X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmaterial.cpp;h=a8ecb51a5a3377a6a7153951e4e13c53e89c528a;hp=f3d22776f78e5d8f2740a20f567008d7ab8ab5ed;hb=aa925a0e2905042a978860a75798398cb79b2600;hpb=6d117e4a23dd1a3a22d5553b4ac15d9d15f0aafe diff --git a/src/material.cpp b/src/material.cpp index f3d22776..a8ecb51a 100644 --- a/src/material.cpp +++ b/src/material.cpp @@ -28,7 +28,7 @@ #include "material.h" -using std::string; +using namespace std; //// //// Local definitions @@ -40,40 +40,68 @@ namespace { const Value BishopPairMidgameBonus = Value(109); const Value BishopPairEndgameBonus = Value(97); - Key KNNKMaterialKey, KKNNMaterialKey; - + // Polynomial material balance parameters + const Value RedundantQueenPenalty = Value(320); + const Value RedundantRookPenalty = Value(554); + const int LinearCoefficients[6] = { 1709, -137, -1185, -166, 141, 59 }; + + const int QuadraticCoefficientsSameColor[][6] = { + { 0, 0, 0, 0, 0, 0 }, { 33, -6, 0, 0, 0, 0 }, { 29, 269, -12, 0, 0, 0 }, + { 0, 19, -4, 0, 0, 0 }, { -35, -10, 40, 95, 50, 0 }, { 52, 23, 78, 144, -11, -33 } }; + + const int QuadraticCoefficientsOppositeColor[][6] = { + { 0, 0, 0, 0, 0, 0 }, { -5, 0, 0, 0, 0, 0 }, { -33, 23, 0, 0, 0, 0 }, + { 17, 25, -3, 0, 0, 0 }, { 10, -2, -19, -67, 0, 0 }, { 69, 64, -41, 116, 137, 0 } }; + + // Unmapped endgame evaluation and scaling functions, these + // are accessed direcly and not through the function maps. + EvaluationFunction EvaluateKmmKm(WHITE); + EvaluationFunction EvaluateKXK(WHITE), EvaluateKKX(BLACK); + ScalingFunction ScaleKBPK(WHITE), ScaleKKBP(BLACK); + ScalingFunction ScaleKQKRP(WHITE), ScaleKRPKQ(BLACK); + ScalingFunction ScaleKPsK(WHITE), ScaleKKPs(BLACK); + ScalingFunction ScaleKPKPw(WHITE), ScaleKPKPb(BLACK); } + //// //// Classes //// +typedef EndgameEvaluationFunctionBase EF; +typedef EndgameScalingFunctionBase SF; /// See header for a class description. It is declared here to avoid /// to include in the header file. class EndgameFunctions { - public: EndgameFunctions(); - EndgameEvaluationFunctionBase* getEEF(Key key) const; - EndgameScalingFunctionBase* getESF(Key key, Color* c) const; + ~EndgameFunctions(); + template T* get(Key key) const; private: - void add(const string& keyCode, EndgameEvaluationFunctionBase* f); - void add(const string& keyCode, Color c, EndgameScalingFunctionBase* f); - Key buildKey(const string& keyCode); + template void add(const string& keyCode); - struct ScalingInfo - { - Color col; - EndgameScalingFunctionBase* fun; - }; + static Key buildKey(const string& keyCode); + static const string swapColors(const string& keyCode); - std::map EEFmap; - std::map ESFmap; + // Here we store two maps, one for evaluate and one for scaling + pair, map > maps; + + // Maps accessing functions for const and non-const references + template const map& get() const { return maps.first; } + template map& get() { return maps.first; } }; +// Explicit specializations of a member function shall be declared in +// the namespace of which the class template is a member. +template<> const map& +EndgameFunctions::get() const { return maps.second; } + +template<> map& +EndgameFunctions::get() { return maps.second; } + //// //// Functions @@ -89,8 +117,8 @@ MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) { funcs = new EndgameFunctions(); if (!entries || !funcs) { - std::cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) - << " bytes for material hash table." << std::endl; + cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo)) + << " bytes for material hash table." << endl; Application::exit_with_failure(); } } @@ -127,30 +155,22 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { mi->clear(); mi->key = key; - // A special case before