static bool capture_is_good(int move, const board_t * board) {
int piece, capture;
ASSERT(move_is_ok(move));
ASSERT(board!=NULL);
ASSERT(MOVE_IS_TACTICAL(move,board));
// special cases
if (MOVE_IS_EN_PASSANT(move)) return true;
if (MOVE_IS_UNDER_PROMOTE(move)) return false; // REMOVE ME?
// captures and queen promotes
capture = board->square[MOVE_TO(move)];
if (capture != Empty) {
// capture
ASSERT(move_is_capture(move,board));
if (MOVE_IS_PROMOTE(move)) return true; // promote-capture
piece = board->square[MOVE_FROM(move)];
if (VALUE_PIECE(capture) >= VALUE_PIECE(piece)) return true;
}
return see_move(move,board,0) >= 0;
}
static int see_rec(alists_t * alists, const board_t * board, int colour, int to, int piece_value) {
int from, piece;
int value;
ASSERT(alists!=NULL);
ASSERT(board!=NULL);
ASSERT(COLOUR_IS_OK(colour));
ASSERT(SQUARE_IS_OK(to));
ASSERT(piece_value>0);
// find the least valuable attacker
from = alist_pop(alists->alist[colour],board);
if (from == SquareNone) return 0; // no more attackers
// find hidden attackers
alists_hidden(alists,board,from,to);
// calculate the capture value
value = +piece_value; // captured piece
if (value == ValueKing) return value; // do not allow an answer to a king capture
piece = board->square[from];
ASSERT(piece_is_ok(piece));
ASSERT(COLOUR_IS(piece,colour));
piece_value = VALUE_PIECE(piece);
// promote
if (piece_value == ValuePawn && SQUARE_IS_PROMOTE(to)) { // HACK: PIECE_IS_PAWN(piece)
ASSERT(PIECE_IS_PAWN(piece));
piece_value = ValueQueen;
value += ValueQueen - ValuePawn;
}
value -= see_rec(alists,board,COLOUR_OPP(colour),to,piece_value);
if (value < 0) value = 0;
return value;
}
int see_square(const board_t * board, int to, int colour) {
int att, def;
alists_t alists[1];
alist_t * alist;
int piece_value;
int piece;
ASSERT(board!=NULL);
ASSERT(SQUARE_IS_OK(to));
ASSERT(COLOUR_IS_OK(colour));
ASSERT(COLOUR_IS(board->square[to],COLOUR_OPP(colour)));
// build attacker list
att = colour;
alist = alists->alist[att];
ALIST_CLEAR(alist);
alist_build(alist,board,to,att);
if (alist->size == 0) return 0; // no attacker => stop SEE
// build defender list
def = COLOUR_OPP(att);
alist = alists->alist[def];
ALIST_CLEAR(alist);
alist_build(alist,board,to,def);
// captured piece
piece = board->square[to];
ASSERT(piece_is_ok(piece));
ASSERT(COLOUR_IS(piece,def));
piece_value = VALUE_PIECE(piece);
// SEE search
return see_rec(alists,board,att,to,piece_value);
}
int see_move(int move, const board_t * board) {
int att, def;
int from, to;
alists_t alists[1];
int value, piece_value;
int piece, capture;
alist_t * alist;
int pos;
ASSERT(move_is_ok(move));
ASSERT(board!=NULL);
// init
from = MOVE_FROM(move);
to = MOVE_TO(move);
// move the piece
piece_value = 0;
piece = board->square[from];
ASSERT(piece_is_ok(piece));
att = PIECE_COLOUR(piece);
def = COLOUR_OPP(att);
// promote
if (MOVE_IS_PROMOTE(move)) {
ASSERT(PIECE_IS_PAWN(piece));
piece = move_promote(move);
ASSERT(piece_is_ok(piece));
ASSERT(COLOUR_IS(piece,att));
}
piece_value += VALUE_PIECE(piece);
// clear attacker lists
ALIST_CLEAR(alists->alist[Black]);
ALIST_CLEAR(alists->alist[White]);
// find hidden attackers
alists_hidden(alists,board,from,to);
// capture the piece
value = 0;
capture = board->square[to];
if (capture != Empty) {
ASSERT(piece_is_ok(capture));
ASSERT(COLOUR_IS(capture,def));
value += VALUE_PIECE(capture);
}
// promote
if (MOVE_IS_PROMOTE(move)) {
value += VALUE_PIECE(piece) - ValuePawn;
}
// en-passant
if (MOVE_IS_EN_PASSANT(move)) {
ASSERT(value==0);
ASSERT(PIECE_IS_PAWN(board->square[SQUARE_EP_DUAL(to)]));
value += ValuePawn;
alists_hidden(alists,board,SQUARE_EP_DUAL(to),to);
}
// build defender list
alist = alists->alist[def];
alist_build(alist,board,to,def);
if (alist->size == 0) return value; // no defender => stop SEE
// build attacker list
alist = alists->alist[att];
alist_build(alist,board,to,att);
// remove the moved piece (if it's an attacker)
for (pos = 0; pos < alist->size && alist->square[pos] != from; pos++)
;
if (pos < alist->size) alist_remove(alist,pos);
// SEE search
value -= see_rec(alists,board,def,to,piece_value);
return value;
}
bool capture_is_good(int move, const board_t * board, bool in_pv) {
#else
static bool capture_is_good(int move, const board_t * board, bool in_pv) {
#endif
int piece, capture;
int see_value; // WHM 11/22/08
ASSERT(move_is_ok(move));
ASSERT(board!=NULL);
ASSERT(move_is_tactical(move,board));
// special cases
if (MOVE_IS_EN_PASSANT(move)) return true;
if (move_is_under_promote(move)) return false; // REMOVE ME? Keep, looks good to me. WHM;
// if (MOVE_IS_PROMOTE(move)) return true; // WHM; promote-to-queen, measures a little weaker
// too many garbage lines going nuts.
