Thread::Thread(size_t n) : idx(n), stdThread(&Thread::idle_loop, this) {
wait_for_search_finished();
+ clear(); // Zero-init histories (based on std::array)
}
}
+/// Thread::clear() reset histories, usually before a new game
+
+void Thread::clear() {
+
+ counterMoves.fill(MOVE_NONE);
+ mainHistory.fill(0);
+ captureHistory.fill(0);
+
+ for (auto& to : contHistory)
+ for (auto& h : to)
+ h.fill(0);
+
+ contHistory[NO_PIECE][0].fill(Search::CounterMovePruneThreshold - 1);
+}
+
/// Thread::start_searching() wakes up the thread that will start the search
void Thread::start_searching() {
/// ThreadPool::init() creates and launches the threads that will go
-/// immediately to sleep in idle_loop. We cannot use the c'tor because
+/// immediately to sleep in idle_loop. We cannot use the constructor because
/// Threads is a static object and we need a fully initialized engine at
/// this point due to allocation of Endgames in the Thread constructor.
if (states.get())
setupStates = std::move(states); // Ownership transfer, states is now empty
- // We use Position::set() to set root position across threads. So we
- // need to save and later to restore st->previous, cleared by set().
- // Note that setupStates is shared by threads but is accessed in read-only mode.
- StateInfo* previous = setupStates->back().previous;
+ // We use Position::set() to set root position across threads. But there are
+ // some StateInfo fields (previous, pliesFromNull, capturedPiece) that cannot
+ // be deduced from a fen string, so set() clears them and to not lose the info
+ // we need to backup and later restore setupStates->back(). Note that setupStates
+ // is shared by threads but is accessed in read-only mode.
+ StateInfo tmp = setupStates->back();
for (Thread* th : Threads)
{
th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
}
- setupStates->back().previous = previous;
+ setupStates->back() = tmp;
main()->start_searching();
}