Offload node score buffers

Solver/Crafty/ArenaBuffer.cs

@@ -5,7 +5,7 @@ using System.Runtime.CompilerServices;
 namespace Craftimizer.Solver.Crafty;
 
 // Adapted from https://github.com/dtao/ConcurrentList/blob/4fcf1c76e93021a41af5abb2d61a63caeba2adad/ConcurrentList/ConcurrentList.cs
-public struct ArenaBuffer<T>
+public struct ArenaBuffer<T> where T : struct
 {
     // Technically 25, but it's very unlikely to actually get to there.
     // The benchmark reaches 20 at most, but here we have a little leeway just in case.
@@ -17,39 +17,41 @@ public struct ArenaBuffer<T>
 
     private static int BatchCount = MaxSize / BatchSize;
 
-    public T[][] Data;
+    public ArenaNode<T>[][] Data;
     private int index; // Unused in single threaded workload
     private int count;
 
     public readonly int Count => count;
 
-    public void AddConcurrent(T node)
+    public void AddConcurrent(ArenaNode<T> node)
     {
         if (Data == null)
-            Interlocked.CompareExchange(ref Data, new T[BatchCount][], null);
+            Interlocked.CompareExchange(ref Data, new ArenaNode<T>[BatchCount][], null);
 
         var idx = Interlocked.Increment(ref index) - 1;
 
         var (arrayIdx, subIdx) = GetArrayIndex(idx);
 
         if (Data[arrayIdx] == null)
-            Interlocked.CompareExchange(ref Data[arrayIdx], new T[BatchSize], null);
+            Interlocked.CompareExchange(ref Data[arrayIdx], new ArenaNode<T>[BatchSize], null);
 
+        node.ChildIdx = (arrayIdx, subIdx);
         Data[arrayIdx][subIdx] = node;
 
         Interlocked.Increment(ref count);
     }
 
-    public void Add(T node)
+    public void Add(ArenaNode<T> node)
     {
-        Data ??= new T[BatchCount][];
+        Data ??= new ArenaNode<T>[BatchCount][];
 
         var idx = count++;
 
         var (arrayIdx, subIdx) = GetArrayIndex(idx);
 
-        Data[arrayIdx] ??= new T[BatchSize];
+        Data[arrayIdx] ??= new ArenaNode<T>[BatchSize];
 
+        node.ChildIdx = (arrayIdx, subIdx);
         Data[arrayIdx][subIdx] = node;
     }
 

Solver/Crafty/ArenaNode.cs

@@ -5,21 +5,30 @@ namespace Craftimizer.Solver.Crafty;
 public sealed class ArenaNode<T> where T : struct
 {
     public T State;
-    public ArenaBuffer<ArenaNode<T>> Children;
+    public ArenaBuffer<T> Children;
+    public NodeScoresBuffer ChildScores;
+    public (int arrayIdx, int subIdx) ChildIdx;
     public readonly ArenaNode<T>? Parent;
 
+    public NodeScoresBuffer? ParentScores => Parent?.ChildScores;
+
     public ArenaNode(T state, ArenaNode<T>? parent = null)
     {
         State = state;
         Children = new();
+        ChildScores = new();
         Parent = parent;
     }
 
+    public ArenaNode<T> ChildAt((int arrayIdx, int subIdx) at) =>
+        Children.Data[at.arrayIdx][at.subIdx];
+
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public ArenaNode<T> AddConcurrent(T state)
     {
         var node = new ArenaNode<T>(state, this);
         Children.AddConcurrent(node);
+        ChildScores.AddConcurrent();
         return node;
     }
 
@@ -28,6 +37,7 @@ public sealed class ArenaNode<T> where T : struct
     {
         var node = new ArenaNode<T>(state, this);
         Children.Add(node);
+        ChildScores.Add();
         return node;
     }
 }

Solver/Crafty/ISolver.cs

@@ -4,9 +4,7 @@ namespace Craftimizer.Solver.Crafty;
 
 public interface ISolver
 {
-    abstract static void LoadChildData(Span<float> scoreSums, Span<int> visits, Span<float> maxScores, ref Node[] chunk, int iterCount);
+    abstract static bool SearchIter(ref SolverConfig config, RootScores rootScores, Node rootNode, Random random, Simulator simulator);
 
