//*********************************************************
//
/// <summary>
/// Find the best move for a player using alpha-beta for a given depth
/// </summary>
/// <param name="chessBoard"> Chess board</param>
/// <param name="searchMode"> Search mode</param>
/// <param name="ePlayerColor"> Color doing the move</param>
/// <param name="moveList"> List of move to try</param>
/// <param name="iTotalMoveCount"> Total list of moves</param>
/// <param name="iDepth"> Maximum depth</param>
/// <param name="iAlpha"> Alpha bound</param>
/// <param name="iBeta"> Beta bound</param>
/// <param name="transTable"> Transposition table or null if not using one</param>
/// <param name="dtTimeOut"> Time limit (DateTime.MaxValue for no time limit)</param>
/// <param name="iPermCount"> Total permutation evaluated</param>
/// <param name="iBestMoveIndex"> Index of the best move</param>
/// <param name="bTimeOut"> Return true if time out</param>
/// <param name="arrPoints"> Returns point of each move in move list</param>
/// <returns>
/// Points
/// </returns>
//
//*********************************************************
private int FindBestMoveUsingAlphaBetaAtDepth(ChessBoard chessBoard, SearchMode searchMode, ChessBoard.PlayerColorE ePlayerColor, List<ChessBoard.MovePosS> moveList, int iTotalMoveCount, int iDepth, int iAlpha, int iBeta, TransTable transTable, DateTime dtTimeOut, out int iPermCount, out int iBestMoveIndex, out bool bTimeOut, out int[] arrPoints) {
int iRetVal = -10000000;
int iWhiteMoveCount;
int iBlackMoveCount;
int iMoveCount;
int iIndex;
int iPts;
ChessBoard.MovePosS move;
AlphaBetaInfo abInfo;
ChessBoard.RepeatResultE eResult;
bTimeOut = false;
abInfo = new AlphaBetaInfo();
abInfo.m_arrMovePos = new ChessBoard.MovePosS[iDepth];
abInfo.m_iPermCount = 0;
abInfo.m_dtTimeOut = dtTimeOut;
abInfo.m_transTable = transTable;
abInfo.m_iMaxDepth = iDepth;
abInfo.m_searchMode = searchMode;
abInfo.m_iAttackedPos = 0;
abInfo.m_iAttackedPieces = 0;
iBestMoveIndex = -1;
arrPoints = new int[moveList.Count];
if (ePlayerColor == ChessBoard.PlayerColorE.White) {
iWhiteMoveCount = iTotalMoveCount;
iBlackMoveCount = 0;
} else {
iWhiteMoveCount = 0;
iBlackMoveCount = iTotalMoveCount;
}
iMoveCount = moveList.Count;
iIndex = 0;
iRetVal = iAlpha;
while (iIndex < iMoveCount && !bTimeOut) {
move = moveList[iIndex];
eResult = chessBoard.DoMoveNoLog(move);
abInfo.m_arrMovePos[iDepth - 1] = move;
if (eResult == ChessBoard.RepeatResultE.NoRepeat) {
iPts = -AlphaBeta(chessBoard,
(ePlayerColor == ChessBoard.PlayerColorE.Black) ? ChessBoard.PlayerColorE.White : ChessBoard.PlayerColorE.Black,
iDepth - 1,
-iBeta,
-iRetVal,
iWhiteMoveCount,
iBlackMoveCount,
abInfo);
} else {
iPts = 0;
}
arrPoints[iIndex] = iPts;
chessBoard.UndoMoveNoLog(move);
if (iPts == Int32.MinValue) {
iRetVal = iPts;
bTimeOut = true;
} else {
if (iPts > iRetVal) {
TraceSearch(iDepth, ePlayerColor, move, iPts);
iRetVal = iPts;
iBestMoveIndex = iIndex;
}
}
iIndex++;
}
iPermCount = abInfo.m_iPermCount;
return(iRetVal);
}
//*********************************************************
//
/// <summary>
/// Gets one of the static translation table
/// </summary>
/// <param name="iIndex"> Index of the table (0..ProcessorCount-1)</param>
/// <returns>
/// Translation table
/// </returns>
//
//*********************************************************
static public TransTable GetTransTable(int iIndex) {
if (m_arrTransTable[iIndex] == null) {
m_arrTransTable[iIndex] = new TransTable(TranslationTableSize);
}
return(m_arrTransTable[iIndex]);
}
