OpenChess

Code: Select all

    private double deepEvaluateBoard(Board board, int currentDepth, double alpha, double beta, Move initialMove) {
        if (board.isCheckmate() || board.isDraw() || currentDepth <= 0) {
            this.moveHistorys.put(initialMove, board.getMoveHistory()); // this is not working
            return evaluateBoard(board); // evaluateBoard evaluates from the perspective of color whose turn it is.
        } else {
            double totalPositionValue = -1e40;

            List<Move> allPossibleMoves = board.getAllPossibleMoves();
            for (Move move : allPossibleMoves) {
                board.makeMove(move);
                totalPositionValue = max(-deepEvaluateBoard(board, currentDepth - 1, -beta, -alpha, initialMove), value);
                board.unMakeMove(1);

                alpha = max(alpha, totalPositionValue);
                if (alpha >= beta) {
                    break;
                }
            }

            return totalPositionValue;
        }
    }
    

Code: Select all

function Search(Board: TBitBoard; Depth: Integer; Alpha, Beta: Integer; CurrentBoardKey: UInt64; MoveInfo: TMoveInfo): TMoveWithScore;
var
  i: Integer;
  MoveList: TInt64List;
  TmpBoard: TBitBoard;
  Score: TMoveWithScore;
  CurScore: TMoveWithScore;
  MovStr: string;
  Key: UInt64;
  Entry: TTEntry;
  CurMove: TMoveInfo;
begin
  nodes := nodes + 1;
  Score.Move := 0;
  Result.Move := 0;
  if Depth = 0 then
  begin
    Result.MovStr :='';
    Result.Score := QuiescenceSearch(Board,2,Alpha,Beta).Score;
    Exit;
  end;
  if GetTTEntry(CurrentBoardKey,Entry) and (entry.Depth>=Depth) then
  begin
    if Entry.EntryType = EXACT_VALUE then
    begin
      Result.Score := Entry.Value;
      Exit;
    end
    else
    if entry.EntryType = LOWERBOUND then
      Alpha := max(Alpha,Entry.Value)
    else
    if Entry.EntryType = UPPERBOUND then
      Beta := min(Beta,Entry.Value);
    if Alpha>=Beta then
    begin
      Result.Score := Entry.Value;
      Exit;
    end
  end;
  MoveList := TInt64List.Create;
  GenMoves(Board,MoveList);
  Score.Score := -MAXINT;
  if (MoveList.Count = 0) then
  begin
    if (Board.IsWhiteToMove and IsWhiteKingInCheck(Board)) or ((not Board.IsWhiteToMove) and IsBlackKingInCheck(Board)) then
      Score.Score := -10000 - Depth
    else
      Score.Score := 0;
  end
  else
  begin
    SortMoves(Board,MoveList{,CurrentBoardKey});
    for i := 0 to MoveList.Count - 1 do
    begin
      Key := CurrentBoardKey;
      TmpBoard := Board;
      CurMove := MoveList.Items[i];
      MovStr := MoveToStr(CurMove);
      DoMoveBK(TmpBoard,CurMove,Key);
      if IsThreefoldRepeatition(Key) or (TmpBoard.FiftyMove = 50) then
      begin
        PositionKeyList.Add(Key);
        Score.Score := 0;
      end
      else
      begin
        CurScore := Search(TmpBoard,Depth-1, -beta, -alpha, Key,MoveList.Items[i]);
        CurScore.Score := -CurScore.Score;
        CurScore.Move := CurMove;
        if CurScore.Score>Score.Score then
        begin
          Score := CurScore;
          Score.Move := Integer(CurMove);
        end;
      end;

      if Score.Score>=Beta then
      begin
        Result.Score := Score.Score;
        Result.MovStr := MoveToStr(CurMove)+' '+Score.MovStr;
        Result.Move := CurMove;
        break;
      end;

      if Score.Score>Alpha then
      begin
        Alpha := Score.Score;
        Result.MovStr := MoveToStr(CurMove)+' '+Score.MovStr;
        Score.Move := CurMove;
      end;
    end;
  end;
  Entry.Value := Score.Score;
  if Score.Score<=Alpha then
    Entry.EntryType := LOWERBOUND
  else
  if Score.Score>=Beta then
    Entry.EntryType := UPPERBOUND
  else
    Entry.EntryType := EXACT_VALUE;
  Entry.Depth := Depth;
  StoreTTEntry(CurrentBoardKey, Entry.Value, Entry.EntryType, Depth);
  Result.Score := Score.Score;
  Result.Move := Score.Move;
  MoveList.Free;
end;