/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2013 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
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
+#include <algorithm> // For std::min
#include <cassert>
-#include <sstream>
-#include <map>
+#include <cstring>
#include "material.h"
using namespace std;
-
-////
-//// Local definitions
-////
-
namespace {
// Values modified by Joona Kiiski
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] = { 1617, -162, -1172, -190, 105, 26 };
+ // Scale factors used when one side has no more pawns
+ const int NoPawnsSF[4] = { 6, 12, 32 };
- const int QuadraticCoefficientsSameColor[][6] = {
- { 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] = {
- { 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 } };
-
- // 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<KBPsK> ScaleKBPsK(WHITE), ScaleKKBPs(BLACK);
- ScalingFunction<KQKRPs> ScaleKQKRPs(WHITE), ScaleKRPsKQ(BLACK);
- ScalingFunction<KPsK> ScaleKPsK(WHITE), ScaleKKPs(BLACK);
- ScalingFunction<KPKP> ScaleKPKPw(WHITE), ScaleKPKPb(BLACK);
-
- typedef EndgameEvaluationFunctionBase EF;
- typedef EndgameScalingFunctionBase SF;
+ // Polynomial material balance parameters
+ const Value RedundantQueen = Value(320);
+ const Value RedundantRook = Value(554);
+
+ // pair pawn knight bishop rook queen
+ const int LinearCoefficients[6] = { 1617, -162, -1172, -190, 105, 26 };
+
+ const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = {
+ // pair pawn knight bishop rook queen
+ { 7 }, // 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
+ };
+
+ 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
+ };
+
+ // Endgame evaluation and scaling functions accessed direcly and not through
+ // the function maps because correspond to more then one material hash key.
+ Endgame<KmmKm> EvaluateKmmKm[] = { Endgame<KmmKm>(WHITE), Endgame<KmmKm>(BLACK) };
+ Endgame<KXK> EvaluateKXK[] = { Endgame<KXK>(WHITE), Endgame<KXK>(BLACK) };
+
+ Endgame<KBPsK> ScaleKBPsK[] = { Endgame<KBPsK>(WHITE), Endgame<KBPsK>(BLACK) };
+ Endgame<KQKRPs> ScaleKQKRPs[] = { Endgame<KQKRPs>(WHITE), Endgame<KQKRPs>(BLACK) };
+ Endgame<KPsK> ScaleKPsK[] = { Endgame<KPsK>(WHITE), Endgame<KPsK>(BLACK) };
+ Endgame<KPKP> ScaleKPKP[] = { Endgame<KPKP>(WHITE), Endgame<KPKP>(BLACK) };
// Helper templates used to detect a given material distribution
template<Color Us> bool is_KXK(const Position& pos) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- return pos.non_pawn_material(Them) == Value(0)
- && pos.piece_count(Them, PAWN) == 0
- && pos.non_pawn_material(Us) >= RookValueMidgame;
+ return !pos.count<PAWN>(Them)
+ && pos.non_pawn_material(Them) == VALUE_ZERO
+ && pos.non_pawn_material(Us) >= RookValueMg;
}
- template<Color Us> bool is_KBPsK(const Position& pos) {
- return pos.non_pawn_material(Us) == BishopValueMidgame
- && pos.piece_count(Us, BISHOP) == 1
- && pos.piece_count(Us, PAWN) >= 1;
+ template<Color Us> bool is_KBPsKs(const Position& pos) {
+ return pos.non_pawn_material(Us) == BishopValueMg
+ && pos.count<BISHOP>(Us) == 1
+ && pos.count<PAWN >(Us) >= 1;
}
template<Color Us> bool is_KQKRPs(const Position& pos) {
const Color Them = (Us == WHITE ? BLACK : WHITE);
- return pos.piece_count(Us, PAWN) == 0
- && pos.non_pawn_material(Us) == QueenValueMidgame
- && pos.piece_count(Us, QUEEN) == 1
- && pos.piece_count(Them, ROOK) == 1
- && pos.piece_count(Them, PAWN) >= 1;
+ return !pos.count<PAWN>(Us)
+ && pos.non_pawn_material(Us) == QueenValueMg
+ && pos.count<QUEEN>(Us) == 1
+ && pos.count<ROOK>(Them) == 1
+ && pos.count<PAWN>(Them) >= 1;
}
-}
-
-////
-//// Classes
-////
+ /// imbalance() calculates imbalance comparing piece count of each
+ /// piece type for both colors.
