volatile SignalsType Signals;
LimitsType Limits;
- RootMoveVector RootMoves;
- Position RootPos;
StateStackPtr SetupStates;
}
Move pv[3];
};
- size_t PVIdx;
EasyMoveManager EasyMove;
double BestMoveChanges;
Value DrawValue[COLOR_NB];
- HistoryStats History;
CounterMovesHistoryStats CounterMovesHistory;
- MovesStats Countermoves;
- template <NodeType NT, bool SpNode>
+ template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
template <NodeType NT, bool InCheck>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
- void id_loop(Position& pos);
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
void update_pv(Move* pv, Move move, Move* childPv);
void Search::reset () {
TT.clear();
- History.clear();
CounterMovesHistory.clear();
- Countermoves.clear();
+
+ for (Thread* th : Threads)
+ {
+ th->History.clear();
+ th->Countermoves.clear();
+ }
}
template uint64_t Search::perft<true>(Position& pos, Depth depth);
-/// Search::think() is the external interface to Stockfish's search, and is
-/// called by the main thread when the program receives the UCI 'go' command. It
-/// searches from RootPos and at the end prints the "bestmove" to output.
+/// MainThread::think() is called by the main thread when the program receives
+/// the UCI 'go' command. It searches from root position and at the end prints
+/// the "bestmove" to output.
-void Search::think() {
+void MainThread::think() {
- Color us = RootPos.side_to_move();
- Time.init(Limits, us, RootPos.game_ply(), now());
+ Color us = rootPos.side_to_move();
+ Time.init(Limits, us, rootPos.game_ply());
int contempt = Options["Contempt"] * PawnValueEg / 100; // From centipawns
DrawValue[ us] = VALUE_DRAW - Value(contempt);
TB::ProbeDepth = DEPTH_ZERO;
}
- if (RootMoves.empty())
+ if (rootMoves.empty())
{
- RootMoves.push_back(RootMove(MOVE_NONE));
+ rootMoves.push_back(RootMove(MOVE_NONE));
sync_cout << "info depth 0 score "
- << UCI::value(RootPos.checkers() ? -VALUE_MATE : VALUE_DRAW)
+ << UCI::value(rootPos.checkers() ? -VALUE_MATE : VALUE_DRAW)
<< sync_endl;
}
else
{
- if (TB::Cardinality >=
RootPos.count<ALL_PIECES>(WHITE)
- +
RootPos.count<ALL_PIECES>(BLACK))
+ if (TB::Cardinality >=
rootPos.count<ALL_PIECES>(WHITE)
+ +
rootPos.count<ALL_PIECES>(BLACK))
{
// If the current root position is in the tablebases then RootMoves
// contains only moves that preserve the draw or win.
- TB::RootInTB = Tablebases::root_probe(RootPos, RootMoves, TB::Score);
+ TB::RootInTB = Tablebases::root_probe(rootPos, rootMoves, TB::Score);
if (TB::RootInTB)
TB::Cardinality = 0; // Do not probe tablebases during the search
else // If DTZ tables are missing, use WDL tables as a fallback
{
// Filter out moves that do not preserve a draw or win
- TB::RootInTB = Tablebases::root_probe_wdl(RootPos, RootMoves, TB::Score);
+ TB::RootInTB = Tablebases::root_probe_wdl(rootPos, rootMoves, TB::Score);
// Only probe during search if winning
if (TB::Score <= VALUE_DRAW)
if (TB::RootInTB)
{
- TB::Hits = RootMoves.size();
+ TB::Hits = rootMoves.size();
if (!TB::UseRule50)
TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1
for (Thread* th : Threads)
{
th->maxPly = 0;
- th->notify_one(); // Wake up all the threads
+ th->depth = DEPTH_ZERO;
+ th->searching = true;
+ if (th != this)
+ {
+ th->rootPos = Position(rootPos, th);
+ th->rootMoves = rootMoves;
+ th->notify_one(); // Wake up the thread and start searching
+ }
}
Threads.timer->run = true;
Threads.timer->notify_one(); // Start the recurring timer
- id_loop(RootPos); // Let's start searching !
+ search(true); // Let's start searching!
