/**
* Converts the string representation of a move into a move and then applies it to the current
* board.
*
* @param m the move string.
*/
public void applyMove(String m) {
if (board.plyCount() != plyCount++) {
throw new IllegalStateException("Did you forget to call undoMove() somewhere?");
}
board.applyMove(board.createMoveFromString(m));
}
/*
* evalHigh
*
* This function evaluates the board according to the above spec. It
* loops through all the pieces on the board and assigns two sums:
* whiteSum and blackSum, for the value of white's and black's pieces,
* respectively. Then it adds them and sets the sign according to whose
* turn it is.
*/
private int evalHigh(ArrayBoard board, int color) {
if (color == ArrayBoard.WHITE) {
int whiteSum = 0;
if (board.hasCastled[ArrayBoard.WHITE]) whiteSum += CASTLE_BONUS;
for (ArrayPiece p : board.allPiecesOfColor(ArrayBoard.WHITE)) {
switch (p.type()) {
case ArrayPiece.KING:
whiteSum += kingval;
break;
case ArrayPiece.QUEEN:
whiteSum += queenval;
break;
case ArrayPiece.ROOK:
whiteSum += rookval;
break;
case ArrayPiece.BISHOP:
whiteSum += bishoppos[p.row()][p.col()] + bishopval;
break;
case ArrayPiece.KNIGHT:
whiteSum += knightpos[p.row()][p.col()] + knightval;
break;
case ArrayPiece.PAWN:
whiteSum += pawnpos[p.row()][p.col()] + pawnval;
break;
}
}
return whiteSum;
} else {
int blackSum = 0;
for (ArrayPiece p : board.allPiecesOfColor(ArrayBoard.BLACK)) {
switch (p.type()) {
case ArrayPiece.KING:
blackSum += kingval;
break;
case ArrayPiece.QUEEN:
blackSum += queenval;
break;
case ArrayPiece.ROOK:
blackSum += rookval;
break;
case ArrayPiece.BISHOP:
blackSum += bishoppos[7 - p.row()][p.col()] + bishopval;
break;
case ArrayPiece.KNIGHT:
blackSum += knightpos[7 - p.row()][p.col()] + knightval;
break;
case ArrayPiece.PAWN:
blackSum += pawnpos[7 - p.row()][p.col()] + pawnval;
break;
}
}
return blackSum;
}
}
/*
* eval
*
* This function figures out if it's endgame. if so,
* evaluate with that knowledge. Else, use the regular evaluator,
* which just counts pieces.
*/
public int eval(ArrayBoard board) {
int whiteSum = 0, blackSum = 0;
int numWhitePieces = board.countOfColor(ArrayBoard.WHITE);
int numBlackPieces = board.countOfColor(ArrayBoard.BLACK);
if (numWhitePieces <= 5 || numBlackPieces <= 5) {
whiteSum = evalLow(board, ArrayBoard.WHITE);
blackSum = evalLow(board, ArrayBoard.BLACK);
} else {
whiteSum = evalHigh(board, ArrayBoard.WHITE);
blackSum = evalHigh(board, ArrayBoard.BLACK);
}
return (board.toPlay() == ArrayBoard.WHITE) ? (whiteSum - blackSum) : (blackSum - whiteSum);
}
/*
* evalLow
*
* This function evaluates the board according to the above spec,
* but makes pieces more valuable. It also uses the kingpos array to
* encourage the king to move towards the middle of the board.
*/
private int evalLow(ArrayBoard board, int color) {
if (color == ArrayBoard.WHITE) {
int whiteSum = 0;
if (board.hasCastled[ArrayBoard.WHITE]) whiteSum += CASTLE_BONUS;
for (ArrayPiece p : board.allPiecesOfColor(ArrayBoard.WHITE)) {
switch (p.type()) {
case ArrayPiece.KING:
whiteSum +=
4
* (calculateWhiteKingWeight(
p,
board.countOfColor(ArrayBoard.WHITE),
board.countOfColor(ArrayBoard.BLACK)));
break;
case ArrayPiece.QUEEN:
whiteSum += 2 * queenval;
break;
case ArrayPiece.ROOK:
whiteSum += 2 * rookval;
break;
case ArrayPiece.BISHOP:
whiteSum += 2 * (bishoppos[p.row()][p.col()] + bishopval);
break;
case ArrayPiece.KNIGHT:
whiteSum += 2 * (knightpos[p.row()][p.col()] + knightval);
break;
case ArrayPiece.PAWN:
whiteSum += 2 * (pawnpos[p.row()][p.col()] + pawnval);
break;
}
}
return whiteSum;
} else {
int blackSum = 0;
for (ArrayPiece p : board.allPiecesOfColor(ArrayBoard.BLACK)) {
switch (p.type()) {
case ArrayPiece.KING:
blackSum +=
4
* (calculateBlackKingWeight(
p,
board.countOfColor(ArrayBoard.WHITE),
board.countOfColor(ArrayBoard.BLACK)));
break;
case ArrayPiece.QUEEN:
blackSum += 2 * queenval;
break;
case ArrayPiece.ROOK:
blackSum += 2 * rookval;
break;
case ArrayPiece.BISHOP:
blackSum += 2 * (bishoppos[7 - p.row()][p.col()] + bishopval);
break;
case ArrayPiece.KNIGHT:
blackSum += 2 * (knightpos[7 - p.row()][p.col()] + knightval);
break;
case ArrayPiece.PAWN:
blackSum += 2 * (pawnpos[7 - p.row()][p.col()] + pawnval);
break;
}
}
return blackSum;
}
}
