void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
const Search::LimitsType& limits, bool ponderMode) {
main()->wait_for_search_finished();
stopOnPonderhit = stop = false;
ponder = ponderMode;
Search::Limits = limits;
Search::RootMoves rootMoves;
for (const auto& m : MoveList<LEGAL>(pos))
if ( limits.searchmoves.empty()
|| std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
rootMoves.emplace_back(m);
if (!rootMoves.empty())
Tablebases::filter_root_moves(pos, rootMoves);
// After ownership transfer 'states' becomes empty, so if we stop the search
// and call 'go' again without setting a new position states.get() == NULL.
assert(states.get() || setupStates.get());
if (states.get())
setupStates = std::move(states); // Ownership transfer, states is now empty
// 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 : *this)
{
th->nodes = th->tbHits = 0;
th->rootDepth = th->completedDepth = DEPTH_ZERO;
th->rootMoves = rootMoves;
th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
th->nmp_ply = 0;
th->pair = -1;
}
setupStates->back() = tmp;
main()->start_searching();
}
void ThreadPool::start_thinking(Position& pos, StateListPtr& states,
const Search::LimitsType& limits) {
main()->wait_for_search_finished();
Search::Signals.stopOnPonderhit = Search::Signals.stop = false;
Search::Limits = limits;
Search::RootMoves rootMoves;
for (const auto& m : MoveList<LEGAL>(pos))
if ( limits.searchmoves.empty()
|| std::count(limits.searchmoves.begin(), limits.searchmoves.end(), m))
rootMoves.push_back(Search::RootMove(m));
if (!rootMoves.empty())
Tablebases::rank_root_moves(pos, rootMoves);
// After ownership transfer 'states' becomes empty, so if we stop the search
// and call 'go' again without setting a new position states.get() == NULL.
assert(states.get() || setupStates.get());
if (states.get())
setupStates = std::move(states); // Ownership transfer, states is now empty
StateInfo tmp = setupStates->back();
for (Thread* th : Threads)
{
th->maxPly = 0;
th->tbHits = 0;
th->rootDepth = DEPTH_ZERO;
th->rootMoves = rootMoves;
th->rootPos.set(pos.fen(), pos.is_chess960(), &setupStates->back(), th);
}
setupStates->back() = tmp; // Restore st->previous, cleared by Position::set()
main()->start_searching();
}