Simplify ThreatByKing to be a single Score.

[stockfish] / src / evaluate.cpp

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index 0130b05733282e00daf64488e8269b02f2be7cd4..ef69ee6cc1b47c921f6ccf89271cd21333dd2bcc 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -140,10 +140,6 @@ namespace {
     S(0, 0), S(0, 24), S(38, 71), S(38, 61), S(0, 38), S(36, 38)
   };
 
-  // ThreatByKing[on one/on many] contains bonuses for king attacks on
-  // pawns or pieces which are not pawn-defended.
-  constexpr Score ThreatByKing[] = { S(30, 62), S(-9, 160) };
-
   // PassedRank[Rank] contains a bonus according to the rank of a passed pawn
   constexpr Score PassedRank[RANK_NB] = {
     S(0, 0), S(4, 17), S(7, 20), S(14, 36), S(42, 62), S(165, 171), S(279, 252)
@@ -175,6 +171,7 @@ namespace {
   constexpr Score PawnlessFlank      = S( 20, 80);
   constexpr Score RookOnPawn         = S(  8, 24);
   constexpr Score SliderOnQueen      = S( 42, 21);
+  constexpr Score ThreatByKing       = S( 31, 75);
   constexpr Score ThreatByPawnPush   = S( 49, 30);
   constexpr Score ThreatByRank       = S( 16,  3);
   constexpr Score ThreatBySafePawn   = S(165,133);
@@ -558,9 +555,9 @@ namespace {
                 score += ThreatByRank * (int)relative_rank(Them, s);
         }
 
-        b = weak & attackedBy[Us][KING];
-        if (b)
-            score += ThreatByKing[more_than_one(b)];
+        // Bonus for king attacks on pawns or pieces which are not pawn-defended
+        if (weak & attackedBy[Us][KING])
+            score += ThreatByKing;
 
         score += Hanging * popcount(weak & ~attackedBy[Them][ALL_PIECES]);