private void ScoringNode(EstimateMoveNode node)
{
// 頓死の確認
if (node.Children.Any(c => c.Finished && c.Result != GameResult.Draw))
{
// 次手で終わる＝敗北確定手
node.ExpectedScore = new BoardScore(node.Turn.GetNextUser(), node.Depth + 1);
return;
}
// 確定結果の統計取得
var determinResults = node.Children
.Select(c => c.ExpectedScore)
.GroupBy(s => s?.Result)
.OrderBy(g => g.Key)
.Select(g => new
{
Result = g.Key,
Count = g.Count(),
MinTurnCount = g.Min(s => s.DeterminsticTurnCount),
MaxTurnCount = g.Max(s => s.DeterminsticTurnCount),
})
.ToArray();
if (determinResults.Length == 1)
{
var result = determinResults.First();
if (result.Result.HasValue)
{
// 何をやっても結果が確定
node.ExpectedScore = new BoardScore(result.Result.Value, result.Result == node.Turn.GetNextUser().ToResult() ? result.MinTurnCount : result.MaxTurnCount);
return;
}
}
var nextTurnResult = determinResults.FirstOrDefault(s => s.Result == node.Turn.GetNextUser().ToResult());
if (null != nextTurnResult)
{
// 次手の最善で敗北確定
node.ExpectedScore = new BoardScore(node.Turn.GetNextUser().ToResult(), nextTurnResult.MinTurnCount);
return;
}
// 読み切り範囲外なので機械的なScoringに頼る
if (node.Children?.IsEmpty() ?? true)
{
node.AtomicScore = boardEvaluator.Evaluate(node.Board);
node.ExpectedScore = node.AtomicScore;
}
else
{
node.ExpectedScore = node.Children.OrderByDescending(c => c.ExpectedScore.GetScore(c.Turn)).Select(c => c.ExpectedScore).First();
}
}
public IList <StoneMove> EstimateStoneMove(ISimpleBoard board, int fetchCount = 1)
{
var root = new EstimateMoveNode(board);
BuildNode(root, this.maxDepth);
root.DebugOutputEstimateInternal(3);
return(root.Children
.OrderByDescending(c => c.ExpectedScore.GetScore(c.Turn))
.ThenByDescending(c => c.ExpectedScore.DeterminsticTurnCount)
.ThenByDescending(c => c.AtomicScore?.GetScore(c.Turn) ?? 0)
.Take(fetchCount)
.Select(c => c.Move)
.ToList());
}
private void BuildNode(EstimateMoveNode node, int maxDepth)
{
// tree終了条件
if (node.Depth < maxDepth && !node.Finished)
{
var isAbsoluteNextTurnMine = node.IsAbsoluteNextTurnMine;
var _lock = new object();
int?minWinTurnCount = null;
var isBreak = false;
Action <StoneMove> childProcess = move =>
{
if (isBreak)
{
return;
}
var child = node.AddChild(move);
BuildNode(child, minWinTurnCount ?? maxDepth);
// 勝利手数の最小を保持する。
if (child.ExpectedScore.Result == child.Turn.ToResult())
{
lock (_lock)
{
if (!minWinTurnCount.HasValue || minWinTurnCount > child.ExpectedScore.DeterminsticTurnCount)
{
minWinTurnCount = child.ExpectedScore.DeterminsticTurnCount;
}
}
}
// 敗北確定手を発見したならそこで止める。
if (child.Result == node.Turn.GetNextUser().ToResult())
{
isBreak = true;
return;
}
if (isAbsoluteNextTurnMine && child.ExpectedScore.Result == child.Turn.ToResult())
{
// 勝利確定手発見時は探索中止。勝ち方にこだわらない。
// ここを調整すると賢く見えそう。
// 相手のターンでも打ち切っていいんだけど、難しい手の時にあきらめ挙動になってしまうのを回避する。
isBreak = true;
return;
}
};
if (0 >= node.Depth)
{
moveNominator.GetCandidateStoneMove(node.Board).AsParallel().ForAll(childProcess);
}
else
{
moveNominator.GetCandidateStoneMove(node.Board).ForEach(childProcess);
}
}
ScoringNode(node);
node.ReleaseData();
}