+ // Stop the threads and the timer
+ Signals.stop = true;
Threads.timer->run = false;
+
+ // Wait until all threads have finished
+ for (Thread* th : Threads)
+ if (th != this)
+ th->wait_while(th->searching);
}
// When playing in 'nodes as time' mode, subtract the searched nodes from
// the available ones before to exit.
if (Limits.npmsec)
- Time.availableNodes += Limits.inc[us] - RootPos.nodes_searched();
+ Time.availableNodes += Limits.inc[us] - Threads.nodes_searched();
// When we reach the maximum depth, we can arrive here without a raise of
// Signals.stop. However, if we are pondering or in an infinite search,
if (!Signals.stop && (Limits.ponder || Limits.infinite))
{
Signals.stopOnPonderhit = true;
- RootPos.this_thread()->wait_for(Signals.stop);
+ wait(Signals.stop);
}
- sync_cout << "bestmove " << UCI::move(RootMoves[0].pv[0], RootPos.is_chess960());
+ sync_cout << "bestmove " << UCI::move(rootMoves[0].pv[0], rootPos.is_chess960());
- if (RootMoves[0].pv.size() > 1 || RootMoves[0].extract_ponder_from_tt(RootPos))
- std::cout << " ponder " << UCI::move(RootMoves[0].pv[1], RootPos.is_chess960());
+ if (rootMoves[0].pv.size() > 1 || rootMoves[0].extract_ponder_from_tt(rootPos))
+ std::cout << " ponder " << UCI::move(rootMoves[0].pv[1], rootPos.is_chess960());
std::cout << sync_endl;
}
-namespace {
+// Thread::search() is the main iterative deepening loop. It calls search()
+// repeatedly with increasing depth until the allocated thinking time has been
+// consumed, user stops the search, or the maximum search depth is reached.
- // id_loop() is the main iterative deepening loop. It calls search() repeatedly
- // with increasing depth until the allocated thinking time has been consumed,
- // user stops the search, or the maximum search depth is reached.
+void Thread::search(bool isMainThread) {
- void id_loop(Position& pos) {
+ Stack* ss = stack + 2; // To allow referencing (ss-2) and (ss+2)
+ Value bestValue, alpha, beta, delta;
+ Move easyMove = MOVE_NONE;
- Stack stack[MAX_PLY+4], *ss = stack+2; // To allow referencing (ss-2) and (ss+2)
- Depth depth;
- Value bestValue, alpha, beta, delta;
+ std::memset(ss-2, 0, 5 * sizeof(Stack));
- Move easyMove = EasyMove.get(pos.key());
- EasyMove.clear();
+ bestValue = delta = alpha = -VALUE_INFINITE;
+ beta = VALUE_INFINITE;
- std::memset(ss-2, 0, 5 * sizeof(Stack));
+ if (isMainThread)
+ {
+ easyMove = EasyMove.get(rootPos.key());
+ EasyMove.clear();
+ BestMoveChanges = 0;
+ TT.new_search();
+ }
- depth = DEPTH_ZERO;
- BestMoveChanges = 0;
- bestValue = delta = alpha = -VALUE_INFINITE;
- beta = VALUE_INFINITE;
+ size_t multiPV = Options["MultiPV"];
+ Skill skill(Options["Skill Level"]);
- TT.new_search();
+ // When playing with strength handicap enable MultiPV search that we will
+ // use behind the scenes to retrieve a set of possible moves.
+ if (skill.enabled())
+ multiPV = std::max(multiPV, (size_t)4);
- size_t multiPV = Options["MultiPV"];
- Skill skill(Options["Skill Level"]);
+ multiPV = std::min(multiPV, rootMoves.size());
- // When playing with strength handicap enable MultiPV search that we will
- // use behind the scenes to retrieve a set of possible moves.
- if (skill.enabled())
- multiPV = std::max(multiPV, (size_t)4);
+ // Iterative deepening loop until requested to stop or target depth reached
+ while (++depth < DEPTH_MAX && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
+ {
+ // Set up the new depth for the helper threads
+ if (!isMainThread)
+ depth = Threads.main()->depth + Depth(int(3 * log(1 + this->idx)));
- multiPV = std::min(multiPV, RootMoves.size());
+ // Age out PV variability metric
+ if (isMainThread)
+ BestMoveChanges *= 0.5;
- // Iterative deepening loop until requested to stop or target depth reached
- while (++depth < DEPTH_MAX && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
- {
- // Age out PV variability metric
- BestMoveChanges *= 0.5;
+ // Save the last iteration's scores before first PV line is searched and
+ // all the move scores except the (new) PV are set to -VALUE_INFINITE.
+ for (RootMove& rm : rootMoves)
+ rm.previousScore = rm.score;
- // Save the last iteration's scores before first PV line is searched and
- // all the move scores except the (new) PV are set to -VALUE_INFINITE.
