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);
<< std::endl;
}
- // Reset and wake up the threads
+ // Reset the threads, still sleeping: will be wake up at split time
for (size_t i = 0; i < Threads.size(); i++)
- {
Threads[i].maxPly = 0;
- Threads[i].do_sleep = false;
- if (!Threads.use_sleeping_threads())
- Threads[i].notify_one();
- }
+ Threads.sleepWhileIdle = Options["Use Sleeping Threads"];
// Set best timer interval to avoid lagging under time pressure. Timer is
// used to check for remaining available thinking time.
- if (Limits.use_time_management())
- Threads.set_timer(std::min(100, std::max(TimeMgr.available_time() / 16,
- TimerResolution)));
- else if (Limits.nodes)
- Threads.set_timer(2 * TimerResolution);
- else
- Threads.set_timer(100);
+ Threads.timer_thread()->msec =
+ Limits.use_time_management() ? std::min(100, std::max(TimeMgr.available_time() / 16, TimerResolution)) :
+ Limits.nodes ? 2 * TimerResolution
+ : 100;
- id_loop(RootPos); // Let's start searching !
+ Threads.timer_thread()->notify_one(); // Wake up the recurring timer
- Threads.set_timer(0); // Stop timer
+ id_loop(RootPos); // Let's start searching !
- // Main thread will go to sleep by itself to avoid a race with start_searching()
- for (size_t i = 0; i < Threads.size(); i++)
- if (&Threads[i] != Threads.main_thread())
- Threads[i].do_sleep = true;
+ Threads.timer_thread()->msec = 0; // Stop the timer
+ Threads.sleepWhileIdle = true; // Send idle threads to sleep
if (Options["Use Search Log"])
{
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()
- && Threads.available_slave_exists(thisThread))
+ && depth >= Threads.minimumSplitDepth
+ && Threads.slave_available(thisThread)
+ && thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
{
assert(bestValue < beta);
Bitboard b = (enemies ^ ksq) & newAtt & ~oldAtt;
while (b)
{
- // Note that here we generate illegal "double move"!
if (futilityBase + PieceValue[EG][pos.piece_on(pop_lsb(&b))] >= beta)
return true;
}
}
- // 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
void Thread::idle_loop() {
- // Pointer 'sp_master', if non-NULL, points to the active SplitPoint
- // object for which the thread is the master.
- const SplitPoint* sp_master = splitPointsCnt ? curSplitPoint : NULL;
+ // Pointer 'this_sp' is not null only if we are called from split(), and not
+ // at the thread creation. So it means we are the split point's master.
+ const SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : NULL;
- assert(!sp_master || (sp_master->master == this && is_searching));
+ assert(!this_sp || (this_sp->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.
- while (!sp_master || sp_master->slavesMask)
+ // 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.
+ while (!this_sp || this_sp->slavesMask)
{
- // If we are not searching, wait for a condition to be signaled
- // instead of wasting CPU time polling for work.
- while ( do_sleep
- || do_exit
- || (!is_searching && Threads.use_sleeping_threads()))
+ // If we are not searching, wait for a condition to be signaled instead of
+ // wasting CPU time polling for work.
+ while ((!searching && Threads.sleepWhileIdle) || exit)
{
- if (do_exit)
+ if (exit)
{
- assert(!sp_master);
+ assert(!this_sp);
return;
}
- // Grab the lock to avoid races with Thread::wake_up()
+ // Grab the lock to avoid races with Thread::notify_one()
mutex.lock();
- // If we are master and all slaves have finished don't go to sleep
- if (sp_master && !sp_master->slavesMask)
+ // If we are master and all slaves have finished then exit idle_loop
+ if (this_sp && !this_sp->slavesMask)
{
mutex.unlock();
break;
// Do sleep after retesting sleep conditions under lock protection, in
// 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 (do_sleep || !is_searching)
+ // in the meanwhile, allocated us and sent the notify_one() call before
+ // we had the chance to grab the lock.
+ 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_sleep && !do_exit);
+ assert(!exit);
Threads.mutex.lock();
- assert(is_searching);
- SplitPoint* sp = curSplitPoint;
+ assert(searching);
+ SplitPoint* sp = activeSplitPoint;
Threads.mutex.unlock();
sp->mutex.lock();
- assert(sp->activePositions[idx] == NULL);
+ assert(sp->slavesPositions[idx] == NULL);
- sp->activePositions[idx] = &pos;
+ sp->slavesPositions[idx] = &pos;
- if (sp->nodeType == Root)
+ switch (sp->nodeType) {
+ case Root:
search<SplitPointRoot>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
- else if (sp->nodeType == PV)
+ break;
+ case PV:
search<SplitPointPV>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
- else if (sp->nodeType == NonPV)
+ break;
+ case NonPV:
search<SplitPointNonPV>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
- else
+ break;
+ default:
assert(false);
+ }
- assert(is_searching);
+ assert(searching);
- is_searching = false;
- sp->activePositions[idx] = NULL;
+ searching = false;
+ sp->slavesPositions[idx] = NULL;
sp->slavesMask &= ~(1ULL << idx);
sp->nodes += pos.nodes_searched();
- // Wake up master thread so to allow it to return from the idle loop in
- // case we are the last slave of the split point.
- if ( Threads.use_sleeping_threads()
+ // Wake up master thread so to allow it to return from the idle loop
+ // in case we are the last slave of the split point.
+ if ( Threads.sleepWhileIdle
&& this != sp->master
&& !sp->slavesMask)
{
- assert(!sp->master->is_searching);
+ assert(!sp->master->searching);
sp->master->notify_one();
}
// Loop across all split points and sum accumulated SplitPoint nodes plus
// all the currently active slaves positions.
for (size_t i = 0; i < Threads.size(); i++)
- for (int j = 0; j < Threads[i].splitPointsCnt; j++)
+ for (int j = 0; j < Threads[i].splitPointsSize; j++)
{
SplitPoint& sp = Threads[i].splitPoints[j];
Bitboard sm = sp.slavesMask;
while (sm)
{
- Position* pos = sp.activePositions[pop_lsb(&sm)];
+ Position* pos = sp.slavesPositions[pop_lsb(&sm)];
nodes += pos ? pos->nodes_searched() : 0;
}