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Simplify trapped rook

Browse source 
As far as can tell, semiopenFiles are set if there is a pawn anywhere on
the file. The removed condition would be true even if the pawns were very
advanced, which doesn't make sense if we're looking for a trapped rook.
Seems the engine fairs better with this removed. My guess s that the
condition that mobility is 3 or less does this well enough.

Begs the question whether this is a mobility issue alone... not sure.
Should I do LTC test?

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 13377 W: 3009 L: 2871 D: 7497
http://tests.stockfishchess.org/tests/view/5a855be40ebc590297cc8166

Passed LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 16288 W: 2813 L: 2685 D: 10790
http://tests.stockfishchess.org/tests/view/5a8575a80ebc590297cc817e

Bench: 5006365
This commit is contained in:
Mike Whiteley 2018-02-15 19:34:23 +01:00 • committed by Stéphane Nicolet
parent 860223c5e6
commit 80ea80e451
2 changed files with 2 additions and 7 deletions
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5
src/evaluate.cpp
View file

@ -396,10 +396,9 @@ namespace {
// Penalty when trapped by the king, even more if the king cannot castle
else if (mob <= 3)
{
Square ksq = pos.square<KING>(Us);
File kf = file_of(pos.square<KING>(Us));
if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
&& !pe->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
if ((kf < FILE_E) == (file_of(s) < kf))
score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us));
}
}

4
src/pawns.h
View file

@ -45,10 +45,6 @@ struct Entry {
return semiopenFiles[c] & (1 << f);
}
int semiopen_side(Color c, File f, bool leftSide) const {
return semiopenFiles[c] & (leftSide ? (1 << f) - 1 : ~((1 << (f + 1)) - 1));
}
int pawns_on_same_color_squares(Color c, Square s) const {
return pawnsOnSquares[c][bool(DarkSquares & s)];
}