-    abstract static bool SearchIter(ref SolverConfig config, Node rootNode, Random random, Simulator simulator);
-
-    abstract static void Search(ref SolverConfig config, Node rootNode, CancellationToken token);
+    abstract static void Search(ref SolverConfig config, RootScores rootScores, Node rootNode, CancellationToken token);
 }

Solver/Crafty/Intrinsics.cs

@@ -101,9 +101,8 @@ internal static class Intrinsics
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static int NthBitSet(uint value, int n)
     {
-        // TODO: debug
         if (n >= BitOperations.PopCount(value))
-            throw new ArgumentException(null, nameof(value));
+            return 32;
 
         return Bmi2.IsSupported ?
             NthBitSetBMI2(value, n) :

Solver/Crafty/NodeScoresBuffer.cs

@@ -0,0 +1,90 @@
+using System;
+using System.ComponentModel;
+using System.Diagnostics.Contracts;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Craftimizer.Solver.Crafty;
+
+// Adapted from https://github.com/dtao/ConcurrentList/blob/4fcf1c76e93021a41af5abb2d61a63caeba2adad/ConcurrentList/ConcurrentList.cs
+public struct NodeScoresBuffer
+{
+    public sealed class ScoresBatch
+    {
+        public Memory<float> ScoreSum;
+        public Memory<float> MaxScore;
+        public Memory<int> Visits;
+
+        public ScoresBatch()
+        {
+            ScoreSum = new float[BatchSize];
+            MaxScore = new float[BatchSize];
+            Visits = new int[BatchSize];
+        }
+    }
+
+    // Technically 25, but it's very unlikely to actually get to there.
+    // The benchmark reaches 20 at most, but here we have a little leeway just in case.
+    private const int MaxSize = 24;
+
+    private static int BatchSize = Vector<float>.Count;
+    private static int BatchSizeBits = int.Log2(BatchSize);
+    private static int BatchSizeMask = BatchSize - 1;
+
+    private static int BatchCount = MaxSize / BatchSize;
+
+    public ScoresBatch[] Data;
+    private int index;
+    private int count;
+
+    public readonly int Count => count;
+
+    public void AddConcurrent()
+    {
+        if (Data == null)
+            Interlocked.CompareExchange(ref Data, new ScoresBatch[BatchCount], null);
+
+        var idx = Interlocked.Increment(ref index) - 1;
+
+        var (arrayIdx, _) = GetArrayIndex(idx);
+
+        if (Data[arrayIdx] == null)
+            Interlocked.CompareExchange(ref Data[arrayIdx], new ScoresBatch(), null);
+
+        Interlocked.Increment(ref count);
+    }
+
+    public void Add()
+    {
+        Data ??= new ScoresBatch[BatchCount];
+
+        var idx = count++;
+
+        var (arrayIdx, _) = GetArrayIndex(idx);
+
+        Data[arrayIdx] ??= new();
+    }
+
+    public readonly void VisitConcurrent((int arrayIdx, int subIdx) at, float score)
+    {
+        Intrinsics.CASAdd(ref Data[at.arrayIdx].ScoreSum.Span[at.subIdx], score);
+        Intrinsics.CASMax(ref Data[at.arrayIdx].MaxScore.Span[at.subIdx], score);
+        Interlocked.Increment(ref Data[at.arrayIdx].Visits.Span[at.subIdx]);
+    }
+
+    public readonly void Visit((int arrayIdx, int subIdx) at, float score)
+    {
+        Data[at.arrayIdx].ScoreSum.Span[at.subIdx] += score;
+        Data[at.arrayIdx].MaxScore.Span[at.subIdx] = Math.Max(Data[at.arrayIdx].MaxScore.Span[at.subIdx], score);
+        Data[at.arrayIdx].Visits.Span[at.subIdx]++;
+    }
+
+    public readonly int GetVisits((int arrayIdx, int subIdx) at) =>
+        Data[at.arrayIdx].Visits.Span[at.subIdx];
+
+    [Pure]
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static (int arrayIdx, int subIdx) GetArrayIndex(int idx) =>
+        (idx >> BatchSizeBits, idx & BatchSizeMask);
+}

Solver/Crafty/RootScores.cs

@@ -3,7 +3,7 @@ using System.Runtime.InteropServices;
 namespace Craftimizer.Solver.Crafty;
 
