🐛 Fix index out of range exception (#708)

* Add a buffer to array size for those ones accessed by depth or ply
lynx-chess · Apr 5, 2024 · 431d769 · 431d769
1 parent b3d6934
commit 431d769
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Showing 4 changed files with 14 additions and 9 deletions.
diff --git a/src/Lynx/Constants.cs b/src/Lynx/Constants.cs
@@ -326,6 +326,11 @@ public static class Constants
 
     public const int AbsoluteMaxDepth = 255;
 
+    /// <summary>
+    /// To take into account array access by depth and depth extensions
+    /// </summary>
+    public const int ArrayDepthMargin = 16;
+
     /// <summary>
     /// From https://lichess.org/RViT3UWL
     /// Failes input parsing fail if default input buffer size is used (see Lynx.Cli.Listener

diff --git a/src/Lynx/EvaluationConstants.cs b/src/Lynx/EvaluationConstants.cs
@@ -190,12 +190,12 @@ public static class EvaluationConstants
     /// <summary>
     /// <see cref="Constants.AbsoluteMaxDepth"/> x <see cref="Constants.MaxNumberOfPossibleMovesInAPosition"/>
     /// </summary>
-    public static readonly int[][] LMRReductions = new int[Configuration.EngineSettings.MaxDepth][];
+    public static readonly int[][] LMRReductions = new int[Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin][];
 
     /// <summary>
     /// [0, 4, 136, 276, 424, 580, 744, 916, 1096, 1284, 1480, 1684, 1896, 1896, 1896, 1896, ...]
     /// </summary>
-    public static readonly int[] HistoryBonus = new int[Configuration.EngineSettings.MaxDepth];
+    public static readonly int[] HistoryBonus = new int[Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin];
 
     static EvaluationConstants()
     {
@@ -262,7 +262,7 @@ static EvaluationConstants()
             }
         }
 
-        for (int searchDepth = 1; searchDepth < Configuration.EngineSettings.MaxDepth; ++searchDepth)    // Depth > 0 or we'd be in QSearch
+        for (int searchDepth = 1; searchDepth < Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin; ++searchDepth)    // Depth > 0 or we'd be in QSearch
         {
             LMRReductions[searchDepth] = new int[Constants.MaxNumberOfPossibleMovesInAPosition];
 

diff --git a/src/Lynx/Model/PVTable.cs b/src/Lynx/Model/PVTable.cs
@@ -8,7 +8,7 @@ public static class PVTable
 
     private static ImmutableArray<int> Initialize()
     {
-        var indexes = new int[Configuration.EngineSettings.MaxDepth + 1];
+        var indexes = new int[Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin];
         int previousPVIndex = 0;
         indexes[0] = previousPVIndex;
 
@@ -18,6 +18,6 @@ private static ImmutableArray<int> Initialize()
             previousPVIndex = indexes[depth + 1];
         }
 
-        return indexes.ToImmutableArray();
+        return [.. indexes];
     }
 }
diff --git a/src/Lynx/Search/IDDFS.cs b/src/Lynx/Search/IDDFS.cs
@@ -16,9 +16,9 @@ public sealed partial class Engine
     /// </summary>
     private readonly int[][] _killerMoves =
     [
-        new int[Configuration.EngineSettings.MaxDepth],
-        new int[Configuration.EngineSettings.MaxDepth],
-        new int[Configuration.EngineSettings.MaxDepth]
+        new int[Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin],
+        new int[Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin],
+        new int[Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin]
     ];
 
     /// <summary>
@@ -31,7 +31,7 @@ public sealed partial class Engine
     /// </summary>
     private readonly int[][][] _captureHistory;
 
-    private readonly int[] _maxDepthReached = new int[Configuration.EngineSettings.MaxDepth];
+    private readonly int[] _maxDepthReached = new int[Configuration.EngineSettings.MaxDepth + Constants.ArrayDepthMargin];
     private TranspositionTable _tt = [];
     private int _ttMask;