/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008 Marco Costalba
+ Copyright (C) 2008-2009 Marco Costalba
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
////
#include <cassert>
+#include <sstream>
+#include <map>
#include "material.h"
+using namespace std;
////
//// Local definitions
namespace {
- const Value BishopPairMidgameBonus = Value(100);
- const Value BishopPairEndgameBonus = Value(100);
-
- Key KPKMaterialKey, KKPMaterialKey;
- Key KBNKMaterialKey, KKBNMaterialKey;
- Key KRKPMaterialKey, KPKRMaterialKey;
- Key KRKBMaterialKey, KBKRMaterialKey;
- Key KRKNMaterialKey, KNKRMaterialKey;
- Key KQKRMaterialKey, KRKQMaterialKey;
- Key KRPKRMaterialKey, KRKRPMaterialKey;
- Key KRPPKRPMaterialKey, KRPKRPPMaterialKey;
- Key KNNKMaterialKey, KKNNMaterialKey;
- Key KBPKBMaterialKey, KBKBPMaterialKey;
- Key KBPKNMaterialKey, KNKBPMaterialKey;
- Key KNPKMaterialKey, KKNPMaterialKey;
- Key KPKPMaterialKey;
-
+ // Values modified by Joona Kiiski
+ const Value BishopPairMidgameBonus = Value(109);
+ const Value BishopPairEndgameBonus = Value(97);
+
+ // 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<KmmKm> EvaluateKmmKm(WHITE);
+ EvaluationFunction<KXK> EvaluateKXK(WHITE), EvaluateKKX(BLACK);
+ ScalingFunction<KBPK> ScaleKBPK(WHITE), ScaleKKBP(BLACK);
+ ScalingFunction<KQKRP> ScaleKQKRP(WHITE), ScaleKRPKQ(BLACK);
+ ScalingFunction<KPsK> ScaleKPsK(WHITE), ScaleKKPs(BLACK);
+ ScalingFunction<KPKP> 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 <map> in the header file.
+
+class EndgameFunctions {
+public:
+ EndgameFunctions();
+ ~EndgameFunctions();
+ template<class T> T* get(Key key) const;
+
+private:
+ template<class T> void add(const string& keyCode);
+
+ static Key buildKey(const string& keyCode);
+ static const string swapColors(const string& keyCode);
+
+ // Here we store two maps, one for evaluate and one for scaling
+ pair<map<Key, EF*>, map<Key, SF*> > maps;
+
+ // Maps accessing functions for const and non-const references
+ template<typename T> const map<Key, T*>& get() const { return maps.first; }
+ template<typename T> map<Key, T*>& 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<Key, SF*>&
+EndgameFunctions::get<SF>() const { return maps.second; }
+
+template<> map<Key, SF*>&
+EndgameFunctions::get<SF>() { return maps.second; }
+
+
////
//// Functions
////
-/// MaterialInfo::init() is called during program initialization. It
-/// precomputes material hash keys for a few basic endgames, in order
-/// to make it easy to recognize such endgames when they occur.