 [StructLayout(LayoutKind.Auto)]
-public struct NodeScores
+public sealed class RootScores
 {
     public float ScoreSum;
     public float MaxScore;

Solver/Crafty/SimulationNode.cs

@@ -12,7 +12,6 @@ public struct SimulationNode
     public readonly CompletionState SimulationCompletionState;
 
     public ActionSet AvailableActions;
-    public NodeScores Scores;
 
     public readonly CompletionState CompletionState => GetCompletionState(SimulationCompletionState, AvailableActions);
 

Solver/Crafty/SolverConcurrent.cs

@@ -7,29 +7,18 @@ namespace Craftimizer.Solver.Crafty;
 // https://github.com/alostsock/crafty/blob/cffbd0cad8bab3cef9f52a3e3d5da4f5e3781842/crafty/src/simulator.rs
 public sealed class SolverConcurrent : ISolver
 {
-    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    public static void LoadChildData(Span<float> scoreSums, Span<int> visits, Span<float> maxScores, ref Node[] chunk, int iterCount)
-    {
-        for (var j = 0; j < iterCount; ++j)
-        {
-            var node = chunk[j]?.State.Scores ?? new();
-            scoreSums[j] = node.ScoreSum;
-            visits[j] = node.Visits;
-            maxScores[j] = node.MaxScore;
-        }
-    }
-
     [Pure]
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static Node? EvalBestChild(ref SolverConfig config, int parentVisits, ref Node.ChildBuffer children) =>
+    public static (int arrayIdx, int subIdx)? EvalBestChild(ref SolverConfig config, int parentVisits, ref NodeScoresBuffer children) =>
         parentVisits == 0 ?
             null :
             SolverUtils.EvalBestChild<SolverConcurrent>(ref config, parentVisits, ref children);
 
     [Pure]
-    public static Node Select(ref SolverConfig config, Node rootNode)
+    public static Node Select(ref SolverConfig config, int rootNodeVisits, Node rootNode)
     {
         var node = rootNode;
+        var nodeVisits = rootNodeVisits;
         while (true)
         {
             var expandable = !node.State.AvailableActions.IsEmpty;
@@ -39,11 +28,21 @@ public sealed class SolverConcurrent : ISolver
 
             // select the node with the highest score
             // if null (current node is invalid & not backpropagated just yet), try again from root
-            node = EvalBestChild(ref config, node.State.Scores.Visits, ref node.Children) ?? rootNode;
+            var at = EvalBestChild(ref config, nodeVisits, ref node.ChildScores);
+            if (at.HasValue)
+            {
+                nodeVisits = node.ChildScores.GetVisits(at.Value);
+                node = node.ChildAt(at.Value);
+            }
+            else
+            {
+                node = rootNode;
+                nodeVisits = rootNodeVisits;
+            }
         }
     }
 
-    public static (Node ExpandedNode, float Score)? ExpandAndRollout(ref SolverConfig config, Node rootNode, Random random, Simulator simulator, Node initialNode)
+    public static (Node ExpandedNode, float Score)? ExpandAndRollout(ref SolverConfig config, float maxScore, Node rootNode, Random random, Simulator simulator, Node initialNode)
     {
         ref var initialState = ref initialNode.State;
         // expand once
@@ -55,43 +54,45 @@ public sealed class SolverConcurrent : ISolver
             return null;
         var expandedNode = initialNode.AddConcurrent(SolverUtils.Execute(simulator, initialState.State, poppedAction.Value, true));
 
-        return SolverUtils.Rollout(ref config, rootNode, expandedNode, random, simulator);
+        return SolverUtils.Rollout(ref config, maxScore, rootNode, expandedNode, random, simulator);
     }
 
-    public static void Backpropagate(Node rootNode, Node startNode, float score)
+    public static void Backpropagate(RootScores rootScores, Node rootNode, Node startNode, float score)
     {
         while (true)
         {
-            startNode.State.Scores.VisitConcurrent(score);
-
             if (startNode == rootNode)
+            {
+                rootScores.VisitConcurrent(score);
                 break;
+            }
+            startNode.ParentScores!.Value.VisitConcurrent(startNode.ChildIdx, score);
 
