87 lines
2.2 KiB
C++
87 lines
2.2 KiB
C++
#include "../pieces/piece.hpp"
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#include "../utils/threadpool.hpp"
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#include "ai.hpp"
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static int INFINITY = std::numeric_limits<int>::max();
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Move ai::v1_simple::_search(const Board& b) {
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ThreadPool pool(std::thread::hardware_concurrency());
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Move best_move;
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int best_eval = -INFINITY;
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std::vector<Move> moves = b.all_legal_moves();
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for (const Move& move : moves) {
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Board tmp_board = b.make_move(move);
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int eval = _search(tmp_board, 4);
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if (!am_white)
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eval *= -1;
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if (eval > best_eval) {
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best_eval = eval;
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best_move = move;
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}
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}
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return best_move;
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}
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int ai::v1_simple::_search(const Board& b, int depth) {
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if (b.is_checkmate_for(b.white_to_play ? White : Black))
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return -INFINITY;
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if (depth == 0 || stop_computation)
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return eval(b);
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std::vector<Move> moves = b.all_legal_moves();
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int best_evaluation = 0;
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Move best_move;
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for (const Move& move : moves) {
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Board tmp_board = b.make_move(move);
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int tmp_eval = -_search(tmp_board, depth - 1);
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best_evaluation = std::max(best_evaluation, tmp_eval);
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}
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return best_evaluation;
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}
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static int PawnValue = 100;
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static int KnightValue = 300;
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static int BishopValue = 320;
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static int RookValue = 500;
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static int QueenValue = 900;
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int count_material(const Board& b, int8_t colour) {
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int ret = 0;
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for (int i = 0; i < 64; i++) {
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if (b.colour_at(i) == colour)
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switch (b.piece_at(i)) {
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case Piece::Pawn:
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ret += PawnValue;
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break;
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case Piece::Knigt:
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ret += KnightValue;
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break;
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case Piece::Bishop:
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ret += BishopValue;
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break;
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case Piece::Rook:
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ret += RookValue;
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break;
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case Piece::Queen:
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ret += QueenValue;
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break;
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}
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}
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return ret;
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}
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int ai::v1_simple::eval(const Board& b) {
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int white_eval = count_material(b, Colour::White);
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int black_eval = count_material(b, Colour::Black);
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int evaluation = white_eval - black_eval;
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int perspective = b.white_to_play ? 1 : -1;
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return perspective * evaluation;
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}
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