public MCTSAgent()
{
_root = new MCTSNode(null, CheckerColor.Red);
}
// For GC
public void RemoveParent()
{
_parent = null;
}
public void Traverse()
{
if (_result != MoveResult.Continue)
{
ColorResult cr;
switch (_result)
{
case MoveResult.Win:
cr = (PrevMover == CheckerColor.Red ? ColorResult.RedWins : ColorResult.YellowWins);
break;
case MoveResult.Tie:
cr = ColorResult.Tie;
break;
default: // loss or invalid
cr = (PrevMover == CheckerColor.Red ? ColorResult.YellowWins : ColorResult.RedWins);
break;
}
Backpropagate(cr);
return;
}
// Choose
byte[] choices = MCTSAgent.Byte42;
byte choicesCount = 0;
float bestUCT = 0;
for (byte i = 0; i < 7; i++)
{
// Expand
if (_nodes[i] == null)
{
choicesCount = 0;
for (byte j = i; j < 7; j++)
{
if (_nodes[j] == null)
{
choices[choicesCount] = j;
choicesCount++;
}
}
byte choice = choices[MCTSAgent.Rand.Next(choicesCount)];
_nodes[choice] = new MCTSNode(_moveList, NextNextMover, this, choice);
_nodes[choice].Traverse();
return;
}
// Traverse if expanded
float iScore = _nextMover == CheckerColor.Red
? _nodes[i]._redScore
: _nodes[i]._visits - _nodes[i]._redScore;
float UCT = iScore / _nodes[i]._visits + C * (float)Math.Sqrt(Math.Log(_visits) / _nodes[i]._visits);
if (Math.Abs(UCT - bestUCT) < 0.0000001f)
{
choices[choicesCount] = i;
choicesCount++;
}
else if (UCT > bestUCT)
{
choices[0] = i;
choicesCount = 1;
bestUCT = UCT;
}
}
// Traverse chosen
byte choose = choices[MCTSAgent.Rand.Next(choicesCount)];
_nodes[choose].Traverse();
}
