int Board::qsearch(int ply, int alpha, int beta)
{
// quiescence search
int i, j, val;
if (timedout) return 0;
triangularLength[ply] = ply;
if (isOwnKingAttacked()) return alphabetapvs(ply, 1, alpha, beta);
if(EVAL_FUNC == 0){
val = board.eval();
}else {
val = board.evalJL(PARAM_EVAL_MATERIAL, PARAM_EVAL_ESPACIAL, PARAM_EVAL_DINAMICA, PARAM_EVAL_POS_TABLERO, ply);
}
if (val >= beta) return val;
if (val > alpha) alpha = val;
// generate captures & promotions:
// captgen returns a sorted move list
moveBufLen[ply+1] = captgen(moveBufLen[ply]);
for (i = moveBufLen[ply]; i < moveBufLen[ply+1]; i++)
{
makeMove(moveBuffer[i]);
{
if (!isOtherKingAttacked())
{
inodes++;
if (--countdown <=0) readClockAndInput();
val = -qsearch(ply+1, -beta, -alpha);
unmakeMove(moveBuffer[i]);
if (val >= beta) return val;
if (val > alpha)
{
alpha = val;
triangularArray[ply][ply] = moveBuffer[i];
for (j = ply + 1; j < triangularLength[ply+1]; j++)
{
triangularArray[ply][j] = triangularArray[ply+1][j];
}
triangularLength[ply] = triangularLength[ply+1];
}
}
else unmakeMove(moveBuffer[i]);
}
}
return alpha;
}
int Board::alphabetapvs(int ply, int depth, int alpha, int beta)
{
// PV search
int i, j, movesfound, pvmovesfound, val;
triangularLength[ply] = ply;
if (depth <= 0)
{
followpv = false;
return qsearch(ply, alpha, beta);
}
// repetition check:
if (repetitionCount() >= 3) return DRAWSCORE;
// now try a null move to get an early beta cut-off:
if (!followpv && allownull)
{
if ((nextMove && (board.totalBlackPieces > NULLMOVE_LIMIT)) || (!nextMove && (board.totalWhitePieces > NULLMOVE_LIMIT)))
{
if (!isOwnKingAttacked())
{
allownull = false;
inodes++;
if (--countdown <=0) readClockAndInput();
nextMove = !nextMove;
hashkey ^= KEY.side;
val = -alphabetapvs(ply, depth - NULLMOVE_REDUCTION, -beta, -beta+1);
nextMove = !nextMove;
hashkey ^= KEY.side;
if (timedout) return 0;
allownull = true;
if (val >= beta) return val;
}
}
}
allownull = true;
movesfound = 0;
pvmovesfound = 0;
moveBufLen[ply+1] = movegen(moveBufLen[ply]);
for (i = moveBufLen[ply]; i < moveBufLen[ply+1]; i++)
{
selectmove(ply, i, depth, followpv);
makeMove(moveBuffer[i]);
{
if (!isOtherKingAttacked())
{
inodes++;
if (--countdown <=0) readClockAndInput();
movesfound++;
if (!ply) displaySearchStats(3, ply, i);
if (pvmovesfound)
{
val = -alphabetapvs(ply+1, depth-1, -alpha-1, -alpha);
if ((val > alpha) && (val < beta))
{
// in case of failure, proceed with normal alphabeta
val = -alphabetapvs(ply+1, depth - 1, -beta, -alpha);
}
}
// normal alphabeta
else val = -alphabetapvs(ply+1, depth-1, -beta, -alpha);
unmakeMove(moveBuffer[i]);
if (timedout) return 0;
if (val >= beta)
{
// update the history heuristic
if (nextMove)
blackHeuristics[moveBuffer[i].getFrom()][moveBuffer[i].getTosq()] += depth*depth;
else
whiteHeuristics[moveBuffer[i].getFrom()][moveBuffer[i].getTosq()] += depth*depth;
return beta;
}
if (val > alpha)
{
alpha = val; // both sides want to maximize from *their* perspective
pvmovesfound++;
triangularArray[ply][ply] = moveBuffer[i]; // save this move
for (j = ply + 1; j < triangularLength[ply+1]; j++)
{
triangularArray[ply][j] = triangularArray[ply+1][j]; // and append the latest best PV from deeper plies
}
triangularLength[ply] = triangularLength[ply+1];
if (!ply) displaySearchStats(2, depth, val);
}
}
else unmakeMove(moveBuffer[i]);
}
}
// update the history heuristic
if (pvmovesfound)
{
if (nextMove)
blackHeuristics[triangularArray[ply][ply].getFrom()][triangularArray[ply][ply].getTosq()] += depth*depth;
else
whiteHeuristics[triangularArray[ply][ply].getFrom()][triangularArray[ply][ply].getTosq()] += depth*depth;
}
// 50-move rule:
if (fiftyMove >= 100) return DRAWSCORE;
// Checkmate/stalemate detection:
if (!movesfound)
{
if (isOwnKingAttacked()) return (-CHECKMATESCORE+ply-1);
else return (STALEMATESCORE);
}
return alpha;
}
