private Node TreePolicy(Node node)
{
var state = node.State;
while (state?.State != State.COMPLETE && node.TurnDepth < TurnDepth)
{
if (state == null)
{
return(node);
}
if (FullyExpanded(node))
{
var selectionStrategy = SelectionStrategies.GetSelectionStrategy(Selection);
var stateRateStrategy = StateRateStrategies.GetStateRateStrategy(StateRate);
node = ChildSelection.SelectBestChild(state, node, EXPLORATION_CONSTANT, player, selectionStrategy, stateRateStrategy);
state = state.Simulate(new List <PlayerTask> {
node.Action
})[node.Action];
}
else
{
return(Expand(node, state));
}
}
return(node);
}
public PlayerTask Search()
{
List <PlayerTask> options = player.Options();
if (options.Count == 1 && options[0].PlayerTaskType == PlayerTaskType.END_TURN)
{
return(options.First());
}
StopWatch.Start();
var selectionStrategy = SelectionStrategies.GetSelectionStrategy(Selection);
var stateRateStrategy = StateRateStrategies.GetStateRateStrategy(StateRate);
while (StopWatch.ElapsedMilliseconds < COMPUTATIONAL_BUDGET)
{
POGame state = InitialState.getCopy();
Node lastNode = TreePolicy(Root);
float delta = DefaultPolicyHeuristic(lastNode);
Backup(lastNode, delta);
}
StopWatch.Stop();
return(ChildSelection.SelectBestChild(InitialState, Root, EXPLORATION_CONSTANT, player, selectionStrategy, stateRateStrategy).Action);
}
