Add basic ConnectedRooksBonus

lynx-chess · Jan 5, 2025 · b0d4225 · b0d4225
1 parent 4083bca
commit b0d4225
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diff --git a/src/Lynx/Model/Position.cs b/src/Lynx/Model/Position.cs
@@ -712,6 +712,11 @@ private int RookAdditionalEvaluation(int squareIndex, int pieceIndex, int pieceS
 
         packedBonus += CheckBonus[(int)Piece.R] * checks;
 
+        if ((attacks & PieceBitBoards[pieceIndex]).CountBits() >= 2)
+        {
+            packedBonus += ConnectedRooksBonus;
+        }
+
         return packedBonus;
     }
 

diff --git a/src/Lynx/TunableEvalParameters.cs b/src/Lynx/TunableEvalParameters.cs
@@ -6048,6 +6048,11 @@ public static class EvaluationParams
 	/// </summary>
 	public const int BishopPairBonus = 4653086;
 
+	/// <summary>
+	/// <see cref="Utils.Pack(30, 71)"/>
+	/// </summary>
+	public const int ConnectedRooksBonus = 4653086;
+
 	/// <summary>
 	/// <see cref="Utils.Pack(-48, -33)"/>
 	/// </summary>