-/// 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.
+ template<Color Us>
+ int imbalance(const int pieceCount[][PIECE_TYPE_NB]) {
-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, for evaluate and scaling functions
- pair<map<Key, EF*>, map<Key, SF*> > maps;
-
- // 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; }
-};
-
-// 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; }
+ const Color Them = (Us == WHITE ? BLACK : WHITE);
+ int pt1, pt2, pc, v;
+ int value = 0;
-////
-//// Functions
-////
+ // 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];
-/// MaterialInfoTable c'tor and d'tor, called once by each thread
+ // Second-degree polynomial material imbalance by Tord Romstad
+ for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++)
+ {
+ pc = pieceCount[Us][pt1];
+ if (!pc)
+ continue;
-MaterialInfoTable::MaterialInfoTable(unsigned int numOfEntries) {
+ v = LinearCoefficients[pt1];
- size = numOfEntries;
- entries = new MaterialInfo[size];
- funcs = new EndgameFunctions();
+ for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; pt2++)
+ v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
+ + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];
- if (!entries || !funcs)
- {
- cerr << "Failed to allocate " << numOfEntries * sizeof(MaterialInfo)
- << " bytes for material hash table." << endl;
- Application::exit_with_failure();
+ value += pc * v;
+ }
+ return value;
}
-}
-
-MaterialInfoTable::~MaterialInfoTable() {
-
- delete funcs;
- delete [] entries;
-}
+} // namespace
-/// 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.
+namespace Material {
-Phase MaterialInfoTable::game_phase(const Position& pos) {
+/// Material::probe() takes a position object as input, looks up a MaterialEntry
+/// object, and returns a pointer to it. If the material configuration is not
+/// already present in the table, it is computed and stored there, so we don't
+/// have to recompute everything when the same material configuration occurs again.
- Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK);
+Entry* probe(const Position& pos, Table& entries, Endgames& endgames) {
- if (npm >= MidgameLimit)
- return PHASE_MIDGAME;
- else if (npm <= EndgameLimit)
- return PHASE_ENDGAME;
+ Key key = pos.material_key();
+ Entry* e = entries[key];
- 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
-/// 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) {
-
- Key key = pos.get_material_key();
- int index = key & (size - 1);
- MaterialInfo* mi = entries + index;
-
- // If mi->key matches the position's material hash key, it means that we
+ // If e->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;
-
- // Clear the MaterialInfo object, and set its key
- mi->clear();
- mi->key = key;
+ if (e->key == key)
+ return e;
- // Store game phase
- mi->gamePhase = MaterialInfoTable::game_phase(pos);
+ std::memset(e, 0, sizeof(Entry));
+ e->key = key;
+ 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.
- if ((mi->evaluationFunction = funcs->get<EF>(key)) != NULL)
- return mi;
+ if (endgames.probe(key, e->evaluationFunction))
+ return e;
+
+ if (is_KXK<WHITE>(pos))
+ {
+ e->evaluationFunction = &EvaluateKXK[WHITE];
+ return e;
+ }
+
+ if (is_KXK<BLACK>(pos))
+ {
+ e->evaluationFunction = &EvaluateKXK[BLACK];
+ return e;
+ }
- else if (is_KXK<WHITE>(pos) || is_KXK<BLACK>(pos))
+ // Draw by insufficient material (trivial draws like KK, KBK and KNK)
+ if ( !pos.pieces(PAWN)
+ && pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) <= BishopValueMg)
{
- mi->evaluationFunction = is_KXK<WHITE>(pos) ? &EvaluateKXK : &EvaluateKKX;
- return mi;
+ e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()];
+ return e;
}
- 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. Note that the case KmmK is already handled by KXK.
