101 lines
2.6 KiB
C++
101 lines
2.6 KiB
C++
/*
|
|
Glaurung, a UCI chess playing engine.
|
|
Copyright (C) 2004-2008 Tord Romstad
|
|
|
|
Glaurung is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
Glaurung is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
|
|
////
|
|
//// Includes
|
|
////
|
|
|
|
#include <cassert>
|
|
|
|
#include "history.h"
|
|
|
|
|
|
////
|
|
//// Functions
|
|
////
|
|
|
|
/// Constructor
|
|
|
|
History::History() {
|
|
this->clear();
|
|
}
|
|
|
|
|
|
/// History::clear() clears the history tables.
|
|
|
|
void History::clear() {
|
|
memset(history, 0, 2 * 8 * 64 * sizeof(int));
|
|
memset(successCount, 0, 2 * 8 * 64 * sizeof(int));
|
|
memset(failureCount, 0, 2 * 8 * 64 * sizeof(int));
|
|
}
|
|
|
|
|
|
/// History::success() registers a move as being successful. This is done
|
|
/// whenever a non-capturing move causes a beta cutoff in the main search.
|
|
/// The three parameters are the moving piece, the move itself, and the
|
|
/// search depth.
|
|
|
|
void History::success(Piece p, Move m, Depth d) {
|
|
assert(piece_is_ok(p));
|
|
assert(move_is_ok(m));
|
|
|
|
history[p][move_to(m)] += int(d) * int(d);
|
|
successCount[p][move_to(m)]++;
|
|
|
|
// Prevent history overflow:
|
|
if(history[p][move_to(m)] >= HistoryMax)
|
|
for(int i = 0; i < 16; i++)
|
|
for(int j = 0; j < 64; j++)
|
|
history[i][j] /= 2;
|
|
}
|
|
|
|
|
|
/// History::failure() registers a move as being unsuccessful. The function is
|
|
/// called for each non-capturing move which failed to produce a beta cutoff
|
|
/// at a node where a beta cutoff was finally found.
|
|
|
|
void History::failure(Piece p, Move m) {
|
|
assert(piece_is_ok(p));
|
|
assert(move_is_ok(m));
|
|
|
|
failureCount[p][move_to(m)]++;
|
|
}
|
|
|
|
|
|
/// History::move_ordering_score() returns an integer value used to order the
|
|
/// non-capturing moves in the MovePicker class.
|
|
|
|
int History::move_ordering_score(Piece p, Move m) const {
|
|
assert(piece_is_ok(p));
|
|
assert(move_is_ok(m));
|
|
|
|
return history[p][move_to(m)];
|
|
}
|
|
|
|
|
|
/// History::ok_to_prune() decides whether a move has been sufficiently
|
|
/// unsuccessful that it makes sense to prune it entirely.
|
|
|
|
bool History::ok_to_prune(Piece p, Move m, Depth d) const {
|
|
assert(piece_is_ok(p));
|
|
assert(move_is_ok(m));
|
|
|
|
return (int(d) * successCount[p][move_to(m)] < failureCount[p][move_to(m)]);
|
|
}
|