/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2009 Marco Costalba
+ Copyright (C) 2008-2010 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
using namespace std;
+
////
//// Local definitions
////
namespace {
// Values modified by Joona Kiiski
- const Value BishopPairMidgameBonus = Value(109);
- const Value BishopPairEndgameBonus = Value(97);
+ const Value MidgameLimit = Value(15581);
+ const Value EndgameLimit = Value(3998);
// 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 LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 };
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 } };
+ { 7, 7, 7, 7, 7, 7 }, { 39, 2, 7, 7, 7, 7 }, { 35, 271, -4, 7, 7, 7 },
+ { 7, 25, 4, 7, 7, 7 }, { -27, -2, 46, 100, 56, 7 }, { 58, 29, 83, 148, -3, -25 } };
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 } };
+ { 41, 41, 41, 41, 41, 41 }, { 37, 41, 41, 41, 41, 41 }, { 10, 62, 41, 41, 41, 41 },
+ { 57, 64, 39, 41, 41, 41 }, { 50, 40, 23, -22, 41, 41 }, { 106, 101, 3, 151, 171, 41 } };
- // Unmapped endgame evaluation and scaling functions, these
+ // Named 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<KBPsK> ScaleKBPsK(WHITE), ScaleKKBPs(BLACK);
+ ScalingFunction<KQKRPs> ScaleKQKRPs(WHITE), ScaleKRPsKQ(BLACK);
ScalingFunction<KPsK> ScaleKPsK(WHITE), ScaleKKPs(BLACK);
ScalingFunction<KPKP> ScaleKPKPw(WHITE), ScaleKPKPb(BLACK);
- Key KNNKMaterialKey, KKNNMaterialKey;
+ typedef EndgameEvaluationFunctionBase EF;
+ typedef EndgameScalingFunctionBase SF;
}
//// 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.
+/// EndgameFunctions class stores endgame evaluation and scaling functions
+/// in two std::map. Because STL library is not guaranteed to be thread
+/// safe even for read access, the maps, although with identical content,
+/// are replicated for each thread. This is faster then using locks.
class EndgameFunctions {
public:
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
+ // Here we store two maps, for evaluate and scaling functions
pair<map<Key, EF*>, map<Key, SF*> > maps;
- // Maps accessing functions for const and non-const references
+ // Maps accessing functions returning 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; }
};
//// Functions
////
-
-/// Constructor for the MaterialInfoTable class
+/// MaterialInfoTable c'tor and d'tor, called once by each thread
MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) {
size = numOfEntries;
entries = new MaterialInfo[size];
funcs = new EndgameFunctions();
+
if (!entries || !funcs)
{
- cerr << "Failed to allocate " << (numOfEntries * sizeof(MaterialInfo))
+ cerr << "Failed to allocate " << numOfEntries * sizeof(MaterialInfo)
<< " bytes for material hash table." << endl;
Application::exit_with_failure();
}
}
-
-/// Destructor for the MaterialInfoTable class
-
MaterialInfoTable::~MaterialInfoTable() {
delete funcs;
}
+/// MaterialInfoTable::game_phase() calculates the phase given the current
+/// position. Because the phase is strictly a function of the material, it
+/// is stored in MaterialInfo.
+
+Phase MaterialInfoTable::game_phase(const Position& pos) {
+
+ Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK);
+
+ if (npm >= MidgameLimit)
+ return PHASE_MIDGAME;
+ else if (npm <= EndgameLimit)
+ return PHASE_ENDGAME;
+
+ return Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit));
+}
+
/// MaterialInfoTable::get_material_info() takes a position object as input,
/// computes or looks up a MaterialInfo object, and returns a pointer to it.
/// If the material configuration is not already present in the table, it
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;
- }
+ // Store game phase
+ mi->gamePhase = MaterialInfoTable::game_phase(pos);
// Let's look if we have a specialized evaluation function for this
// particular material configuration. First we look for a fixed
mi->evaluationFunction = &EvaluateKKX;
return mi;
}
- else if ( pos.pawns() == EmptyBoardBB
- && pos.rooks() == EmptyBoardBB
- && pos.queens() == EmptyBoardBB)
+ else if ( pos.pieces(PAWN) == EmptyBoardBB
+ && pos.pieces(ROOK) == EmptyBoardBB
+ && pos.pieces(QUEEN) == 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));
+ // 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(KNIGHT, WHITE) | pos.pieces(BISHOP, WHITE)));
+ assert((pos.pieces(KNIGHT, BLACK) | pos.pieces(BISHOP, BLACK)));
if ( pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2
&& pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2)
return mi;
}
+ // Generic scaling functions that refer to more then one material
+ // distribution. Should be probed after the specialized ones.