-
-void MaterialInfo::init() {
- KPKMaterialKey = Position::zobMaterial[WHITE][PAWN][1];
- KKPMaterialKey = Position::zobMaterial[BLACK][PAWN][1];
- KBNKMaterialKey =
- Position::zobMaterial[WHITE][BISHOP][1] ^
- Position::zobMaterial[WHITE][KNIGHT][1];
- KKBNMaterialKey =
- Position::zobMaterial[BLACK][BISHOP][1] ^
- Position::zobMaterial[BLACK][KNIGHT][1];
- KRKPMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[BLACK][PAWN][1];
- KPKRMaterialKey =
- Position::zobMaterial[WHITE][PAWN][1] ^
- Position::zobMaterial[BLACK][ROOK][1];
- KRKBMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[BLACK][BISHOP][1];
- KBKRMaterialKey =
- Position::zobMaterial[WHITE][BISHOP][1] ^
- Position::zobMaterial[BLACK][ROOK][1];
- KRKNMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[BLACK][KNIGHT][1];
- KNKRMaterialKey =
- Position::zobMaterial[WHITE][KNIGHT][1] ^
- Position::zobMaterial[BLACK][ROOK][1];
- KQKRMaterialKey =
- Position::zobMaterial[WHITE][QUEEN][1] ^
- Position::zobMaterial[BLACK][ROOK][1];
- KRKQMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[BLACK][QUEEN][1];
- KRPKRMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[WHITE][PAWN][1] ^
- Position::zobMaterial[BLACK][ROOK][1];
- KRKRPMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[BLACK][ROOK][1] ^
- Position::zobMaterial[BLACK][PAWN][1];
- KRPPKRPMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[WHITE][PAWN][1] ^
- Position::zobMaterial[WHITE][PAWN][2] ^
- Position::zobMaterial[BLACK][ROOK][1] ^
- Position::zobMaterial[BLACK][PAWN][1];
- KRPKRPPMaterialKey =
- Position::zobMaterial[WHITE][ROOK][1] ^
- Position::zobMaterial[WHITE][PAWN][1] ^
- Position::zobMaterial[BLACK][ROOK][1] ^
- Position::zobMaterial[BLACK][PAWN][1] ^
- Position::zobMaterial[BLACK][PAWN][2];
- KNNKMaterialKey =
- Position::zobMaterial[WHITE][KNIGHT][1] ^
- Position::zobMaterial[WHITE][KNIGHT][2];
- KKNNMaterialKey =
- Position::zobMaterial[BLACK][KNIGHT][1] ^
- Position::zobMaterial[BLACK][KNIGHT][2];
- KBPKBMaterialKey =
- Position::zobMaterial[WHITE][BISHOP][1] ^
- Position::zobMaterial[WHITE][PAWN][1] ^
- Position::zobMaterial[BLACK][BISHOP][1];
- KBKBPMaterialKey =
- Position::zobMaterial[WHITE][BISHOP][1] ^
- Position::zobMaterial[BLACK][BISHOP][1] ^
- Position::zobMaterial[BLACK][PAWN][1];
- KBPKNMaterialKey =
- Position::zobMaterial[WHITE][BISHOP][1] ^
- Position::zobMaterial[WHITE][PAWN][1] ^
- Position::zobMaterial[BLACK][KNIGHT][1];
- KNKBPMaterialKey =
- Position::zobMaterial[WHITE][KNIGHT][1] ^
- Position::zobMaterial[BLACK][BISHOP][1] ^
- Position::zobMaterial[BLACK][PAWN][1];
- KNPKMaterialKey =
- Position::zobMaterial[WHITE][KNIGHT][1] ^
- Position::zobMaterial[WHITE][PAWN][1];
- KKNPMaterialKey =
- Position::zobMaterial[BLACK][KNIGHT][1] ^
- Position::zobMaterial[BLACK][PAWN][1];
- KPKPMaterialKey =
- Position::zobMaterial[WHITE][PAWN][1] ^
- Position::zobMaterial[BLACK][PAWN][1];
-}
+/// Constructor for the MaterialInfoTable class
-/// Constructor for the MaterialInfoTable class.
+MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) {
-MaterialInfoTable::MaterialInfoTable(unsigned numOfEntries) {
size = numOfEntries;
entries = new MaterialInfo[size];
- if(entries == NULL) {
- std::cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo))
- << " bytes for material hash table." << std::endl;
- exit(EXIT_FAILURE);
+ funcs = new EndgameFunctions();
+ if (!entries || !funcs)
+ {
+ cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo))
+ << " bytes for material hash table." << endl;
+ Application::exit_with_failure();
}
- this->clear();
}
-/// Destructor for the MaterialInfoTable class.
+/// Destructor for the MaterialInfoTable class
MaterialInfoTable::~MaterialInfoTable() {
- delete [] entries;
-}
-
-/// MaterialInfoTable::clear() clears a material hash table by setting
-/// all entries to 0.
-
-void MaterialInfoTable::clear() {
- memset(entries, 0, size * sizeof(MaterialInfo));
+ delete funcs;
+ delete [] entries;
}
/// is stored there, so we don't have to recompute everything when the
/// same material configuration occurs again.