looking for a specialized evaluation function - // KNN vs K is a draw. - if (key == KNNKMaterialKey || key == KKNNMaterialKey) - { - mi->factor[WHITE] = mi->factor[BLACK] = 0; - return mi; - } - // 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->getEEF(key)) != NULL) + if ((mi->evaluationFunction = funcs->get(key)) != NULL) return mi; else if ( pos.non_pawn_material(BLACK) == Value(0) && pos.piece_count(BLACK, PAWN) == 0 - && pos.non_pawn_material(WHITE) >= RookValueEndgame) + && pos.non_pawn_material(WHITE) >= RookValueMidgame) { mi->evaluationFunction = &EvaluateKXK; return mi; } else if ( pos.non_pawn_material(WHITE) == Value(0) && pos.piece_count(WHITE, PAWN) == 0 - && pos.non_pawn_material(BLACK) >= RookValueEndgame) + && pos.non_pawn_material(BLACK) >= RookValueMidgame) { mi->evaluationFunction = &EvaluateKKX; return mi; @@ -176,15 +196,14 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { // material configuration. Is there a suitable scaling function? // // The code below is rather messy, and it could easily get worse later, - // if we decide to add more special cases. We face problems when there + // if we decide to add more special cases. We face problems when there // are several conflicting applicable scaling functions and we need to // decide which one to use. - Color c; - EndgameScalingFunctionBase* sf; + SF* sf; - if ((sf = funcs->getESF(key, &c)) != NULL) + if ((sf = funcs->get(key)) != NULL) { - mi->scalingFunction[c] = sf; + mi->scalingFunction[sf->color()] = sf; return mi; } @@ -245,9 +264,10 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { // Evaluate the material balance + const int bishopsPair_count[2] = { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(BLACK, BISHOP) > 1 }; + Color c, them; int sign; - Value egValue = Value(0); - Value mgValue = Value(0); + int matValue = 0; for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) { @@ -274,30 +294,37 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { } } - // Bishop pair - if (pos.piece_count(c, BISHOP) >= 2) - { - mgValue += sign * BishopPairMidgameBonus; - egValue += sign * BishopPairEndgameBonus; - } - - // Knights are stronger when there are many pawns on the board. The - // formula is taken from Larry Kaufman's paper "The Evaluation of Material - // Imbalances in Chess": + // 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 - mgValue += sign * Value(pos.piece_count(c, KNIGHT)*(pos.piece_count(c, PAWN)-5)*16); - egValue += sign * Value(pos.piece_count(c, KNIGHT)*(pos.piece_count(c, PAWN)-5)*16); - - // Redundancy of major pieces, again based on Kaufman's paper: if (pos.piece_count(c, ROOK) >= 1) + matValue -= sign * ((pos.piece_count(c, ROOK) - 1) * RedundantRookPenalty + pos.piece_count(c, QUEEN) * RedundantQueenPenalty); + + // 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. + them = opposite_color(c); + for (PieceType pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++) { - Value v = Value((pos.piece_count(c, ROOK) - 1) * 32 + pos.piece_count(c, QUEEN) * 16); - mgValue -= sign * v; - egValue -= sign * v; + int c1, c2, c3; + c1 = sign * (pt1 != NO_PIECE_TYPE ? pos.piece_count(c, pt1) : bishopsPair_count[c]); + if (!c1) + continue; + + matValue += c1 * LinearCoefficients[pt1]; + + for (PieceType pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++) + { + c2 = (pt2 != NO_PIECE_TYPE ? pos.piece_count(c, pt2) : bishopsPair_count[c]); + c3 = (pt2 != NO_PIECE_TYPE ? pos.piece_count(them, pt2) : bishopsPair_count[them]); + matValue += c1 * c2 * QuadraticCoefficientsSameColor[pt1][pt2]; + matValue += c1 * c3 * QuadraticCoefficientsOppositeColor[pt1][pt2]; + } } } - mi->mgValue = int16_t(mgValue); - mi->egValue = int16_t(egValue); + + mi->value = int16_t(matValue / 16); return mi; } @@ -305,42 +332,37 @@ MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) { /// EndgameFunctions member definitions. This class is used to store the maps /// of end game and scaling functions that MaterialInfoTable will query for /// each key. The maps are constant and are populated only at construction, -/// but are per-thread instead of globals to avoid expensive locks. +/// but are per-thread instead of globals to avoid expensive locks needed +/// because std::map is not guaranteed to be thread-safe even if accessed +/// only for a lookup. EndgameFunctions::EndgameFunctions() { - KNNKMaterialKey = buildKey("KNNK"); - KKNNMaterialKey = buildKey("KKNN"); - - add("KPK", &EvaluateKPK); - add("KKP", &EvaluateKKP); - add("KBNK", &EvaluateKBNK); - add("KKBN", &EvaluateKKBN); - add("KRKP", &EvaluateKRKP); - add("KPKR", &EvaluateKPKR); - add("KRKB", &EvaluateKRKB); - add("KBKR", &EvaluateKBKR); - add("KRKN", &EvaluateKRKN); - add("KNKR", &EvaluateKNKR); - add("KQKR", &EvaluateKQKR); - add("KRKQ", &EvaluateKRKQ); - add("KBBKN", &EvaluateKBBKN); - add("KNKBB", &EvaluateKNKBB); - - add("KNPK", WHITE, &ScaleKNPK); - add("KKNP", BLACK, &ScaleKKNP); - add("KRPKR", WHITE, &ScaleKRPKR); - add("KRKRP", BLACK, &ScaleKRKRP); - add("KBPKB", WHITE, &ScaleKBPKB); - add("KBKBP", BLACK, &ScaleKBKBP); - add("KBPPKB", WHITE, &ScaleKBPPKB); - add("KBKBPP", BLACK, &ScaleKBKBPP); - add("KBPKN", WHITE, &ScaleKBPKN); - add("KNKBP", BLACK, &ScaleKNKBP); - add("KRPPKRP", WHITE, &ScaleKRPPKRP); - add("KRPKRPP", BLACK, &ScaleKRPKRPP); - add("KRPPKRP", WHITE, &ScaleKRPPKRP); - add("KRPKRPP", BLACK, &ScaleKRPKRPP); + 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"); + add >("KRPPKRP"); +} + +EndgameFunctions::~EndgameFunctions() { + + for (map::iterator it = maps.first.begin(); it != maps.first.end(); ++it) + delete (*it).second; + + for (map::iterator it = maps.second.begin(); it != maps.second.end(); ++it) + delete (*it).second; } Key EndgameFunctions::buildKey(const string& keyCode) { @@ -348,7 +370,7 @@ Key EndgameFunctions::buildKey(const string& keyCode) { assert(keyCode.length() > 0 && keyCode[0] == 'K'); assert(keyCode.length() < 8); - std::stringstream s; + stringstream s; bool upcase = false; // Build up a fen substring with the given pieces, note @@ -364,29 +386,25 @@ Key EndgameFunctions::buildKey(const string& keyCode) { return Position(s.str()).get_material_key(); } -void EndgameFunctions::add(const string& keyCode, EndgameEvaluationFunctionBase* f) { +const string EndgameFunctions::swapColors(const string& keyCode) { - EEFmap.insert(std::pair(buildKey(keyCode), f)); + // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP" + size_t idx = keyCode.find("K", 1); + return keyCode.substr(idx) + keyCode.substr(0, idx); } -void EndgameFunctions::add(const string& keyCode, Color c, EndgameScalingFunctionBase* f) { +template +void EndgameFunctions::add(const string& keyCode) { - ScalingInfo s = {c, f}; - ESFmap.insert(std::pair(buildKey(keyCode), s)); -} - -EndgameEvaluationFunctionBase* EndgameFunctions::getEEF(Key key) const { + typedef typename T::Base F; - std::map::const_iterator it(EEFmap.find(key)); - return (it != EEFmap.end() ? it->second : NULL); + get().insert(pair(buildKey(keyCode), new T(WHITE))); + get().insert(pair(buildKey(swapColors(keyCode)), new T(BLACK))); } -EndgameScalingFunctionBase* EndgameFunctions::getESF(Key key, Color* c) const { - - std::map::const_iterator it(ESFmap.find(key)); - if (it == ESFmap.end()) - return NULL; +template +T* EndgameFunctions::get(Key key) const { - *c = it->second.col; - return it->second.fun; + typename map::const_iterator it(get().find(key)); + return (it != get().end() ? it->second : NULL); }