X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=a0097d135c2a9b5e8741df74f37a7fc0bc503e5d;hp=63033d80ee5a86a74025c5578ea49325f466bdfe;hb=37e38639279bf58558b92932739da57e7c2e3bdc;hpb=7dd0c39714cbb6829d7cbf9da36fa46995e7a61e diff --git a/src/material.cpp b/src/material.cpp index 63033d80..7e212461 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -1,13 +1,15 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad - Glaurung is free software: you can redistribute it and/or modify + 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. - Glaurung is distributed in the hope that it will be useful, + 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. @@ -16,391 +18,202 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include +#include // For std::memset #include "material.h" +#include "thread.h" - -//// -//// Local definitions -//// +using namespace std; namespace { - const Value BishopPairMidgameBonus = Value(100); - const Value BishopPairEndgameBonus = Value(100); - - Key KPKMaterialKey, KKPMaterialKey; - Key KBNKMaterialKey, KKBNMaterialKey; - Key KRKPMaterialKey, KPKRMaterialKey; - Key KRKBMaterialKey, KBKRMaterialKey; - Key KRKNMaterialKey, KNKRMaterialKey; - Key KQKRMaterialKey, KRKQMaterialKey; - Key KRPKRMaterialKey, KRKRPMaterialKey; - Key KRPPKRPMaterialKey, KRPKRPPMaterialKey; - Key KNNKMaterialKey, KKNNMaterialKey; - Key KBPKBMaterialKey, KBKBPMaterialKey; - Key KBPKNMaterialKey, KNKBPMaterialKey; - Key KNPKMaterialKey, KKNPMaterialKey; - Key KPKPMaterialKey; + // Polynomial material imbalance parameters -} + constexpr int QuadraticOurs[][PIECE_TYPE_NB] = { + // OUR PIECES + // pair pawn knight bishop rook queen + {1438 }, // Bishop pair + { 40, 38 }, // Pawn + { 32, 255, -62 }, // Knight OUR PIECES + { 0, 104, 4, 0 }, // Bishop + { -26, -2, 47, 105, -208 }, // Rook + {-189, 24, 117, 133, -134, -6 } // Queen + }; + constexpr int QuadraticTheirs[][PIECE_TYPE_NB] = { + // THEIR PIECES + // pair pawn knight bishop rook queen + { 0 }, // Bishop pair + { 36, 0 }, // Pawn + { 9, 63, 0 }, // Knight OUR PIECES + { 59, 65, 42, 0 }, // Bishop + { 46, 39, 24, -24, 0 }, // Rook + { 97, 100, -42, 137, 268, 0 } // Queen + }; -//// -//// Functions -//// - -/// MaterialInfo::init() is called during program initialization. It -/// precomputes material hash keys for a few basic endgames, in order -/// to make it easy to recognize such endgames when they occur. - -void MaterialInfo::init() { - KPKMaterialKey = Position::zobMaterial[WHITE][PAWN][1]; - KKPMaterialKey = Position::zobMaterial[BLACK][PAWN][1]; - KBNKMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[WHITE][KNIGHT][1]; - KKBNMaterialKey = - Position::zobMaterial[BLACK][BISHOP][1] ^ - Position::zobMaterial[BLACK][KNIGHT][1]; - KRKPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KPKRMaterialKey = - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKBMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][BISHOP][1]; - KBKRMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKNMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][KNIGHT][1]; - KNKRMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KQKRMaterialKey = - Position::zobMaterial[WHITE][QUEEN][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKQMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][QUEEN][1]; - KRPKRMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][ROOK][1]; - KRKRPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[BLACK][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KRPPKRPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[WHITE][PAWN][2] ^ - Position::zobMaterial[BLACK][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KRPKRPPMaterialKey = - Position::zobMaterial[WHITE][ROOK][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][ROOK][1] ^ - Position::zobMaterial[BLACK][PAWN][1] ^ - Position::zobMaterial[BLACK][PAWN][2]; - KNNKMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[WHITE][KNIGHT][2]; - KKNNMaterialKey = - Position::zobMaterial[BLACK][KNIGHT][1] ^ - Position::zobMaterial[BLACK][KNIGHT][2]; - KBPKBMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][BISHOP][1]; - KBKBPMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[BLACK][BISHOP][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KBPKNMaterialKey = - Position::zobMaterial[WHITE][BISHOP][1] ^ - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][KNIGHT][1]; - KNKBPMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[BLACK][BISHOP][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KNPKMaterialKey = - Position::zobMaterial[WHITE][KNIGHT][1] ^ - Position::zobMaterial[WHITE][PAWN][1]; - KKNPMaterialKey = - Position::zobMaterial[BLACK][KNIGHT][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; - KPKPMaterialKey = - Position::zobMaterial[WHITE][PAWN][1] ^ - Position::zobMaterial[BLACK][PAWN][1]; -} + // 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) }; -/// Constructor for the MaterialInfoTable class. + // Helper used to detect a given material distribution + bool is_KXK(const Position& pos, Color us) { + return !more_than_one(pos.pieces(~us)) + && pos.non_pawn_material(us) >= RookValueMg; + } -MaterialInfoTable::MaterialInfoTable(unsigned numOfEntries) { - size = numOfEntries; - entries = new MaterialInfo[size]; - if(entries == NULL) { - std::cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) - << " bytes for material hash table." << std::endl; - exit(EXIT_FAILURE); + bool is_KBPsK(const Position& pos, Color us) { + return pos.non_pawn_material(us) == BishopValueMg + && pos.count(us) >= 1; } - this->clear(); -} + bool is_KQKRPs(const Position& pos, Color us) { + return !pos.count(us) + && pos.non_pawn_material(us) == QueenValueMg + && pos.count(~us) == 1 + && pos.count(~us) >= 1; + } -/// Destructor for the MaterialInfoTable class. + /// 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]) { -MaterialInfoTable::~MaterialInfoTable() { - delete [] entries; -} + constexpr Color Them = (Us == WHITE ? BLACK : WHITE); + int bonus = 0; -/// MaterialInfoTable::clear() clears a material hash table by setting -/// all entries to 0. + // Second-degree polynomial material imbalance, by Tord Romstad + for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) + { + if (!pieceCount[Us][pt1]) + continue; -void MaterialInfoTable::clear() { - memset(entries, 0, size * sizeof(MaterialInfo)); -} + int v = 0; + for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) + v += QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2]; -/// MaterialInfoTable::get_material_info() takes a position object as input, -/// computes or looks up a MaterialInfo object, and returns a pointer to it. -/// If the material configuration is not already present in the table, it -/// is stored there, so we don't have to recompute everything when the -/// same material configuration occurs again. - -MaterialInfo *MaterialInfoTable::get_material_info(const Position &pos) { - Key key = pos.get_material_key(); - int index = key & (size - 1); - MaterialInfo *mi = entries + index; - - // If mi->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(mi->key == key) - return mi; - - // Clear the MaterialInfo object, and set its key: - mi->clear(); - mi->key = key; - - // A special case before looking for a specialized evaluation function: - // KNN vs K is a draw: - if(key == KNNKMaterialKey || key == KKNNMaterialKey) { - mi->factor[WHITE] = mi->factor[BLACK] = 0; - return mi; - } + bonus += pieceCount[Us][pt1] * v; + } - // Let's look if we have a specialized evaluation function for this - // particular material configuration: - if(key == KPKMaterialKey) { - mi->evaluationFunction = &EvaluateKPK; - return mi; - } - else if(key == KKPMaterialKey) { - mi->evaluationFunction = &EvaluateKKP; - return mi; - } - else if(key == KBNKMaterialKey) { - mi->evaluationFunction = &EvaluateKBNK; - return