-MaterialInfo *MaterialInfoTable::get_material_info(const Position &pos) {
+MaterialInfo* MaterialInfoTable::get_material_info(const Position& pos) {
+
Key key = pos.get_material_key();
int index = key & (size - 1);
- MaterialInfo *mi = entries + index;
+ MaterialInfo* mi = entries + index;
// If mi->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(mi->key == key)
- return mi;
+ // return the information we found the last time instead of recomputing it.
+ if (mi->key == key)
+ return mi;
- // Clear the MaterialInfo object, and set its key:
+ // Clear the MaterialInfo object, and set its key
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:
- if(key == KPKMaterialKey) {
- mi->evaluationFunction = &EvaluateKPK;
- return mi;
- }
- else if(key == KKPMaterialKey) {
- mi->evaluationFunction = &EvaluateKKP;
- return mi;
- }
- else if(key == KBNKMaterialKey) {
- mi->evaluationFunction = &EvaluateKBNK;
- return mi;
- }
- else if(key == KKBNMaterialKey) {
- mi->evaluationFunction = &EvaluateKKBN;
- return mi;
- }
- else if(key == KRKPMaterialKey) {
- mi->evaluationFunction = &EvaluateKRKP;
- return mi;
- }
- else if(key == KPKRMaterialKey) {
- mi->evaluationFunction = &EvaluateKPKR;
- return mi;
- }
- else if(key == KRKBMaterialKey) {
- mi->evaluationFunction = &EvaluateKRKB;
- return mi;
- }
- else if(key == KBKRMaterialKey) {
- mi->evaluationFunction = &EvaluateKBKR;
- return mi;
+ // particular material configuration. First we look for a fixed
+ // configuration one, then a generic one if previous search failed.
+ if ((mi->evaluationFunction = funcs->get<EF>(key)) != NULL)
+ return mi;
+
+ else if ( pos.non_pawn_material(BLACK) == Value(0)
+ && pos.piece_count(BLACK, PAWN) == 0
+ && pos.non_pawn_material(WHITE) >= RookValueMidgame)
+ {
+ mi->evaluationFunction = &EvaluateKXK;
+ return mi;
}
- else if(key == KRKNMaterialKey) {
- mi->evaluationFunction = &EvaluateKRKN;
- return mi;
+ else if ( pos.non_pawn_material(WHITE) == Value(0)
+ && pos.piece_count(WHITE, PAWN) == 0
+ && pos.non_pawn_material(BLACK) >= RookValueMidgame)
+ {
+ mi->evaluationFunction = &EvaluateKKX;
+ return mi;
}
- else if(key == KNKRMaterialKey) {
- mi->evaluationFunction = &EvaluateKNKR;
- return mi;
- }
- else if(key == KQKRMaterialKey) {
- mi->evaluationFunction = &EvaluateKQKR;
- return mi;
- }
- else if(key == KRKQMaterialKey) {
- mi->evaluationFunction = &EvaluateKRKQ;
- return mi;
- }
- else if(pos.non_pawn_material(BLACK) == Value(0) &&
- pos.piece_count(BLACK, PAWN) == 0 &&
- pos.non_pawn_material(WHITE) >= RookValueEndgame) {
- 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) {
- mi->evaluationFunction = &EvaluateKKX;
- return mi;
+ else if ( pos.pawns() == EmptyBoardBB
+ && pos.rooks() == EmptyBoardBB
+ && pos.queens() == EmptyBoardBB)
+ {
+ // Minor piece endgame with at least one minor piece per side,
+ // and no pawns.
+ assert(pos.knights(WHITE) | pos.bishops(WHITE));
+ assert(pos.knights(BLACK) | pos.bishops(BLACK));
+
+ if ( pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2
+ && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2)
+ {
+ mi->evaluationFunction = &EvaluateKmmKm;
+ return mi;
+ }
}
// OK, we didn't find any special evaluation function for the current
- // material configuration. Is there a suitable scaling function?
+ // 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.
