read_evaluation_uci_options(pos.side_to_move());
Threads.read_uci_options();
- // Allocate pawn and material hash tables if number of active threads
- // increased and set a new TT size if changed.
- Threads.init_hash_tables();
+ // Set a new TT size if changed
TT.set_size(Options["Hash"].value<int>());
if (Options["Clear Hash"].value<bool>())
Rml.bestMoveChanges = 0;
- // MultiPV iteration loop
- for (MultiPVIteration = 0; MultiPVIteration < Min(MultiPV, (int)Rml.size()); MultiPVIteration++)
+ // MultiPV iteration loop. At depth 1 perform at least 2 iterations to
+ // get a score of the second best move for easy move detection.
+ int e = Min(Max(MultiPV, 2 * int(depth == 1)), (int)Rml.size());
+ for (MultiPVIteration = 0; MultiPVIteration < e; MultiPVIteration++)
{
// Calculate dynamic aspiration window based on previous iterations
if (depth >= 5 && abs(Rml[MultiPVIteration].prevScore) < VALUE_KNOWN_WIN)
: can_return_tt(tte, depth, beta, ss->ply)))
{
TT.refresh(tte);
- ss->bestMove = ttMove; // Can be MOVE_NONE
- return value_from_tt(tte->value(), ss->ply);
+ ss->bestMove = move = ttMove; // Can be MOVE_NONE
+ value = value_from_tt(tte->value(), ss->ply);
+
+ if ( value >= beta
+ && move
+ && !pos.move_is_capture_or_promotion(move)
+ && move != ss->killers[0])
+ {
+ ss->killers[1] = ss->killers[0];
+ ss->killers[0] = move;
+ }
+ return value;
}
// Step 5. Evaluate the position statically and update parent's gain statistics
<< " currmovenumber " << moveCount + MultiPVIteration << endl;
}
- // At Root and at first iteration do a PV search on all the moves to score root moves
- isPvMove = (PvNode && moveCount <= (RootNode && depth <= ONE_PLY ? MAX_MOVES : 1));
+ isPvMove = (PvNode && moveCount == 1);
givesCheck = pos.move_gives_check(move, ci);
captureOrPromotion = pos.move_is_capture_or_promotion(move);
Piece p1, p2;
Square ksq;
- assert(m1 && move_is_ok(m1));
- assert(m2 && move_is_ok(m2));
+ assert(move_is_ok(m1));
+ assert(move_is_ok(m2));
// Case 1: The moving piece is the same in both moves
f2 = move_from(m2);
bool connected_threat(const Position& pos, Move m, Move threat) {
assert(move_is_ok(m));
- assert(threat && move_is_ok(threat));
+ assert(move_is_ok(threat));
assert(!pos.move_is_capture_or_promotion(m));
assert(!pos.move_is_passed_pawn_push(m));
} // namespace
-// ThreadsManager::idle_loop() is where the threads are parked when they have no work
-// to do. The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint
-// object for which the current thread is the master.
+// Little helper used by idle_loop() to check that all the slave threads of a
+// split point have finished searching.
+
+static bool all_slaves_finished(SplitPoint* sp) {
+
+ for (int i = 0; i < Threads.size(); i++)
+ if (sp->is_slave[i])
+ return false;
+
+ return true;
+}
-void ThreadsManager::idle_loop(int threadID, SplitPoint* sp) {
- assert(threadID >= 0 && threadID < MAX_THREADS);
+// Thread::idle_loop() is where the thread is parked when it has no work to do.
+// The parameter 'sp', if non-NULL, is a pointer to an active SplitPoint object
+// for which the thread is the master.
- int i;
- bool allFinished;
+void Thread::idle_loop(SplitPoint* sp) {
while (true)
{
- // Slave threads can exit as soon as allThreadsShouldExit flag raises,
- // master should exit as last one.
- if (allThreadsShouldExit)
- {
- assert(!sp);
- threads[threadID].state = Thread::TERMINATED;
- return;
- }
-
// If we are not searching, wait for a condition to be signaled
// instead of wasting CPU time polling for work.
- while ( threadID >= activeThreads
- || threads[threadID].state == Thread::INITIALIZING
- || (useSleepingThreads && threads[threadID].state == Thread::AVAILABLE))
+ while ( do_sleep
+ || do_terminate
+ || (Threads.use_sleeping_threads() && !is_searching))
{
- assert(!sp || useSleepingThreads);
- assert(threadID != 0 || useSleepingThreads);
+ assert((!sp && threadID) || Threads.use_sleeping_threads());
- if (threads[threadID].state == Thread::INITIALIZING)
- threads[threadID].state = Thread::AVAILABLE;
+ // Slave thread should exit as soon as do_terminate flag raises
+ if (do_terminate)
+ {
+ assert(!sp);
+ return;
+ }
// Grab the lock to avoid races with Thread::wake_up()
- lock_grab(&threads[threadID].sleepLock);
+ lock_grab(&sleepLock);
// If we are master and all slaves have finished don't go to sleep
- for (i = 0; sp && i < activeThreads && !sp->is_slave[i]; i++) {}
- allFinished = (i == activeThreads);
-
- if (allFinished || allThreadsShouldExit)
+ if (sp && all_slaves_finished(sp))
{
- lock_release(&threads[threadID].sleepLock);
+ lock_release(&sleepLock);
break;
}
// 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 (threadID >= activeThreads || threads[threadID].state == Thread::AVAILABLE)
- cond_wait(&threads[threadID].sleepCond, &threads[threadID].sleepLock);
+ if (do_sleep || !is_searching)
+ cond_wait(&sleepCond, &sleepLock);
- lock_release(&threads[threadID].sleepLock);
+ lock_release(&sleepLock);
}
// If this thread has been assigned work, launch a search
- if (threads[threadID].state == Thread::WORKISWAITING)
+ if (is_searching)
{
- assert(!allThreadsShouldExit);
-
- threads[threadID].state = Thread::SEARCHING;
+ assert(!do_terminate);
// Copy split point position and search stack and call search()
SearchStack ss[PLY_MAX_PLUS_2];
- SplitPoint* tsp = threads[threadID].splitPoint;
+ SplitPoint* tsp = splitPoint;
Position pos(*tsp->pos, threadID);
memcpy(ss, tsp->ss - 1, 4 * sizeof(SearchStack));
else
assert(false);
- assert(threads[threadID].state == Thread::SEARCHING);
+ assert(is_searching);
- threads[threadID].state = Thread::AVAILABLE;
+ is_searching = false;
// 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 ( useSleepingThreads
+ if ( Threads.use_sleeping_threads()
&& threadID != tsp->master
- && threads[tsp->master].state == Thread::AVAILABLE)
- threads[tsp->master].wake_up();
+ && !Threads[tsp->master].is_searching)
+ Threads[tsp->master].wake_up();
}
// 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.
- for (i = 0; sp && i < activeThreads && !sp->is_slave[i]; i++) {}
- allFinished = (i == activeThreads);
-
- if (allFinished)
+ if (sp && all_slaves_finished(sp))
{
// Because sp->is_slave[] is reset under lock protection,
// be sure sp->lock has been released before to return.