X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fpawns.cpp;h=c6d390b32efb0ea9e9a22276605a0c688485a0ae;hp=aefda8d2e9d3f44110a8d41fc55b0b16b73c66a7;hb=fc89dbcab2616603ba6edbf6277c3edecfc3a64a;hpb=82a1e2d5fcd1c4d1c6ce3079cab24e286b2a1917 diff --git a/src/pawns.cpp b/src/pawns.cpp index aefda8d2..c6d390b3 100644 --- a/src/pawns.cpp +++ b/src/pawns.cpp @@ -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 @@ -38,65 +38,41 @@ namespace { /// Constants and variables - // Doubled pawn penalty by file, middle game - const Value DoubledPawnMidgamePenalty[8] = { - Value(13), Value(20), Value(23), Value(23), - Value(23), Value(23), Value(20), Value(13) - }; - - // Doubled pawn penalty by file, endgame - const Value DoubledPawnEndgamePenalty[8] = { - Value(43), Value(48), Value(48), Value(48), - Value(48), Value(48), Value(48), Value(43) - }; - - // Isolated pawn penalty by file, middle game - const Value IsolatedPawnMidgamePenalty[8] = { - Value(25), Value(36), Value(40), Value(40), - Value(40), Value(40), Value(36), Value(25) - }; - - // Isolated pawn penalty by file, endgame - const Value IsolatedPawnEndgamePenalty[8] = { - Value(30), Value(35), Value(35), Value(35), - Value(35), Value(35), Value(35), Value(30) - }; + #define S(mg, eg) make_score(mg, eg) - // Backward pawn penalty by file, middle game - const Value BackwardPawnMidgamePenalty[8] = { - Value(20), Value(29), Value(33), Value(33), - Value(33), Value(33), Value(29), Value(20) + // Doubled pawn penalty by file + const Score DoubledPawnPenalty[8] = { + S(13, 43), S(20, 48), S(23, 48), S(23, 48), + S(23, 48), S(23, 48), S(20, 48), S(13, 43) }; - // Backward pawn penalty by file, endgame - const Value BackwardPawnEndgamePenalty[8] = { - Value(28), Value(31), Value(31), Value(31), - Value(31), Value(31), Value(31), Value(28) + // Isolated pawn penalty by file + const Score IsolatedPawnPenalty[8] = { + S(25, 30), S(36, 35), S(40, 35), S(40, 35), + S(40, 35), S(40, 35), S(36, 35), S(25, 30) }; - // Pawn chain membership bonus by file, middle game - const Value ChainMidgameBonus[8] = { - Value(11), Value(13), Value(13), Value(14), - Value(14), Value(13), Value(13), Value(11) + // Backward pawn penalty by file + const Score BackwardPawnPenalty[8] = { + S(20, 28), S(29, 31), S(33, 31), S(33, 31), + S(33, 31), S(33, 31), S(29, 31), S(20, 28) }; - // Pawn chain membership bonus by file, endgame - const Value ChainEndgameBonus[8] = { - Value(-1), Value(-1), Value(-1), Value(-1), - Value(-1), Value(-1), Value(-1), Value(-1) + // Pawn chain membership bonus by file + const Score ChainBonus[8] = { + S(11,-1), S(13,-1), S(13,-1), S(14,-1), + S(14,-1), S(13,-1), S(13,-1), S(11,-1) }; - // Candidate passed pawn bonus by rank, middle game - const Value CandidateMidgameBonus[8] = { - Value( 0), Value( 6), Value(6), Value(14), - Value(34), Value(83), Value(0), Value( 0) + // Candidate passed pawn bonus by rank + const Score CandidateBonus[8] = { + S( 0, 0), S( 6, 13), S(6,13), S(14,29), + S(34,68), S(83,166), S(0, 0), S( 0, 0) }; - // Candidate passed pawn bonus by rank, endgame - const Value CandidateEndgameBonus[8] = { - Value( 0), Value( 13), Value(13), Value(29), - Value(68), Value(166), Value( 0), Value( 0) - }; + // UnpairedPawnsTable[] gives a score according to