void sp_update_pv(SearchStack *pss, SearchStack ss[], int ply);
bool connected_moves(const Position &pos, Move m1, Move m2);
bool move_is_killer(Move m, const SearchStack& ss);
- Depth extension(const Position &pos, Move m, bool pvNode, bool check, bool singleReply, bool mateThreat, bool* extendable);
+ Depth extension(const Position &pos, Move m, bool pvNode, bool check, bool singleReply, bool mateThreat, bool* dangerous);
bool ok_to_do_nullmove(const Position &pos);
bool ok_to_prune(const Position &pos, Move m, Move threat, Depth d);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
<< " currmovenumber " << i + 1 << std::endl;
// Decide search depth for this move
- bool dummy;
- ext = extension(pos, move, true, pos.move_is_check(move), false, false, &dummy);
+ bool dangerous;
+ ext = extension(pos, move, true, pos.move_is_check(move), false, false, &dangerous);
newDepth = (Iteration - 2) * OnePly + ext + InitialDepth;
// Make the move, and search it
Value value, bestValue = -VALUE_INFINITE;
Bitboard dcCandidates = mp.discovered_check_candidates();
bool isCheck = pos.is_check();
- bool mateThreat = MateThreatExtension[1] > Depth(0)
- && pos.has_mate_threat(opposite_color(pos.side_to_move()));
+ bool mateThreat = pos.has_mate_threat(opposite_color(pos.side_to_move()));
// Loop through all legal moves until no moves remain or a beta cutoff
// occurs.
bool singleReply = (isCheck && mp.number_of_moves() == 1);
bool moveIsCheck = pos.move_is_check(move, dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
- bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
movesSearched[moveCount++] = ss[ply].currentMove = move;
ss[ply].currentMoveCaptureValue = Value(0);
// Decide the new search depth
- bool extendable;
- Depth ext = extension(pos, move, true, moveIsCheck, singleReply, mateThreat, &extendable);
+ bool dangerous;
+ Depth ext = extension(pos, move, true, moveIsCheck, singleReply, mateThreat, &dangerous);
Depth newDepth = depth - OnePly + ext;
// Make and search the move
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
if ( depth >= 2*OnePly
- && !extendable
&& moveCount >= LMRPVMoves
+ && !dangerous
&& !moveIsCapture
&& !move_promotion(move)
- && !moveIsPassedPawnPush
&& !move_is_castle(move)
&& !move_is_killer(move, ss[ply]))
{
bool singleReply = (isCheck && mp.number_of_moves() == 1);
bool moveIsCheck = pos.move_is_check(move, dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
- bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
movesSearched[moveCount++] = ss[ply].currentMove = move;
// Decide the new search depth
- bool extendable;
- Depth ext = extension(pos, move, false, moveIsCheck, singleReply, mateThreat, &extendable);
+ bool dangerous;
+ Depth ext = extension(pos, move, false, moveIsCheck, singleReply, mateThreat, &dangerous);
Depth newDepth = depth - OnePly + ext;
// Futility pruning
if ( useFutilityPruning
- && !extendable
+ && !dangerous
&& !moveIsCapture
- && !moveIsPassedPawnPush
&& !move_promotion(move))
{
if ( moveCount >= 2 + int(depth)
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
- if ( depth >= 2*OnePly
- && !extendable
- && moveCount >= LMRNonPVMoves
+ if ( depth >= 2*OnePly
+ && moveCount >= LMRNonPVMoves
+ && !dangerous
&& !moveIsCapture
&& !move_promotion(move)
- && !moveIsPassedPawnPush
&& !move_is_castle(move)
&& !move_is_killer(move, ss[ply]))
{
{
assert(move_is_ok(move));
- bool moveIsCheck = pos.move_is_check(move, dcCandidates);
- bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
-
moveCount++;
ss[ply].currentMove = move;
// Futility pruning
if ( UseQSearchFutilityPruning
+ && enoughMaterial
&& !isCheck
- && !moveIsCheck
- && !move_promotion(move)
- && !moveIsPassedPawnPush
&& !pvNode
- && enoughMaterial)
+ && !move_promotion(move)
+ && !pos.move_is_check(move, dcCandidates)
+ && !pos.move_is_passed_pawn_push(move))
{
Value futilityValue = staticValue
+ Max(pos.midgame_value_of_piece_on(move_to(move)),
bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
- bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
lock_grab(&(sp->lock));
int moveCount = ++sp->moves;
ss[sp->ply].currentMove = move;
// Decide the new search depth.