+ SF* sf;
- if(key == KRPKRMaterialKey) {
- mi->scalingFunction[WHITE] = &ScaleKRPKR;
- return mi;
- }
- if(key == KRKRPMaterialKey) {
- mi->scalingFunction[BLACK] = &ScaleKRKRP;
- return mi;
- }
- if(key == KRPPKRPMaterialKey) {
- mi->scalingFunction[WHITE] = &ScaleKRPPKRP;
- return mi;
- }
- else if(key == KRPKRPPMaterialKey) {
- mi->scalingFunction[BLACK] = &ScaleKRPKRPP;
- return mi;
- }
- if(key == KBPKBMaterialKey) {
- mi->scalingFunction[WHITE] = &ScaleKBPKB;
- return mi;
- }
- if(key == KBKBPMaterialKey) {
- mi->scalingFunction[BLACK] = &ScaleKBKBP;
- return mi;
- }
- if(key == KBPKNMaterialKey) {
- mi->scalingFunction[WHITE] = &ScaleKBPKN;
- return mi;
- }
- if(key == KNKBPMaterialKey) {
- mi->scalingFunction[BLACK] = &ScaleKNKBP;
- return mi;
- }
- if(key == KNPKMaterialKey) {
- mi->scalingFunction[WHITE] = &ScaleKNPK;
- return mi;
- }
- if(key == KKNPMaterialKey) {
- mi->scalingFunction[BLACK] = &ScaleKKNP;
- return mi;
+ if ((sf = funcs->get<SF>(key)) != NULL)
+ {
+ mi->scalingFunction[sf->color()] = sf;
+ return mi;
}
- if(pos.non_pawn_material(WHITE) == BishopValueMidgame &&
- pos.piece_count(WHITE, BISHOP) == 1 && pos.piece_count(WHITE, PAWN) >= 1)
- mi->scalingFunction[WHITE] = &ScaleKBPK;
- if(pos.non_pawn_material(BLACK) == BishopValueMidgame &&
- pos.piece_count(BLACK, BISHOP) == 1 && pos.piece_count(BLACK, PAWN) >= 1)
- mi->scalingFunction[BLACK] = &ScaleKKBP;
-
- if(pos.piece_count(WHITE, PAWN) == 0 &&
- pos.non_pawn_material(WHITE) == QueenValueMidgame &&
- pos.piece_count(WHITE, QUEEN) == 1 &&
- pos.piece_count(BLACK, ROOK) == 1 && pos.piece_count(BLACK, PAWN) >= 1)
- mi->scalingFunction[WHITE] = &ScaleKQKRP;
- else if(pos.piece_count(BLACK, PAWN) == 0 &&
- pos.non_pawn_material(BLACK) == QueenValueMidgame &&
- pos.piece_count(BLACK, QUEEN) == 1 &&
- pos.piece_count(WHITE, ROOK) == 1 && pos.piece_count(WHITE, PAWN) >= 1)
- mi->scalingFunction[BLACK] = &ScaleKRPKQ;
-
- if(pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0)) {
- if(pos.piece_count(BLACK, PAWN) == 0) {
- assert(pos.piece_count(WHITE, PAWN) >= 2);
- mi->scalingFunction[WHITE] = &ScaleKPsK;
- }
- else if(pos.piece_count(WHITE, PAWN) == 0) {
- assert(pos.piece_count(BLACK, PAWN) >= 2);
- mi->scalingFunction[BLACK] = &ScaleKKPs;
- }
- else if(pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1) {
- mi->scalingFunction[WHITE] = &ScaleKPKPw;
- mi->scalingFunction[BLACK] = &ScaleKPKPb;
- }
+ if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
+ && pos.piece_count(WHITE, BISHOP) == 1
+ && pos.piece_count(WHITE, PAWN) >= 1)
+ mi->scalingFunction[WHITE] = &ScaleKBPK;
+
+ if ( pos.non_pawn_material(BLACK) == BishopValueMidgame
+ && pos.piece_count(BLACK, BISHOP) == 1
+ && pos.piece_count(BLACK, PAWN) >= 1)
+ mi->scalingFunction[BLACK] = &ScaleKKBP;
+
+ if ( pos.piece_count(WHITE, PAWN) == 0
+ && pos.non_pawn_material(WHITE) == QueenValueMidgame
+ && pos.piece_count(WHITE, QUEEN) == 1
+ && pos.piece_count(BLACK, ROOK) == 1
+ && pos.piece_count(BLACK, PAWN) >= 1)
+ mi->scalingFunction[WHITE] = &ScaleKQKRP;
+
+ else if ( pos.piece_count(BLACK, PAWN) == 0
+ && pos.non_pawn_material(BLACK) == QueenValueMidgame
+ && pos.piece_count(BLACK, QUEEN) == 1
+ && pos.piece_count(WHITE, ROOK) == 1
+ && pos.piece_count(WHITE, PAWN) >= 1)
+ mi->scalingFunction[BLACK] = &ScaleKRPKQ;
+
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0))
+ {
+ if (pos.piece_count(BLACK, PAWN) == 0)
+ {
+ assert(pos.piece_count(WHITE, PAWN) >= 2);
+ mi->scalingFunction[WHITE] = &ScaleKPsK;
+ }
+ else if (pos.piece_count(WHITE, PAWN) == 0)
+ {
+ assert(pos.piece_count(BLACK, PAWN) >= 2);
+ mi->scalingFunction[BLACK] = &ScaleKKPs;
+ }
+ else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1)
+ {
+ mi->scalingFunction[WHITE] = &ScaleKPKPw;
+ mi->scalingFunction[BLACK] = &ScaleKPKPb;
+ }
}
- // Evaluate the material balance.
