X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=b8b6233cc278dc523f94d755c802b90d74480bbe;hp=068d88e702092a67259ae312165bb33683cb101e;hb=057c3d60cd1037c6c54ae86414d9282bfc8a9afa;hpb=3ed86ed3f95f712587bea62f4a7fc474812db458 diff --git a/src/material.cpp b/src/material.cpp index 068d88e7..b8b6233c 100644 --- a/src/material.cpp +++ b/src/material.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) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2014 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 @@ -27,17 +27,10 @@ using namespace std; namespace { - // Values modified by Joona Kiiski - const Value MidgameLimit = Value(15581); - const Value EndgameLimit = Value(3998); - - // Scale factors used when one side has no more pawns - const int NoPawnsSF[4] = { 6, 12, 32 }; - // Polynomial material balance parameters // pair pawn knight bishop rook queen - const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -52 }; + const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -154 }; const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = { // pair pawn knight bishop rook queen @@ -46,7 +39,7 @@ namespace { { 35, 271, -4 }, // Knight { 0, 105, 4, 0 }, // Bishop { -27, -2, 46, 100, -141 }, // Rook - { 58, 29, 83, 148, -163, 0 } // Queen + {-177, 25, 129, 142, -137, 0 } // Queen }; const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = { @@ -57,12 +50,11 @@ namespace { { 10, 62, 0 }, // Knight OUR PIECES { 57, 64, 39, 0 }, // Bishop { 50, 40, 23, -22, 0 }, // Rook - { 106, 101, 3, 151, 171, 0 } // Queen + { 98, 105, -39, 141, 274, 0 } // Queen }; - // Endgame evaluation and scaling functions accessed direcly and not through - // the function maps because correspond to more then one material hash key. - Endgame EvaluateKmmKm[] = { Endgame(WHITE), Endgame(BLACK) }; + // Endgame evaluation and scaling functions are accessed directly and not through + // the function maps because they correspond to more than one material hash key. Endgame EvaluateKXK[] = { Endgame(WHITE), Endgame(BLACK) }; Endgame ScaleKBPsK[] = { Endgame(WHITE), Endgame(BLACK) }; @@ -93,7 +85,7 @@ namespace { && pos.count(Them) >= 1; } - /// imbalance() calculates imbalance comparing piece count of each + /// imbalance() calculates the imbalance by comparing the piece count of each /// piece type for both colors. template @@ -119,6 +111,7 @@ namespace { value += pc * v; } + return value; } @@ -147,9 +140,9 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL; e->gamePhase = game_phase(pos); - // Let's look if we have a specialized evaluation function for this - // particular material configuration. First we look for a fixed - // configuration one, then a generic one if previous search failed. + // Let's look if we have a specialized evaluation function for this particular + // material configuration. Firstly we look for a fixed configuration one, then + // for a generic one if the previous search failed. if (endgames.probe(key, e->evaluationFunction)) return e; @@ -165,21 +158,6 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { return e; } - if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN)) - { - // Minor piece endgame with at least one minor piece per side and - // no pawns. Note that the case KmmK is already handled by KXK. - assert((pos.pieces(WHITE, KNIGHT) | pos.pieces(WHITE, BISHOP))); - assert((pos.pieces(BLACK, KNIGHT) | pos.pieces(BLACK, BISHOP))); - - if ( pos.count(WHITE) + pos.count(WHITE) <= 2 - && pos.count(BLACK) + pos.count(BLACK) <= 2) - { - e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()]; - return e; - } - } - // OK, we didn't find any special evaluation function for the current // material configuration. Is there a suitable scaling function? // @@ -193,8 +171,8 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { return e; } - // Generic scaling functions that refer to more then one material - // distribution. Should be probed after the specialized ones. + // Generic scaling functions that refer to more than one material + // distribution. They should be probed after the specialized ones. // Note that these ones don't return after setting the function. if (is_KBPsKs(pos)) e->scalingFunction[WHITE] = &ScaleKBPsK[WHITE]; @@ -211,7 +189,7 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { Value npm_w = pos.non_pawn_material(WHITE); Value npm_b = pos.non_pawn_material(BLACK); - if (npm_w + npm_b == VALUE_ZERO) + if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) { if (!pos.count(BLACK)) { @@ -233,18 +211,19 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { } // No pawns makes it difficult to win, even with a material advantage. This - // catches some trivial draws like KK, KBK and KNK + // catches some trivial draws like KK, KBK and KNK and gives a very drawish + // scale factor for cases such as KRKBP and KmmKm (except for KBBKN). if (!pos.count(WHITE) && npm_w - npm_b <= BishopValueMg) - { - e->factor[WHITE] = (uint8_t) - (npm_w == npm_b || npm_w < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count(WHITE), 2)]); - } + e->factor[WHITE] = uint8_t(npm_w < RookValueMg ? SCALE_FACTOR_DRAW : npm_b <= BishopValueMg ? 4 : 12); if (!pos.count(BLACK) && npm_b - npm_w <= BishopValueMg) - { - e->factor[BLACK] = (uint8_t) - (npm_w == npm_b || npm_b < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count(BLACK), 2)]); - } + e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW : npm_w <= BishopValueMg ? 4 : 12); + + if (pos.count(WHITE) == 1 && npm_w - npm_b <= BishopValueMg) + e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN; + + if (pos.count(BLACK) == 1 && npm_b - npm_w <= BishopValueMg) + e->factor[BLACK] = (uint8_t) SCALE_FACTOR_ONEPAWN; // Compute the space weight if (npm_w + npm_b >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg) @@ -256,7 +235,7 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { } // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder - // for the bishop pair "extended piece", this allow us to be more flexible + // for the bishop pair "extended piece", which allows us to be more flexible // in defining bishop pair bonuses. const int pieceCount[COLOR_NB][PIECE_TYPE_NB] = { { pos.count(WHITE) > 1, pos.count(WHITE), pos.count(WHITE),