From a0d8634ea6560e47d91271de4c7116e921f70425 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eduardo=20C=C3=A1ceres?=
 <eduherminio@users.noreply.github.com>
Date: Fri, 9 Feb 2024 12:17:05 +0100
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20Clear=20history=20on=20`newgame`?=
 =?UTF-8?q?=20(#649)?=
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* Clear history on `newgame`
* Cleanup after fake ponder hit removal
---
 src/Lynx/Engine.cs       | 15 ++++++++++++++-
 src/Lynx/Search/IDDFS.cs |  8 --------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/src/Lynx/Engine.cs b/src/Lynx/Engine.cs
index b57e5c538..4f074cd55 100644
--- a/src/Lynx/Engine.cs
+++ b/src/Lynx/Engine.cs
@@ -72,7 +72,20 @@ public void NewGame()
         Game = new Game();
         _isNewGameComing = true;
         _isNewGameCommandSupported = true;
-        InitializeTT();
+
+        InitializeTT(); // TODO SPRT clearing instead
+
+        // Clear histories
+        for (int i = 0; i < 12; ++i)
+        {
+            Array.Clear(_quietHistory[i]);
+            for (var j = 0; j < 64; ++j)
+            {
+                Array.Clear(_captureHistory[i][j]);
+            }
+        }
+
+        // No need to clear killer move or pv table because they're cleared on every search (IDDFS)
     }
 
     public void AdjustPosition(ReadOnlySpan<char> rawPositionCommand)
diff --git a/src/Lynx/Search/IDDFS.cs b/src/Lynx/Search/IDDFS.cs
index 473c624a8..30f091702 100644
--- a/src/Lynx/Search/IDDFS.cs
+++ b/src/Lynx/Search/IDDFS.cs
@@ -40,12 +40,6 @@ public sealed partial class Engine
     private bool _isScoringPV;
 
     private SearchResult? _previousSearchResult;
-    private readonly int[][] _previousKillerMoves =
-    [
-        new int[Configuration.EngineSettings.MaxDepth],
-        new int[Configuration.EngineSettings.MaxDepth],
-        new int[Configuration.EngineSettings.MaxDepth]
-    ];
 
     private readonly Move _defaultMove = default;
 
@@ -151,8 +145,6 @@ public sealed partial class Engine
                 lastSearchResult = UpdateLastSearchResult(lastSearchResult, bestEvaluation, alpha, beta, depth, isMateDetected, bestEvaluationAbs);
 
                 await _engineWriter.WriteAsync(InfoCommand.SearchResultInfo(lastSearchResult));
-
-                Array.Copy(_killerMoves, _previousKillerMoves, _killerMoves.Length);
             } while (StopSearchCondition(++depth, maxDepth, isMateDetected, decisionTime));
         }
         catch (OperationCanceledException)