public static void ExpandTree(object t)
{
//start the tree
MonteCarloSearchTree tree = (MonteCarloSearchTree)t;
tree.currentSimulation = tree.startingSimulation.Clone();
tree.rootNode = new Node(tree.currentSimulation.isPlayersTurn);
Node selectedNode;
Node expandedNode;
//for up to so many times, try to expand the nodes and find a winning outcome
for (int i = 0; i < tree.nbIteration; i++)
{
tree.currentSimulation = tree.startingSimulation.Clone();
selectedNode = tree.rootNode.SelectNodeToExpand(tree.rootNode.numberOfSimulations, tree.currentSimulation);
expandedNode = selectedNode.Expand(tree.currentSimulation);
expandedNode.BackPropagate(expandedNode.Simulate(tree.currentSimulation));
}
tree.doneEvent.Set();
}
private IEnumerator Play(bool isFirstTurn)
{
//choose 3 4 5 at random if goes first
if (isFirstTurn)
{
Utils.GetGameController().AddPiece(new Vector2Int(0, Random.Range(3, 6)));
yield break;
}
//show wait popup
Utils.GetUIController().OpponentPopup(true);
yield return(new WaitForSeconds(0.1f));
//simulate current board
simulation = new Simulation(false, Utils.GetGameController().board);
// One event is used for each MCTS.
ManualResetEvent[] doneEvents = new ManualResetEvent[parallelProcesses];
MonteCarloSearchTree[] trees = new MonteCarloSearchTree[parallelProcesses];
//set threads
for (int i = 0; i < parallelProcesses; i++)
{
doneEvents[i] = new ManualResetEvent(false);
trees[i] = new MonteCarloSearchTree(simulation, doneEvents[i], mctsIterations);
ThreadPool.QueueUserWorkItem(new WaitCallback(ExpandTree), trees[i]);
}
//wait until they all finish
WaitHandle.WaitAll(doneEvents);
//regrouping all results
Node rootNode = new Node();
for (int i = 0; i < parallelProcesses; i++)
{
//sort children
var sortedChildren = trees[i].rootNode.children.ToList();
sortedChildren.Sort((pair1, pair2) => pair1.Value.CompareTo(pair2.Value));
//get only the first children of each choice
foreach (var child in sortedChildren)
{
if (!rootNode.children.ContainsValue(child.Value))
{
Node rootChild = new Node {
numberOfWinSimulations = child.Key.numberOfWinSimulations,
numberOfSimulations = child.Key.numberOfSimulations
};
rootNode.children.Add(rootChild, child.Value);
}
else
{
Node rootChild = rootNode.children.First(p => p.Value == child.Value).Key;
rootChild.numberOfWinSimulations += child.Key.numberOfWinSimulations;
rootChild.numberOfSimulations += child.Key.numberOfSimulations;
}
}
}
//gets the best choice and perform it
int choice = rootNode.MostSelectedMove();
var movements = Utils.GetGameController().possibleMovements;
Vector2Int indexes = movements.Find(element => element.y == choice);
Utils.GetGameController().AddPiece(indexes);
//hide wait popup
Utils.GetUIController().OpponentPopup(false);
}
