#include "material.h"
-using std::string;
+using namespace std;
////
//// Local definitions
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.
//// 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 {
-
- typedef EndgameEvaluationFunctionBase EF;
- typedef EndgameScalingFunctionBase SF;
-
public:
EndgameFunctions();
~EndgameFunctions();
static Key buildKey(const string& keyCode);
static const string swapColors(const string& keyCode);
- std::map<Key, EF*> EEFmap;
- std::map<Key, SF*> ESFmap;
+ // 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 std::map<Key, T*>& map() const { return EEFmap; }
- template<> const std::map<Key, SF*>& map<SF>() const { return ESFmap; }
- template<typename T> std::map<Key, T*>& map() { return EEFmap; }
- template<> std::map<Key, SF*>& map<SF>() { return ESFmap; }
+ 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
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();
}
}
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->get<EndgameEvaluationFunctionBase>(key)) != NULL)
+ if ((mi->evaluationFunction = funcs->get<EF>(key)) != NULL)
return mi;
else if ( pos.non_pawn_material(BLACK) == Value(0)
// 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.
- EndgameScalingFunctionBase* sf;
+ SF* sf;
- if ((sf = funcs->get<EndgameScalingFunctionBase>(key)) != NULL)
+ if ((sf = funcs->get<SF>(key)) != NULL)
{
mi->scalingFunction[sf->color()] = sf;
return mi;
// Evaluate the material balance
- Color c;
+ 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)
{
}
}
- // 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;
}
EndgameFunctions::EndgameFunctions() {
- KNNKMaterialKey = buildKey("KNNK");
- KKNNMaterialKey = buildKey("KKNN");
-
+ add<EvaluationFunction<KNNK> >("KNNK");
add<EvaluationFunction<KPK> >("KPK");
add<EvaluationFunction<KBNK> >("KBNK");
add<EvaluationFunction<KRKP> >("KRKP");
EndgameFunctions::~EndgameFunctions() {
- for (std::map<Key, EF*>::iterator it = EEFmap.begin(); it != EEFmap.end(); ++it)
+ for (map<Key, EF*>::iterator it = maps.first.begin(); it != maps.first.end(); ++it)
delete (*it).second;
- for (std::map<Key, SF*>::iterator it = ESFmap.begin(); it != ESFmap.end(); ++it)
+ for (map<Key, SF*>::iterator it = maps.second.begin(); it != maps.second.end(); ++it)
delete (*it).second;
}
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
typedef typename T::Base F;
- map<F>().insert(std::pair<Key, F*>(buildKey(keyCode), new T(WHITE)));
- map<F>().insert(std::pair<Key, F*>(buildKey(swapColors(keyCode)), new T(BLACK)));
+ 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 {
- std::map<Key, T*>::const_iterator it(map<T>().find(key));
- return (it != map<T>().end() ? it->second : NULL);
+ typename map<Key, T*>::const_iterator it(get<T>().find(key));
+ return (it != get<T>().end() ? it->second : NULL);
}
projects / stockfish / blobdiff