             startNode = startNode.Parent!;
         }
     }
 
-    public static bool SearchIter(ref SolverConfig config, Node rootNode, Random random, Simulator simulator)
+    public static bool SearchIter(ref SolverConfig config, RootScores rootScores, Node rootNode, Random random, Simulator simulator)
     {
-        var selectedNode = Select(ref config, rootNode);
-        var rolledOut = ExpandAndRollout(ref config, rootNode, random, simulator, selectedNode);
+        var selectedNode = Select(ref config, rootScores.Visits, rootNode);
+        var rolledOut = ExpandAndRollout(ref config, rootScores.MaxScore, rootNode, random, simulator, selectedNode);
         if (!rolledOut.HasValue)
             return false;
 
         var (endNode, score) = rolledOut.Value;
-        Backpropagate(rootNode, endNode, score);
+        Backpropagate(rootScores, rootNode, endNode, score);
         return true;
     }
 
-    public static void SearchThread(SolverConfig config, Node rootNode, CancellationToken token) =>
-        SolverUtils.Search<SolverConcurrent>(ref config, config.Iterations / config.ThreadCount, rootNode, token);
+    public static void SearchThread(SolverConfig config, RootScores rootScores, Node rootNode, CancellationToken token) =>
+        SolverUtils.Search<SolverConcurrent>(ref config, config.Iterations / config.ThreadCount, rootScores, rootNode, token);
 
-    public static void Search(ref SolverConfig config, Node rootNode, CancellationToken token)
+    public static void Search(ref SolverConfig config, RootScores rootScores, Node rootNode, CancellationToken token)
     {
         var configP = config;
         var tasks = new Task[config.ThreadCount];
         for (var i = 0; i < config.ThreadCount; ++i)
-            tasks[i] = Task.Run(() => SearchThread(configP, rootNode, token), token);
+            tasks[i] = Task.Run(() => SearchThread(configP, rootScores, rootNode, token), token);
         Task.WaitAll(tasks, CancellationToken.None);
     }
 }

Solver/Crafty/SolverSingle.cs

@@ -7,25 +7,13 @@ namespace Craftimizer.Solver.Crafty;
 // https://github.com/alostsock/crafty/blob/cffbd0cad8bab3cef9f52a3e3d5da4f5e3781842/crafty/src/simulator.rs
 public sealed class SolverSingle : ISolver
 {
-    [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    public static void LoadChildData(Span<float> scoreSums, Span<int> visits, Span<float> maxScores, ref Node[] chunk, int iterCount)
-    {
-        for (var j = 0; j < iterCount; ++j)
-        {
-            ref var node = ref chunk[j].State.Scores;
-            scoreSums[j] = node.ScoreSum;
-            visits[j] = node.Visits;
-            maxScores[j] = node.MaxScore;
-        }
-    }
-
     [Pure]
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static Node EvalBestChild(ref SolverConfig config, int parentVisits, ref Node.ChildBuffer children) =>
+    public static (int arrayIdx, int subIdx) EvalBestChild(ref SolverConfig config, int parentVisits, ref NodeScoresBuffer children) =>
         SolverUtils.EvalBestChild<SolverSingle>(ref config, parentVisits, ref children);
 
     [Pure]
-    public static Node Select(ref SolverConfig config, Node node)
+    public static Node Select(ref SolverConfig config, int nodeVisits, Node node)
     {
         while (true)
         {
@@ -35,11 +23,13 @@ public sealed class SolverSingle : ISolver
                 return node;
 
             // select the node with the highest score
-            node = EvalBestChild(ref config, node.State.Scores.Visits, ref node.Children);
+            var at = EvalBestChild(ref config, nodeVisits, ref node.ChildScores);
+            nodeVisits = node.ChildScores.GetVisits(at);
+            node = node.ChildAt(at);
         }
     }
 
-    public static (Node ExpandedNode, float Score) ExpandAndRollout(ref SolverConfig config, Node rootNode, Random random, Simulator simulator, Node initialNode)
+    public static (Node ExpandedNode, float Score) ExpandAndRollout(ref SolverConfig config, float maxScore, Node rootNode, Random random, Simulator simulator, Node initialNode)
     {
         ref var initialState = ref initialNode.State;
         // expand once
@@ -49,31 +39,33 @@ public sealed class SolverSingle : ISolver
         var poppedAction = initialState.AvailableActions.PopRandom(random);
         var expandedNode = initialNode.Add(SolverUtils.Execute(simulator, initialState.State, poppedAction, true));
 
