/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish 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,
+
+ Stockfish 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/>.
*/
////
#include <cassert>
+#include <cstring>
#include "history.h"
//// Functions
////
+
/// Constructor
-History::History() {
- this->clear();
-}
+History::History() { clear(); }
-/// History::clear() clears the history tables.
+/// 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));
+ memset(history, 0, 16 * 64 * sizeof(int));
+ memset(maxStaticValueDelta, 0, 16 * 64 * sizeof(int));
}
-/// History::success() registers a move as being successful. This is done
+/// 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.
+/// The three parameters are the moving piece, the destination square, and
+/// the search depth.
+
+void History::success(Piece p, Square to, Depth d) {
-void History::success(Piece p, Move m, Depth d) {
assert(piece_is_ok(p));
- assert(move_is_ok(m));
+ assert(square_is_ok(to));
- history[p][move_to(m)] += int(d) * int(d);
- successCount[p][move_to(m)]++;
+ history[p][to] += int(d) * int(d);
- // 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;
+ // Prevent history overflow
+ if (history[p][to] >= 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
+/// 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)]++;
-}
-
+void History::failure(Piece p, Square to, Depth d) {
-/// 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));
+ assert(square_is_ok(to));
+
+ history[p][to] -= int(d) * int(d);
- return history[p][move_to(m)];
+ // Prevent history underflow
+ if (history[p][to] <= -HistoryMax)
+ for (int i = 0; i < 16; i++)
+ for (int j = 0; j < 64; j++)
+ history[i][j] /= 2;
}
-/// History::ok_to_prune() decides whether a move has been sufficiently
-/// unsuccessful that it makes sense to prune it entirely.
+/// History::set_gain() and History::gain() store and retrieve the
+/// gain of a move given the delta of the static position evaluations
+/// before and after the move.
-bool History::ok_to_prune(Piece p, Move m, Depth d) const {
- assert(piece_is_ok(p));
- assert(move_is_ok(m));
+void History::set_gain(Piece p, Square to, Value delta) {
- return (int(d) * successCount[p][move_to(m)] < failureCount[p][move_to(m)]);
+ if (delta >= maxStaticValueDelta[p][to])
+ maxStaticValueDelta[p][to] = delta;
+ else
+ maxStaticValueDelta[p][to]--;
}