132 lines
3.9 KiB
C
132 lines
3.9 KiB
C
/* perft.c - perft functions.
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*
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* Copyright (C) 2023-2024 Bruno Raoult ("br")
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* Licensed under the GNU General Public License v3.0 or later.
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* Some rights reserved. See COPYING.
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*
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* You should have received a copy of the GNU General Public License along with this
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* program. If not, see <https://www.gnu.org/licenses/gpl-3.0-standalone.html>.
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*
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* SPDX-License-Identifier: GPL-3.0-or-later <https://spdx.org/licenses/GPL-3.0-or-later.html>
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*
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*/
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#include <stdio.h>
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#include <brlib.h>
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#include "perft.h"
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#include "move-gen.h"
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#include "move-do.h"
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/**
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* perft() - Perform perft on position
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* @pos: &position to search
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* @depth: Wanted depth.
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* @ply: current perft depth level (root = 1)
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* @divide: output total for 1st level moves.
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*
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* Run perft on a position. This function displays the available moves at @depth
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* level for each possible first move, and the total of moves.
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*
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* This version uses the algorithm:
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* if last depth
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* return 1;
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* gen legal moves
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* loop for legal move
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* do-move
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* perft (depth -1)
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* undo-move
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*
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* @return: total moves found at @depth level.
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*/
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u64 perft(pos_t *pos, int depth, int ply, bool divide)
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{
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u64 subnodes = 0, nodes = 0;
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movelist_t movelist;
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move_t *move, *last;
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state_t state;
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pos_set_checkers_pinners_blockers(pos);
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pos_legal(pos, pos_gen_pseudo(pos, &movelist));
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last = movelist.move + movelist.nmoves;
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for (move = movelist.move; move < last; ++move) {
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if (depth == 1) {
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subnodes = 1;
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} else {
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move_do(pos, *move, &state);
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if (depth == 2) {
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movelist_t movelist2;
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pos_set_checkers_pinners_blockers(pos);
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subnodes = pos_legal(pos, pos_gen_pseudo(pos, &movelist2))->nmoves;
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} else if (ply >= 3) {
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hentry_t *entry = tt_probe_perft(pos->key, depth);
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if (entry != TT_MISS) {
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subnodes = HASH_PERFT_VAL(entry->data);
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} else {
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subnodes = perft(pos, depth - 1, ply + 1, divide);
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tt_store_perft(pos->key, depth, subnodes);
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}
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} else {
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subnodes = perft(pos, depth - 1, ply + 1, divide);
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}
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move_undo(pos, *move, &state);
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}
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nodes += subnodes;
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if (ply == 1 && divide) {
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char movestr[8];
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printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
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}
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}
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return nodes;
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}
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/**
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* perft_alt() - Perform perft on position, experimental version.
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* @pos: &position to search
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* @depth: Wanted depth.
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* @ply: current perft depth level (root = 1)
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* @divide: output total for 1st level moves.
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*
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* Run perft on a position. This function displays the available moves at @depth
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* level for each possible first move, and the total of moves.
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*
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* @return: total moves found at @depth level.
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*/
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u64 perft_alt(pos_t *pos, int depth, int ply, bool divide)
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{
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u64 subnodes = 0, nodes = 0;
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movelist_t movelist;
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move_t *move, *last;
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state_t state;
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pos_set_checkers_pinners_blockers(pos);
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pos_legal(pos, pos_gen_pseudo(pos, &movelist));
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last = movelist.move + movelist.nmoves;
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for (move = movelist.move; move < last; ++move) {
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if (depth == 1) {
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subnodes = 1;
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} else {
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move_do_alt(pos, *move, &state);
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if (depth == 2) {
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movelist_t movelist2;
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pos_set_checkers_pinners_blockers(pos);
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subnodes = pos_legal(pos, pos_gen_pseudo(pos, &movelist2))->nmoves;
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} else {
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subnodes = perft_alt(pos, depth - 1, ply + 1, divide);
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}
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move_undo_alt(pos, *move, &state);
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}
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nodes += subnodes;
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if (ply == 1 && divide) {
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char movestr[8];
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printf("%s: %lu\n", move_to_str(movestr, *move, 0), subnodes);
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}
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}
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return nodes;
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}
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