public override Node PrepareAction(Node currState, Player oponent)
{
Node nextPlay = null;
// Verify if the last state belongs to the mcts game tree
// If the curr state is null, that means the previous player had no moves
// and the game state did not changed.
if (currState != null)
{
if (!GameTree.Childs.Contains(currState))
{
GameTree = currState;
}
else
{
foreach (Node node in GameTree.Childs)
{
if (node.Equals(currState))
{
GameTree = node;
break;
}
}
}
}
if (Selection != null && Simulation != null)
{
List <Node> selectionPath = new List <Node>();
Stopwatch cron = new Stopwatch();
TimeSpan max = new TimeSpan(0, 0, MAX_TIME);
SelectionParameters args;
int simulationResult = 0;
Node auxRoot = GameTree;
selectionPath.Add(auxRoot);
// Traverse the game tree searching until it reaches a node that has no childs
if (auxRoot != null)
{
while ((auxRoot.Childs != null) && (auxRoot.Childs.Count > 0))
{
args.root = auxRoot;
args.validStates = auxRoot.Childs;
auxRoot = Selection.Execute(args);
auxRoot.VisitCount++;
selectionPath.Add(auxRoot);
}
}
// Starts to simulate games from the last node visited in the previous loop
cron.Start();
while (cron.Elapsed < max)
{
if (auxRoot != null)
{
simulationResult = RunSimulation(auxRoot);
Backpropagation(selectionPath, simulationResult);
selectionPath.Clear();
}
auxRoot = GameTree;
}
Random rnd = new Random();
nextPlay = GameTree.Childs.ElementAt(rnd.Next(auxRoot.Childs.Count));
GameTree = nextPlay;
}
return(nextPlay);
}
