X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovepick.h;h=c444615f5b9f2e8ab4a0952ff47e3c97bf642079;hp=93061ee6fc6a81c8aaf277b817dab41a0d02dd34;hb=343544f3f7fe780a4231b78646ab2fd61760e294;hpb=13d1f0ae4301b86c610a58332c3c19d9101704da diff --git a/src/movepick.h b/src/movepick.h index 93061ee6..c444615f 100644 --- a/src/movepick.h +++ b/src/movepick.h @@ -30,13 +30,14 @@ /// The Stats struct stores moves statistics. According to the template parameter -/// the class can store History and Countermoves. History records how often +/// the class can store History, Gains and Countermoves. History records how often /// different moves have been successful or unsuccessful during the current search -/// and is used for reduction and move ordering decisions. +/// and is used for reduction and move ordering decisions. Gains records the move's +/// best evaluation gain from one ply to the next and is used for pruning decisions. /// Countermoves store the move that refute a previous one. Entries are stored /// according only to moving piece and destination square, hence two moves with /// different origin but same destination and piece will be considered identical. -template +template struct Stats { static const Value Max = Value(2000); @@ -55,7 +56,10 @@ struct Stats { void update(Piece p, Square to, Value v) { - if (abs(table[p][to] + v) < Max) + if (Gain) + table[p][to] = std::max(v, table[p][to] - 1); + + else if (abs(table[p][to] + v) < Max) table[p][to] += v; } @@ -63,8 +67,9 @@ private: T table[PIECE_NB][SQUARE_NB]; }; -typedef Stats HistoryStats; -typedef Stats > CountermovesStats; +typedef Stats< true, Value> GainsStats; +typedef Stats HistoryStats; +typedef Stats > CountermovesStats; /// MovePicker class is used to pick one pseudo legal move at a time from the