X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=e22942128f4a98974f856ecefb836c15b091ff8a;hp=62ff1a747990b6ee043864224a20f26f78636226;hb=f7d8ea3866c26df10617e97513e906d1f5a5b833;hpb=c9dcda6ac488c0058ebd567e1f52e30b8cd0db20 diff --git a/src/material.cpp b/src/material.cpp index 62ff1a74..e2294212 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -1,7 +1,7 @@ /* 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 Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,39 +17,34 @@ along with this program. If not, see . */ -#include // For std::min +#include // For std::min #include -#include +#include // For std::memset #include "material.h" +#include "thread.h" using namespace std; namespace { - // Values modified by Joona Kiiski - const Value MidgameLimit = Value(15581); - const Value EndgameLimit = Value(3998); + // Polynomial material imbalance parameters - // Scale factors used when one side has no more pawns - const int NoPawnsSF[4] = { 6, 12, 32 }; + // pair pawn knight bishop rook queen + const int Linear[6] = { 1852, -162, -1122, -183, 249, -154 }; - // Polynomial material balance parameters - - // pair pawn knight bishop rook queen - const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -52 }; - - const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = { + const int QuadraticOurs[][PIECE_TYPE_NB] = { + // OUR PIECES // pair pawn knight bishop rook queen { 0 }, // Bishop pair { 39, 2 }, // Pawn - { 35, 271, -4 }, // Knight + { 35, 271, -4 }, // Knight OUR PIECES { 0, 105, 4, 0 }, // Bishop { -27, -2, 46, 100, -141 }, // Rook - { 58, 29, 83, 148, -163, 0 } // Queen + {-177, 25, 129, 142, -137, 0 } // Queen }; - const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = { + const int QuadraticTheirs[][PIECE_TYPE_NB] = { // THEIR PIECES // pair pawn knight bishop rook queen { 0 }, // Bishop pair @@ -57,13 +52,12 @@ namespace { { 10, 62, 0 }, // Knight OUR PIECES { 57, 64, 39, 0 }, // Bishop { 50, 40, 23, -22, 0 }, // Rook - { 106, 101, 3, 151, 171, 0 } // Queen + { 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 then one material hash key. - Endgame EvaluateKmmKm[] = { Endgame(WHITE), Endgame(BLACK) }; - Endgame EvaluateKXK[] = { Endgame(WHITE), Endgame(BLACK) }; + // 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) }; @@ -73,8 +67,7 @@ namespace { // 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.count(Them) - && pos.non_pawn_material(Them) == VALUE_ZERO + return !more_than_one(pos.pieces(Them)) && pos.non_pawn_material(Us) >= RookValueMg; } @@ -101,56 +94,52 @@ namespace { const 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) + 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 = Linear[pt1]; - for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2) - v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2] - + QuadraticCoefficientsOppositeColor[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); + e->gamePhase = pos.game_phase(); // 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 = pos.this_thread()->endgames.probe(key)) != nullptr) return e; if (is_KXK(pos)) @@ -165,37 +154,19 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { return e; } - if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN)) - { - // 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(WHITE, KNIGHT) | pos.pieces(WHITE, BISHOP))); - assert((pos.pieces(BLACK, KNIGHT) | pos.pieces(BLACK, BISHOP))); - - if ( pos.count(WHITE) + pos.count(WHITE) <= 2 - && pos.count(BLACK) + pos.count(BLACK) <= 2) - { - e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()]; - 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. + // OK, we didn't find any special evaluation function for the current material + // configuration. Is there a suitable specialized scaling function? EndgameBase* sf; - if (endgames.probe(key, sf)) + if ((sf = pos.this_thread()->endgames.probe(key)) != nullptr) { - e->scalingFunction[sf->color()] = sf; + e->scalingFunction[sf->strong_side()] = sf; // Only strong color assigned return e; } - // Generic scaling functions that refer to more then one material - // distribution. They should be probed after the specialized ones. - // Note that these ones don't return after setting the function. + // 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. if (is_KBPsKs(pos)) e->scalingFunction[WHITE] = &ScaleKBPsK[WHITE]; @@ -211,16 +182,18 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { Value npm_w = pos.non_pawn_material(WHITE); Value npm_b = pos.non_pawn_material(BLACK); - if (npm_w + npm_b == VALUE_ZERO) + 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) @@ -232,54 +205,34 @@ 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 + // 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 == npm_b || npm_w < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count(WHITE), 2)]); - } + 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_w == npm_b || npm_b < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count(BLACK), 2)]); - } + e->factor[BLACK] = uint8_t(npm_b < RookValueMg ? SCALE_FACTOR_DRAW : + npm_w <= BishopValueMg ? 4 : 12); - // 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); + if (pos.count(WHITE) == 1 && npm_w - npm_b <= BishopValueMg) + e->factor[WHITE] = (uint8_t) SCALE_FACTOR_ONEPAWN; - e->spaceWeight = make_score(minorPieceCount * minorPieceCount, 0); - } + 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] = { + 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); + 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