+ if (!pos.pieces(PAWN) && !pos.pieces(ROOK) && !pos.pieces(QUEEN))
{
- // 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)));
+ assert((pos.pieces(WHITE, KNIGHT) | pos.pieces(WHITE, BISHOP)));
+ assert((pos.pieces(BLACK, KNIGHT) | pos.pieces(BLACK, BISHOP)));
- if ( pos.piece_count(WHITE, BISHOP) + pos.piece_count(WHITE, KNIGHT) <= 2
- && pos.piece_count(BLACK, BISHOP) + pos.piece_count(BLACK, KNIGHT) <= 2)
+ if ( pos.count<BISHOP>(WHITE) + pos.count<KNIGHT>(WHITE) <= 2
+ && pos.count<BISHOP>(BLACK) + pos.count<KNIGHT>(BLACK) <= 2)
{
- mi->evaluationFunction = &EvaluateKmmKm;
- return mi;
+ e->evaluationFunction = &EvaluateKmmKm[pos.side_to_move()];
+ return e;
}
}
// OK, we didn't find any special evaluation function for the current
// 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
- // are several conflicting applicable scaling functions and we need to
- // decide which one to use.
- SF* sf;
+ // We face problems when there are several conflicting applicable
+ // scaling functions and we need to decide which one to use.
+ EndgameBase<ScaleFactor>* sf;
- if ((sf = funcs->get<SF>(key)) != NULL)
+ if (endgames.probe(key, sf))
{
- mi->scalingFunction[sf->color()] = sf;
- return mi;
+ e->scalingFunction[sf->color()] = sf;
+ return e;
}
// 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 (is_KBPsK<WHITE>(pos))
- mi->scalingFunction[WHITE] = &ScaleKBPsK;
+ if (is_KBPsKs<WHITE>(pos))
+ e->scalingFunction[WHITE] = &ScaleKBPsK[WHITE];
- if (is_KBPsK<BLACK>(pos))
- mi->scalingFunction[BLACK] = &ScaleKKBPs;
+ if (is_KBPsKs<BLACK>(pos))
+ e->scalingFunction[BLACK] = &ScaleKBPsK[BLACK];
if (is_KQKRPs<WHITE>(pos))
- mi->scalingFunction[WHITE] = &ScaleKQKRPs;
+ e->scalingFunction[WHITE] = &ScaleKQKRPs[WHITE];
else if (is_KQKRPs<BLACK>(pos))
- mi->scalingFunction[BLACK] = &ScaleKRPsKQ;
+ e->scalingFunction[BLACK] = &ScaleKQKRPs[BLACK];
+
+ Value npm_w = pos.non_pawn_material(WHITE);
+ Value npm_b = pos.non_pawn_material(BLACK);
- if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == Value(0))
+ if (npm_w + npm_b == VALUE_ZERO)
{
- if (pos.piece_count(BLACK, PAWN) == 0)
+ if (!pos.count<PAWN>(BLACK))
{
- assert(pos.piece_count(WHITE, PAWN) >= 2);
- mi->scalingFunction[WHITE] = &ScaleKPsK;
+ assert(pos.count<PAWN>(WHITE) >= 2);
+ e->scalingFunction[WHITE] = &ScaleKPsK[WHITE];
}
- else if (pos.piece_count(WHITE, PAWN) == 0)
+ else if (!pos.count<PAWN>(WHITE))
{
- assert(pos.piece_count(BLACK, PAWN) >= 2);
- mi->scalingFunction[BLACK] = &ScaleKKPs;
+ assert(pos.count<PAWN>(BLACK) >= 2);
+ e->scalingFunction[BLACK] = &ScaleKPsK[BLACK];
}
- else if (pos.piece_count(WHITE, PAWN) == 1 && pos.piece_count(BLACK, PAWN) == 1)
+ else if (pos.count<PAWN>(WHITE) == 1 && pos.count<PAWN>(BLACK) == 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;
+ e->scalingFunction[WHITE] = &ScaleKPKP[WHITE];
+ e->scalingFunction[BLACK] = &ScaleKPKP[BLACK];
}
}
- // Compute the space weight
- if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) >=
- 2*QueenValueMidgame + 4*RookValueMidgame + 2*KnightValueMidgame)
+ // No pawns makes it difficult to win, even with a material advantage
+ if (!pos.count<PAWN>(WHITE) && npm_w - npm_b <= BishopValueMg)
{
- int minorPieceCount = pos.piece_count(WHITE, KNIGHT)
- + pos.piece_count(BLACK, KNIGHT)
- + pos.piece_count(WHITE, BISHOP)
- + pos.piece_count(BLACK, BISHOP);
-
- mi->spaceWeight = minorPieceCount * minorPieceCount;
+ e->factor[WHITE] = (uint8_t)
+ (npm_w == npm_b || npm_w < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count<BISHOP>(WHITE), 2)]);
}
- // 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, pt1, pt2, pc;
- int v, vv, matValue = 0;
-
- for (c = WHITE, sign = 1; c <= BLACK; c++, sign = -sign)
+ if (!pos.count<PAWN>(BLACK) && npm_b - npm_w <= BishopValueMg)
{
- // 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;
- }
- }
- }
-
- // 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);
-
- 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.
