Add bonus for KQR forks

lynx-chess · Nov 22, 2024 · 735f4ba · 735f4ba
1 parent eaec907
commit 735f4ba
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Showing 3 changed files with 2,992 additions and 2,970 deletions.
diff --git a/...Lynx/Generated/Lynx.Generator/Lynx.Generator.GeneratedPackGenerator/EvaluationParams.g.cs b/...Lynx/Generated/Lynx.Generator/Lynx.Generator.GeneratedPackGenerator/EvaluationParams.g.cs
@@ -47,4 +47,9 @@ static partial class EvaluationParams
     /// </summary>
     public const int PieceAttackedByPawnPenalty = -2162735;
 
+    /// <summary>
+    /// <see cref="Utils.Pack(55, 94)"/>
+    /// </summary>
+    public const int KnightForkBounus = 6160439;
+
 }
diff --git a/src/Lynx/Model/Position.cs b/src/Lynx/Model/Position.cs
@@ -1,5 +1,6 @@
 using System.Buffers;
 using System.Diagnostics;
+using System.Drawing;
 using System.Runtime.CompilerServices;
 using System.Text;
 
@@ -732,6 +733,19 @@ private int KnightAdditionalEvaluation(int squareIndex, int pieceSide, int oppos
 
         packedBonus += CheckBonus[(int)Piece.N] * checks;
 
+        // Forks
+        var offset = Utils.PieceOffset(pieceSide);
+        var majorPieces = PieceBitBoards[(int)Piece.k - offset] |
+                          PieceBitBoards[(int)Piece.q - offset] |
+                          PieceBitBoards[(int)Piece.r - offset];
+
+        var enemyPiecesAttackedCount = (attacks & majorPieces).CountBits();
+
+        if (enemyPiecesAttackedCount > 1)
+        {
+            packedBonus += KnightForkBounus * enemyPiecesAttackedCount;
+        }
+
         return packedBonus;
     }