opelly/Stockfish
1
0
Fork 0
mirror of https://github.com/opelly27/Stockfish.git synced 2026-05-20 13:17:44 +00:00
Code Issues Packages Projects Releases Wiki Activity

Better document how history works

Browse Source 
Both with added comment and changing the API to
reflect that only destination square and moved piece
is important for history.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2009-05-15 16:42:30 +02:00
parent 8df816f869
commit 436fa5c8fa
4 changed files with 50 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/history.cpp
+32 -29
View File
@@ -32,14 +32,13 @@
//// 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));
@@ -48,55 +47,59 @@ void History::clear() {
}
/// 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);
successCount[p][to]++;
// 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));
void History::failure(Piece p, Square to) {
failureCount[p][move_to(m)]++;
assert(piece_is_ok(p));
assert(square_is_ok(to));
failureCount[p][to]++;
}
/// 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));
int History::move_ordering_score(Piece p, Square to) const {
return history[p][move_to(m)];
assert(piece_is_ok(p));
assert(square_is_ok(to));
return history[p][to];
}
/// 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));
bool History::ok_to_prune(Piece p, Square to, Depth d) const {
return (int(d) * successCount[p][move_to(m)] < failureCount[p][move_to(m)]);
assert(piece_is_ok(p));
assert(square_is_ok(to));
return (int(d) * successCount[p][to] < failureCount[p][to]);
}