X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=3a05f3faf6b374aee5bd72ea221dd12fce3281b4;hp=0949a1bf418a899072865ad043d1048c39a1598b;hb=dc243a3c880d0a736fb93848cf56e3221e07f8a3;hpb=264c8637a30247f1054f60b7b728fb4340185efa diff --git a/src/material.cpp b/src/material.cpp index 0949a1bf..3a05f3fa 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) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2015-2019 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 @@ -17,188 +18,169 @@ along with this program. If not, see . */ -#include // For std::min #include -#include +#include // For std::memset #include "material.h" +#include "thread.h" using namespace std; namespace { - // Polynomial material balance parameters + // Polynomial material imbalance parameters - // pair pawn knight bishop rook queen - const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -154 }; - - const int QuadraticCoefficientsSameSide[][PIECE_TYPE_NB] = { + constexpr int QuadraticOurs[][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 + {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 }; - const int QuadraticCoefficientsOppositeSide[][PIECE_TYPE_NB] = { + constexpr int QuadraticTheirs[][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 + { 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 }; // 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 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; + // 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_KBPsKs(const Position& pos) { - return pos.non_pawn_material(Us) == BishopValueMg - && pos.count(Us) == 1 - && pos.count(Us) >= 1; + bool is_KBPsK(const Position& pos, Color us) { + return pos.non_pawn_material(us) == BishopValueMg + && 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; + 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]) { - const Color Them = (Us == WHITE ? BLACK : WHITE); + constexpr Color Them = (Us == WHITE ? BLACK : WHITE); - int pt1, pt2, pc, v; - int value = 0; + int bonus = 0; - // Second-degree polynomial material imbalance by Tord Romstad - for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) + // Second-degree polynomial material imbalance, by Tord Romstad + for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) { - pc = pieceCount[Us][pt1]; - if (!pc) + if (!pieceCount[Us][pt1]) continue; - v = LinearCoefficients[pt1]; + int v = 0; - for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) - v += QuadraticCoefficientsSameSide[pt1][pt2] * pieceCount[Us][pt2] - + QuadraticCoefficientsOppositeSide[pt1][pt2] * pieceCount[Them][pt2]; + for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) + v += QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2] + + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2]; - value += pc * v; + bonus += pieceCount[Us][pt1] * v; } - return value; + return bonus; } } // 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. +/// 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, Table& entries, Endgames& endgames) { +Entry* probe(const Position& pos) { Key key = pos.material_key(); - Entry* e = entries[key]; + Entry* e = pos.this_thread()->materialTable[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); + + 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); + + // 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 (endgames.probe(key, e->evaluationFunction)) + if ((e->evaluationFunction = Endgames::probe(key)) != nullptr) return e; - if (is_KXK(pos)) - { - e->evaluationFunction = &EvaluateKXK[WHITE]; - return e; - } - - if (is_KXK(pos)) - { - e->evaluationFunction = &EvaluateKXK[BLACK]; - return e; - } + for (Color c = WHITE; c <= BLACK; ++c) + if (is_KXK(pos, c)) + { + 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. - EndgameBase* sf; + // 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); - if (endgames.probe(key, sf)) + if (sf) { - e->scalingFunction[sf->color()] = sf; + e->scalingFunction[sf->strongSide] = sf; // Only strong color assigned 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]; + // 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_KBPsK(pos, c)) + e->scalingFunction[c] = &ScaleKBPsK[c]; - Value npm_w = pos.non_pawn_material(WHITE); - Value npm_b = pos.non_pawn_material(BLACK); + else if (is_KQKRPs(pos, c)) + e->scalingFunction[c] = &ScaleKQKRPs[c]; + } - if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) + if (npm_w + npm_b == VALUE_ZERO && pos.pieces(PAWN)) // Only pawns on the board { 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) @@ -210,29 +192,16 @@ 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 and gives a very drawish - // scale factor for cases such as KRKBP and KmmKm (except for KBBKN). + // 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 : 12); + 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 : 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); - } + 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 @@ -243,22 +212,8 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { { 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); + 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