No Queen in the MobilityArea

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

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 1505bf67facd53bcd028eac73d795b25d49ee8af..ad63e21630126499e168dba7fef10a550909e8ec 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -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);
 
     // 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.
     // 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));
 
     // 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;
     Bitboard b, bb;
     Square s;
     Score score = SCORE_ZERO;

-    int mob;

 
     attackedBy[Us][Pt] = 0;
 
 
     attackedBy[Us][Pt] = 0;
 


@@ -326,8 +325,7 @@ namespace {
             kingAttacksCount[Us] += popcount(b & attackedBy[Them][KING]);
         }
 
             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];
 
 
         mobility[Us] += MobilityBonus[Pt - 2][mob];