- for (RootMove& rm : RootMoves)
- rm.previousScore = rm.score;
+ // MultiPV loop. We perform a full root search for each PV line
+ for (PVIdx = 0; PVIdx < multiPV && !Signals.stop; ++PVIdx)
+ {
+ // Reset aspiration window starting size
+ if (depth >= 5 * ONE_PLY)
+ {
+ delta = Value(16);
+ alpha = std::max(rootMoves[PVIdx].previousScore - delta,-VALUE_INFINITE);
+ beta = std::min(rootMoves[PVIdx].previousScore + delta, VALUE_INFINITE);
+ }
- // MultiPV loop. We perform a full root search for each PV line
- for (PVIdx = 0; PVIdx < multiPV && !Signals.stop; ++PVIdx)
- {
- // Reset aspiration window starting size
- if (depth >= 5 * ONE_PLY)
- {
- delta = Value(16);
- alpha = std::max(RootMoves[PVIdx].previousScore - delta,-VALUE_INFINITE);
- beta = std::min(RootMoves[PVIdx].previousScore + delta, VALUE_INFINITE);
- }
+ // Start with a small aspiration window and, in the case of a fail
+ // high/low, re-search with a bigger window until we're not failing
+ // high/low anymore.
+ while (true)
+ {
+ bestValue = ::search<Root>(rootPos, ss, alpha, beta, depth, false);
+
+ // Bring the best move to the front. It is critical that sorting
+ // is done with a stable algorithm because all the values but the
+ // first and eventually the new best one are set to -VALUE_INFINITE
+ // and we want to keep the same order for all the moves except the
+ // new PV that goes to the front. Note that in case of MultiPV
+ // search the already searched PV lines are preserved.
+ std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.end());
+
+ // Write PV back to transposition table in case the relevant
+ // entries have been overwritten during the search.
+ for (size_t i = 0; i <= PVIdx; ++i)
+ rootMoves[i].insert_pv_in_tt(rootPos);
+
+ // If search has been stopped break immediately. Sorting and
+ // writing PV back to TT is safe because RootMoves is still
+ // valid, although it refers to previous iteration.
+ if (Signals.stop)
+ break;
- // Start with a small aspiration window and, in the case of a fail
- // high/low, re-search with a bigger window until we're not failing
- // high/low anymore.
- while (true)
- {
- bestValue = search<Root, false>(pos, ss, alpha, beta, depth, false);
-
- // Bring the best move to the front. It is critical that sorting
- // is done with a stable algorithm because all the values but the
- // first and eventually the new best one are set to -VALUE_INFINITE
- // and we want to keep the same order for all the moves except the
- // new PV that goes to the front. Note that in case of MultiPV
- // search the already searched PV lines are preserved.
- std::stable_sort(RootMoves.begin() + PVIdx, RootMoves.end());
-
- // Write PV back to transposition table in case the relevant
- // entries have been overwritten during the search.
- for (size_t i = 0; i <= PVIdx; ++i)
- RootMoves[i].insert_pv_in_tt(pos);
-
- // If search has been stopped break immediately. Sorting and
- // writing PV back to TT is safe because RootMoves is still
- // valid, although it refers to previous iteration.
- if (Signals.stop)
- break;
-
- // When failing high/low give some update (without cluttering
- // the UI) before a re-search.
- if ( multiPV == 1
- && (bestValue <= alpha || bestValue >= beta)
- && Time.elapsed() > 3000)
- sync_cout << UCI::pv(pos, depth, alpha, beta) << sync_endl;
-
- // In case of failing low/high increase aspiration window and
- // re-search, otherwise exit the loop.
- if (bestValue <= alpha)
- {
- beta = (alpha + beta) / 2;
- alpha = std::max(bestValue - delta, -VALUE_INFINITE);
-
- Signals.failedLowAtRoot = true;
- Signals.stopOnPonderhit = false;
- }
- else if (bestValue >= beta)
- {
- alpha = (alpha + beta) / 2;
- beta = std::min(bestValue + delta, VALUE_INFINITE);
- }
- else
- break;
-
- delta += delta / 2;
-
- assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
- }
+ // When failing high/low give some update (without cluttering
+ // the UI) before a re-search.
+ if ( isMainThread
+ && multiPV == 1
+ && (bestValue <= alpha || bestValue >= beta)
+ && Time.elapsed() > 3000)
+ sync_cout << UCI::pv(rootPos, depth, alpha, beta) << sync_endl;
+
+ // In case of failing low/high increase aspiration window and
+ // re-search, otherwise exit the loop.
