protected int quiescence(Position position, int alpha, int beta, boolean maxTurn)
throws IllegalMoveException {
int evaluation = handleTerminal(position, maxTurn).eval;
if (maxTurn) {
if (evaluation >= beta) return beta;
else alpha = evaluation;
} else {
if (evaluation <= alpha) return alpha;
else beta = evaluation;
}
MoveValuePair bestMove = new MoveValuePair();
bestMove.updateMinMax((short) 0, evaluation, maxTurn);
LinkedList<MoveValuePair> sortedMoves = getCapturingSortedMoves(position, maxTurn);
for (MoveValuePair movepair : sortedMoves) {
short move = movepair.move;
// collect values from further moves
// get and update transposition table if possible
position.doMove(move);
int value = quiescence(position, alpha, beta, !maxTurn);
bestMove.updateMinMax(move, value, maxTurn);
position.undoMove();
// update the alpha beta boundary
if (maxTurn) alpha = bestMove.eval;
else beta = bestMove.eval;
// prune the subtree if needed
if (alpha >= beta) return bestMove.eval;
}
return bestMove.eval;
}
@Override
protected MoveValuePair ABMaxMinValue(
Position position, int depth, int alpha, int beta, boolean maxTurn)
throws IllegalMoveException {
if (depth <= 0 || position.isTerminal()) {
return handleTerminal(position, maxTurn, alpha, beta);
} else {
MoveValuePair bestMove = new MoveValuePair();
LinkedList<MoveValuePair> sortedMoves = getSortedMoves(position, maxTurn);
for (MoveValuePair movepair : sortedMoves) {
short move = movepair.move;
// collect values from further moves
// get and update transposition table if possible
position.doMove(move);
if (this.p2tte.containsKey(position.getHashCode())
&& (this.p2tte.get(position.getHashCode()).depth >= depth)) {
// System.out.println("trans table at level: " + depth);
TransTableEntry tte = p2tte.get(position.getHashCode());
bestMove.updateMinMax(move, tte.eval, maxTurn);
} else {
// recursive method
MoveValuePair childMove = ABMaxMinValue(position, depth - 1, alpha, beta, !maxTurn);
bestMove.updateMinMax(move, childMove.eval, maxTurn);
p2tte.put(position.getHashCode(), new TransTableEntry(childMove.eval, depth, move));
}
position.undoMove();
// update the alpha beta boundary
if (maxTurn) alpha = bestMove.eval;
else beta = bestMove.eval;
// prune the subtree if needed
if (alpha >= beta) return bestMove;
}
return bestMove;
}
}
// protected MoveValuePair handleTerminal(Position position, boolean maxTurn) {
// MoveValuePair finalMove = new MoveValuePair();
// if (position.isTerminal() && position.isMate()) {
// this.terminalFound = position.isTerminal();
// finalMove.eval = (maxTurn ? BE_MATED : MATE);
// } else if (position.isTerminal() && position.isStaleMate())
// finalMove.eval = 0;
// else {
// finalMove.eval = (int) ( (position.getMaterial() + position.getDomination()));
// }
//// System.out.print(finalMove.eval + " ");
// return finalMove;
// }
protected LinkedList<MoveValuePair> getCapturingSortedMoves(Position position, boolean maxTurn)
throws IllegalMoveException {
LinkedList<MoveValuePair> sortedMoves = new LinkedList<MoveValuePair>();
short[] moves = position.getAllCapturingMoves();
MoveValuePair theMove = null;
ASCENDING = maxTurn ? false : true;
for (short move : moves) {
position.doMove(move);
if (p2tte.containsKey(position.getHashCode())) {
theMove = new MoveValuePair(move, p2tte.get(position.getHashCode()).eval);
} else {
// for max turn, I assign worst values those unvisited positions
// theMove = new MoveValuePair(move, maxTurn ? BE_MATED : MATE);
int eval = (int) ((maxTurn ? -1 : 1) * (position.getMaterial() + position.getDomination()));
theMove = new MoveValuePair(move, eval);
}
position.undoMove();
sortedMoves.add(theMove);
}
Collections.sort(
sortedMoves,
new Comparator<MoveValuePair>() {
@Override
public int compare(MoveValuePair c1, MoveValuePair c2) {
// System.out.println(c1.eval + " vs " + c2.eval);
return (int) ((ASCENDING ? 1 : -1) * Math.signum(c1.eval - c2.eval)); // use your logic
}
});
return sortedMoves;
}
public Move getNextMove(int whichLine) {
short shortMove = m_moves.getMove(m_moves.goForward(m_cur, whichLine));
if (shortMove == GameMoveModel.NO_MOVE) return null; // =====>
try {
m_position.setNotifyListeners(false);
m_position.doMove(shortMove);
// ChMove move = m_position.getLastMove(shortMove);
Move move = m_position.getLastMove();
m_position.undoMove();
m_position.setNotifyListeners(true);
return move;
} catch (IllegalMoveException ex) {
ex.printStackTrace();
return null;
}
}
private boolean goBackInLine(boolean silent) {
if (DEBUG) System.out.println("goBackInLine");
int index = m_moves.goBack(m_cur, false);
if (index != -1) {
m_cur =
index; // needs to be set before undoing the move to allow listeners to check for curNode
m_ignoreNotifications = true;
if (silent) m_position.setNotifyListeners(false);
m_position.undoMove();
if (silent) m_position.setNotifyListeners(true);
m_ignoreNotifications = false;
return true;
} else {
return false;
}
}
private boolean goBack(boolean silent) {
if (DEBUG) System.out.println("goBack");
int index = m_moves.goBack(m_cur, true);
if (index != -1) {
// if (m_position.canUndoMove()) { // do not rely on position since in silent mode it
// is not updated
// m_cur = m_moves.goBack(m_cur, true);
m_cur = index;
m_ignoreNotifications = true;
if (silent) m_position.setNotifyListeners(false);
m_position.undoMove();
if (silent) m_position.setNotifyListeners(true);
m_ignoreNotifications = false;
return true;
} else {
return false;
}
}
public Move[] getMainLine() {
int num = 0;
int index = m_cur;
while (m_moves.hasNextMove(index)) {
index = m_moves.goForward(index);
num++;
}
Move[] moves = new Move[num];
for (int i = 0; i < num; i++) {
moves[i] = goForwardAndGetMove(true);
}
m_position.setNotifyListeners(false);
for (int i = 0; i < moves.length; i++) m_position.undoMove();
m_position.setNotifyListeners(true);
return moves;
}
public Move[] getNextMoves() {
m_position.setNotifyListeners(false);
Move[] moves = new Move[m_moves.getNumOfNextMoves(m_cur)];
for (int i = 0; i < moves.length; i++) {
short move = m_moves.getMove(m_moves.goForward(m_cur, i));
try {
m_position.doMove(move);
// moves[i] = m_position.getLastMove(move);
moves[i] = m_position.getLastMove();
m_position.undoMove();
} catch (IllegalMoveException ex) {
m_moves.write(System.out);
System.out.println("cur = " + m_cur + " move=" + GameMoveModel.valueToString(move));
ex.printStackTrace();
}
}
m_position.setNotifyListeners(true);
return moves;
}