X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=0e1308780dd20d86d22662cceadc3e8473887f74;hp=ce7d7ab591881c2a030ac57efd954822c6ad9425;hb=3b70932b0dee0cf1817baf0daa43ac92e18003c4;hpb=73cce873de9ae241d30d405893dcc25e85293b98 diff --git a/src/material.cpp b/src/material.cpp index ce7d7ab5..0e130878 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -1,7 +1,8 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008 Marco Costalba + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2020 Marco Costalba, Joona Kiiski, Gary Linscott, 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 @@ -17,348 +18,202 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include -#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); + // Polynomial material imbalance parameters - Key KRPKRMaterialKey, KRKRPMaterialKey; - Key KNNKMaterialKey, KKNNMaterialKey; - Key KBPKBMaterialKey, KBKBPMaterialKey; - Key KBPKNMaterialKey, KNKBPMaterialKey; - Key KNPKMaterialKey, KKNPMaterialKey; - Key KPKPMaterialKey; - Key KRPPKRPMaterialKey, KRPKRPPMaterialKey; + 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 + }; - std::map EEFmap; + 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 + }; - void EEFAdd(Key k, EndgameEvaluationFunction* f) { + // 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) }; - EEFmap.insert(std::pair(k, f)); + 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 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; } -} + bool is_KBPsK(const Position& pos, Color us) { + return pos.non_pawn_material(us) == BishopValueMg + && pos.count(us) >= 1; + } -//// -//// 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() { - - typedef Key ZM[2][8][16]; - const ZM& z = Position::zobMaterial; - - static const Color W = WHITE; - static const Color B = BLACK; - - EEFAdd(z[W][PAWN][1], &EvaluateKPK); - EEFAdd(z[B][PAWN][1], &EvaluateKKP); - - EEFAdd(z[W][BISHOP][1] ^ z[W][KNIGHT][1], &EvaluateKBNK); - EEFAdd(z[B][BISHOP][1] ^ z[B][KNIGHT][1], &EvaluateKKBN); - EEFAdd(z[W][ROOK][1] ^ z[B][PAWN][1], &EvaluateKRKP); - EEFAdd(z[W][PAWN][1] ^ z[B][ROOK][1], &EvaluateKPKR); - EEFAdd(z[W][ROOK][1] ^ z[B][BISHOP][1], &EvaluateKRKB); - EEFAdd(z[W][BISHOP][1] ^ z[B][ROOK][1], &EvaluateKBKR); - EEFAdd(z[W][ROOK][1] ^ z[B][KNIGHT][1], &EvaluateKRKN); - EEFAdd(z[W][KNIGHT][1] ^ z[B][ROOK][1], &EvaluateKNKR); - EEFAdd(z[W][QUEEN][1] ^ z[B][ROOK][1], &EvaluateKQKR); - EEFAdd(z[W][ROOK][1] ^ z[B][QUEEN][1], &EvaluateKRKQ); - - KRPKRMaterialKey = z[W][ROOK][1] - ^ z[W][PAWN][1] - ^ z[B][ROOK][1]; - - KRKRPMaterialKey = z[W][ROOK][1] - ^ z[B][ROOK][1] - ^ z[B][PAWN][1]; - - KRPPKRPMaterialKey = - z[W][ROOK][1] ^ - z[W][PAWN][1] ^ - z[W][PAWN][2] ^ - z[B][ROOK][1] ^ - z[B][PAWN][1]; - KRPKRPPMaterialKey = - z[W][ROOK][1] ^ - z[W][PAWN][1] ^ - z[B][ROOK][1] ^ - z[B][PAWN][1] ^ - z[B][PAWN][2]; - KNNKMaterialKey = - z[W][KNIGHT][1] ^ - z[W][KNIGHT][2]; - KKNNMaterialKey = - z[B][KNIGHT][1] ^ - z[B][KNIGHT][2]; - KBPKBMaterialKey = - z[W][BISHOP][1] ^ - z[W][PAWN][1] ^ - z[B][BISHOP][1]; - KBKBPMaterialKey = - z[W][BISHOP][1] ^ - z[B][BISHOP][1] ^ - z[B][PAWN][1]; - KBPKNMaterialKey = - z[W][BISHOP][1] ^ - z[W][PAWN][1] ^ - z[B][KNIGHT][1]; - KNKBPMaterialKey = - z[W][KNIGHT][1] ^ - z[B][BISHOP][1] ^ - z[B][PAWN][1]; - KNPKMaterialKey = - z[W][KNIGHT][1] ^ - z[W][PAWN][1]; - KKNPMaterialKey = - z[B][KNIGHT][1] ^ - z[B][PAWN][1]; - KPKPMaterialKey = - z[W][PAWN][1] ^ - z[B][PAWN][1]; + 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; + } + /// 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]) { -} + constexpr Color Them = (Us == WHITE ? BLACK : WHITE); + int bonus = 0; -/// Constructor for the MaterialInfoTable class. + // Second-degree polynomial material imbalance, by Tord Romstad + for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) + { + if (!pieceCount[Us][pt1]) + continue; -MaterialInfoTable::MaterialInfoTable(unsigned numOfEntries) { + int v = 0; - size = numOfEntries; - entries = new MaterialInfo[size]; - if (!entries) - { - std::cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) - << " bytes for material hash table." << std::endl; - exit(EXIT_FAILURE); - } - clear(); -} + for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) + v += QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2]; + bonus += pieceCount[Us][pt1] * v; + } -/// Destructor for the MaterialInfoTable class. + return bonus; + } -MaterialInfoTable::~MaterialInfoTable() { +} // namespace - delete [] entries; -} +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. -/// MaterialInfoTable::clear() clears a material hash table by setting -/// all entries to 0. +Entry* probe(const Position& pos) { -void MaterialInfoTable::clear() { + Key key = pos.material_key(); + Entry* e = pos.this_thread()->materialTable[key]; - memset(entries, 0, size * sizeof(MaterialInfo)); -} + 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; -/// 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. + Value npm_w = pos.non_pawn_material(WHITE); + Value npm_b = pos.non_pawn_material(BLACK); + Value npm = clamp(npm_w + npm_b, EndgameLimit, MidgameLimit); -MaterialInfo *MaterialInfoTable::get_material_info(const Position &pos) { + // Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME] + e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit)); - Key key = pos.get_material_key(); - int index = key & (size - 1); - MaterialInfo *mi = entries + index; + // 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; - // 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; + for (Color c : { WHITE, BLACK }) + if (is_KXK(pos, c)) + { + e->evaluationFunction = &EvaluateKXK[c]; + return e; + } - // Clear the MaterialInfo object, and set its key: - mi->clear(); - mi->key = key; + // 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); - // A special case before looking for a specialized evaluation function: - // KNN vs K is a draw: - if (key == KNNKMaterialKey || key == KKNNMaterialKey) + if (sf) { - mi->factor[WHITE] = mi->factor[BLACK] = 0; - return mi; + e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned + return e; } - // Let's look if we have a specialized evaluation function for this - // particular material configuration - if (EEFmap.find(key) != EEFmap.end()) + // 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 }) { - mi->evaluationFunction = EEFmap[key]; - return mi; - } - else if ( pos.non_pawn_material(BLACK) == Value(0) - && pos.piece_count(BLACK, PAWN) == 0 - && pos.non_pawn_material(WHITE) >= RookValueEndgame) - { - mi->evaluationFunction = &EvaluateKXK; - return mi; - } - else if ( pos.non_pawn_material(WHITE) == Value(0) - && pos.piece_count(WHITE, PAWN) == 0 - && pos.non_pawn_material(BLACK) >= RookValueEndgame) - { - mi->evaluationFunction = &EvaluateKKX; - return mi; - } + if (is_KBPsK(pos, c)) + e->scalingFunction[c] = &ScaleKBPsK[c]; - // 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; + else if (is_KQKRPs(pos, c)) + e->scalingFunction[c] = &ScaleKQKRPs[c]; } - if(pos.non_pawn_material(WHITE) == BishopValueMidgame && - pos.piece_count(WHITE, BISHOP) == 1 && pos.piece_count(WHITE, PAWN) >= 1) - mi->scalingFunction[WHITE] = &ScaleKBPK; - if(pos.non_pawn_material(BLACK) == BishopValueMidgame && - pos.piece_count(BLACK, BISHOP) == 1 && pos.piece_count(BLACK, PAWN) >= 1) - mi->scalingFunction[BLACK] = &ScaleKKBP; - - if(pos.piece_count(WHITE, PAWN) == 0 && - pos.non_pawn_material(WHITE) == QueenValueMidgame && - pos.piece_count(WHITE, QUEEN) == 1 && - pos.piece_count(BLACK, ROOK) == 1 && pos.piece_count(BLACK, PAWN) >= 1) - mi->scalingFunction[WHITE] = &ScaleKQKRP; - else if(pos.piece_count(BLACK, PAWN) == 0 && - pos.non_pawn_material(BLACK) == QueenValueMidgame && - pos.piece_count(BLACK, QUEEN) == 1 && - pos.piece_count(WHITE, ROOK) == 1 && pos.piece_count(WHITE, PAWN) >= 1) - mi->scalingFunction[BLACK] = &ScaleKRPKQ; - - if(pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0)) { - if(pos.piece_count(BLACK, PAWN) == 0) { - assert(pos.piece_count(WHITE, PAWN) >= 2); - mi->scalingFunction[WHITE] = &ScaleKPsK; - } - else if(pos.piece_count(WHITE, PAWN) == 0) { - assert(pos.piece_count(BLACK, PAWN) >= 2); - mi->scalingFunction[BLACK] = &ScaleKKPs; - } - else if(pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1) { - mi->scalingFunction[WHITE] = &ScaleKPKPw; - mi->scalingFunction[BLACK] = &ScaleKPKPb; - } - } + if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board + { + if (!pos.count(BLACK)) + { + assert(pos.count(WHITE) >= 2); - // 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.piece_count(c, PAWN) == 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.piece_count(c, BISHOP)) { - case 2: - mi->factor[c] = 32; break; - case 1: - mi->factor[c] = 12; break; - case 0: - mi->factor[c] = 6; break; - } + e->scalingFunction[WHITE] = &ScaleKPsK[WHITE]; } - } - - // Bishop pair: - if(pos.piece_count(c, BISHOP) >= 2) { - mgValue += sign * BishopPairMidgameBonus; - egValue += sign * BishopPairEndgameBonus; - } - - // 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.piece_count(c, KNIGHT)*(pos.piece_count(c, PAWN)-5)*16); - egValue += sign * Value(pos.piece_count(c, KNIGHT)*(pos.piece_count(c, PAWN)-5)*16); - - // Redundancy of major pieces, again based on Kaufman's paper: - if(pos.piece_count(c, ROOK) >= 1) { - Value v = Value((pos.piece_count(c, ROOK) - 1) * 32 + pos.piece_count(c, QUEEN) * 16); - mgValue -= sign * v; - egValue -= sign * v; - } + 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]; + } } - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); - - return mi; + // 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