/// <summary>
/// Wykonujemy symulacje
/// </summary>
/// <returns></returns>
private double Rollout(MctsNode node, int numberOfLastKingMovesWithoutBeat)
{
int result = 0;
CheckersBoard board = node.Board;
PieceColor color = node.Color;
while (true)
{
var moves = board.GetAllPossibleMoves(color);
if (moves.Count > 0)
{
var move = moves[RandomGenerator.Next(0, moves.Count - 1)];
board = board.GetBoardAfterMove(move);
if (move.OldPiece.IsKing && (move.BeatedPieces == null || move.BeatedPieces.Count == 0))
{
numberOfLastKingMovesWithoutBeat++;
}
else
{
numberOfLastKingMovesWithoutBeat = 0;
}
if (numberOfLastKingMovesWithoutBeat > 49)
{
return(0.5);
}
}
else
{
result = color == PieceColor.Black ? 1 : -1;
break;
}
color = color == PieceColor.Black ? PieceColor.White : PieceColor.Black;
}
return(result);
}
public MctsTree(int numberOfIterations, double uctParameter, Random generator, CheckersBoard board, PieceColor color)
{
NumberOfTotalSimulations = 0;
NumberOfIterations = numberOfIterations;
UctParameter = uctParameter;
RandomGenerator = generator;
Root = new MctsNode(color, board, null);
}
public MctsNode(PieceColor color, CheckersBoard board, MctsNode parent, Move move)
{
Move = move;
Color = color;
Board = board;
Parent = parent;
NumberOfSimulations = 0;
NumberOfWins = 0;
}
/// <summary>
/// Dodajemy do liścia nowe gałęzie odpowiadające kolejnym ruchom z danego stanu
/// </summary>
/// <param name="node"></param>
private void Expand(MctsNode node)
{
var moves = node.Board.GetAllPossibleMoves(node.Color);
if (moves.Count > 0)
{
var children = new List <MctsNode>();
foreach (var move in moves)
{
var board = node.Board.GetBoardAfterMove(move);
var color = node.Color == PieceColor.White ? PieceColor.Black : PieceColor.White;
children.Add(new MctsNode(color, board, node, move));
}
node.Children = children;
}
}
/// <summary>
/// Wrzucamy wyniki wyżej
/// </summary>
private void Backpropagate(double result, MctsNode node)
{
while (node != null)
{
node.NumberOfSimulations++;
if (result == 0.5)
{
node.NumberOfWins += 0.5;
}
if (result == -1 && node.Color == PieceColor.White)
{
node.NumberOfWins++;
}
if (result == 1 && node.Color == PieceColor.Black)
{
node.NumberOfWins++;
}
node = node.Parent;
}
}