-        return SolverUtils.Rollout(ref config, rootNode, expandedNode, random, simulator);
+        return SolverUtils.Rollout(ref config, maxScore, rootNode, expandedNode, random, simulator);
     }
 
-    public static void Backpropagate(Node rootNode, Node startNode, float score)
+    public static void Backpropagate(RootScores rootScores, Node rootNode, Node startNode, float score)
     {
         while (true)
         {
-            startNode.State.Scores.Visit(score);
-
             if (startNode == rootNode)
+            {
+                rootScores.Visit(score);
                 break;
+            }
+            startNode.ParentScores!.Value.Visit(startNode.ChildIdx, score);
 
             startNode = startNode.Parent!;
         }
     }
 
-    public static bool SearchIter(ref SolverConfig config, Node rootNode, Random random, Simulator simulator)
+    public static bool SearchIter(ref SolverConfig config, RootScores rootScores, Node rootNode, Random random, Simulator simulator)
     {
-        var selectedNode = Select(ref config, rootNode);
-        var (endNode, score) = ExpandAndRollout(ref config, rootNode, random, simulator, selectedNode);
+        var selectedNode = Select(ref config, rootScores.Visits, rootNode);
+        var (endNode, score) = ExpandAndRollout(ref config, rootScores.MaxScore, rootNode, random, simulator, selectedNode);
 
-        Backpropagate(rootNode, endNode, score);
+        Backpropagate(rootScores, rootNode, endNode, score);
         return true;
     }
 
-    public static void Search(ref SolverConfig config, Node rootNode, CancellationToken token) =>
-        SolverUtils.Search<SolverSingle>(ref config, config.Iterations, rootNode, token);
+    public static void Search(ref SolverConfig config, RootScores rootScores, Node rootNode, CancellationToken token) =>
+        SolverUtils.Search<SolverSingle>(ref config, config.Iterations, rootScores, rootNode, token);
 }

Solver/Crafty/SolverUtils.cs

@@ -39,35 +39,32 @@ public static class SolverUtils
 
     [Pure]
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static Node ChildMaxScore(ref Node.ChildBuffer children)
+    public static (int arrayIdx, int subIdx) ChildMaxScore(ref NodeScoresBuffer scores)
     {
-        var length = children.Count;
+        var length = scores.Count;
         var vecLength = Vector<float>.Count;
 
-        Span<float> scores = stackalloc float[vecLength];
-
         var max = (0, 0);
         var maxScore = 0f;
         for (var i = 0; length > 0; ++i)
         {
             var iterCount = Math.Min(vecLength, length);
 
-            ref var chunk = ref children.Data[i];
-            for (var j = 0; j < iterCount; ++j)
-                scores[j] = chunk[j].State.Scores.MaxScore;
+            ref var chunk = ref scores.Data[i];
+            var m = new Vector<float>(chunk.MaxScore.Span);
 
-            var idx = Intrinsics.HMaxIndex(new Vector<float>(scores), iterCount);
+            var idx = Intrinsics.HMaxIndex(m, iterCount);
 
-            if (scores[idx] >= maxScore)
+            if (m[idx] >= maxScore)
             {
                 max = (i, idx);
-                maxScore = scores[idx];
+                maxScore = m[idx];
             }
 
             length -= iterCount;
         }
 
-        return children.Data[max.Item1][max.Item2];
+        return max;
     }
 
     [Pure]
@@ -76,7 +73,7 @@ public static class SolverUtils
         var actions = new List<ActionType>();
         while (node.Children.Count != 0)
         {
-            node = ChildMaxScore(ref node.Children);
+            node = node.ChildAt(ChildMaxScore(ref node.ChildScores));
 
             if (node.State.Action != null)
                 actions.Add(node.State.Action.Value);
@@ -87,9 +84,9 @@ public static class SolverUtils
 
     [Pure]
     [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
-    public static Node EvalBestChild<S>(ref SolverConfig config, int parentVisits, ref Node.ChildBuffer children) where S : ISolver
+    public static (int arrayIdx, int subIdx) EvalBestChild<S>(ref SolverConfig config, int parentVisits, ref NodeScoresBuffer scores) where S : ISolver
     {
-        var length = children.Count;
+        var length = scores.Count;
         var vecLength = Vector<float>.Count;
 
         var C = MathF.Sqrt(config.ExplorationConstant * MathF.Log(parentVisits));
@@ -107,13 +104,14 @@ public static class SolverUtils
         {
             var iterCount = Math.Min(vecLength, length);
 
