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Tidy up middle game specific evaluation

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Also add starting position to benchmarks.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2008-09-25 13:22:14 +02:00
parent 597ef38c39
commit 3e0dc9ee84
2 changed files with 18 additions and 27 deletions
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40
src/evaluate.cpp
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@@ -419,36 +419,26 @@ Value evaluate(const Position &pos, EvalInfo &ei, int threadID) {
&& ( (factor[WHITE] == SCALE_FACTOR_NORMAL && ei.egValue > Value(0))
|| (factor[BLACK] == SCALE_FACTOR_NORMAL && ei.egValue < Value(0))))
{
if (pos.non_pawn_material(WHITE) + pos.non_pawn_material(BLACK) == 2*BishopValueMidgame)
{
// Only the two bishops
if (pos.pawn_count(WHITE) + pos.pawn_count(BLACK) == 1)
ScaleFactor sf;
// Only the two bishops ?
if ( pos.non_pawn_material(WHITE) == BishopValueMidgame
&& pos.non_pawn_material(BLACK) == BishopValueMidgame)
{
// KBP vs KB with only a single pawn; almost certainly a draw.
if (factor[WHITE] == SCALE_FACTOR_NORMAL)
factor[WHITE] = ScaleFactor(8);
if (factor[BLACK] == SCALE_FACTOR_NORMAL)
factor[BLACK] = ScaleFactor(8);
// Check for KBP vs KB with only a single pawn that is almost
// certainly a draw or at least two pawns.
bool one_pawn = (pos.pawn_count(WHITE) + pos.pawn_count(BLACK) == 1);
sf = one_pawn ? ScaleFactor(8) : ScaleFactor(32);
}
else
{
// At least two pawns
if (factor[WHITE] == SCALE_FACTOR_NORMAL)
factor[WHITE] = ScaleFactor(32);
if (factor[BLACK] == SCALE_FACTOR_NORMAL)
factor[BLACK] = ScaleFactor(32);
}
}
else
{
// Endgame with opposite-colored bishops, but also other pieces.
// Still a bit drawish, but not as drawish as with only the two
// bishops.
// Endgame with opposite-colored bishops, but also other pieces. Still
// a bit drawish, but not as drawish as with only the two bishops.
sf = ScaleFactor(50);
if (factor[WHITE] == SCALE_FACTOR_NORMAL)
factor[WHITE] = ScaleFactor(50);
factor[WHITE] = sf;
if (factor[BLACK] == SCALE_FACTOR_NORMAL)
factor[BLACK] = ScaleFactor(50);
}
factor[BLACK] = sf;
}
// Interpolate between the middle game and the endgame score, and