double AlphaBeta(GameDescriptor descriptor, int depth, double alpha, double beta)
{
Ruler.GameResult result = Ruler.CheckGame(descriptor);
if (result != Ruler.GameResult.NotYet)
return Evaluator.EvaluateResult(result,descriptor.Turn)-depth;
if (depth == 0 || nodeCount >= Max_Node)
{
nodeCount++;
return Evaluator.Evaluate(descriptor) - depth; // the quicker, the better
}
List<AI_Action> actions = descriptor.QueryAllActions();
Disturb(actions);
foreach (AI_Action tryAction in actions)
{
descriptor.DoAction(tryAction);
var tmp = -AlphaBeta(descriptor, depth - 1, -beta, -alpha);
tryAction.UnDo(descriptor);
if (tmp >= beta)
return beta;
if (tmp > alpha)
{
alpha = tmp;
if (depth == Max_Depth)
action = tryAction;
}
}
return alpha;
}
double AlphaBeta(GameDescriptor descriptor, int depth, double alpha, double beta)
{
Ruler.GameResult result = Ruler.CheckGame(descriptor);
if (result != Ruler.GameResult.NotYet)
{
return(Evaluator.EvaluateResult(result, descriptor.Turn) - depth);
}
if (depth == 0 || nodeCount >= Max_Node)
{
nodeCount++;
return(Evaluator.Evaluate(descriptor) - depth); // the quicker, the better
}
List <PlayerAction> actions = descriptor.QueryAllActions();
Disturb(actions);
foreach (PlayerAction tryAction in actions)
{
descriptor.DoAction(tryAction);
var tmp = -AlphaBeta(descriptor, depth - 1, -beta, -alpha);
tryAction.UnDo(descriptor);
if (tmp >= beta)
{
return(beta);
}
if (tmp > alpha)
{
alpha = tmp;
if (depth == Max_Depth)
{
action = tryAction;
}
}
}
return(alpha);
}
double AlphaBeta_Slow(GameDescriptor descriptor, int depth, double alpha, double beta)
{
Ruler.GameResult result = Ruler.CheckGame(descriptor);
if (result != Ruler.GameResult.NotYet)
{
return(Evaluator.EvaluateResult(result, descriptor.Turn) - depth);
}
if (depth == 0)
{
nodeCount++;
return(Evaluator.Evaluate(descriptor) - depth);
}
List <PlayerAction> actions = descriptor.QueryAllActions_Slow();
Disturb(actions);
foreach (PlayerAction tryAction in actions)
{
GameDescriptor clone = descriptor.Clone() as GameDescriptor;
clone.DoAction(tryAction);
var tmp = -AlphaBeta_Slow(clone, depth - 1, -beta, -alpha);
if (tmp >= beta)
{
return(beta);
}
if (tmp > alpha)
{
alpha = tmp;
if (depth == Max_Depth)
{
action = tryAction;
}
}
}
return(alpha);
}