Small cleanups

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 7eafacf8233a4a74eb11c748e232cada3854ee18..9d7728c4511f4cb39e9245a10d6399640995b8c1 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -398,9 +398,9 @@ namespace {
 
     // Enemy rooks checks
     rookChecks = b1 & safe & attackedBy[Them][ROOK];
-
     if (rookChecks)
-        kingDanger += RookSafeCheck;
+        kingDanger += more_than_one(rookChecks) ? RookSafeCheck * 3/2
+                                                : RookSafeCheck;
     else
         unsafeChecks |= b1 & attackedBy[Them][ROOK];
 
@@ -411,9 +411,9 @@ namespace {
                  & safe
                  & ~attackedBy[Us][QUEEN]
                  & ~rookChecks;
-
     if (queenChecks)
-        kingDanger += QueenSafeCheck;
+        kingDanger += more_than_one(queenChecks) ? QueenSafeCheck * 3/2
+                                                 : QueenSafeCheck;
 
     // Enemy bishops checks: we count them only if they are from squares from
     // which we can't give a queen check, because queen checks are more valuable.
@@ -421,17 +421,17 @@ namespace {
                   & attackedBy[Them][BISHOP]
                   & safe
                   & ~queenChecks;
-
     if (bishopChecks)
-        kingDanger += BishopSafeCheck;
+        kingDanger += more_than_one(bishopChecks) ? BishopSafeCheck * 3/2
+                                                  : BishopSafeCheck;
     else
         unsafeChecks |= b2 & attackedBy[Them][BISHOP];
 
     // Enemy knights checks
     knightChecks = pos.attacks_from<KNIGHT>(ksq) & attackedBy[Them][KNIGHT];
-
     if (knightChecks & safe)
-        kingDanger += KnightSafeCheck;
+        kingDanger += more_than_one(knightChecks & safe) ? KnightSafeCheck * 3/2
+                                                         : KnightSafeCheck;
     else
         unsafeChecks |= knightChecks;
 
@@ -740,7 +740,7 @@ namespace {
     // Now apply the bonus: note that we find the attacking side by extracting the
     // sign of the midgame or endgame values, and that we carefully cap the bonus
     // so that the midgame and endgame scores do not change sign after the bonus.
-    int u = ((mg > 0) - (mg < 0)) * std::max(std::min(complexity + 50, 0), -abs(mg));
+    int u = ((mg > 0) - (mg < 0)) * Utility::clamp(complexity + 50, -abs(mg), 0);
     int v = ((eg > 0) - (eg < 0)) * std::max(complexity, -abs(eg));
 
     if (T)
@@ -761,11 +761,16 @@ namespace {
     // If scale is not already specific, scale down the endgame via general heuristics
     if (sf == SCALE_FACTOR_NORMAL)
     {
-        if (   pos.opposite_bishops()
-            && pos.non_pawn_material() == 2 * BishopValueMg)
-            sf = 22;
+        if (pos.opposite_bishops())
+        {
+            if (   pos.non_pawn_material(WHITE) == BishopValueMg
+                && pos.non_pawn_material(BLACK) == BishopValueMg)
+                sf = 22;
+            else
+                sf = 22 + 3 * pos.count<ALL_PIECES>(strongSide);
+        }
         else
-            sf = std::min(sf, 36 + (pos.opposite_bishops() ? 2 : 7) * pos.count<PAWN>(strongSide));
+            sf = std::min(sf, 36 + 7 * pos.count<PAWN>(strongSide));
 
         sf = std::max(0, sf - (pos.rule50_count() - 12) / 4);
     }
@@ -810,7 +815,8 @@ namespace {
     initialize<WHITE>();
     initialize<BLACK>();
 
-    // Pieces should be evaluated first (populate attack tables)
+    // Pieces evaluated first (also populates attackedBy, attackedBy2).
+    // Note that the order of evaluation of the terms is left unspecified
     score +=  pieces<WHITE, KNIGHT>() - pieces<BLACK, KNIGHT>()
             + pieces<WHITE, BISHOP>() - pieces<BLACK, BISHOP>()
             + pieces<WHITE, ROOK  >() - pieces<BLACK, ROOK  >()
@@ -818,6 +824,7 @@ namespace {
 
     score += mobility[WHITE] - mobility[BLACK];
 
+    // More complex interactions that require fully populated attack bitboards
     score +=  king<   WHITE>() - king<   BLACK>()
             + threats<WHITE>() - threats<BLACK>()
             + passed< WHITE>() - passed< BLACK>()