Reuse TT score instead of TT static eval in QSearch when possible

lynx-chess · Jan 1, 2025 · 1889876 · 1889876
1 parent c5469fb
commit 1889876
Showing 1 changed file with 12 additions and 5 deletions.
diff --git a/src/Lynx/Search/NegaMax.cs b/src/Lynx/Search/NegaMax.cs
@@ -564,17 +564,24 @@ public int QuiescenceSearch(int ply, int alpha, int beta, CancellationToken canc
 
         Game.UpdateStaticEvalInStack(ply, staticEval);
 
+        int eval =
+            (ttNodeType == NodeType.Exact
+                || (ttNodeType == NodeType.Alpha && ttScore < staticEval)
+                || (ttNodeType == NodeType.Beta && ttScore > staticEval))
+            ? ttScore
+            : staticEval;
+
         // Beta-cutoff (updating alpha after this check)
-        if (staticEval >= beta)
+        if (eval >= beta)
         {
             PrintMessage(ply - 1, "Pruning before starting quiescence search");
-            return staticEval;
+            return eval;
         }
 
         // Better move
-        if (staticEval > alpha)
+        if (eval > alpha)
         {
-            alpha = staticEval;
+            alpha = eval;
         }
 
         Span<Move> moves = stackalloc Move[Constants.MaxNumberOfPossibleMovesInAPosition];
@@ -587,7 +594,7 @@ public int QuiescenceSearch(int ply, int alpha, int beta, CancellationToken canc
 
         var nodeType = NodeType.Alpha;
         Move? bestMove = null;
-        int bestScore = staticEval;
+        int bestScore = eval;
 
         bool isAnyCaptureValid = false;