X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=f73977b5f369641dfc427507ae66fcc035c58928;hp=ffc549ca6962bb637e9d23059bb991a76f792563;hb=2dd24dc4e618dc7b83799890fe7e84b09b6456b4;hpb=94b9c65e09b5d396bebb29b62d9979139b5fbdfa diff --git a/src/material.cpp b/src/material.cpp index ffc549ca..f73977b5 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) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2016 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 @@ -17,415 +18,211 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - +#include // For std::min #include -#include -#include +#include // For std::memset #include "material.h" +#include "thread.h" using namespace std; - -//// -//// Local definitions -//// - namespace { - // Values modified by Joona Kiiski - const Value MidgameLimit = Value(15581); - const Value EndgameLimit = Value(3998); - - // Polynomial material balance parameters - const Value RedundantQueenPenalty = Value(320); - const Value RedundantRookPenalty = Value(554); - - const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 }; - - const int QuadraticCoefficientsSameColor[][6] = { - { 7, 7, 7, 7, 7, 7 }, { 39, 2, 7, 7, 7, 7 }, { 35, 271, -4, 7, 7, 7 }, - { 7, 25, 4, 7, 7, 7 }, { -27, -2, 46, 100, 56, 7 }, { 58, 29, 83, 148, -3, -25 } }; - - const int QuadraticCoefficientsOppositeColor[][6] = { - { 41, 41, 41, 41, 41, 41 }, { 37, 41, 41, 41, 41, 41 }, { 10, 62, 41, 41, 41, 41 }, - { 57, 64, 39, 41, 41, 41 }, { 50, 40, 23, -22, 41, 41 }, { 106, 101, 3, 151, 171, 41 } }; - - typedef EndgameEvaluationFunctionBase EF; - typedef EndgameScalingFunctionBase SF; - typedef map EFMap; - typedef map SFMap; - - // Endgame evaluation and scaling functions accessed direcly and not through - // the function maps because correspond to more then one material hash key. - EvaluationFunction EvaluateKmmKm[] = { EvaluationFunction(WHITE), EvaluationFunction(BLACK) }; - EvaluationFunction EvaluateKXK[] = { EvaluationFunction(WHITE), EvaluationFunction(BLACK) }; - ScalingFunction ScaleKBPsK[] = { ScalingFunction(WHITE), ScalingFunction(BLACK) }; - ScalingFunction ScaleKQKRPs[] = { ScalingFunction(WHITE), ScalingFunction(BLACK) }; - ScalingFunction ScaleKPsK[] = { ScalingFunction(WHITE), ScalingFunction(BLACK) }; - ScalingFunction ScaleKPKP[] = { ScalingFunction(WHITE), ScalingFunction(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 pos.non_pawn_material(Them) == VALUE_ZERO - && pos.piece_count(Them, PAWN) == 0 - && pos.non_pawn_material(Us) >= RookValueMidgame; + // Polynomial material imbalance parameters + + // pair pawn knight bishop rook queen + const int Linear[6] = { 1667, -168, -1027, -166, 238, -138 }; + + const int QuadraticOurs[][PIECE_TYPE_NB] = { + // OUR PIECES + // pair pawn knight bishop rook queen + { 0 }, // Bishop pair + { 40, 2 }, // Pawn + { 32, 255, -3 }, // Knight OUR PIECES + { 0, 104, 4, 0 }, // Bishop + { -26, -2, 47, 105, -149 }, // Rook + {-185, 24, 122, 137, -134, 0 } // Queen + }; + + const 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 + { 101, 100, -37, 141, 268, 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 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; } - template bool is_KBPsK(const Position& pos) { - return pos.non_pawn_material(Us) == BishopValueMidgame - && pos.piece_count(Us, BISHOP) == 1 - && pos.piece_count(Us, PAWN) >= 1; + bool is_KBPsKs(const Position& pos, Color us) { + 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.piece_count(Us, PAWN) == 0 - && pos.non_pawn_material(Us) == QueenValueMidgame - && pos.piece_count(Us, QUEEN) == 1 - && pos.piece_count(Them, ROOK) == 1 - && pos.piece_count(Them, 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 + && pos.count(~us) >= 1; } -} - - -//// -//// Classes -//// - -/// EndgameFunctions class stores endgame evaluation and scaling functions -/// in two std::map. Because STL library is not guaranteed to be thread -/// safe even for read access, the maps, although with identical content, -/// are replicated for each thread. This is faster then using locks. - -class EndgameFunctions { -public: - EndgameFunctions(); - ~EndgameFunctions(); - template T* get(Key key) const; -private: - template void add(const string& keyCode); + /// 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]) { - static Key buildKey(const string& keyCode); - static const string swapColors(const string& keyCode); - - // Here we store two maps, for evaluate and scaling functions... - pair maps; - - // ...and here is the accessing template function - template const map& get() const; -}; - -// Explicit specializations of a member function shall be declared in -// the namespace of which the class template is a member. -template<> const EFMap& EndgameFunctions::get() const { return maps.first; } -template<> const SFMap& EndgameFunctions::get() const { return maps.second; } + const Color Them = (Us == WHITE ? BLACK : WHITE); + int bonus = 0; -//// -//// Functions -//// + // Second-degree polynomial material imbalance by Tord Romstad + for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) + { + if (!pieceCount[Us][pt1]) + continue; -/// MaterialInfoTable c'tor and d'tor, called once by each thread + int v = Linear[pt1]; -MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { + for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) + v += QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2]; - size = numOfEntries; - entries = new MaterialInfo[size]; - funcs = new EndgameFunctions(); + bonus += pieceCount[Us][pt1] * v; + } - if (!entries || !funcs) - { - cerr << "Failed to allocate " << numOfEntries * sizeof(MaterialInfo) - << " bytes for material hash table." << endl; - Application::exit_with_failure(); + return bonus; } -} - -MaterialInfoTable::~MaterialInfoTable() { - - delete funcs; - delete [] entries; -} - - -/// MaterialInfoTable::game_phase() calculates the phase given the current -/// position. Because the phase is strictly a function of the material, it -/// is stored in MaterialInfo. - -Phase MaterialInfoTable::game_phase(const Position& pos) { - - Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK); - - if (npm >= MidgameLimit) - return PHASE_MIDGAME; - if (npm <= EndgameLimit) - return PHASE_ENDGAME; +} // namespace - return Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit)); -} - -/// 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) { +namespace Material { - Key key = pos.get_material_key(); - unsigned index = unsigned(key & (size - 1)); - MaterialInfo* mi = entries + index; +/// 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. - // 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; +Entry* probe(const Position& pos) { - // Clear the MaterialInfo object, and set its key - mi->clear(); - mi->key = key; + Key key = pos.material_key(); + Entry* e = pos.this_thread()->materialTable[key]; - // Store game phase - mi->gamePhase = MaterialInfoTable::game_phase(pos); + if (e->key == key) + return e; - // 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. - if ((mi->evaluationFunction = funcs->get(key)) != NULL) - return mi; - - if (is_KXK(pos) || is_KXK(pos)) - { - mi->evaluationFunction = is_KXK(pos) ? &EvaluateKXK[WHITE] : &EvaluateKXK[BLACK]; - return mi; - } + std::memset(e, 