+ // Compute the space weight
+ if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >=
+ 2*QueenValueMidgame + 4*RookValueMidgame + 2*KnightValueMidgame)
+ {
+ int minorPieceCount = pos.piece_count(WHITE, KNIGHT)
+ + pos.piece_count(BLACK, KNIGHT)
+ + pos.piece_count(WHITE, BISHOP)
+ + pos.piece_count(BLACK, BISHOP);
- Color c;
+ mi->spaceWeight = minorPieceCount * minorPieceCount;
+ }
+
+ // Evaluate the material balance
+ const int pieceCount[2][6] = { { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(WHITE, PAWN), pos.piece_count(WHITE, KNIGHT),
+ pos.piece_count(WHITE, BISHOP), pos.piece_count(WHITE, ROOK), pos.piece_count(WHITE, QUEEN) },
+ { pos.piece_count(BLACK, BISHOP) > 1, pos.piece_count(BLACK, PAWN), pos.piece_count(BLACK, KNIGHT),
+ pos.piece_count(BLACK, BISHOP), pos.piece_count(BLACK, ROOK), pos.piece_count(BLACK, QUEEN) } };
+ Color c, them;
int sign;
- Value egValue = Value(0), mgValue = Value(0);
-
- for(c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign) {
-
- // No pawns makes it difficult to win, even with a material advantage:
- if(pos.piece_count(c, PAWN) == 0 &&
- pos.non_pawn_material(c) - pos.non_pawn_material(opposite_color(c))
- <= BishopValueMidgame) {
- if(pos.non_pawn_material(c) == pos.non_pawn_material(opposite_color(c)))
- mi->factor[c] = 0;
- else if(pos.non_pawn_material(c) < RookValueMidgame)
- mi->factor[c] = 0;
- else {
- switch(pos.piece_count(c, BISHOP)) {
- case 2:
- mi->factor[c] = 32; break;
- case 1:
- mi->factor[c] = 12; break;
- case 0:
- mi->factor[c] = 6; break;
+ int matValue = 0;
+
+ for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign)
+ {
+ // No pawns makes it difficult to win, even with a material advantage
+ if ( pos.piece_count(c, PAWN) == 0
+ && pos.non_pawn_material(c) - pos.non_pawn_material(opposite_color(c)) <= BishopValueMidgame)
+ {
+ if ( pos.non_pawn_material(c) == pos.non_pawn_material(opposite_color(c))
+ || pos.non_pawn_material(c) < RookValueMidgame)
+ mi->factor[c] = 0;
+ else
+ {
+ switch (pos.piece_count(c, BISHOP)) {
+ case 2:
+ mi->factor[c] = 32;
+ break;
+ case 1:
+ mi->factor[c] = 12;
+ break;
+ case 0:
+ mi->factor[c] = 6;
+ break;
+ }
}
- }
}
- // Bishop pair:
- if(pos.piece_count(c, BISHOP) >= 2) {
- mgValue += sign * BishopPairMidgameBonus;
- egValue += sign * BishopPairEndgameBonus;
+ // 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
+ if (pieceCount[c][ROOK] >= 1)
+ matValue -= sign * ((pieceCount[c][ROOK] - 1) * RedundantRookPenalty + pieceCount[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 (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++)
+ {
+ int c1 = sign * pieceCount[c][pt1];
+ if (!c1)
+ continue;
+
+ matValue += c1 * LinearCoefficients[pt1];
+
+ for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)
+ {
+ matValue += c1 * pieceCount[c][pt2] * QuadraticCoefficientsSameColor[pt1][pt2];
+ matValue += c1 * pieceCount[them][pt2] * QuadraticCoefficientsOppositeColor[pt1][pt2];
+ }
}
+ }
- // 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":
- // 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) {
- Value v = Value((pos.piece_count(c, ROOK) - 1) * 32 + pos.piece_count(c, QUEEN) * 16);
- mgValue -= sign * v;
- egValue -= sign * v;
+ mi->value = int16_t(matValue / 16);
+ return mi;
+}
+
+
+/// 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 needed
+/// because std::map is not guaranteed to be thread-safe even if accessed
+/// only for a lookup.
