// Loading the table from a file
public bool Load(string fileName)
{
// Open the file as a Java tokenizer
using (var sr = new StreamReader(fileName))
{
// Create a game board on which to "play" the opening sequences stored in
// the book, so that we know which position to associate with which move
jcBoard board = new jcBoard();
jcMove mov = new jcMove();
jcMoveListGenerator successors = new jcMoveListGenerator();
// How many lines of play do we have in the book?
var lines = File.ReadAllLines(fileName);
int numLines = lines.Length;
for (int wak = 0; wak < numLines; wak++)
{
// Begin the line of play with a clean board
board.StartingBoard();
// Load the continuation
var lineNums = lines[wak].Split(' ');
for (int i = 0; i < lineNums.Length; i++)
{
if (lineNums[i] == "END")
break;
successors.ComputeLegalMoves(board);
var source = Convert.ToInt32(lineNums[i]);
var destination = Convert.ToInt32(lineNums[i + 1]);
i++;
mov = successors.FindMoveForSquares(source, destination);
StoreMove(board, mov);
board.ApplyMove(mov);
}
}
}
return true;
}
// private jcMove UnrolledAlphabeta
// The standard alphabeta, with the top level "unrolled" so that it can
// return a jcMove structure instead of a mere minimax value
// See jcAISearchAgent.Alphabeta for detailed comments on this code
private jcMove UnrolledAlphabeta(jcBoard theBoard, int depth, int alpha, int beta)
{
jcMove BestMov = new jcMove();
jcMoveListGenerator movegen = new jcMoveListGenerator();
movegen.ComputeLegalMoves(theBoard);
HistoryTable.SortMoveList(movegen, theBoard.GetCurrentPlayer());
jcBoard newBoard = new jcBoard();
int bestSoFar;
bestSoFar = ALPHABETA_MINVAL;
int currentAlpha = alpha;
jcMove mov;
// Loop on the successors
while((mov = movegen.Next()) != null) {
// Compute a board position resulting from the current successor
newBoard.Clone(theBoard);
newBoard.ApplyMove(mov);
// And search it in turn
int movScore = AlphaBeta(MINNODE, newBoard, depth - 1, currentAlpha, beta);
// Ignore illegal moves in the alphabeta evaluation
if(movScore == ALPHABETA_ILLEGAL)
continue;
currentAlpha = Math.Max(currentAlpha, movScore);
// Is the current successor better than the previous best?
if(movScore > bestSoFar) {
BestMov.Copy(mov);
bestSoFar = movScore;
BestMov.MoveEvaluation = bestSoFar;
// Can we cutoff now?
if(bestSoFar >= beta) {
TransTable.StoreBoard(theBoard, bestSoFar, jcMove.EVALTYPE_UPPERBOUND, depth, MoveCounter);
// Add this move's efficiency in the HistoryTable
HistoryTable.AddCount(theBoard.GetCurrentPlayer(), mov);
return BestMov;
}
}
}
// Test for checkmate or stalemate
if(bestSoFar <= ALPHABETA_GIVEUP) {
newBoard.Clone(theBoard);
jcMoveListGenerator secondary = new jcMoveListGenerator();
newBoard.SwitchSides();
if(secondary.ComputeLegalMoves(newBoard)) {
// Then, we are not in check and may continue our efforts.
HistoryTable.SortMoveList(movegen, newBoard.GetCurrentPlayer());
movegen.ResetIterator();
BestMov.MoveType = jcMove.MOVE_STALEMATE;
BestMov.MovingPiece = jcBoard.KING + theBoard.GetCurrentPlayer();
while((mov = movegen.Next()) != null) {
newBoard.Clone(theBoard);
newBoard.ApplyMove(mov);
if(secondary.ComputeLegalMoves(newBoard)) {
BestMov.MoveType = jcMove.MOVE_RESIGN;
}
}
} else {
// We're in check and our best hope is GIVEUP or worse, so either we are
// already checkmated or will be soon, without hope of escape
BestMov.MovingPiece = jcBoard.KING + theBoard.GetCurrentPlayer();
BestMov.MoveType = jcMove.MOVE_RESIGN;
}
}
// If we haven't returned yet, we have found an accurate minimax score
// for a position which is neither a checkmate nor a stalemate
TransTable.StoreBoard(theBoard, bestSoFar, jcMove.EVALTYPE_ACCURATE, depth, MoveCounter);
return BestMov;
}