0, sizeof(Entry)); + e->key = key; + e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL; + e->gamePhase = pos.game_phase(); - if ( pos.pieces(PAWN) == EmptyBoardBB - && pos.pieces(ROOK) == EmptyBoardBB - && pos.pieces(QUEEN) == EmptyBoardBB) - { - // 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(KNIGHT, WHITE) | pos.pieces(BISHOP, WHITE))); - assert((pos.pieces(KNIGHT, BLACK) | pos.pieces(BISHOP, BLACK))); + // 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 = pos.this_thread()->endgames.probe(key)) != nullptr) + return e; - if ( pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2 - && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2) + for (Color c = WHITE; c <= BLACK; ++c) + if (is_KXK(pos, c)) { - mi->evaluationFunction = &EvaluateKmmKm[WHITE]; - return mi; + e->evaluationFunction = &EvaluateKXK[c]; + 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. - SF* sf; + // OK, we didn't find any special evaluation function for the current material + // configuration. Is there a suitable specialized scaling function? + EndgameBase* sf; - if ((sf = funcs->get(key)) != NULL) + if ((sf = pos.this_thread()->endgames.probe(key)) != nullptr) { - mi->scalingFunction[sf->color()] = sf; - return mi; + e->scalingFunction[sf->strong_side()] = sf; // Only strong color assigned + return e; } - // Generic scaling functions that refer to more then one material - // distribution. Should be probed after the specialized ones. - // Note that these ones don't return after setting the function. - if (is_KBPsK(pos)) - mi->scalingFunction[WHITE] = &ScaleKBPsK[WHITE]; - - if (is_KBPsK(pos)) - mi->scalingFunction[BLACK] = &ScaleKBPsK[BLACK]; + // 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; c <= BLACK; ++c) + { + if (is_KBPsKs(pos, c)) + e->scalingFunction[c] = &ScaleKBPsK[c]; - if (is_KQKRPs(pos)) - mi->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE]; + else if (is_KQKRPs(pos, c)) + e->scalingFunction[c] = &ScaleKQKRPs[c]; + } - else if (is_KQKRPs(pos)) - mi->scalingFunction[BLACK] = &ScaleKQKRPs[BLACK]; + Value npm_w = pos.non_pawn_material(WHITE); + Value npm_b = pos.non_pawn_material(BLACK); - if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == VALUE_ZERO) + if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board { - if (pos.piece_count(BLACK, PAWN) == 0) + if (!pos.count(BLACK)) { - assert(pos.piece_count(WHITE, PAWN) >= 2); - mi->scalingFunction[WHITE] = &ScaleKPsK[WHITE]; + assert(pos.count(WHITE) >= 2); + + e->scalingFunction[WHITE] = &ScaleKPsK[WHITE]; } - else if (pos.piece_count(WHITE, PAWN) == 0) + else if (!pos.count(WHITE)) { - assert(pos.piece_count(BLACK, PAWN) >= 2); - mi->scalingFunction[BLACK] = &ScaleKPsK[BLACK]; + assert(pos.count(BLACK) >= 2); + + e->scalingFunction[BLACK] = &ScaleKPsK[BLACK]; } - else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1) + 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. - mi->scalingFunction[WHITE] = &ScaleKPKP[WHITE]; - mi->scalingFunction[BLACK] = &ScaleKPKP[BLACK]; + e->scalingFunction[WHITE] = &ScaleKPKP[WHITE]; + e->scalingFunction[BLACK] = &ScaleKPKP[BLACK]; } } - // Compute the space weight - if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >= - 2*QueenValueMidgame + 4*RookValueMidgame + 2*KnightValueMidgame) - { - int minorPieceCount = pos.piece_count(WHITE, KNIGHT) - + pos.piece_count(BLACK, KNIGHT) - + pos.piece_count(WHITE, BISHOP) - + pos.piece_count(BLACK, BISHOP); - - mi->spaceWeight = minorPieceCount * minorPieceCount; - } - - // Evaluate the material balance - const int