/// <summary>
/// Clone method which does a deep copy of the object.
/// This is needed if we are materializing a tranposition subtree and
/// encounter a subnode which is itself tranposition linked; we need to create
/// another instance of the visitor which can then proceed enumerating indpendently.
/// </summary>
/// <returns></returns>
public object Clone()
{
MCTSNodeTranspositionVisitor ret = new MCTSNodeTranspositionVisitor();
ret.Visitor = Visitor.Clone() as MCTSNodeSequentialVisitor;
ret.TranspositionRootNWhenVisitsStarted = TranspositionRootNWhenVisitsStarted;
return(ret);
}
private static LeafEvaluationResult ExtractTranspositionNodesFromSubtree(MCTSNode node, ref MCTSNodeStruct transpositionRootNode,
ref int numAlreadyLinked, MCTSNodeTranspositionVisitor linkedVisitor)
{
LeafEvaluationResult result = default;
// Determine how many evaluations we should extract (based on number requested and number available)
int numAvailable = linkedVisitor.TranspositionRootNWhenVisitsStarted - numAlreadyLinked;
int numDesired = node.NInFlight + node.NInFlight2;
if (numDesired > numAvailable && WARN_COUNT < 10)
{
Console.WriteLine(numDesired + " Warning: multiple nodes were requested from the transposition subtree, available " + numAvailable);
WARN_COUNT++;
}
int numToFetch = Math.Min(numDesired, numAvailable);
Debug.Assert(numToFetch > 0);
// Extract each evaluation
for (int i = 0; i < numToFetch; i++)
{
MCTSNodeStructIndex transpositionSubnodeIndex = linkedVisitor.Visitor.GetNext();
Debug.Assert(!transpositionSubnodeIndex.IsNull);
NumExtractedAndNeverCloned++;
numAlreadyLinked++;
// Prepare the result to return
ref MCTSNodeStruct transpositionSubnode = ref node.Context.Tree.Store.Nodes.nodes[transpositionSubnodeIndex.Index];
LeafEvaluationResult thisResult = new LeafEvaluationResult(transpositionSubnode.Terminal, transpositionRootNode.WinP,
transpositionRootNode.LossP, transpositionRootNode.MPosition);
// Update our result node to include this node
result = AddResultToResults(result, numToFetch, i, thisResult);
if (VERBOSE)
{
Console.WriteLine($"ProcessAlreadyLinked {node.Index} yields {result.WinP} {result.LossP} via linked subnode root {transpositionRootNode.Index.Index} {transpositionRootNode} chose {transpositionSubnode.Index.Index}");
}
node.Ref.NumNodesTranspositionExtracted++;
}