namespace {
- // Values modified by Joona Kiiski
- const Value MidgameLimit = Value(15581);
- const Value EndgameLimit = Value(3998);
-
// Polynomial material balance parameters
- // pair pawn knight bishop rook queen
- const int LinearCoefficients[6] = { 1852, -162, -1122, -183, 249, -154 };
+ // pair pawn knight bishop rook queen
+ const int Linear[6] = { 1852, -162, -1122, -183, 249, -154 };
- const int QuadraticCoefficientsSameColor[][PIECE_TYPE_NB] = {
+ const int QuadraticSameSide[][PIECE_TYPE_NB] = {
+ // OUR PIECES
// pair pawn knight bishop rook queen
{ 0 }, // Bishop pair
{ 39, 2 }, // Pawn
- { 35, 271, -4 }, // Knight
+ { 35, 271, -4 }, // knight OUR PIECES
{ 0, 105, 4, 0 }, // Bishop
{ -27, -2, 46, 100, -141 }, // Rook
{-177, 25, 129, 142, -137, 0 } // Queen
};
- const int QuadraticCoefficientsOppositeColor[][PIECE_TYPE_NB] = {
+ const int QuadraticOppositeSide[][PIECE_TYPE_NB] = {
// THEIR PIECES
// pair pawn knight bishop rook queen
{ 0 }, // Bishop pair
// 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.count<PAWN>(Them)
- && pos.non_pawn_material(Them) == VALUE_ZERO
+ return !more_than_one(pos.pieces(Them))
&& pos.non_pawn_material(Us) >= RookValueMg;
}
const Color Them = (Us == WHITE ? BLACK : WHITE);
- int pt1, pt2, pc, v;
- int value = 0;
+ int bonus = 0;
// Second-degree polynomial material imbalance by Tord Romstad
- for (pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
+ for (int pt1 = NO_PIECE_TYPE; pt1 <= QUEEN; ++pt1)
{
- pc = pieceCount[Us][pt1];
- if (!pc)
+ if (!pieceCount[Us][pt1])
continue;
- v = LinearCoefficients[pt1];
+ int v = Linear[pt1];
- for (pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
- v += QuadraticCoefficientsSameColor[pt1][pt2] * pieceCount[Us][pt2]
- + QuadraticCoefficientsOppositeColor[pt1][pt2] * pieceCount[Them][pt2];
+ for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
+ v += QuadraticSameSide[pt1][pt2] * pieceCount[Us][pt2]
+ + QuadraticOppositeSide[pt1][pt2] * pieceCount[Them][pt2];
- value += pc * v;
+ bonus += pieceCount[Us][pt1] * v;
}
- return value;
+ return bonus;
}
} // namespace
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);
+ e->gamePhase = pos.game_phase();
// Let's look if we have a specialized evaluation function for this particular
// material configuration. Firstly we look for a fixed configuration one, then
return e;
}
-
-/// 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.
-
-Phase game_phase(const Position& pos) {
-
- Value npm = pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK);
-
- return npm >= MidgameLimit ? PHASE_MIDGAME
- : npm <= EndgameLimit ? PHASE_ENDGAME
- : Phase(((npm - EndgameLimit) * 128) / (MidgameLimit - EndgameLimit));
-}
-
} // namespace Material