X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=5b77ddc2b30b7ceb03d4d3b5fa253db9493693aa;hp=8a7fcb8dc6f7f9d53367246dfd44562c7177de35;hb=1574428f64d0368b943e6275c509e02af2047e7e;hpb=3cc47edf622b1d12a37b3637cae503d6862437c4 diff --git a/src/material.cpp b/src/material.cpp index 8a7fcb8d..5b77ddc2 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) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2014 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 @@ -35,35 +35,33 @@ namespace { const int NoPawnsSF[4] = { 6, 12, 32 }; // Polynomial material balance parameters - const Value RedundantQueen = Value(320); - const Value RedundantRook = Value(554); // pair pawn knight bishop rook queen - const int LinearCoefficients[6] = { 1817, -162, -1122, -190, 105, 26 }; + const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -52 }; const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = { // pair pawn knight bishop rook queen - { 7 }, // Bishop pair + { 0 }, // Bishop pair { 39, 2 }, // Pawn { 35, 271, -4 }, // Knight - { 7, 105, 4, 7 }, // Bishop - { -27, -2, 46, 100, 56 }, // Rook - { 58, 29, 83, 148, -3, -25 } // Queen + { 0, 105, 4, 0 }, // Bishop + { -27, -2, 46, 100, -141 }, // Rook + { 58, 29, 83, 148, -163, 0 } // Queen }; const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = { // THEIR PIECES // pair pawn knight bishop rook queen - { 41 }, // Bishop pair - { 37, 41 }, // Pawn - { 10, 62, 41 }, // Knight OUR PIECES - { 57, 64, 39, 41 }, // Bishop - { 50, 40, 23, -22, 41 }, // Rook - { 106, 101, 3, 151, 171, 41 } // Queen + { 0 }, // Bishop pair + { 37, 0 }, // Pawn + { 10, 62, 0 }, // Knight OUR PIECES + { 57, 64, 39, 0 }, // Bishop + { 50, 40, 23, -22, 0 }, // Rook + { 106, 101, 3, 151, 171, 0 } // Queen }; - // Endgame evaluation and scaling functions accessed direcly and not through - // the function maps because correspond to more then one material hash key. + // 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 EvaluateKmmKm[] = { Endgame(WHITE), Endgame(BLACK) }; Endgame EvaluateKXK[] = { Endgame(WHITE), Endgame(BLACK) }; @@ -95,7 +93,7 @@ namespace { && pos.count(Them) >= 1; } - /// imbalance() calculates imbalance comparing piece count of each + /// imbalance() calculates the imbalance by comparing the piece count of each /// piece type for both colors. template @@ -106,12 +104,6 @@ namespace { int pt1, pt2, pc, v; int value = 0; - // Redundancy of major pieces, formula based on Kaufman's paper - // "The Evaluation of Material Imbalances in Chess" - if (pieceCount[Us][ROOK] > 0) - value -= RedundantRook * (pieceCount[Us][ROOK] - 1) - + RedundantQueen * pieceCount[Us][QUEEN]; - // Second-degree polynomial material imbalance by Tord Romstad for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1) { @@ -155,9 +147,9 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { e->factor[WHITE] = e->factor[BLACK] = (uint8_t)SCALE_FACTOR_NORMAL; e->gamePhase = game_phase(pos); - // 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. + // 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)) return e; @@ -202,7 +194,7 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { } // Generic scaling functions that refer to more then one material - // distribution. Should be probed after the specialized ones. + // 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]; @@ -254,6 +246,16 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { (npm_w == npm_b || npm_b < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count(BLACK), 2)]); } + 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) { @@ -264,7 +266,7 @@ Entry* probe(const Position& pos, Table& entries, Endgames& endgames) { } // Evaluate the material imbalance. We use PIECE_TYPE_NONE as a place holder - // for the bishop pair "extended piece", this allow us to be more flexible + // 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),