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No Queen in the MobilityArea

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Queen was recently excluded from the mobility area of friendly minor
pieces. Exclude queen also from the mobility area of friendly majors too.

Run as a simplification:

STC
http://tests.stockfishchess.org/tests/view/5ade396f0ebc59602d053742
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 46972 W: 9511 L: 9437 D: 28024

LTC
http://tests.stockfishchess.org/tests/view/5ade64b50ebc5949f20a24d3
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 66855 W: 10157 L: 10105 D: 46593

How to continue from there?

The mobilityArea is used in various places of the evaluation as a
soft proxy for "not attacked by the opponent pawns". Now that the
mobility area is getting smaller and smaller, it may be worth to
hunt for Elo gains by trying the more direct ~attackedBy[Them][PAWN]
instead of mobilityArea[Us] in these places.

Bench: 4650572
This commit is contained in:
Alain SAVARD 2018-04-23 15:49:34 -04:00 • committed by Stéphane Nicolet
parent c794c8c801
commit 45072612d4
1 changed files with 3 additions and 5 deletions
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8
src/evaluate.cpp
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@ -258,9 +258,9 @@ namespace {
// Find our pawns that are blocked or on the first two ranks
Bitboard b = pos.pieces(Us, PAWN) & (shift<Down>(pos.pieces()) | LowRanks);
// Squares occupied by those pawns, by our king, or controlled by enemy pawns
// Squares occupied by those pawns, by our king or queen, or controlled by enemy pawns
// are excluded from the mobility area.
mobilityArea[Us] = ~(b | pos.square<KING>(Us) | pe->pawn_attacks(Them));
mobilityArea[Us] = ~(b | pos.pieces(Us, KING, QUEEN) | pe->pawn_attacks(Them));
// Initialise attackedBy bitboards for kings and pawns
attackedBy[Us][KING] = pos.attacks_from<KING>(pos.square<KING>(Us));
@ -301,7 +301,6 @@ namespace {
Bitboard b, bb;
Square s;
Score score = SCORE_ZERO;
int mob;
attackedBy[Us][Pt] = 0;
@ -326,8 +325,7 @@ namespace {
kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
}
mob = (Pt == KNIGHT || Pt == BISHOP) ? popcount(b & mobilityArea[Us] & ~pos.pieces(Us, QUEEN))
: popcount(b & mobilityArea[Us]);
int mob = popcount(b & mobilityArea[Us]);
mobility[Us] += MobilityBonus[Pt - 2][mob];