HCha/Stockfish
1
0
Fork 0
mirror of https://github.com/HChaZZY/Stockfish.git synced 2025-12-22 01:56:58 +08:00
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

23
src/history.h
View File

@@ -34,19 +34,22 @@
//// Types
////
/// The History class stores statistics about how often different moves have
/// been successful or unsuccessful during the current search. These
/// statistics are used for reduction and move ordering decisions.
/// The History class stores statistics about how often different moves
/// have been successful or unsuccessful during the current search. These
/// statistics are used for reduction and move ordering decisions. History
/// entries are stored according only to moving piece and destination square,
/// in particular two moves with different origin but same destination and
/// same piece will be considered identical.
class History {
public:
History();
void clear();
void success(Piece p, Move m, Depth d);
void failure(Piece p, Move m);
int move_ordering_score(Piece p, Move m) const;
bool ok_to_prune(Piece p, Move m, Depth d) const;
void success(Piece p, Square to, Depth d);
void failure(Piece p, Square to);
int move_ordering_score(Piece p, Square to) const;
bool ok_to_prune(Piece p, Square to, Depth d) const;
private:
int history[16][64]; // [piece][square]
@@ -61,14 +64,14 @@ private:
/// HistoryMax controls how often the history counters will be scaled down:
/// When the history score for a move gets bigger than HistoryMax, all
/// entries in the table are divided by 2. It is difficult to guess what
/// the ideal value of this constant is. Scaling down the scores often has
/// entries in the table are divided by 2. It is difficult to guess what
/// the ideal value of this constant is. Scaling down the scores often has
/// the effect that parts of the search tree which have been searched
/// recently have a bigger importance for move ordering than the moves which
/// have been searched a long time ago.
///
/// Note that HistoryMax should probably be changed whenever the constant
/// OnePly in depth.h is changed. This is somewhat annoying. Perhaps it
/// OnePly in depth.h is changed. This is somewhat annoying. Perhaps it
/// would be better to scale down the history table at regular intervals?
const int HistoryMax = 50000;