mi; - } - else if(key == KKBNMaterialKey) { - mi->evaluationFunction = &EvaluateKKBN; - return mi; - } - else if(key == KRKPMaterialKey) { - mi->evaluationFunction = &EvaluateKRKP; - return mi; - } - else if(key == KPKRMaterialKey) { - mi->evaluationFunction = &EvaluateKPKR; - return mi; - } - else if(key == KRKBMaterialKey) { - mi->evaluationFunction = &EvaluateKRKB; - return mi; - } - else if(key == KBKRMaterialKey) { - mi->evaluationFunction = &EvaluateKBKR; - return mi; - } - else if(key == KRKNMaterialKey) { - mi->evaluationFunction = &EvaluateKRKN; - return mi; - } - else if(key == KNKRMaterialKey) { - mi->evaluationFunction = &EvaluateKNKR; - return mi; - } - else if(key == KQKRMaterialKey) { - mi->evaluationFunction = &EvaluateKQKR; - return mi; - } - else if(key == KRKQMaterialKey) { - mi->evaluationFunction = &EvaluateKRKQ; - return mi; - } - else if(pos.non_pawn_material(BLACK) == Value(0) && - pos.pawn_count(BLACK) == 0 && - pos.non_pawn_material(WHITE) >= RookValueEndgame) { - mi->evaluationFunction = &EvaluateKXK; - return mi; - } - else if(pos.non_pawn_material(WHITE) == Value(0) && - pos.pawn_count(WHITE) == 0 && - pos.non_pawn_material(BLACK) >= RookValueEndgame) { - mi->evaluationFunction = &EvaluateKKX; - return mi; + return bonus; } - // OK, we didn't find any special evaluation function for the current - // material configuration. Is there a suitable scaling function? - // - // The code below is rather messy, and it could easily get worse later, - // if we decide to add more special cases. We face problems when there - // are several conflicting applicable scaling functions and we need to - // decide which one to use. - - if(key == KRPKRMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKRPKR; - return mi; - } - if(key == KRKRPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKRKRP; - return mi; - } - if(key == KRPPKRPMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKRPPKRP; - return mi; - } - else if(key == KRPKRPPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKRPKRPP; - return mi; - } - if(key == KBPKBMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKBPKB; - return mi; - } - if(key == KBKBPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKBKBP; - return mi; - } - if(key == KBPKNMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKBPKN; - return mi; - } - if(key == KNKBPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKNKBP; - return mi; - } - if(key == KNPKMaterialKey) { - mi->scalingFunction[WHITE] = &ScaleKNPK; - return mi; - } - if(key == KKNPMaterialKey) { - mi->scalingFunction[BLACK] = &ScaleKKNP; - return mi; - } +} // namespace - if(pos.non_pawn_material(WHITE) == BishopValueMidgame && - pos.bishop_count(WHITE) == 1 && pos.pawn_count(WHITE) >= 1) - mi->scalingFunction[WHITE] = &ScaleKBPK; - if(pos.non_pawn_material(BLACK) == BishopValueMidgame && - pos.bishop_count(BLACK) == 1 && pos.pawn_count(BLACK) >= 1) - mi->scalingFunction[BLACK] = &ScaleKKBP; - - if(pos.pawn_count(WHITE) == 0 && - pos.non_pawn_material(WHITE) == QueenValueMidgame && - pos.queen_count(WHITE) == 1 && - pos.rook_count(BLACK) == 1 && pos.pawn_count(BLACK) >= 1) - mi->scalingFunction[WHITE] = &ScaleKQKRP; - else if(pos.pawn_count(BLACK) == 0 && - pos.non_pawn_material(BLACK) == QueenValueMidgame && - pos.queen_count(BLACK) == 1 && - pos.rook_count(WHITE) == 1 && pos.pawn_count(WHITE) >= 1) - mi->scalingFunction[BLACK] = &ScaleKRPKQ; - - if(pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0)) { - if(pos.pawn_count(BLACK) == 0) { - assert(pos.pawn_count(WHITE) >= 2); - mi->scalingFunction[WHITE] = &ScaleKPsK; - } - else if(pos.pawn_count(WHITE) == 0) { - assert(pos.pawn_count(BLACK) >= 2); - mi->scalingFunction[BLACK] = &ScaleKKPs; - } - else if(pos.pawn_count(WHITE) == 1 && pos.pawn_count(BLACK) == 1) { - mi->scalingFunction[WHITE] = &ScaleKPKPw; - mi->scalingFunction[BLACK] = &ScaleKPKPb; - } - } +namespace Material { + +/// Material::probe() looks