the number + // of panws that do not have an enemy pawn in front of them. + const int UnpairedPawnsTable[8] = { 32, 48, 64, 80, 96, 112, 128, 128 }; // Pawn storm tables for positions with opposite castling const int QStormTable[64] = { @@ -197,11 +173,8 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) { pi->pawnAttacks[BLACK] = ((blackPawns >> 7) & ~FileABB) | ((blackPawns >> 9) & ~FileHBB); // Evaluate pawns for both colors - Values whiteValues = evaluate_pawns(pos, whitePawns, blackPawns, pi); - Values blackValues = evaluate_pawns(pos, blackPawns, whitePawns, pi); - - pi->mgValue = int16_t(whiteValues.first - blackValues.first); - pi->egValue = int16_t(whiteValues.second - blackValues.second); + pi->value = evaluate_pawns(pos, whitePawns, blackPawns, pi) + - evaluate_pawns(pos, blackPawns, whitePawns, pi); return pi; } @@ -209,16 +182,16 @@ PawnInfo* PawnInfoTable::get_pawn_info(const Position& pos) { /// PawnInfoTable::evaluate_pawns() evaluates each pawn of the given color template -PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns, - Bitboard theirPawns, PawnInfo* pi) { +Score PawnInfoTable::evaluate_pawns(const Position& pos, Bitboard ourPawns, + Bitboard theirPawns, PawnInfo* pi) { Square s; File f; Rank r; - bool passed, isolated, doubled, chain, backward, candidate; + bool passed, isolated, doubled, opposed, chain, backward, candidate; int bonus; - Value mgValue = Value(0); - Value egValue = Value(0); + Score value = make_score(0, 0); const Square* ptr = pos.piece_list_begin(Us, PAWN); + int unpairedPawnsNum = pos.piece_count(Us, PAWN); // Initialize pawn storm scores by giving bonuses for open files for (f = FILE_A; f <= FILE_H; f++) @@ -238,9 +211,14 @@ PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboar assert(pos.piece_on(s) == piece_of_color_and_type(Us, PAWN)); // Passed, isolated or doubled pawn? - passed = Position::pawn_is_passed(theirPawns, Us, s); - isolated = Position::pawn_is_isolated(ourPawns, s); - doubled = Position::pawn_is_doubled(ourPawns, Us, s); + passed = !(theirPawns & passed_pawn_mask(Us, s)); + isolated = !(ourPawns & neighboring_files_bb(s)); + doubled = ourPawns & squares_behind(Us, s); + opposed = theirPawns & squares_in_front_of(Us, s); + + // Decrease number of unpaired pawns + if (opposed) + unpairedPawnsNum--; // We calculate kingside and queenside pawn storm // scores for both colors. These are used when evaluating @@ -258,21 +236,16 @@ PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboar Bitboard b = outpost_mask(Us, s) & theirPawns & (FileFBB | FileGBB | FileHBB); while (b) { + // Give a bonus according to the distance of the nearest enemy pawn Square s2 = pop_1st_bit(&b); + int v = StormLeverBonus[f] - 2 * square_distance(s, s2); + + // If enemy pawn has no pawn beside itself is particularly vulnerable. + // Big bonus, especially against a weakness on the rook file if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2))) - { - // The enemy pawn has no pawn beside itself, which makes it - // particularly vulnerable. Big bonus, especially against a - // weakness on the rook file. - if (square_file(s2) == FILE_H) - bonus += 4*StormLeverBonus[f] - 8*square_distance(s, s2); - else - bonus += 2*StormLeverBonus[f] - 4*square_distance(s, s2); - } else - // There is at least one enemy pawn beside the enemy pawn we look - // at, which means that the pawn has somewhat better chances of - // defending itself by advancing. Smaller bonus. - bonus += StormLeverBonus[f] - 2*square_distance(s, s2); + v *= (square_file(s2) == FILE_H ? 