92 lines
2.4 KiB
C++
92 lines
2.4 KiB
C++
#include "../pieces/piece.hpp"
|
|
#include "../utils/threadpool.hpp"
|
|
#include "../utils/utils.hpp"
|
|
#include "ai.hpp"
|
|
|
|
#include <map>
|
|
|
|
#define MULTITHREADED 1
|
|
|
|
static int position_counter = 0;
|
|
|
|
Move ai::v1_pure_minimax::_search(const Board& b) {
|
|
position_counter = 0;
|
|
std::vector<Move> moves = b.all_legal_moves();
|
|
|
|
Move best_move;
|
|
int best_eval = -INFINITY;
|
|
#if MULTITHREADED
|
|
ThreadPool pool(std::thread::hardware_concurrency());
|
|
|
|
std::cout << "Have to look at " << moves.size() << " moves" << std::endl;
|
|
|
|
std::map<Move, std::future<int>> futures;
|
|
for (const Move& move : moves) {
|
|
Board tmp_board = b.make_move(move);
|
|
futures.insert({move, pool.enqueue([&, tmp_board]() {
|
|
return _search(tmp_board, 3);
|
|
})});
|
|
}
|
|
|
|
int counter = 0;
|
|
for (auto& [move, future] : futures) {
|
|
int eval = future.get();
|
|
counter++;
|
|
if (!am_white)
|
|
eval *= -1;
|
|
if (eval > best_eval) {
|
|
best_eval = eval;
|
|
best_move = move;
|
|
}
|
|
}
|
|
#else
|
|
for (const Move& move : moves) {
|
|
Board tmp_board = b.make_move(move);
|
|
std::cout << "Looking at " << move << std::endl;
|
|
int eval = _search(tmp_board, 3);
|
|
if (!am_white)
|
|
eval *= -1;
|
|
if (eval > best_eval) {
|
|
best_eval = eval;
|
|
best_move = move;
|
|
}
|
|
}
|
|
#endif
|
|
std::cout << "Looked at " << position_counter << " positions" << std::endl;
|
|
return best_move;
|
|
}
|
|
|
|
int ai::v1_pure_minimax::_search(const Board& b, int depth) {
|
|
if (depth == 0 || stop_computation)
|
|
return eval(b);
|
|
|
|
if (b.no_legal_moves()) {
|
|
if (b.is_check())
|
|
return -INFINITY;
|
|
return 0;
|
|
}
|
|
|
|
std::vector<Move> moves = b.all_legal_moves();
|
|
|
|
int best_evaluation = -INFINITY;
|
|
Move best_move;
|
|
for (const Move& move : moves) {
|
|
Board tmp_board = b.make_move(move);
|
|
int tmp_eval = -_search(tmp_board, depth - 1);
|
|
best_evaluation = std::max(best_evaluation, tmp_eval);
|
|
}
|
|
return best_evaluation;
|
|
}
|
|
|
|
int ai::v1_pure_minimax::eval(const Board& b) {
|
|
position_counter++;
|
|
int white_eval = count_material(b, Colour::White);
|
|
int black_eval = count_material(b, Colour::Black);
|
|
|
|
int evaluation = white_eval - black_eval;
|
|
|
|
int perspective = b.white_to_play ? 1 : -1;
|
|
|
|
return perspective * evaluation;
|
|
}
|