+ if (bestValue <= alpha)
+ {
+ beta = (alpha + beta) / 2;
+ alpha = std::max(bestValue - delta, -VALUE_INFINITE);
- // Sort the PV lines searched so far and update the GUI
- std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
+ if (isMainThread)
+ {
+ Signals.failedLowAtRoot = true;
+ Signals.stopOnPonderhit = false;
+ }
+ }
+ else if (bestValue >= beta)
+ {
+ alpha = (alpha + beta) / 2;
+ beta = std::min(bestValue + delta, VALUE_INFINITE);
+ }
+ else
+ break;
- if (Signals.stop)
- sync_cout << "info nodes " << RootPos.nodes_searched()
- << " time " << Time.elapsed() << sync_endl;
+ delta += delta / 2;
- else if (PVIdx + 1 == multiPV || Time.elapsed() > 3000)
- sync_cout << UCI::pv(pos, depth, alpha, beta) << sync_endl;
- }
+ assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
+ }
- // If skill level is enabled and time is up, pick a sub-optimal best move
- if (skill.enabled() && skill.time_to_pick(depth))
- skill.pick_best(multiPV);
+ // Sort the PV lines searched so far and update the GUI
+ std::stable_sort(rootMoves.begin(), rootMoves.begin() + PVIdx + 1);
- // Have we found a "mate in x"?
- if ( Limits.mate
- && bestValue >= VALUE_MATE_IN_MAX_PLY
- && VALUE_MATE - bestValue <= 2 * Limits.mate)
- Signals.stop = true;
+ if (!isMainThread)
+ break;
- // Do we have time for the next iteration? Can we stop searching now?
- if (Limits.use_time_management())
- {
- if (!Signals.stop && !Signals.stopOnPonderhit)
- {
- // Take some extra time if the best move has changed
- if (depth > 4 * ONE_PLY && multiPV == 1)
- Time.pv_instability(BestMoveChanges);
-
- // Stop the search if only one legal move is available or all
- // of the available time has been used or we matched an easyMove
- // from the previous search and just did a fast verification.
- if ( RootMoves.size() == 1
- || Time.elapsed() > Time.available()
- || ( RootMoves[0].pv[0] == easyMove
- && BestMoveChanges < 0.03
- && Time.elapsed() > Time.available() / 10))
- {
- // If we are allowed to ponder do not stop the search now but
- // keep pondering until the GUI sends "ponderhit" or "stop".
- if (Limits.ponder)
- Signals.stopOnPonderhit = true;
- else
- Signals.stop = true;
- }
- }
+ if (Signals.stop)
+ sync_cout << "info nodes " << Threads.nodes_searched()
+ << " time " << Time.elapsed() << sync_endl;
- if (RootMoves[0].pv.size() >= 3)
- EasyMove.update(pos, RootMoves[0].pv);
- else
- EasyMove.clear();
- }
- }
+ else if (PVIdx + 1 == multiPV || Time.elapsed() > 3000)
+ sync_cout << UCI::pv(rootPos, depth, alpha, beta) << sync_endl;
+ }
- // Clear any candidate easy move that wasn't stable for the last search
- // iterations; the second condition prevents consecutive fast moves.
- if (EasyMove.stableCnt < 6 || Time.elapsed() < Time.available())
- EasyMove.clear();
+ if (!isMainThread)
+ continue;
- // If skill level is enabled, swap best PV line with the sub-optimal one
- if (skill.enabled())
- std::swap(RootMoves[0], *std::find(RootMoves.begin(),
- RootMoves.end(), skill.best_move(multiPV)));
+ // If skill level is enabled and time is up, pick a sub-optimal best move
+ if (skill.enabled() && skill.time_to_pick(depth))
+ skill.pick_best(multiPV);
+
+ // Have we found a "mate in x"?
+ if ( Limits.mate
+ && bestValue >= VALUE_MATE_IN_MAX_PLY
+ && VALUE_MATE - bestValue <= 2 * Limits.mate)
+ Signals.stop = true;
+
+ // Do we have time for the next iteration? Can we stop searching now?
+ if (Limits.use_time_management())
+ {
+ if (!Signals.stop && !Signals.stopOnPonderhit)
+ {
+ // Take some extra time if the best move has changed
+ if (depth > 4 * ONE_PLY && multiPV == 1)
+ Time.pv_instability(BestMoveChanges);
+
+ // Stop the search if only one legal move is available or all
+ // of the available time has been used or we matched an easyMove
+ // from the previous search and just did a fast verification.
+ if ( rootMoves.size() == 1
+ || Time.elapsed() > Time.available()
+ || ( rootMoves[0].pv[0] == easyMove
+ && BestMoveChanges < 0.03
+ && Time.elapsed() > Time.available() / 10))
+ {
+ // If we are allowed to ponder do not stop the search now but
+ // keep pondering until the GUI sends "ponderhit" or "stop".
