Exclude this case entirely.

31m059 · May 16, 2018 · 30f1b6e · 30f1b6e
1 parent 7ba6594
commit 30f1b6e
Showing 1 changed file with 4 additions and 8 deletions.
diff --git a/src/evaluate.cpp b/src/evaluate.cpp
@@ -379,16 +379,12 @@ namespace {
 
         if (Pt == ROOK)
         {
-            // Bonus for aligning rook with enemy pawns on the same rank/file
-            // Half bonus for passed pawns attacked along a rank
+            // Bonus for aligning rook with enemy pawns on the same rank/file, except passed pawns on the same rank
             if (relative_rank(Us, s) >= RANK_5)
             {
-                b = pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s];
-                while (b)
-                {
-                    Square s2 = pop_lsb(&b);
-                    score += RookOnPawn / (1 + bool(rank_bb(s) & pe->passedPawns[Them] & s2));
-                }
+                b =    pos.pieces(Them, PAWN) & PseudoAttacks[ROOK][s]
+                   & ~(rank_bb(s) & pe->passed_pawns(Them));
+                score += RookOnPawn * popcount(b);
             }
 
             // Bonus for rook on an open or semi-open file