// captures and queen promotes
capture = board->square[MOVE_TO(move)];
piece = board->square[MOVE_FROM(move)];
if (capture != Empty) {
// capture
ASSERT(move_is_capture(move,board));
if (MOVE_IS_PROMOTE(move)) return true; // capture a piece on Rank8 and promote to queen
if (VALUE_PIECE(capture) >= VALUE_PIECE(piece)) return true;
}
// return see_move(move,board) >= 0; WHM 11/22/08
// WHM 11/22/08 START
see_value = see_move(move,board);
if (see_value >= 0) return true;
if (TryNodePVQueenPromotes) {
if (in_pv && MOVE_IS_PROMOTE(move)) {
ASSERT(!move_is_under_promote(move));
return true; // WHM:
}
}
if (TryKingAttackSacs || TryKingBoxSacs || TryPasserSacs) {
if (in_pv && see_value > -ValueBishop && capture != Empty) {
ASSERT(COLOUR_IS(capture,COLOUR_OPP(board->turn)));
// king attack sacs.
if (TryKingAttackSacs) {
if (narrow_piece_attack_king(board, piece, MOVE_TO(move), KING_POS(board,COLOUR_OPP(board->turn)))) {
return true;
}
}
// sacrifice attacks around the narrow/close king box can be examined more fully. Rybka lessons.
if (TryKingBoxSacs) {
if (DISTANCE(MOVE_TO(move),KING_POS(board,COLOUR_OPP(board->turn))) <= 1) {
return true;
}
}
// passer sacrifices...
if (TryPasserSacs) {
if (PIECE_IS_PAWN(capture) && PAWN_RANK(MOVE_TO(move),COLOUR_OPP(board->turn)) >= Rank6) {
return true;
}
}
}
} // WHM 11/22/08 END
return false;
}
static void square_set(board_t * board, int square, int piece, int pos, bool update) {
int piece_12, colour;
int sq;
int i, size;
int sq_64;
uint64 hash_xor;
ASSERT(board!=NULL);
ASSERT(SQUARE_IS_OK(square));
ASSERT(piece_is_ok(piece));
ASSERT(pos>=0);
ASSERT(update==true||update==false);
// init
piece_12 = PIECE_TO_12(piece);
colour = PIECE_COLOUR(piece);
// square
ASSERT(board->square[square]==Empty);
board->square[square] = piece;
// piece list
if (!PIECE_IS_PAWN(piece)) {
// init
size = board->piece_size[colour];
ASSERT(size>=0);
// size
size++;
board->piece[colour][size] = SquareNone;
board->piece_size[colour] = size;
// stable swap
ASSERT(pos>=0&&pos<size);
for (i = size-1; i > pos; i--) {
sq = board->piece[colour][i-1];
board->piece[colour][i] = sq;
ASSERT(board->pos[sq]==i-1);
board->pos[sq] = i;
}
board->piece[colour][pos] = square;
ASSERT(board->pos[square]==-1);
board->pos[square] = pos;
} else {
// init
size = board->pawn_size[colour];
ASSERT(size>=0);
// size
size++;
board->pawn[colour][size] = SquareNone;
board->pawn_size[colour] = size;
// stable swap
ASSERT(pos>=0&&pos<size);
for (i = size-1; i > pos; i--) {
sq = board->pawn[colour][i-1];
board->pawn[colour][i] = sq;
ASSERT(board->pos[sq]==i-1);
board->pos[sq] = i;
}
board->pawn[colour][pos] = square;
ASSERT(board->pos[square]==-1);
board->pos[square] = pos;
// pawn "bitboard"
board->pawn_file[colour][SQUARE_FILE(square)] ^= BIT(PAWN_RANK(square,colour));
}
// material
ASSERT(board->piece_nb<32);
board->piece_nb++;;
ASSERT(board->number[piece_12]<9);
board->number[piece_12]++;
board->piece_material[colour] += VALUE_PIECE(piece); // Thomas
// update
if (update) {
// init
sq_64 = SQUARE_TO_64(square);
// PST
board->opening += PST(piece_12,sq_64,Opening);
board->endgame += PST(piece_12,sq_64,Endgame);
// hash key
hash_xor = RANDOM_64(RandomPiece+(piece_12^1)*64+sq_64); // HACK: ^1 for PolyGlot book
board->key ^= hash_xor;
if (PIECE_IS_PAWN(piece)) board->pawn_key ^= hash_xor;
// material key
board->material_key ^= RANDOM_64(piece_12*16+(board->number[piece_12]-1));
}
}
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;
}