static int full_quiescence(board_t * board, int alpha, int beta, int depth, int height, mv_t pv[]) {
bool in_check;
int old_alpha;
int value, best_value;
int best_move;
int move;
int opt_value;
attack_t attack[1];
sort_t sort[1];
undo_t undo[1];
mv_t new_pv[HeightMax];
int cd;
ASSERT(board!=NULL);
ASSERT(range_is_ok(alpha,beta));
ASSERT(depth_is_ok(depth));
ASSERT(height_is_ok(height));
ASSERT(pv!=NULL);
ASSERT(board_is_legal(board));
ASSERT(depth<=0);
// init
SearchStack[height].best_move = MoveNone;
SearchStack[height].move = MoveNone;
SearchStack[height].threat_move = MoveNone;
SearchStack[height].reduced = false;
SearchCurrent->node_nb++;
SearchInfo->check_nb--;
PV_CLEAR(pv);
if (height > SearchCurrent->max_depth) SearchCurrent->max_depth = height;
if (SearchInfo->check_nb <= 0) {
SearchInfo->check_nb += SearchInfo->check_inc;
search_check();
}
// draw?
if (board_is_repetition(board) || recog_draw(board)) return ValueDraw;
// mate-distance pruning
if (UseDistancePruning) {
// lower bound
value = VALUE_MATE(height+2); // does not work if the current position is mate
if (value > alpha && board_is_mate(board)) value = VALUE_MATE(height);
if (value > alpha) {
alpha = value;
if (value >= beta) return value;
}
// upper bound
value = -VALUE_MATE(height+1);
if (value < beta) {
beta = value;
if (value <= alpha) return value;
}
}
// more init
attack_set(attack,board);
in_check = ATTACK_IN_CHECK(attack);
if (in_check) {
ASSERT(depth<0);
depth++; // in-check extension
}
// height limit
if (height >= HeightMax-1) return eval(board, alpha, beta);
// more init
old_alpha = alpha;
best_value = ValueNone;
best_move = MoveNone;
/* if (UseDelta) */ opt_value = +ValueInf;
if (!in_check) {
// lone-king stalemate?
if (simple_stalemate(board)) return ValueDraw;
// stand pat
value = eval(board, alpha, beta);
ASSERT(value>best_value);
best_value = value;
if (value > alpha) {
alpha = value;
if (value >= beta) goto cut;
}
if (UseDelta) {
opt_value = value + DeltaMargin;
ASSERT(opt_value<+ValueInf);
}
}
// move loop
/* cd = CheckDepth;
if(cd < 0 && board->piece_size[board->turn] <= 5)
cd++; */
sort_init_qs(sort,board,attack, depth>=CheckDepth /* depth>=cd */);
while ((move=sort_next_qs(sort)) != MoveNone) {
SearchStack[height].move = move;
// delta pruning
if (UseDelta && beta == old_alpha+1) {
if (!in_check && !move_is_check(move,board) && !capture_is_dangerous(move,board)) {
ASSERT(move_is_tactical(move,board));
// optimistic evaluation
value = opt_value;
int to = MOVE_TO(move);
int capture = board->square[to];
if (capture != Empty) {
value += VALUE_PIECE(capture);
} else if (MOVE_IS_EN_PASSANT(move)) {
value += ValuePawn;
}
if (MOVE_IS_PROMOTE(move)) value += ValueQueen - ValuePawn;
// pruning
if (value <= alpha) {
if (value > best_value) {
best_value = value;
PV_CLEAR(pv);
}
continue;
}
}
}
move_do(board,move,undo);
value = -full_quiescence(board,-beta,-alpha,depth-1,height+1,new_pv);
move_undo(board,move,undo);
if (value > best_value) {
best_value = value;
pv_cat(pv,new_pv,move);
if (value > alpha) {
alpha = value;
best_move = move;
SearchStack[height].best_move = move;
if (value >= beta) goto cut;
}
}
}
// ALL node
if (best_value == ValueNone) { // no legal move
ASSERT(board_is_mate(board));
return VALUE_MATE(height);
}
cut:
ASSERT(value_is_ok(best_value));
return best_value;
}
static int full_quiescence(board_t * board, int alpha, int beta, int depth, int height, mv_t pv[], int ThreadId) {
bool in_check;
int old_alpha;
int value, best_value;
int best_move;
int move;
int opt_value;
attack_t attack[1];
sort_t sort[1];
undo_t undo[1];
mv_t new_pv[HeightMax];
int probe_score, probe_depth;
int trans_move, trans_depth, trans_flags, trans_value;
entry_t * found_entry;
ASSERT(board!=NULL);
ASSERT(range_is_ok(alpha,beta));
ASSERT(depth_is_ok(depth));
ASSERT(height_is_ok(height));
ASSERT(pv!=NULL);
ASSERT(board_is_legal(board));
ASSERT(depth<=0);
// init
SearchCurrent[ThreadId]->node_nb++;
SearchInfo[ThreadId]->check_nb--;
PV_CLEAR(pv);
if (height > SearchCurrent[ThreadId]->max_depth) SearchCurrent[ThreadId]->max_depth = height;
if (SearchInfo[ThreadId]->check_nb <= 0) {
SearchInfo[ThreadId]->check_nb += SearchInfo[ThreadId]->check_inc;
search_check(ThreadId);
}
// draw?
if (board_is_repetition(board)) return ValueDraw;
/*
Interior node recognizer from scorpio by Daniel Shawul
-> dont probe at the leaves as this will slow down search
For 4/3 pieces probe there also.