+ // Note that these ones don't return after setting the function.
if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
&& pos.piece_count(WHITE, BISHOP) == 1
&& pos.piece_count(WHITE, PAWN) >= 1)
- mi->scalingFunction[WHITE] = &ScaleKBPK;
+ mi->scalingFunction[WHITE] = &ScaleKBPsK;
if ( pos.non_pawn_material(BLACK) == BishopValueMidgame
&& pos.piece_count(BLACK, BISHOP) == 1
&& pos.piece_count(BLACK, PAWN) >= 1)
- mi->scalingFunction[BLACK] = &ScaleKKBP;
+ mi->scalingFunction[BLACK] = &ScaleKKBPs;
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;
+ mi->scalingFunction[WHITE] = &ScaleKQKRPs;
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;
+ mi->scalingFunction[BLACK] = &ScaleKRPsKQ;
if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0))
{
}
else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1)
{
+ // This is a special case because we set scaling functions
+ // for both colors instead of only one.
mi->scalingFunction[WHITE] = &ScaleKPKPw;
mi->scalingFunction[BLACK] = &ScaleKPKPb;
}
}
// Evaluate the material balance
-
- const int bishopsPair_count[2] = { pos.piece_count(WHITE, BISHOP) > 1, pos.piece_count(BLACK, BISHOP) > 1 };
+ 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;
- int matValue = 0;
+ int sign, pt1, pt2, pc;
+ int v, vv, matValue = 0;
for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign)
{
{
if ( pos.non_pawn_material(c) == pos.non_pawn_material(opposite_color(c))
|| pos.non_pawn_material(c) < RookValueMidgame)
- mi->factor[c] = 0;
+ mi->factor[c] = SCALE_FACTOR_ZERO;
else
{
switch (pos.piece_count(c, BISHOP)) {
// 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 (pos.piece_count(c, ROOK) >= 1)
- matValue -= sign * ((pos.piece_count(c, ROOK) - 1) * RedundantRookPenalty + pos.piece_count(c, QUEEN) * RedundantQueenPenalty);
+ if (pieceCount[c][ROOK] >= 1)
+ matValue -= sign * ((pieceCount[c][ROOK] - 1) * RedundantRookPenalty + pieceCount[c][QUEEN] * RedundantQueenPenalty);
+
+ them = opposite_color(c);
+ v = 0;
// 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++)
+ for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++)
{
- int c1, c2, c3;
- c1 = sign * (pt1 != NO_PIECE_TYPE ? pos.piece_count(c, pt1) : bishopsPair_count[c]);
- if (!c1)
+ pc = pieceCount[c][pt1];
+ if (!pc)
continue;
- matValue += c1 * LinearCoefficients[pt1];
+ vv = 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];
- }
+ for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)
+ vv += pieceCount[c][pt2] * QuadraticCoefficientsSameColor[pt1][pt2]
+ + pieceCount[them][pt2] * QuadraticCoefficientsOppositeColor[pt1][pt2];
+
+ v += pc * vv;
}
+ matValue += 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 member definitions.
EndgameFunctions::EndgameFunctions() {
- KNNKMaterialKey = buildKey("KNNK");
- KKNNMaterialKey = buildKey("KKNN");
-
+ add<EvaluationFunction<KNNK> >("KNNK");
add<EvaluationFunction<KPK> >("KPK");
add<EvaluationFunction<KBNK> >("KBNK");
add<EvaluationFunction<KRKP> >("KRKP");
add<ScalingFunction<KBPPKB> >("KBPPKB");
add<ScalingFunction<KBPKN> >("KBPKN");
add<ScalingFunction<KRPPKRP> >("KRPPKRP");
- add<ScalingFunction<KRPPKRP> >("KRPPKRP");
}
EndgameFunctions::~EndgameFunctions() {
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.
+ // Build up a fen string 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')
projects / stockfish / blobdiff