X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=7102f8799ea9c6a4939ac884a50479cf9f63b472;hp=0949a1bf418a899072865ad043d1048c39a1598b;hb=HEAD;hpb=264c8637a30247f1054f60b7b728fb4340185efa diff --git a/src/material.cpp b/src/material.cpp deleted file mode 100644 index 0949a1bf..00000000 --- a/src/material.cpp +++ /dev/null @@ -1,264 +0,0 @@ -/* - Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - 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 - the Free Software Foundation, either version 3 of the License, or - (at your option) any later version. - - Stockfish is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see . -*/ - -#include // For std::min -#include -#include - -#include "material.h" - -using namespace std; - -namespace { - - // Polynomial material balance parameters - - // pair pawn knight bishop rook queen - const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -154 }; - - const int QuadraticCoefficientsSameSide[][PIECE_TYPE_NB] = { - // OUR PIECES - // pair pawn knight bishop rook queen - { 0 }, // Bishop pair - { 39, 2 }, // Pawn - { 35, 271, -4 }, // knight OUR PIECES - { 0, 105, 4, 0 }, // Bishop - { -27, -2, 46, 100, -141 }, // Rook - {-177, 25, 129, 142, -137, 0 } // Queen - }; - - const int QuadraticCoefficientsOppositeSide[][PIECE_TYPE_NB] = { - // THEIR PIECES - // pair pawn knight bishop rook queen - { 0 }, // Bishop pair - { 37, 0 }, // Pawn - { 10, 62, 0 }, // Knight OUR PIECES - { 57, 64, 39, 0 }, // Bishop - { 50, 40, 23, -22, 0 }, // Rook - { 98, 105, -39, 141, 274, 0 } // Queen - }; - - // 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) }; - Endgame ScaleKQKRPs[] = { Endgame(WHITE), Endgame(BLACK) }; - Endgame ScaleKPsK[] = { Endgame(WHITE), Endgame(BLACK) }; - Endgame ScaleKPKP[] = { Endgame(WHITE), Endgame(BLACK) }; - - // Helper templates used to detect a given material distribution - template bool is_KXK(const Position& pos) { - const Color Them = (Us == WHITE ? BLACK : WHITE); - return !more_than_one(pos.pieces(Them)) - && pos.non_pawn_material(Us) >= RookValueMg; - } - - template bool is_KBPsKs(const Position& pos) { - return pos.non_pawn_material(Us) == BishopValueMg - && pos.count(Us) == 1 - && pos.count(Us) >= 1; - } - - template bool is_KQKRPs(const Position& pos) { - const Color Them = (Us == WHITE ? BLACK : WHITE); - return !pos.count(Us) - && pos.non_pawn_material(Us) == QueenValueMg - && pos.count(Us) == 1 - && pos.count(Them) == 1 - && pos.count(Them) >= 1; - } - - /// imbalance() calculates the imbalance by comparing the piece count of each - /// piece type for both colors. - - template - int imbalance(const int pieceCount[][PIECE_TYPE_NB]) { - - const Color Them = (Us == WHITE ? BLACK : WHITE); - - int pt1, pt2, pc, v; - int value = 0; - - // Second-degree polynomial material imbalance by Tord Romstad - for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) - { - pc = pieceCount[Us][pt1]; - if (!pc) - continue; - - v = LinearCoefficients[pt1]; - - for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) - v += QuadraticCoefficientsSameSide[pt1][pt2] * pieceCount[Us][pt2] - + QuadraticCoefficientsOppositeSide[pt1][pt2] * pieceCount[Them][pt2]; - - value += pc * v; - } - - return value; - } - -} // namespace - -namespace Material { - -/// Material::probe() takes a position object as input, looks up a MaterialEntry -/// object, and returns a pointer to it. If the material configuration is not -/// already present in the table, it is computed and stored there, so we don't -/// have to recompute everything when the same material configuration occurs again. - -Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { - - Key key = pos.material_key(); - Entry* e = entries[key]; - - // If e->key matches the position's material hash key, it means that we - // have analysed this material configuration before, and we can simply - // return the information we found the last time instead of recomputing it. - if (e->key == key) - return e; - - std::memset(e, 0, sizeof(Entry)); - e->key = key; - 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. 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; - - if (is_KXK(pos)) - { - e->evaluationFunction = &EvaluateKXK[WHITE]; - return e; - } - - if (is_KXK(pos)) - { - e->evaluationFunction = &EvaluateKXK[BLACK]; - return e; - } - - // OK, we didn't find any special evaluation function for the current - // material configuration. Is there a suitable scaling function? - // - // We face problems when there are several conflicting applicable - // scaling functions and we need to decide which one to use. - EndgameBase* sf; - - if (endgames.probe(key, sf)) - { - e->scalingFunction[sf->color()] = sf; - return e; - } - - // 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]; - - if (is_KBPsKs(pos)) - e->scalingFunction[BLACK] = &ScaleKBPsK[BLACK]; - - if (is_KQKRPs(pos)) - e->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE]; - - else if (is_KQKRPs(pos)) - e->scalingFunction[BLACK] = &ScaleKQKRPs[BLACK]; - - Value npm_w = pos.non_pawn_material(WHITE); - Value npm_b = pos.non_pawn_material(BLACK); - - if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) - { - if (!pos.count(BLACK)) - { - assert(pos.count(WHITE) >= 2); - e->scalingFunction[WHITE] = &ScaleKPsK[WHITE]; - } - else if (!pos.count(WHITE)) - { - assert(pos.count(BLACK) >= 2); - e->scalingFunction[BLACK] = &ScaleKPsK[BLACK]; - } - else if (pos.count(WHITE) == 1 && pos.count(BLACK) == 1) - { - // This is a special case because we set scaling functions - // for both colors instead of only one. - e->scalingFunction[WHITE] = &ScaleKPKP[WHITE]; - e->scalingFunction[BLACK] = &ScaleKPKP[BLACK]; - } - } - - // No pawns makes it difficult to win, even with a material advantage. This - // 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 < RookValueMg ? SCALE_FACTOR_DRAW : npm_b <= BishopValueMg ? 4 : 12); - - if (!pos.count(BLACK) && npm_b - npm_w <= BishopValueMg) - 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) - { - int minorPieceCount = pos.count(WHITE) + pos.count(WHITE) - + pos.count(BLACK) + pos.count(BLACK); - - e->spaceWeight = make_score(minorPieceCount * minorPieceCount, 0); - } - - // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder - // 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), - pos.count(WHITE) , pos.count(WHITE), pos.count(WHITE) }, - { pos.count(BLACK) > 1, pos.count(BLACK), pos.count(BLACK), - pos.count(BLACK) , pos.count(BLACK), pos.count(BLACK) } }; - - e->value = (int16_t)((imbalance(pieceCount) - imbalance(pieceCount)) / 16); - return e; -} - - -/// Material::game_phase() calculates the phase given the current -/// position. Because the phase is strictly a function of the material, it -/// is stored in MaterialEntry. - -Phase game_phase(const Position& pos) { - - Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK); - - return npm >= MidgameLimit ? PHASE_MIDGAME - : npm <= EndgameLimit ? PHASE_ENDGAME - : Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit)); -} - -} // namespace Material