-> After captures and pawn moves assume exact score and cutoff tree,
because we are making progress. Note this is not done only for speed.
-> if we are far from root (depth / 2), assume exact score and cutoff tree
*/
/* if (egbb_is_loaded && board->piece_nb <= 4){
if (probe_bitbases(board, probe_score)){
probe_score = value_from_trans(probe_score,height);
return probe_score;
}
}*/
if (recog_draw(board,ThreadId)) return ValueDraw;
// mate-distance pruning
if (UseDistancePruning) {
// lower bound
value = VALUE_MATE(height+2); // does not work if the current position is mate
if (value > alpha && board_is_mate(board)) value = VALUE_MATE(height);
if (value > alpha) {
alpha = value;
if (value >= beta) return value;
}
// upper bound
value = -VALUE_MATE(height+1);
if (value < beta) {
beta = value;
if (value <= alpha) return value;
}
}
// transposition table: added by Jerry Donald, about +20 elo self-play
// new in Toga II 4.0: accept hash hits in PV ~ +3 elo
trans_move = MoveNone;
if (UseTrans) {
if (trans_retrieve(Trans,&found_entry,board->key,&trans_move,&trans_depth,&trans_flags,&trans_value)) {
trans_value = value_from_trans(trans_value,height);
if ((UseExact && trans_value != ValueNone && TRANS_IS_EXACT(trans_flags))
|| (TRANS_IS_LOWER(trans_flags) && trans_value >= beta)
|| (TRANS_IS_UPPER(trans_flags) && trans_value <= alpha)) {
return trans_value;
}
}
}
// more init
attack_set(attack,board);
in_check = ATTACK_IN_CHECK(attack);
if (in_check) {
ASSERT(depth<0);
depth++; // in-check extension
}
// height limit
if (height >= HeightMax-1) return eval(board, alpha, beta, ThreadId);
// more init
old_alpha = alpha;
best_value = ValueNone;
best_move = MoveNone;
/* if (UseDelta) */ opt_value = +ValueInf;
if (!in_check) {
// lone-king stalemate?
if (simple_stalemate(board)) return ValueDraw;
// stand pat
value = eval(board, alpha, beta, ThreadId);
ASSERT(value>best_value);
best_value = value;
if (value > alpha) {
alpha = value;
if (value >= beta) goto cut;
}
if (UseDelta) {
opt_value = value + DeltaMargin;
ASSERT(opt_value<+ValueInf);
}
}
// move loop
/* cd = CheckDepth;
if(cd < 0 && board->piece_size[board->turn] <= 5)
cd++; */
sort_init_qs(sort,board,attack, depth>=SearchCurrent[ThreadId]->CheckDepth /* depth>=cd */);
while ((move=sort_next_qs(sort)) != MoveNone) {
// delta pruning
if (UseDelta && beta == old_alpha+1) { // i.e. non-PV
if (!in_check && !move_is_check(move,board) && !capture_is_dangerous(move,board)) {
ASSERT(move_is_tactical(move,board));
// optimistic evaluation
value = opt_value;
int to = MOVE_TO(move);
int capture = board->square[to];
if (capture != Empty) {
value += VALUE_PIECE(capture);
} else if (MOVE_IS_EN_PASSANT(move)) {
value += ValuePawn;
}
if (MOVE_IS_PROMOTE(move)) value += ValueQueen - ValuePawn;
// pruning
if (value <= alpha) {
if (value > best_value) {
best_value = value;
PV_CLEAR(pv);
}
continue;
}
}
}
move_do(board,move,undo);
value = -full_quiescence(board,-beta,-alpha,depth-1,height+1,new_pv,ThreadId);
move_undo(board,move,undo);
if (value > best_value) {
best_value = value;
pv_cat(pv,new_pv,move);
if (value > alpha) {
alpha = value;
best_move = move;
if (value >= beta) goto cut;
}
}
}
// ALL node
if (best_value == ValueNone) { // no legal move
ASSERT(board_is_mate(board));
return VALUE_MATE(height);
}
cut:
// store result in hash table (JD)
if (UseTrans) {
trans_move = best_move;
trans_depth = 0;
trans_flags = TransUnknown;
if (best_value > old_alpha) trans_flags |= TransLower;
if (best_value < beta) trans_flags |= TransUpper;
trans_value = value_to_trans(best_value,height);
trans_store(Trans,board->key,trans_move,trans_depth,trans_flags,trans_value);
}
ASSERT(value_is_ok(best_value));
return best_value;
}