up the current position's material configuration in +/// the material hash table. It returns a pointer to the Entry if the position +/// is found. Otherwise a new Entry is computed and stored there, so we don't +/// have to recompute all when the same material configuration occurs again. + +Entry* probe(const Position& pos) { + + Key key = pos.material_key(); + Entry* e = pos.this_thread()->materialTable[key]; + + 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; + + Value npm_w = pos.non_pawn_material(WHITE); + Value npm_b = pos.non_pawn_material(BLACK); + Value npm = Utility::clamp(npm_w + npm_b, EndgameLimit, MidgameLimit); - // Evaluate the material balance. - - Color c; - int sign; - Value egValue = Value(0), mgValue = Value(0); - - for(c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) { - - // No pawns makes it difficult to win, even with a material advantage: - if(pos.pawn_count(c) == 0 && - pos.non_pawn_material(c) - pos.non_pawn_material(opposite_color(c)) - <= BishopValueMidgame) { - if(pos.non_pawn_material(c) == pos.non_pawn_material(opposite_color(c))) - mi->factor[c] = 0; - else if(pos.non_pawn_material(c) < RookValueMidgame) - mi->factor[c] = 0; - else { - switch(pos.bishop_count(c)) { - case 2: - mi->factor[c] = 32; break; - case 1: - mi->factor[c] = 12; break; - case 0: - mi->factor[c] = 6; break; - } + // Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME] + e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit)); + + // 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 ((e->evaluationFunction = Endgames::probe(key)) != nullptr) + return e; + + for (Color c : { WHITE, BLACK }) + if (is_KXK(pos, c)) + { + e->evaluationFunction = &EvaluateKXK[c]; + return e; } - } - // Bishop pair: - if(pos.bishop_count(c) >= 2) { - mgValue += sign * BishopPairMidgameBonus; - egValue += sign * BishopPairEndgameBonus; - } + // OK, we didn't find any special evaluation function for the current material + // configuration. Is there a suitable specialized scaling function? + const auto* sf = Endgames::probe(key); - // Knights are stronger when there are many pawns on the board. The - // formula is taken from Larry Kaufman's paper "The Evaluation of Material - // Imbalances in Chess": - // http://mywebpages.comcast.net/danheisman/Articles/evaluation_of_material_imbalance.htm - mgValue += sign * Value(pos.knight_count(c)*(pos.pawn_count(c)-5)*16); - egValue += sign * Value(pos.knight_count(c)*(pos.pawn_count(c)-5)*16); - - // Redundancy of major pieces, again based on Kaufman's paper: - if(pos.rook_count(c) >= 1) { - Value v = Value((pos.rook_count(c) - 1) * 32 + pos.queen_count(c) * 16); - mgValue -= sign * v; - egValue -= sign * v; - } + if (sf) + { + e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned + return e; + } + + // We didn't find any specialized scaling function, so fall back on generic + // ones that refer to more than one material distribution. Note that in this + // case we don't return after setting the function. + for (Color c : { WHITE, BLACK }) + { + if (is_KBPsK(pos, c)) + e->scalingFunction[c] = &ScaleKBPsK[c]; + else if (is_KQKRPs(pos, c)) + e->scalingFunction[c] = &ScaleKQKRPs[c]; } - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); + if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board + { + if (!pos.count(BLACK)) + { + assert(pos.count(WHITE) >= 2); - return mi; + 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]; + } + } + + // Zero or just one pawn makes it difficult to win, even with a small material + // advantage. This catches some trivial draws like KK, KBK and KNK and gives a + // 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 : 14); + + if (!pos.count(BLACK) && npm_b - npm_w <= BishopValueMg) + e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW : + npm_w <= BishopValueMg ? 4 : 14); + + // 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; } + +} // namespace Material