].id);
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operator_info* attempted_point_type = nullptr;
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blt::size_t counter = 0;
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do
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{
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if (counter >= config.max_crossover_tries)
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{
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if (config.should_crossover_try_forward)
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{
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for (auto i = attempted_point + 1; i < c2_ops.size(); i++)
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{
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auto* info = &program.get_operator_info(c2_ops[i].id);
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if (info->return_type == crossover_point_type.return_type)
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{
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attempted_point = i;
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attempted_point_type = info;
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break;
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}
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}
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}
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// should we try again over the whole tree? probably not.
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return blt::unexpected(error_t::NO_VALID_TYPE);
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} else
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{
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attempted_point = op_sel2(program.get_random());
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attempted_point_type = &program.get_operator_info(c2_ops[attempted_point].id);
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counter++;
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}
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} while (crossover_point_type.return_type != attempted_point_type->return_type);
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const auto& found_point_type = *attempted_point_type;
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return result;
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}
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} |