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Simplify other checks (#1337)

Replace an intricate definition with a more natural one.

Master was excluding squares occupied by a pawn which was blocked by a pawn.
This version excludes any squares occupied by a pawn which is blocked by "something"

Passed STC
http://tests.stockfishchess.org/tests/view/5a2f557b0ebc590ccbb8bc0d
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 44211 W: 8009 L: 7928 D: 28274

and LTC
http://tests.stockfishchess.org/tests/view/5a301d440ebc590ccbb8bc80
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 31958 W: 4108 L: 4002 D: 23848

Bench 5000136
pull/1340/merge
Rocky640 2017-12-17 02:50:45 -05:00 committed by Marco Costalba
parent 020dd69a35
commit be6fafd079
1 changed files with 3 additions and 6 deletions

View File

@ -423,13 +423,11 @@ namespace {
Score Evaluation<T>::evaluate_king() {
const Color Them = (Us == WHITE ? BLACK : WHITE);
const Direction Up = (Us == WHITE ? NORTH : SOUTH);
const Bitboard Camp = (Us == WHITE ? AllSquares ^ Rank6BB ^ Rank7BB ^ Rank8BB
: AllSquares ^ Rank1BB ^ Rank2BB ^ Rank3BB);
const Square ksq = pos.square<KING>(Us);
Bitboard weak, b, b1, b2, safe, unsafeChecks;
int kingDanger;
// King shelter and enemy pawns storm
Score score = pe->king_safety<Us>(pos, ksq);
@ -442,7 +440,7 @@ namespace {
& ~attackedBy2[Us]
& (attackedBy[Us][KING] | attackedBy[Us][QUEEN] | ~attackedBy[Us][ALL_PIECES]);
kingDanger = unsafeChecks = 0;
int kingDanger = unsafeChecks = 0;
// Analyse the safe enemy's checks which are possible on next move
safe = ~pos.pieces(Them);
@ -478,9 +476,8 @@ namespace {
unsafeChecks |= b;
// Unsafe or occupied checking squares will also be considered, as long as
// the square is not defended by our pawns or occupied by a blocked pawn.
unsafeChecks &= ~( attackedBy[Us][PAWN]
| (pos.pieces(Them, PAWN) & shift<Up>(pos.pieces(PAWN))));
// the square is in the attacker's mobility area.
unsafeChecks &= mobilityArea[Them];
kingDanger += kingAttackersCount[Them] * kingAttackersWeight[Them]
+ 102 * kingAdjacentZoneAttacksCount[Them]