- bool extendable;
- Depth ext = extension(pos, move, false, moveIsCheck, false, false, &extendable);
+ bool dangerous;
+ Depth ext = extension(pos, move, false, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Prune?
if ( useFutilityPruning
- && !extendable
+ && !dangerous
&& !moveIsCapture
- && !moveIsPassedPawnPush
&& !move_promotion(move)
&& moveCount >= 2 + int(sp->depth)
&& ok_to_prune(pos, move, ss[sp->ply].threatMove, sp->depth))
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
- if ( !extendable
+ if ( !dangerous
&& moveCount >= LMRNonPVMoves
&& !moveIsCapture
- && !moveIsPassedPawnPush
&& !move_promotion(move)
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
{
bool moveIsCheck = pos.move_is_check(move, sp->dcCandidates);
bool moveIsCapture = pos.move_is_capture(move);
- bool moveIsPassedPawnPush = pos.move_is_passed_pawn_push(move);
assert(move_is_ok(move));
ss[sp->ply].currentMove = move;
// Decide the new search depth.
- bool extendable;
- Depth ext = extension(pos, move, true, moveIsCheck, false, false, &extendable);
+ bool dangerous;
+ Depth ext = extension(pos, move, true, moveIsCheck, false, false, &dangerous);
Depth newDepth = sp->depth - OnePly + ext;
// Make and search the move.
// Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth.
- if ( !extendable
+ if ( !dangerous
&& moveCount >= LMRPVMoves
&& !moveIsCapture
- && !moveIsPassedPawnPush
&& !move_promotion(move)
&& !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply]))
// extension() decides whether a move should be searched with normal depth,
// or with extended depth. Certain classes of moves (checking moves, in
- // particular) are searched with bigger depth than ordinary moves.
+ // particular) are searched with bigger depth than ordinary moves and in
+ // any case are marked as 'dangerous'. Note that also if a move is not
+ // extended, as example because the corresponding UCI option is set to zero,
+ // the move is marked as 'dangerous' so, at least, we avoid to prune it.
- Depth extension(const Position &pos, Move m, bool pvNode,
- bool check, bool singleReply, bool mateThreat, bool* extendable) {
+ Depth extension(const Position &pos, Move m, bool pvNode, bool check,
+ bool singleReply, bool mateThreat, bool* dangerous) {
Depth result = Depth(0);
- *extendable = check || singleReply || mateThreat;
+ *dangerous = check || singleReply || mateThreat;
if (check)
result += CheckExtension[pvNode];
if (pos.move_is_pawn_push_to_7th(m))
{
result += PawnPushTo7thExtension[pvNode];
- *extendable = true;
+ *dangerous = true;
}
if (pos.move_is_passed_pawn_push(m))
{
result += PassedPawnExtension[pvNode];
- *extendable = true;
+ *dangerous = true;
}
if ( pos.midgame_value_of_piece_on(move_to(m)) >= RookValueMidgame
&& !move_promotion(m))
{
result += PawnEndgameExtension[pvNode];
- *extendable = true;
+ *dangerous = true;
}
if ( pvNode
&& pos.see(m) >= 0)
{
result += OnePly/2;
- *extendable = true;
+ *dangerous = true;
}
return Min(result, OnePly);