-            S.LoadChildData(scoreSums, visits, maxScores, ref children.Data[i], iterCount);
+            ref var chunk = ref scores.Data[i];
+            var s = new Vector<float>(chunk.ScoreSum.Span);
+            var vInt = new Vector<int>(chunk.Visits.Span);
+            var m = new Vector<float>(chunk.MaxScore.Span);
 
-            var s = new Vector<float>(scoreSums);
-            var m = new Vector<float>(maxScores);
-            var vInt = new Vector<int>(visits);
             vInt = Vector.Max(vInt, Vector<int>.One);
             var v = Vector.ConvertToSingle(vInt);
+
             var exploitation = (W * (s / v)) + (w * m);
             var exploration = CVector * Intrinsics.ReciprocalSqrt(v);
             var evalScores = exploitation + exploration;
@@ -129,11 +127,11 @@ public static class SolverUtils
             length -= iterCount;
         }
 
-        return children.Data[max.Item1][max.Item2];
+        return max;
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static (Node ExpandedNode, float Score) Rollout(ref SolverConfig config, Node rootNode, Node expandedNode, Random random, Simulator simulator)
+    public static (Node ExpandedNode, float Score) Rollout(ref SolverConfig config, float maxScore, Node rootNode, Node expandedNode, Random random, Simulator simulator)
     {
         // playout to a terminal state
         var currentState = expandedNode.State.State;
@@ -157,7 +155,7 @@ public static class SolverUtils
         var score = SimulationNode.CalculateScoreForState(currentState, currentCompletionState, config.MaxStepCount) ?? 0;
         if (currentCompletionState == CompletionState.ProgressComplete)
         {
-            if (score >= config.ScoreStorageThreshold && score >= rootNode.State.Scores.MaxScore)
+            if (score >= config.ScoreStorageThreshold && score >= maxScore)
             {
                 (var terminalNode, _) = ExecuteActions(simulator, expandedNode, actions[..actionCount], true);
                 return (terminalNode, score);
@@ -167,7 +165,7 @@ public static class SolverUtils
     }
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static void Search<S>(ref SolverConfig config, int iterations, Node rootNode, CancellationToken token) where S : ISolver
+    public static void Search<S>(ref SolverConfig config, int iterations, RootScores rootScores, Node rootNode, CancellationToken token) where S : ISolver
     {
         Simulator simulator = new(rootNode.State.State, config.MaxStepCount);
         var random = rootNode.State.State.Input.Random;
@@ -176,7 +174,7 @@ public static class SolverUtils
             if (token.IsCancellationRequested)
                 break;
 
-            if (!S.SearchIter(ref config, rootNode, random, simulator))
+            if (!S.SearchIter(ref config, rootScores, rootNode, random, simulator))
             {
                 // Retry, count this iteration as moot
                 i--;
@@ -211,15 +209,16 @@ public static class SolverUtils
         var actions = new List<ActionType>();
         var sim = new Simulator(state, config.MaxStepCount);
         var rootNode = CreateRootNode(config, state, true);
+        RootScores rootScores = new();
         while (!sim.IsComplete)
         {
             if (token.IsCancellationRequested)
                 break;
 
-            S.Search(ref config, rootNode, token);
+            S.Search(ref config, rootScores, rootNode, token);
             var (solution_actions, solution_node) = Solution(rootNode);
 
-            if (solution_node.Scores.MaxScore >= 1.0)
+            if (rootScores.MaxScore >= 1.0)
             {
                 actions.AddRange(solution_actions);
                 return (actions, solution_node.State);
@@ -243,7 +242,8 @@ public static class SolverUtils
     public static (List<ActionType> Actions, SimulationState State) SearchOneshot<S>(SolverConfig config, SimulationState state, CancellationToken token = default) where S : ISolver
     {
         var rootNode = CreateRootNode(config, state, false);
-        S.Search(ref config, rootNode, token);
+        RootScores rootScores = new();
+        S.Search(ref config, rootScores, rootNode, token);
         var (solution_actions, solution_node) = Solution(rootNode);
         return (solution_actions, solution_node.State);
     }