- for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; pt1++)
- {
- pc = pieceCount[c][pt1];
- if (!pc)
- continue;
-
- vv = LinearCoefficients[pt1];
-
- 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;
+ e->factor[BLACK] = (uint8_t)
+ (npm_w == npm_b || npm_b < RookValueMg ? 0 : NoPawnsSF[std::min(pos.count<BISHOP>(BLACK), 2)]);
}
- mi->value = int16_t(matValue / 16);
- return mi;
-}
-
-
-/// EndgameFunctions member definitions.
-
-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");
-}
-
-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;
+ // Compute the space weight
+ if (npm_w + npm_b >= 2 * QueenValueMg + 4 * RookValueMg + 2 * KnightValueMg)
+ {
+ int minorPieceCount = pos.count<KNIGHT>(WHITE) + pos.count<BISHOP>(WHITE)
+ + pos.count<KNIGHT>(BLACK) + pos.count<BISHOP>(BLACK);
- // 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')
- upcase = !upcase;
+ e->spaceWeight = make_score(minorPieceCount * minorPieceCount, 0);
+ }
- 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();
+ // 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
+ // in defining bishop pair bonuses.
+ const int pieceCount[COLOR_NB][PIECE_TYPE_NB] = {
+ { pos.count<BISHOP>(WHITE) > 1, pos.count<PAWN>(WHITE), pos.count<KNIGHT>(WHITE),
+ pos.count<BISHOP>(WHITE) , pos.count<ROOK>(WHITE), pos.count<QUEEN >(WHITE) },
+ { pos.count<BISHOP>(BLACK) > 1, pos.count<PAWN>(BLACK), pos.count<KNIGHT>(BLACK),
+ pos.count<BISHOP>(BLACK) , pos.count<ROOK>(BLACK), pos.count<QUEEN >(BLACK) } };
+
+ e->value = (int16_t)((imbalance<WHITE>(pieceCount) - imbalance<BLACK>(pieceCount)) / 16);
+ return e;
}
-const string EndgameFunctions::swapColors(const string& keyCode) {
- // Build corresponding key for the opposite color: "KBPKN" -> "KNKBP"
- size_t idx = keyCode.find("K", 1);
- return keyCode.substr(idx) + keyCode.substr(0, idx);
-}
+/// Material::game_phase() calculates the phase given the current
+/// position. Because the phase is strictly a function of the material, it
+/// is stored in MaterialEntry.
-template<class T>
-void EndgameFunctions::add(const string& keyCode) {
+Phase game_phase(const Position& pos) {
- typedef typename T::Base F;
+ Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK);
- get<F>().insert(pair<Key, F*>(buildKey(keyCode), new T(WHITE)));
- get<F>().insert(pair<Key, F*>(buildKey(swapColors(keyCode)), new T(BLACK)));
+ return npm >= MidgameLimit ? PHASE_MIDGAME
+ : npm <= EndgameLimit ? PHASE_ENDGAME
+ : Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit));
}
-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);
-}
+} // namespace Material
projects / stockfish / blobdiff