+
+EndgameFunctions::EndgameFunctions() {
+
+ add<EvaluationFunction<KNNK> >("KNNK");
+ add<EvaluationFunction<KPK> >("KPK");
+ add<EvaluationFunction<KBNK> >("KBNK");
+ add<EvaluationFunction<KRKP> >("KRKP");
+ add<EvaluationFunction<KRKB> >("KRKB");
+ add<EvaluationFunction<KRKN> >("KRKN");
+ add<EvaluationFunction<KQKR> >("KQKR");
+ add<EvaluationFunction<KBBKN> >("KBBKN");
+
+ add<ScalingFunction<KNPK> >("KNPK");
+ add<ScalingFunction<KRPKR> >("KRPKR");
+ add<ScalingFunction<KBPKB> >("KBPKB");
+ add<ScalingFunction<KBPPKB> >("KBPPKB");
+ add<ScalingFunction<KBPKN> >("KBPKN");
+ add<ScalingFunction<KRPPKRP> >("KRPPKRP");
+ add<ScalingFunction<KRPPKRP> >("KRPPKRP");
+}
+
+EndgameFunctions::~EndgameFunctions() {
+
+ for (map<Key, EF*>::iterator it = maps.first.begin(); it != maps.first.end(); ++it)
+ delete (*it).second;
+
+ for (map<Key, SF*>::iterator it = maps.second.begin(); it != maps.second.end(); ++it)
+ delete (*it).second;
+}
+
+Key EndgameFunctions::buildKey(const string& keyCode) {
+
+ assert(keyCode.length() > 0 && keyCode[0] == 'K');
+ assert(keyCode.length() < 8);
+
+ stringstream s;
+ bool upcase = false;
+
+ // Build up a fen substring with the given pieces, note
+ // that the fen string could be of an illegal position.
+ for (size_t i = 0; i < keyCode.length(); i++)
+ {
+ if (keyCode[i] == 'K')
+ upcase = !upcase;
+
+ s << char(upcase? toupper(keyCode[i]) : tolower(keyCode[i]));
}
+ s << 8 - keyCode.length() << "/8/8/8/8/8/8/8 w -";
+ return Position(s.str()).get_material_key();
+}
- }
+const string EndgameFunctions::swapColors(const string& keyCode) {
- mi->mgValue = int16_t(mgValue);
- mi->egValue = int16_t(egValue);
+ // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP"
+ size_t idx = keyCode.find("K", 1);
+ return keyCode.substr(idx) + keyCode.substr(0, idx);
+}
- return mi;
+template<class T>
+void EndgameFunctions::add(const string& keyCode) {
+
+ typedef typename T::Base F;
+
+ get<F>().insert(pair<Key, F*>(buildKey(keyCode), new T(WHITE)));
+ get<F>().insert(pair<Key, F*>(buildKey(swapColors(keyCode)), new T(BLACK)));
+}
+
+template<class T>
+T* EndgameFunctions::get(Key key) const {
+
+ typename map<Key, T*>::const_iterator it(get<T>().find(key));
+ return (it != get<T>().end() ? it->second : NULL);
}
projects / stockfish / blobdiff