}
- // interpolate() interpolates between a middlegame and an endgame score,
- // based on game phase. It also scales the return value by a ScaleFactor array.
-
- Value interpolate(const Score& v, Phase ph, ScaleFactor sf) {
-
- assert(-VALUE_INFINITE < mg_value(v) && mg_value(v) < VALUE_INFINITE);
- assert(-VALUE_INFINITE < eg_value(v) && eg_value(v) < VALUE_INFINITE);
- assert(PHASE_ENDGAME <= ph && ph <= PHASE_MIDGAME);
-
- int eg = (eg_value(v) * int(sf)) / SCALE_FACTOR_NORMAL;
- return Value((mg_value(v) * int(ph) + eg * int(PHASE_MIDGAME - ph)) / PHASE_MIDGAME);
- }
-
-
// init_eval_info() initializes king bitboards for given color adding
// pawn attacks. To be done at the beginning of the evaluation.
ei.attackedBy[WHITE][ALL_PIECES] |= ei.attackedBy[WHITE][KING];
ei.attackedBy[BLACK][ALL_PIECES] |= ei.attackedBy[BLACK][KING];
- // Do not include in mobility squares protected by enemy pawns or occupied by our pieces
+ // Do not include in mobility squares protected by enemy pawns or occupied by our pawns or king
Bitboard mobilityArea[] = { ~(ei.attackedBy[BLACK][PAWN] | pos.pieces(WHITE, PAWN, KING)),
~(ei.attackedBy[WHITE][PAWN] | pos.pieces(BLACK, PAWN, KING)) };
sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
}
- Value v = interpolate(score, ei.mi->game_phase(), sf);
+ // Interpolate between a middlegame and an endgame score, scaling by 'sf'
+ Value v = mg_value(score) * int(ei.mi->game_phase())
+ + eg_value(score) * int(sf) / SCALE_FACTOR_NORMAL * int(PHASE_MIDGAME - ei.mi->game_phase());
+
+ v /= PHASE_MIDGAME;
// In case of tracing add all single evaluation contributions for both white and black
if (Trace)