+ if (Limits.ponder)
+ Signals.stopOnPonderhit = true;
+ else
+ Signals.stop = true;
+ }
+ }
+
+ if (rootMoves[0].pv.size() >= 3)
+ EasyMove.update(rootPos, rootMoves[0].pv);
+ else
+ EasyMove.clear();
+ }
}
+ searching = false;
+ notify_one(); // Wake up main thread if is sleeping waiting for us
+
+ if (!isMainThread)
+ return;
+
+ // Clear any candidate easy move that wasn't stable for the last search
+ // iterations; the second condition prevents consecutive fast moves.
+ if (EasyMove.stableCnt < 6 || Time.elapsed() < Time.available())
+ EasyMove.clear();
+
+ // If skill level is enabled, swap best PV line with the sub-optimal one
+ if (skill.enabled())
+ std::swap(rootMoves[0], *std::find(rootMoves.begin(),
+ rootMoves.end(), skill.best_move(multiPV)));
+}
+
+
+namespace {
// search<>() is the main search function for both PV and non-PV nodes and for
// normal and SplitPoint nodes. When called just after a split point the search
// repeat all this work again. We also don't need to store anything to the hash
// table here: This is taken care of after we return from the split point.
- template <NodeType NT, bool SpNode>
+ template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
const bool RootNode = NT == Root;
Move pv[MAX_PLY+1], quietsSearched[64];
StateInfo st;
TTEntry* tte;
- SplitPoint* splitPoint;
Key posKey;
Move ttMove, move, excludedMove, bestMove;
Depth extension, newDepth, predictedDepth;
// Step 1. Initialize node
Thread* thisThread = pos.this_thread();
inCheck = pos.checkers();
-
- if (SpNode)
- {
- splitPoint = ss->splitPoint;
- bestMove = splitPoint->bestMove;
- bestValue = splitPoint->bestValue;
- tte = nullptr;
- ttHit = false;
- ttMove = excludedMove = MOVE_NONE;
- ttValue = VALUE_NONE;
-
- assert(splitPoint->bestValue > -VALUE_INFINITE && splitPoint->moveCount > 0);
-
- goto moves_loop;
- }
-
moveCount = quietCount = ss->moveCount = 0;
bestValue = -VALUE_INFINITE;
ss->ply = (ss-1)->ply + 1;
excludedMove = ss->excludedMove;
posKey = excludedMove ? pos.exclusion_key() : pos.key();
tte = TT.probe(posKey, ttHit);
- ss->ttMove = ttMove = RootNode ? RootMoves[PVIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE;
+ ss->ttMove = ttMove = RootNode ? thisThread->rootMoves[thisThread->PVIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE;
ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
// At non-PV nodes we check for a fail high/low. We don't prune at PV nodes
pos.do_null_move(st);
(ss+1)->skipEarlyPruning = true;
nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -beta+1, DEPTH_ZERO)
- : - search<NonPV, false>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode);
+ : - search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode);
(ss+1)->skipEarlyPruning = false;
pos.undo_null_move();
// Do verification search at high depths
ss->skipEarlyPruning = true;
Value v = depth-R < ONE_PLY ? qsearch<NonPV, false>(pos, ss, beta-1, beta, DEPTH_ZERO)
- : search<NonPV, false>(pos, ss, beta-1, beta, depth-R, false);
+ : search<NonPV>(pos, ss, beta-1, beta, depth-R, false);
ss->skipEarlyPruning = false;
if (v >= beta)
assert((ss-1)->currentMove != MOVE_NONE);
assert((ss-1)->currentMove != MOVE_NULL);
- MovePicker mp(pos, ttMove, History, CounterMovesHistory, PieceValue[MG][pos.captured_piece_type()]);
+ MovePicker mp(pos, ttMove, thisThread->History, CounterMovesHistory, PieceValue[MG][pos.captured_piece_type()]);
CheckInfo ci(pos);
- while ((move = mp.next_move<false>()) != MOVE_NONE)
+ while ((move = mp.next_move()) != MOVE_NONE)
if (pos.legal(move, ci.pinned))
{
ss->currentMove = move;
pos.do_move(move, st, pos.gives_check(move, ci));
- value = -search<NonPV, false>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
+ value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
pos.undo_move(move);
if (value >= rbeta)
return value;
{
Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
ss->skipEarlyPruning = true;
- search<PvNode ? PV : NonPV, false>(pos, ss, alpha, beta, d, true);
+ search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d, true);
ss->skipEarlyPruning = false;
tte = TT.probe(posKey, ttHit);
ttMove = ttHit ? tte->move() : MOVE_NONE;
}
-moves_loop: // When in check and at SpNode search starts from here
+moves_loop: // When in check search starts from here
Square prevMoveSq = to_sq((ss-1)->currentMove);
- Move countermove = Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq];
+ Move countermove = thisThread->Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq];
- MovePicker mp(pos, ttMove, depth, History, CounterMovesHistory, countermove, ss);
+ MovePicker mp(pos, ttMove, depth, thisThread->History, CounterMovesHistory, countermove, ss);
CheckInfo ci(pos);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
improving = ss->staticEval >= (ss-2)->staticEval
||(ss-2)->staticEval == VALUE_NONE;
singularExtensionNode = !RootNode
- && !SpNode
&& depth >= 8 * ONE_PLY
&& ttMove != MOVE_NONE
/* && ttValue != VALUE_NONE Already implicit in the next condition */
// Step 11. Loop through moves
// Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
- while ((move = mp.next_move<SpNode>()) != MOVE_NONE)
+ while ((move = mp.next_move()) != MOVE_NONE)
{
assert(is_ok(move));
// At root obey the "searchmoves" option and skip moves not listed in Root
// Move List. As a consequence any illegal move is also skipped. In MultiPV
// mode we also skip PV moves which have been already searched.
