Add knight forks impl and tuned values, when attacks >=1

lynx-chess · Nov 22, 2024 · fb92d7b · fb92d7b
1 parent eaec907
commit fb92d7b
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Showing 3 changed files with 3,789 additions and 3,766 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
@@ -3,9 +3,9 @@
 static partial class EvaluationParams
 {
     /// <summary>
-    /// <see cref="Utils.Pack(-17, -14)"/>
+    /// <see cref="Utils.Pack(-16, -14)"/>
     /// </summary>
-    public const int IsolatedPawnPenalty = -917521;
+    public const int IsolatedPawnPenalty = -917520;
 
     /// <summary>
     /// <see cref="Utils.Pack(40, 2)"/>
@@ -43,8 +43,8 @@ static partial class EvaluationParams
     public const int PieceProtectedByPawnBonus = 983052;
 
     /// <summary>
-    /// <see cref="Utils.Pack(-47, -33)"/>
+    /// <see cref="Utils.Pack(-49, -32)"/>
     /// </summary>
-    public const int PieceAttackedByPawnPenalty = -2162735;
+    public const int PieceAttackedByPawnPenalty = -2097201;
 
 }
diff --git a/src/Lynx/Model/Position.cs b/src/Lynx/Model/Position.cs
@@ -1,5 +1,7 @@
 using System.Buffers;
 using System.Diagnostics;
+using System.Drawing;
+using System.Linq;
 using System.Runtime.CompilerServices;
 using System.Text;
 
@@ -732,6 +734,14 @@ private int KnightAdditionalEvaluation(int squareIndex, int pieceSide, int oppos
 
         packedBonus += CheckBonus[(int)Piece.N] * checks;
 
+        // Forks
+        var enemyPiecesAttackedCount = (attacks & OccupancyBitBoards[Utils.OppositeSide(pieceSide)]).CountBits();
+
+        if (enemyPiecesAttackedCount != 0)
+        {
+            packedBonus += KnightForkBounus[enemyPiecesAttackedCount];
+        }
+
         return packedBonus;
     }