Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta);
- bool allows_move(const Position& pos, Move first, Move second);
bool prevents_move(const Position& pos, Move first, Move second);
string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
Value bestValue, value, ttValue;
Value eval, nullValue, futilityValue;
bool inCheck, givesCheck, pvMove, singularExtensionNode;
- bool captureOrPromotion, dangerous, doFullDepthSearch, threatExtension;
+ bool captureOrPromotion, dangerous, doFullDepthSearch;
int moveCount, playedMoveCount;
// Step 1. Initialize node
Thread* thisThread = pos.this_thread();
moveCount = playedMoveCount = 0;
- threatExtension = false;
inCheck = pos.checkers();
if (SpNode)
return nullValue;
}
else
- {
// The null move failed low, which means that we may be faced with
- // some kind of threat. If the previous move was reduced, check if
- // the move that refuted the null move was somehow connected to the
- // move which was reduced. If a connection is found extend moves that
- // defend against threat.
+ // some kind of threat.
threatMove = (ss+1)->currentMove;
-
- if ( depth < 5 * ONE_PLY
- && (ss-1)->reduction
- && threatMove != MOVE_NONE
- && allows_move(pos, (ss-1)->currentMove, threatMove))
- threatExtension = true;
- }
}
// Step 9. ProbCut (is omitted in PV nodes)
if (PvNode && dangerous)
ext = ONE_PLY;
- else if (threatExtension && prevents_move(pos, move, threatMove))
- ext = ONE_PLY;
-
else if (givesCheck && pos.see_sign(move) >= 0)
ext = ONE_PLY / 2;
&& !inCheck
&& !dangerous
&& move != ttMove
+ && (!threatMove || !prevents_move(pos, move, threatMove))
&& (bestValue > VALUE_MATED_IN_MAX_PLY || ( bestValue == -VALUE_INFINITE
&& alpha > VALUE_MATED_IN_MAX_PLY)))
{
// Move count based pruning
- if ( depth < 16 * ONE_PLY
- && moveCount >= FutilityMoveCounts[depth]
- && (!threatMove || !prevents_move(pos, move, threatMove)))
+ if (depth < 16 * ONE_PLY && moveCount >= FutilityMoveCounts[depth])
{
if (SpNode)
sp->mutex.lock();
// Step 19. Check for splitting the search
if ( !SpNode
- && depth >= Threads.min_split_depth()
+ && depth >= Threads.minimumSplitDepth
&& Threads.available_slave_exists(thisThread))
{
assert(bestValue < beta);
}
- // allows_move() tests whether the move at previous ply (first) somehow makes a
- // second move possible, for instance if the moving piece is the same in both
- // moves. Normally the second move is the threat move (the best move returned
- // from a null search that fails low).
-
- bool allows_move(const Position& pos, Move first, Move second) {
-
- assert(is_ok(first));
- assert(is_ok(second));
- assert(color_of(pos.piece_on(from_sq(second))) == ~pos.side_to_move());
- assert(color_of(pos.piece_on(to_sq(first))) == ~pos.side_to_move());
-
- Square m1from = from_sq(first);
- Square m2from = from_sq(second);
- Square m1to = to_sq(first);
- Square m2to = to_sq(second);
-
- // The piece is the same or second's destination was vacated by the first move
- if (m1to == m2from || m2to == m1from)
- return true;
-
- // Second one moves through the square vacated by first one
- if (between_bb(m2from, m2to) & m1from)
- return true;
-
- // Second's destination is defended by the first move's piece
- Bitboard m1att = pos.attacks_from(pos.piece_on(m1to), m1to, pos.pieces() ^ m2from);
- if (m1att & m2to)
- return true;
-
- // Second move gives a discovered check through the first's checking piece
- if (m1att & pos.king_square(pos.side_to_move()))
- {
- assert(between_bb(m1to, pos.king_square(pos.side_to_move())) & m2from);
- return true;
- }
-
- return false;
- }
-
-
// prevents_move() tests whether a move (first) is able to defend against an
// opponent's move (second). In this case will not be pruned. Normally the
// second move is the threat move (the best move returned from a null search
// object for which the thread is the master.
const SplitPoint* sp_master = splitPointsCnt ? curSplitPoint : NULL;
- assert(!sp_master || (sp_master->master == this && is_searching));
+ assert(!sp_master || (sp_master->master == this && searching));
// If this thread is the master of a split point and all slaves have
// finished their work at this split point, return from the idle loop.
{
// If we are not searching, wait for a condition to be signaled
// instead of wasting CPU time polling for work.
- while (do_exit || (!is_searching && Threads.sleepWhileIdle))
+ while ((!searching && Threads.sleepWhileIdle) || exit)
{
- if (do_exit)
+ if (exit)
{
assert(!sp_master);
return;
// particular we need to avoid a deadlock in case a master thread has,
// in the meanwhile, allocated us and sent the wake_up() call before we
// had the chance to grab the lock.
- if (!is_searching && Threads.sleepWhileIdle)
+ if (!searching && !exit)
sleepCondition.wait(mutex);
mutex.unlock();
}
// If this thread has been assigned work, launch a search
- if (is_searching)
+ if (searching)
{
- assert(!do_exit);
+ assert(!exit);
Threads.mutex.lock();
- assert(is_searching);
+ assert(searching);
SplitPoint* sp = curSplitPoint;
Threads.mutex.unlock();
else
assert(false);
- assert(is_searching);
+ assert(searching);
- is_searching = false;
+ searching = false;
sp->activePositions[idx] = NULL;
sp->slavesMask &= ~(1ULL << idx);
sp->nodes += pos.nodes_searched();
&& this != sp->master
&& !sp->slavesMask)
{
- assert(!sp->master->is_searching);
+ assert(!sp->master->searching);
sp->master->notify_one();
}