- if (RootNode && !std::count(RootMoves.begin() + PVIdx, RootMoves.end(), move))
+ if (RootNode && !std::count(thisThread->rootMoves.begin() + thisThread->PVIdx, thisThread->rootMoves.end(), move))
continue;
- if (SpNode)
- {
- // Shared counter cannot be decremented later if the move turns out to be illegal
- if (!pos.legal(move, ci.pinned))
- continue;
+ ss->moveCount = ++moveCount;
- ss->moveCount = moveCount = ++splitPoint->moveCount;
- splitPoint->spinlock.release();
- }
- else
- ss->moveCount = ++moveCount;
-
- if (RootNode)
+ if (RootNode && thisThread == Threads.main())
{
Signals.firstRootMove = (moveCount == 1);
- if (thisThread == Threads.main() && Time.elapsed() > 3000)
+ if (Time.elapsed() > 3000)
sync_cout << "info depth " << depth / ONE_PLY
<< " currmove " << UCI::move(move, pos.is_chess960())
- << " currmovenumber " << moveCount + PVIdx << sync_endl;
+ << " currmovenumber " << moveCount + thisThread->PVIdx << sync_endl;
}
if (PvNode)
Value rBeta = ttValue - 2 * depth / ONE_PLY;
ss->excludedMove = move;
ss->skipEarlyPruning = true;
- value = search<NonPV, false>(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode);
+ value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode);
ss->skipEarlyPruning = false;
ss->excludedMove = MOVE_NONE;
// Move count based pruning
if ( depth < 16 * ONE_PLY
&& moveCount >= FutilityMoveCounts[improving][depth])
- {
- if (SpNode)
- splitPoint->spinlock.acquire();
-
continue;
- }
predictedDepth = newDepth - reduction<PvNode>(improving, depth, moveCount);
if (futilityValue <= alpha)
{
bestValue = std::max(bestValue, futilityValue);
-
- if (SpNode)
- {
- splitPoint->spinlock.acquire();
- if (bestValue > splitPoint->bestValue)
- splitPoint->bestValue = bestValue;
- }
continue;
}
}
// Prune moves with negative SEE at low depths
if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO)
- {
- if (SpNode)
- splitPoint->spinlock.acquire();
-
continue;
- }
}
// Speculative prefetch as early as possible
prefetch(TT.first_entry(pos.key_after(move)));
// Check for legality just before making the move
- if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))
+ if (!RootNode && !pos.legal(move, ci.pinned))
{
ss->moveCount = --moveCount;
continue;
ss->reduction = reduction<PvNode>(improving, depth, moveCount);
if ( (!PvNode && cutNode)
- || ( History[pos.piece_on(to_sq(move))][to_sq(move)] < VALUE_ZERO
+ || ( thisThread->History[pos.piece_on(to_sq(move))][to_sq(move)] < VALUE_ZERO
&& CounterMovesHistory[pos.piece_on(prevMoveSq)][prevMoveSq]
[pos.piece_on(to_sq(move))][to_sq(move)] <= VALUE_ZERO))
ss->reduction += ONE_PLY;
- if ( History[pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO
+ if ( thisThread->History[pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO
&& CounterMovesHistory[pos.piece_on(prevMoveSq)][prevMoveSq]
[pos.piece_on(to_sq(move))][to_sq(move)] > VALUE_ZERO)
ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY);
ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY);
Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
- if (SpNode)
- alpha = splitPoint->alpha;
- value = -search<NonPV, false>(pos, ss+1, -(alpha+1), -alpha, d, true);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO);
ss->reduction = DEPTH_ZERO;
// Step 16. Full depth search, when LMR is skipped or fails high
if (doFullDepthSearch)
- {
- if (SpNode)
- alpha = splitPoint->alpha;
-
value = newDepth < ONE_PLY ?
