X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=f77972e352c0d9395054750bca0ebe93aef3e73c;hp=0ef9926f02226a2727efdbea6db7fe5258396530;hb=HEAD;hpb=84f3e867903f62480c33243dd0ecbffd342796fc diff --git a/src/material.cpp b/src/material.cpp deleted file mode 100644 index 0ef9926f..00000000 --- a/src/material.cpp +++ /dev/null @@ -1,220 +0,0 @@ -/* - Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2020 The Stockfish developers (see AUTHORS file) - - 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. - - 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. - - You should have received a copy of the GNU General Public License - along with this program. If not, see . -*/ - -#include -#include // For std::memset - -#include "material.h" -#include "thread.h" - -using namespace std; - -namespace { - - // 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 - { }, // Bishop pair - { 36, }, // Pawn - { 9, 63, }, // Knight OUR PIECES - { 59, 65, 42, }, // Bishop - { 46, 39, 24, -24, }, // Rook - { 97, 100, -42, 137, 268, } // 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; - } - - bool is_KBPsK(const Position& pos, Color us) { - return pos.non_pawn_material(us) == BishopValueMg - && pos.count(us) >= 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; - - int bonus = 0; - - // Second-degree polynomial material imbalance, by Tord Romstad - for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) - { - if (!pieceCount[Us][pt1]) - continue; - - int v = QuadraticOurs[pt1][pt1] * pieceCount[Us][pt1]; - - 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; - } - - return bonus; - } - -} // namespace - -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); - - // 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; - } - - // 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 (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]; - } - - 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) - { - // 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