X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fhistory.h;h=c265777b42a6c4d0bcf60485aae9d80a64625f43;hp=b08c8d33ce7034c3a0f9355e5fdaffc621ed9f2c;hb=d372f2e39a65e2b14fc0335841e652a9d208d3ec;hpb=5c81602d14539f8259a715477315e28b5de7cb54

diff --git a/src/history.h b/src/history.h
index b08c8d33..c265777b 100644
--- a/src/history.h
+++ b/src/history.h
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2009 Marco Costalba
+  Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -17,61 +17,54 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-
 #if !defined(HISTORY_H_INCLUDED)
 #define HISTORY_H_INCLUDED
 
-////
-//// Includes
-////
-
-#include "depth.h"
-#include "move.h"
-#include "piece.h"
-
+#include <cstring>
+#include "types.h"
 
-////
-//// 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;
+  Value value(Piece p, Square to) const;
+  void update(Piece p, Square to, Value bonus);
+  Value gain(Piece p, Square to) const;
+  void update_gain(Piece p, Square to, Value gain);
+
+  static const Value MaxValue = Value(1 << 29); // To avoid an overflow
 
 private:
-  int history[16][64];  // [piece][square]
-  int successCount[16][64];
-  int failureCount[16][64];
+  Value history[16][64];  // [piece][to_square]
+  Value maxGains[16][64]; // [piece][to_square]
 };
 
+inline void History::clear() {
+  memset(history,  0, 16 * 64 * sizeof(Value));
+  memset(maxGains, 0, 16 * 64 * sizeof(Value));
+}
 
-////
-//// Constants and variables
-////
+inline Value History::value(Piece p, Square to) const {
+  return history[p][to];
+}
 
-/// 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
-/// 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
-/// would be better to scale down the history table at regular intervals?
+inline void History::update(Piece p, Square to, Value bonus) {
+  if (abs(history[p][to] + bonus) < MaxValue) history[p][to] += bonus;
+}
 
-const int HistoryMax = 50000;
+inline Value History::gain(Piece p, Square to) const {
+  return maxGains[p][to];
+}
 
+inline void History::update_gain(Piece p, Square to, Value gain) {
+  maxGains[p][to] = Max(gain, maxGains[p][to] - 1);
+}
 
 #endif // !defined(HISTORY_H_INCLUDED)