givesCheck ? -qsearch<NonPV, true>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
: -qsearch<NonPV, false>(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO)
- : - search<NonPV, false>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
- }
+ : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
// For PV nodes only, do a full PV search on the first move or after a fail
// high (in the latter case search only if value < beta), otherwise let the
value = newDepth < ONE_PLY ?
givesCheck ? -qsearch<PV, true>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
: -qsearch<PV, false>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
- : - search<PV, false>(pos, ss+1, -beta, -alpha, newDepth, false);
+ : - search<PV>(pos, ss+1, -beta, -alpha, newDepth, false);
}
// Step 17. Undo move
assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
// Step 18. Check for new best move
- if (SpNode)
- {
- splitPoint->spinlock.acquire();
- bestValue = splitPoint->bestValue;
- alpha = splitPoint->alpha;
- }
-
- // Finished searching the move. If a stop or a cutoff occurred, the return
- // value of the search cannot be trusted, and we return immediately without
+ // Finished searching the move. If a stop occurred, the return value of
+ // the search cannot be trusted, and we return immediately without
// updating best move, PV and TT.
- if (Signals.stop || thisThread->cutoff_occurred())
+ if (Signals.stop)
return VALUE_ZERO;
if (RootNode)
{
- RootMove& rm = *std::find(RootMoves.begin(), RootMoves.end(), move);
+ RootMove& rm = *std::find(thisThread->rootMoves.begin(), thisThread->rootMoves.end(), move);
// PV move or new best move ?
if (moveCount == 1 || value > alpha)
// We record how often the best move has been changed in each
// iteration. This information is used for time management: When
// the best move changes frequently, we allocate some more time.
- if (moveCount > 1)
+ if (moveCount > 1 && thisThread == Threads.main())
++BestMoveChanges;
}
else
if (value > bestValue)
{
- bestValue = SpNode ? splitPoint->bestValue = value : value;
+ bestValue = value;
if (value > alpha)
{
// If there is an easy move for this position, clear it if unstable
if ( PvNode
+ && thisThread == Threads.main()
&& EasyMove.get(pos.key())
&& (move != EasyMove.get(pos.key()) || moveCount > 1))
EasyMove.clear();
- bestMove = SpNode ? splitPoint->bestMove = move : move;
+ bestMove = move;
if (PvNode && !RootNode) // Update pv even in fail-high case
- update_pv(SpNode ? splitPoint->ss->pv : ss->pv, move, (ss+1)->pv);
+ update_pv(ss->pv, move, (ss+1)->pv);
if (PvNode && value < beta) // Update alpha! Always alpha < beta
- alpha = SpNode ? splitPoint->alpha = value : value;
+ alpha = value;
else
{
assert(value >= beta); // Fail high
-
- if (SpNode)
- splitPoint->cutoff = true;
-
break;
}
}
}
- if (!SpNode && !captureOrPromotion && move != bestMove && quietCount < 64)
+ if (!captureOrPromotion && move != bestMove && quietCount < 64)
quietsSearched[quietCount++] = move;
-
- // Step 19. Check for splitting the search
- if ( !SpNode
- && Threads.size() >= 2
- && depth >= Threads.minimumSplitDepth
- && ( !thisThread->activeSplitPoint
- || !thisThread->activeSplitPoint->allSlavesSearching
- || ( Threads.size() > MAX_SLAVES_PER_SPLITPOINT
- && thisThread->activeSplitPoint->slavesMask.count() == MAX_SLAVES_PER_SPLITPOINT))
- && thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
- {
- assert(bestValue > -VALUE_INFINITE && bestValue < beta);
-
- thisThread->split(pos, ss, alpha, beta, &bestValue, &bestMove,
- depth, moveCount, &mp, NT, cutNode);
-
- if (Signals.stop || thisThread->cutoff_occurred())
- return VALUE_ZERO;
-
- if (bestValue >= beta)
- break;
- }
}
- if (SpNode)
- return bestValue;
-
- // Following condition would detect a stop or a cutoff set only after move
- // loop has been completed. But in this case bestValue is valid because we
- // have fully searched our subtree, and we can anyhow save the result in TT.
