From 3e4dfb49a747be902d25ae06783f98ba29fb5030 Mon Sep 17 00:00:00 2001 From: Joona Kiiski Date: Tue, 16 Apr 2013 21:20:31 +0100 Subject: [PATCH] Give a small penalty for bishop for each pawn on the same colored square --- src/bitboard.h | 2 ++ src/evaluate.cpp | 4 ++++ src/material.cpp | 2 +- src/pawns.cpp | 6 ++++++ src/pawns.h | 3 +++ 5 files changed, 16 insertions(+), 1 deletion(-) diff --git a/src/bitboard.h b/src/bitboard.h index 2c51b073..142c4c5a 100644 --- a/src/bitboard.h +++ b/src/bitboard.h @@ -63,6 +63,8 @@ extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB]; extern Bitboard AttackSpanMask[COLOR_NB][SQUARE_NB]; extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB]; +const Bitboard WhiteSquares = 0x55AA55AA55AA55AAULL; +const Bitboard BlackSquares = 0xAA55AA55AA55AA55ULL; /// Overloads of bitwise operators between a Bitboard and a Square for testing /// whether a given bit is set in a bitboard, and for setting and clearing bits. diff --git a/src/evaluate.cpp b/src/evaluate.cpp index 6990a71d..3481b03d 100644 --- a/src/evaluate.cpp +++ b/src/evaluate.cpp @@ -582,6 +582,10 @@ Value do_evaluate(const Position& pos, Value& margin) { && !more_than_one(BetweenBB[s][pos.king_square(Them)] & pos.pieces())) score += BishopPinBonus; + // Penalty for bishop with same coloured pawns + if (Piece == BISHOP) + score -= make_score(4, 4) * ei.pi->same_colored_pawn_count(s, Us); + // Bishop and knight outposts squares if ( (Piece == BISHOP || Piece == KNIGHT) && !(pos.pieces(Them, PAWN) & attack_span_mask(Us, s))) diff --git a/src/material.cpp b/src/material.cpp index 9cc8eead..3474ccd5 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -39,7 +39,7 @@ namespace { const Value RedundantRookPenalty = Value(554); // pair pawn knight bishop rook queen - const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 }; + const int LinearCoefficients[6] = { 1617, -162, -1172, -62, 105, 26 }; const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = { // pair pawn knight bishop rook queen diff --git a/src/pawns.cpp b/src/pawns.cpp index c1a93169..3d99bfc6 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -176,6 +176,12 @@ namespace { value += CandidateBonus[relative_rank(Us, s)]; } + e->pawnsOnWhiteSquaresCount[Us] = popcount(ourPawns & WhiteSquares); + e->pawnsOnWhiteSquaresCount[Them] = popcount(theirPawns & WhiteSquares); + + e->pawnsOnBlackSquaresCount[Us] = popcount(ourPawns & BlackSquares); + e->pawnsOnBlackSquaresCount[Them] = popcount(theirPawns & BlackSquares); + return value; } } diff --git a/src/pawns.h b/src/pawns.h index 2c04e7d2..3ec62334 100644 --- a/src/pawns.h +++ b/src/pawns.h @@ -40,6 +40,7 @@ struct Entry { int file_is_half_open(Color c, File f) const { return halfOpenFiles[c] & (1 << int(f)); } int has_open_file_to_left(Color c, File f) const { return halfOpenFiles[c] & ((1 << int(f)) - 1); } int has_open_file_to_right(Color c, File f) const { return halfOpenFiles[c] & ~((1 << int(f+1)) - 1); } + int same_colored_pawn_count(Square s, Color c) const { return (BlackSquares & s) ? pawnsOnBlackSquaresCount[c] : pawnsOnWhiteSquaresCount[c]; } template Score king_safety(const Position& pos, Square ksq) { @@ -63,6 +64,8 @@ struct Entry { Score value; int halfOpenFiles[COLOR_NB]; Score kingSafety[COLOR_NB]; + int pawnsOnWhiteSquaresCount[COLOR_NB]; + int pawnsOnBlackSquaresCount[COLOR_NB]; }; typedef HashTable Table; -- 2.39.2