public Node Min(Node node, double alpha, double beta)
{
if (IsTerminal(node)) return node;
double v = double.PositiveInfinity;
foreach (var successor in (node.State as IAdversarialState).GetSuccessors())
{
if (!ProcessEvent(node, successor)) return node;
var s = successor.State as IAdversarialState;
var child = new Node(node, successor) { Cost = s.Utility, Depth = node.Depth + 1 };
node.AddChild(child);
var g = Max(child, alpha, beta);
v = Math.Min(v, g.Cost);
child.Cost = g.Cost;
node.Cost = v;
// check to see if we can prune
if (v <= alpha) return child;
beta = Math.Min(beta, v);
}
if (node.Children.Count == 0)
return node;
else
return GetBestChildNode(node, v);
}
private Node Find(Node node, double initial, Func<double, double, double> limit, Func<Node, Node> f)
{
if (IsTerminal(node)) return node;
double v = initial;
foreach (var successor in (node.State as IAdversarialState).GetSuccessors())
{
if (!ProcessEvent(node, successor)) return node;
var s = successor.State as IAdversarialState;
var child = new Node(node, successor) { Cost = s.Utility, Depth = node.Depth + 1 };
node.AddChild(child);
var g = f(child);
v = limit(v, g.Cost);
child.Cost = g.Cost;
node.Cost = v;
}
if (node.Children.Count == 0)
return node;
else
return GetBestChildNode(node, v);
}
public Node Max(Node node, double alpha, double beta)
{
if (IsTerminal(node))
{
return(node);
}
double v = double.NegativeInfinity;
foreach (var successor in (node.State as IAdversarialState).GetSuccessors())
{
if (!ProcessEvent(node, successor))
{
return(node);
}
var s = successor.State as IAdversarialState;
var child = new Node(node, successor)
{
Cost = s.Utility, Depth = node.Depth + 1
};
node.AddChild(child);
var g = Min(child, alpha, beta);
v = Math.Max(v, g.Cost);
child.Cost = g.Cost;
node.Cost = v;
// check to see if we can prune
if (v >= beta)
{
return(child);
}
alpha = Math.Max(alpha, v);
}
if (node.Children.Count == 0)
{
return(node);
}
else
{
return(GetBestChildNode(node, v));
}
}
private Node Find(Node node, double initial, Func <double, double, double> limit, Func <Node, Node> f)
{
if (IsTerminal(node))
{
return(node);
}
double v = initial;
foreach (var successor in (node.State as IAdversarialState).GetSuccessors())
{
if (!ProcessEvent(node, successor))
{
return(node);
}
var s = successor.State as IAdversarialState;
var child = new Node(node, successor)
{
Cost = s.Utility, Depth = node.Depth + 1
};
node.AddChild(child);
var g = f(child);
v = limit(v, g.Cost);
child.Cost = g.Cost;
node.Cost = v;
}
if (node.Children.Count == 0)
{
return(node);
}
else
{
return(GetBestChildNode(node, v));
}
}