- // 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":
- // 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->mgValue = int16_t(mgValue);
- mi->egValue = int16_t(egValue);
- return mi;
-}
-
-
-/// EndgameFunctions members definition. This helper 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. Being per thread avoids to use locks to access them.
-
-EndgameFunctions::EndgameFunctions() {
-
- typedef Key ZM[2][8][16];
- const ZM& z = Position::zobMaterial;
-
- static const Color W = WHITE;
- static const Color B = BLACK;
-
- KNNKMaterialKey = z[W][KNIGHT][1] ^ z[W][KNIGHT][2];
- KKNNMaterialKey = z[B][KNIGHT][1] ^ z[B][KNIGHT][2];
-
- add(z[W][PAWN][1], &EvaluateKPK);
- add(z[B][PAWN][1], &EvaluateKKP);
-
- add(z[W][BISHOP][1] ^ z[W][KNIGHT][1], &EvaluateKBNK);
- add(z[B][BISHOP][1] ^ z[B][KNIGHT][1], &EvaluateKKBN);
- add(z[W][ROOK][1] ^ z[B][PAWN][1], &EvaluateKRKP);
- add(z[W][PAWN][1] ^ z[B][ROOK][1], &EvaluateKPKR);
- add(z[W][ROOK][1] ^ z[B][BISHOP][1], &EvaluateKRKB);
- add(z[W][BISHOP][1] ^ z[B][ROOK][1], &EvaluateKBKR);
- add(z[W][ROOK][1] ^ z[B][KNIGHT][1], &EvaluateKRKN);
- add(z[W][KNIGHT][1] ^ z[B][ROOK][1], &EvaluateKNKR);
- add(z[W][QUEEN][1] ^ z[B][ROOK][1], &EvaluateKQKR);
- add(z[W][ROOK][1] ^ z[B][QUEEN][1], &EvaluateKRKQ);
-
- add(z[W][KNIGHT][1] ^ z[W][PAWN][1], W, &ScaleKNPK);
- add(z[B][KNIGHT][1] ^ z[B][PAWN][1], B, &ScaleKKNP);