pieceCount[2][6] = { { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(WHITE, PAWN), pos.piece_count(WHITE, KNIGHT), - pos.piece_count(WHITE, BISHOP), pos.piece_count(WHITE, ROOK), pos.piece_count(WHITE, QUEEN) }, - { pos.piece_count(BLACK, BISHOP) > 1, pos.piece_count(BLACK, PAWN), pos.piece_count(BLACK, KNIGHT), - pos.piece_count(BLACK, BISHOP), pos.piece_count(BLACK, ROOK), pos.piece_count(BLACK, QUEEN) } }; - Color c, them; - int sign, pt1, pt2, pc; - int v, vv, matValue = 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)) - || 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; - } - } - } - - // Redundancy of major pieces, formula based on Kaufman's paper - // "The Evaluation of Material Imbalances in Chess" - // http://mywebpages.comcast.net/danheisman/Articles/evaluation_of_material_imbalance.htm - if (pieceCount[c][ROOK] >= 1) - matValue -= sign * ((pieceCount[c][ROOK] - 1) * RedundantRookPenalty + pieceCount[c][QUEEN] * RedundantQueenPenalty); - - them = opposite_color(c); - v = 0; - - // Second-degree polynomial material imbalance by Tord Romstad - // - // We use NO_PIECE_TYPE as a place holder for the bishop pair "extended piece", - // this allow us to be more flexible in defining bishop pair bonuses. - for (pt1 = PIECE_TYPE_NONE; pt1 <= QUEEN; pt1++) - { - pc = pieceCount[c][pt1]; - if (!pc) - continue; - - vv = LinearCoefficients[pt1]; - - for (pt2 = PIECE_TYPE_NONE; pt2 <= pt1; pt2++) - vv += pieceCount[c][pt2] * QuadraticCoefficientsSameColor[pt1][pt2] - + pieceCount[them][pt2] * QuadraticCoefficientsOppositeColor[pt1][pt2]; - - v += pc * vv; - } - matValue += sign * v; - } - mi->value = int16_t(matValue / 16); - 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); + + 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; + + // 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; } - -/// EndgameFunctions member definitions. - -EndgameFunctions::EndgameFunctions() { - - add >("KNNK"); - add >("KPK"); - add >("KBNK"); - add >("KRKP"); - add >("KRKB"); - add >("KRKN"); - add >("KQKR"); - add >("KBBKN"); - - add >("KNPK"); - add >("KRPKR"); - add >("KBPKB"); - add >("KBPPKB"); - add >("KBPKN"); - add >("KRPPKRP"); -} - -EndgameFunctions::~EndgameFunctions() { - - for (EFMap::const_iterator it = maps.first.begin(); it != maps.first.end(); ++it) - delete it->second; - - for (SFMap::const_iterator it = maps.second.begin(); it != maps.second.end(); ++it) - delete it->second; -} - -Key EndgameFunctions::buildKey(const string& keyCode) { - - assert(keyCode.length() > 0 && keyCode[0] == 'K'); - assert(keyCode.length() < 8); - - stringstream s; - bool upcase = false; - - // Build up a fen string with the given pieces, note that - // the fen string could be of an illegal position. - for (size_t i = 0; i < keyCode.length(); i++) - { - if (keyCode[i] == 'K') - upcase = !upcase; - - s << char(upcase ? toupper(keyCode[i]) : tolower(keyCode[i])); - } - s << 8 - keyCode.length() << "/8/8/8/8/8/8/8 w - -"; - return Position(s.str(), 0).get_material_key(); -} - -const string EndgameFunctions::swapColors(const string& keyCode) { - - // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" - size_t idx = keyCode.find("K", 1); - return keyCode.substr(idx) + keyCode.substr(0, idx); -} - -template -void EndgameFunctions::add(const string& keyCode) { - - typedef typename T::Base F; - typedef map M; - - const_cast(get()).insert(pair(buildKey(keyCode), new T(WHITE))); - const_cast(get()).insert(pair(buildKey(swapColors(keyCode)), new T(BLACK))); -} - -template -T* EndgameFunctions::get(Key key) const { - - typename map::const_iterator it = get().find(key); - return it != get().end() ? it->second : NULL; -} +} // namespace Material