4 : 2); + + bonus += v; } } pi->ksStormValue[Us] += bonus; @@ -284,21 +257,16 @@ PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboar Bitboard b = outpost_mask(Us, s) & theirPawns & (FileABB | FileBBB | FileCBB); while (b) { + // Give a bonus according to the distance of the nearest enemy pawn Square s2 = pop_1st_bit(&b); + int v = StormLeverBonus[f] - 4 * square_distance(s, s2); + + // If enemy pawn has no pawn beside itself is particularly vulnerable. + // Big bonus, especially against a weakness on the rook file if (!(theirPawns & neighboring_files_bb(s2) & rank_bb(s2))) - { - // The enemy pawn has no pawn beside itself, which makes it - // particularly vulnerable. Big bonus, especially against a - // weakness on the rook file. - if (square_file(s2) == FILE_A) - bonus += 4*StormLeverBonus[f] - 16*square_distance(s, s2); - else - bonus += 2*StormLeverBonus[f] - 8*square_distance(s, s2); - } else - // There is at least one enemy pawn beside the enemy pawn we look - // at, which means that the pawn has somewhat better chances of - // defending itself by advancing. Smaller bonus. - bonus += StormLeverBonus[f] - 4*square_distance(s, s2); + v *= (square_file(s2) == FILE_A ? 4 : 2); + + bonus += v; } } pi->qsStormValue[Us] += bonus; @@ -341,7 +309,7 @@ PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboar // Test for candidate passed pawn candidate = !passed - && !(theirPawns & file_bb(f)) + && !opposed && ( count_1s_max_15(neighboring_files_bb(f) & (behind_bb(Us, r) | rank_bb(r)) & ourPawns) - count_1s_max_15(neighboring_files_bb(f) & in_front_bb(Us, r) & theirPawns) >= 0); @@ -358,42 +326,30 @@ PawnInfoTable::Values PawnInfoTable::evaluate_pawns(const Position& pos, Bitboar if (isolated) { - mgValue -= IsolatedPawnMidgamePenalty[f]; - egValue -= IsolatedPawnEndgamePenalty[f]; + value -= IsolatedPawnPenalty[f]; if (!(theirPawns & file_bb(f))) - { - mgValue -= IsolatedPawnMidgamePenalty[f] / 2; - egValue -= IsolatedPawnEndgamePenalty[f] / 2; - } + value -= IsolatedPawnPenalty[f] / 2; } if (doubled) - { - mgValue -= DoubledPawnMidgamePenalty[f]; - egValue -= DoubledPawnEndgamePenalty[f]; - } + value -= DoubledPawnPenalty[f]; + if (backward) { - mgValue -= BackwardPawnMidgamePenalty[f]; - egValue -= BackwardPawnEndgamePenalty[f]; + value -= BackwardPawnPenalty[f]; if (!(theirPawns & file_bb(f))) - { - mgValue -= BackwardPawnMidgamePenalty[f] / 2; - egValue -= BackwardPawnEndgamePenalty[f] / 2; - } + value -= BackwardPawnPenalty[f] / 2; } if (chain) - { - mgValue += ChainMidgameBonus[f]; - egValue += ChainEndgameBonus[f]; - } + value += ChainBonus[f]; + if (candidate) - { - mgValue += CandidateMidgameBonus[relative_rank(Us, s)]; - egValue += CandidateEndgameBonus[relative_rank(Us, s)]; - } + value += CandidateBonus[relative_rank(Us, s)]; } - return Values(mgValue, egValue); + // Calculate a scale factor to be used to evaluate if position is drawish + pi->factor[Us] = UnpairedPawnsTable[unpairedPawnsNum]; + + return value; }