implemented move ordering to improve on alpha_beta
pruning
This commit is contained in:
Karma Riuk
parent
10de9828be
commit
377e5dfdcc
@ -24,8 +24,9 @@ int main(int argc, char* argv[]) {
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Board b = Board::setup_fen_position(pos);
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ai::v0_random p1(true, std::chrono::milliseconds(1000));
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// ai::v1_pure_minimax p2(false, std::chrono::milliseconds(150000));
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ai::v2_alpha_beta p2(false, std::chrono::milliseconds(150000));
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// ai::v1_pure_minimax p2(false, std::chrono::milliseconds(20000));
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// ai::v2_alpha_beta p2(false, std::chrono::milliseconds(20000));
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ai::v3_AB_ordering p2(false, std::chrono::milliseconds(20000));
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NoOpView gui;
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AIvsAIController manual(b, gui, p1, p2);
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@ -54,4 +54,15 @@ namespace ai {
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Move _search(const Board&) override;
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int eval(const Board&) override;
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};
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class v3_AB_ordering : public AI {
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// looks two moves ahead, with alpha-beta pruning, with move ordering
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int _search(const Board&, int, int, int);
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public:
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v3_AB_ordering(bool w, std::chrono::milliseconds tt): AI(w, tt) {}
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Move _search(const Board&) override;
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int eval(const Board&) override;
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};
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} // namespace ai
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99
cpp/src/model/ais/v3_AB_ordering.cpp
Normal file
99
cpp/src/model/ais/v3_AB_ordering.cpp
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@ -0,0 +1,99 @@
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#include "../pieces/piece.hpp"
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#include "../utils/threadpool.hpp"
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#include "../utils/utils.hpp"
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#include "ai.hpp"
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#include <algorithm>
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#include <map>
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#define MULTITHREADED 1
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static int position_counter;
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Move ai::v3_AB_ordering::_search(const Board& b) {
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position_counter = 0;
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std::vector<Move> moves = b.all_legal_moves();
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Move best_move;
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int best_eval = -INFINITY;
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#if MULTITHREADED
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ThreadPool pool(std::thread::hardware_concurrency());
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std::cout << "Have to look at " << moves.size() << " moves" << std::endl;
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std::map<Move, std::future<int>> futures;
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for (const Move& move : moves) {
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Board tmp_board = b.make_move(move);
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futures.insert({move, pool.enqueue([&, tmp_board]() {
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return _search(tmp_board, 3, -INFINITY, INFINITY);
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})});
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}
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int counter = 0;
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for (auto& [move, future] : futures) {
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int eval = future.get();
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counter++;
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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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#else
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for (const Move& move : moves) {
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Board tmp_board = b.make_move(move);
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std::cout << "Looking at " << move << std::endl;
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int eval = _search(tmp_board, 3);
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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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#endif
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std::cout << "Looked at " << position_counter << " positions" << std::endl;
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return best_move;
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}
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int ai::v3_AB_ordering::_search(
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const Board& b, int depth, int alpha, int beta
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) {
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if (depth == 0 || stop_computation)
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return eval(b);
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if (b.no_legal_moves()) {
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if (b.is_check())
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return -INFINITY;
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return 0;
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}
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std::vector<Move> moves = b.all_legal_moves();
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std::sort(moves.begin(), moves.end(), [&](Move& m1, Move& m2) {
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return m1.score_guess(b) > m2.score_guess(b);
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});
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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, -beta, -alpha);
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if (tmp_eval >= beta)
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return beta;
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alpha = std::max(alpha, tmp_eval);
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}
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return alpha;
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}
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int ai::v3_AB_ordering::eval(const Board& b) {
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position_counter++;
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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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@ -19,7 +19,7 @@ std::vector<Move> pawn_moves(const Board& b, const Coords xy) {
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ret.push_back(Move{
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xy.to_index(),
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left.to_index(),
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(int8_t) (my_colour | piece)
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(Piece) (my_colour | piece)
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});
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else
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ret.push_back(Move{xy.to_index(), left.to_index()});
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@ -39,7 +39,7 @@ std::vector<Move> pawn_moves(const Board& b, const Coords xy) {
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ret.push_back(Move{
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xy.to_index(),
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right.to_index(),
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(int8_t) (my_colour | piece)
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(Piece) (my_colour | piece)
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});
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else
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ret.push_back(Move{xy.to_index(), right.to_index()});
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@ -68,7 +68,7 @@ std::vector<Move> pawn_moves(const Board& b, const Coords xy) {
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ret.push_back(Move{
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xy.to_index(),
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new_xy.to_index(),
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.promoting_to = (int8_t) (my_colour | piece)
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(Piece) (my_colour | piece)
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});
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else
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ret.push_back(Move{
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@ -9,7 +9,6 @@ keep_only_blocking(const std::vector<Move> candidates, const Board& board) {
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if (candidates.size() == 0)
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return {};
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Colour my_colour = board.colour_at(candidates[0].source_square);
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std::vector<Move> ret;
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for (Move move : candidates) {
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Board board_after_move = board.make_move(move, false);
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19
cpp/src/model/utils/move.cpp
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19
cpp/src/model/utils/move.cpp
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@ -0,0 +1,19 @@
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#include "move.hpp"
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#include "../board/board.hpp"
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#include "utils.hpp"
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int Move::score_guess(const Board& b) const {
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int ret = 0;
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Piece me_piece = b.piece_at(source_square);
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Piece captured_piece = b.piece_at(target_square);
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if (captured_piece != Piece::None)
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ret += 10 * piece_value(captured_piece) - piece_value(me_piece);
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if (promoting_to != Piece::None)
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ret += piece_value(promoting_to);
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return ret;
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}
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@ -11,7 +11,9 @@ struct Move {
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int8_t source_square;
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int8_t target_square;
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int8_t promoting_to = Piece::None;
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Piece promoting_to = Piece::None;
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int score_guess(const Board&) const;
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std::string to_string() const {
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std::stringstream ss;
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@ -9,30 +9,27 @@ std::vector<int8_t> to_target_square(std::vector<Move> moves) {
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return ret;
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}
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int piece_value(Piece p) {
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switch (p) {
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case Piece::Pawn:
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return PawnValue;
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case Piece::Knigt:
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return KnightValue;
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case Piece::Bishop:
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return BishopValue;
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case Piece::Rook:
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return RookValue;
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case Piece::Queen:
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return QueenValue;
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default:
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return 0;
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}
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}
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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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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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case Piece::King:
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case Piece::None:
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break;
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}
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}
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ret += piece_value(b.piece_at(i));
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return ret;
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}
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@ -8,6 +8,7 @@
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std::vector<int8_t> to_target_square(std::vector<Move>);
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int count_material(const Board&, int8_t);
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int piece_value(Piece);
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const int INFINITY = std::numeric_limits<int>::max();
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