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Use opposite_color_squares() instead of same_color_squares()

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It is almost alwasy the requested test and is a bit faster too.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2011-01-19 13:43:07 +01:00
parent 4f3fe89fb6
commit 324ca87aff
3 changed files with 13 additions and 35 deletions
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19
src/endgame.cpp
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@@ -155,7 +155,7 @@ Value EvaluationFunction<KBNK>::apply(const Position& pos) const {
// kbnk_mate_table() tries to drive toward corners A1 or H8,
// if we have a bishop that cannot reach the above squares we
// mirror the kings so to drive enemy toward corners A8 or H1.
if (!same_color_squares(bishopSquare, SQ_A1))
if (opposite_color_squares(bishopSquare, SQ_A1))
{
winnerKSq = flop_square(winnerKSq);
loserKSq = flop_square(loserKSq);
@@ -401,7 +401,7 @@ ScaleFactor ScalingFunction<KBPsK>::apply(const Position& pos) const {
Square queeningSq = relative_square(strongerSide, make_square(pawnFile, RANK_8));
Square kingSq = pos.king_square(weakerSide);
if ( !same_color_squares(queeningSq, bishopSq)
if ( opposite_color_squares(queeningSq, bishopSq)
&& file_distance(square_file(kingSq), pawnFile) <= 1)
{
// The bishop has the wrong color, and the defending king is on the
@@ -678,12 +678,12 @@ ScaleFactor ScalingFunction<KBPKB>::apply(const Position& pos) const {
// Case 1: Defending king blocks the pawn, and cannot be driven away
if ( square_file(weakerKingSq) == square_file(pawnSq)
&& relative_rank(strongerSide, pawnSq) < relative_rank(strongerSide, weakerKingSq)
&& ( !same_color_squares(weakerKingSq, strongerBishopSq)
&& ( opposite_color_squares(weakerKingSq, strongerBishopSq)
|| relative_rank(strongerSide, weakerKingSq) <= RANK_6))
return SCALE_FACTOR_ZERO;
// Case 2: Opposite colored bishops
if (!same_color_squares(strongerBishopSq, weakerBishopSq))
if (opposite_color_squares(strongerBishopSq, weakerBishopSq))
{
// We assume that the position is drawn in the following three situations:
//
@@ -728,8 +728,7 @@ ScaleFactor ScalingFunction<KBPPKB>::apply(const Position& pos) const {
Square wbsq = pos.piece_list(strongerSide, BISHOP, 0);
Square bbsq = pos.piece_list(weakerSide, BISHOP, 0);
if (same_color_squares(wbsq, bbsq))
// Not opposite-colored bishops, no scaling
if (!opposite_color_squares(wbsq, bbsq))
return SCALE_FACTOR_NONE;
Square ksq = pos.king_square(weakerSide);
@@ -757,7 +756,7 @@ ScaleFactor ScalingFunction<KBPPKB>::apply(const Position& pos) const {
// some square in the frontmost pawn's path.
if ( square_file(ksq) == square_file(blockSq1)
&& relative_rank(strongerSide, ksq) >= relative_rank(strongerSide, blockSq1)
&& !same_color_squares(ksq, wbsq))
&& opposite_color_squares(ksq, wbsq))
return SCALE_FACTOR_ZERO;
else
return SCALE_FACTOR_NONE;
@@ -767,14 +766,14 @@ ScaleFactor ScalingFunction<KBPPKB>::apply(const Position& pos) const {
// in front of the frontmost pawn's path, and the square diagonally behind
// this square on the file of the other pawn.
if ( ksq == blockSq1
&& !same_color_squares(ksq, wbsq)
&& opposite_color_squares(ksq, wbsq)
&& ( bbsq == blockSq2
|| (pos.attacks_from<BISHOP>(blockSq2) & pos.pieces(BISHOP, weakerSide))
|| rank_distance(r1, r2) >= 2))
return SCALE_FACTOR_ZERO;
else if ( ksq == blockSq2
&& !same_color_squares(ksq, wbsq)
&& opposite_color_squares(ksq, wbsq)
&& ( bbsq == blockSq1
|| (pos.attacks_from<BISHOP>(blockSq1) & pos.pieces(BISHOP, weakerSide))))
return SCALE_FACTOR_ZERO;
@@ -808,7 +807,7 @@ ScaleFactor ScalingFunction<KBPKN>::apply(const Position& pos) const {
if ( square_file(weakerKingSq) == square_file(pawnSq)
&& relative_rank(strongerSide, pawnSq) < relative_rank(strongerSide, weakerKingSq)
&& ( !same_color_squares(weakerKingSq, strongerBishopSq)
&& ( opposite_color_squares(weakerKingSq, strongerBishopSq)
|| relative_rank(strongerSide, weakerKingSq) <= RANK_6))
return SCALE_FACTOR_ZERO;