+ // Following condition would detect a stop only after move loop has been
+ // completed. But in this case bestValue is valid because we have fully
+ // searched our subtree, and we can anyhow save the result in TT.
/*
- if (Signals.stop || thisThread->cutoff_occurred())
+ if (Signals.stop)
return VALUE_DRAW;
*/
// to search the moves. Because the depth is <= 0 here, only captures,
// queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will
// be generated.
- MovePicker mp(pos, ttMove, depth, History, CounterMovesHistory, to_sq((ss-1)->currentMove));
+ MovePicker mp(pos, ttMove, depth, pos.this_thread()->History, CounterMovesHistory, to_sq((ss-1)->currentMove));
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
- while ((move = mp.next_move<false>()) != MOVE_NONE)
+ while ((move = mp.next_move()) != MOVE_NONE)
{
assert(is_ok(move));
Square prevSq = to_sq((ss-1)->currentMove);
HistoryStats& cmh = CounterMovesHistory[pos.piece_on(prevSq)][prevSq];
+ Thread* thisThread = pos.this_thread();
- History.updateH(pos.moved_piece(move), to_sq(move), bonus);
+ thisThread->History.updateH(pos.moved_piece(move), to_sq(move), bonus);
if (is_ok((ss-1)->currentMove))
{
- Countermoves.update(pos.piece_on(prevSq), prevSq, move);
+ thisThread->Countermoves.update(pos.piece_on(prevSq), prevSq, move);
cmh.updateCMH(pos.moved_piece(move), to_sq(move), bonus);
}
// Decrease all the other played quiet moves
for (int i = 0; i < quietsCnt; ++i)
{
- History.updateH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
+ thisThread->History.updateH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
if (is_ok((ss-1)->currentMove))
cmh.updateCMH(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
Move Skill::pick_best(size_t multiPV) {
// PRNG sequence should be non-deterministic, so we seed it with the time at init
+ const Search::RootMoveVector& rootMoves = Threads.main()->rootMoves;
static PRNG rng(now());
// RootMoves are already sorted by score in descending order
- int variance = std::min(RootMoves[0].score - RootMoves[multiPV - 1].score, PawnValueMg);
+ int variance = std::min(rootMoves[0].score - rootMoves[multiPV - 1].score, PawnValueMg);
int weakness = 120 - 2 * level;
int maxScore = -VALUE_INFINITE;
for (size_t i = 0; i < multiPV; ++i)
{
// This is our magic formula
- int push = ( weakness * int(RootMoves[0].score - RootMoves[i].score)
+ int push = ( weakness * int(rootMoves[0].score - rootMoves[i].score)
+ variance * (rng.rand<unsigned>() % weakness)) / 128;
- if (RootMoves[i].score + push > maxScore)
+ if (rootMoves[i].score + push > maxScore)
{
- maxScore = RootMoves[i].score + push;
- best = RootMoves[i].pv[0];
+ maxScore = rootMoves[i].score + push;
+ best = rootMoves[i].pv[0];
}
}
return best;
std::stringstream ss;
int elapsed = Time.elapsed() + 1;
- size_t multiPV = std::min((size_t)Options["MultiPV"], RootMoves.size());
- int selDepth = 0;
-
- for (Thread* th : Threads)
- if (th->maxPly > selDepth)
- selDepth = th->maxPly;
+ const Search::RootMoveVector& rootMoves = pos.this_thread()->rootMoves;
+ size_t PVIdx = pos.this_thread()->PVIdx;
+ size_t multiPV = std::min((size_t)Options["MultiPV"], rootMoves.size());
+ uint64_t nodes_searched = Threads.nodes_searched();
for (size_t i = 0; i < multiPV; ++i)
{
continue;
Depth d = updated ? depth : depth - ONE_PLY;
- Value v = updated ? RootMoves[i].score : RootMoves[i].previousScore;
+ Value v = updated ? rootMoves[i].score : rootMoves[i].previousScore;
bool tb = TB::RootInTB && abs(v) < VALUE_MATE - MAX_PLY;
v = tb ? TB::Score : v;
ss << "info"
<< " depth " << d / ONE_PLY
- << " seldepth " << selDepth
+ << " seldepth " << pos.this_thread()->maxPly
<< " multipv " << i + 1
<< " score " << UCI::value(v);
if (!tb && i == PVIdx)
ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
- ss << " nodes " << pos.nodes_searched()
- << " nps " << pos.nodes_searched() * 1000 / elapsed;
+ ss << " nodes " << nodes_searched
+ << " nps " << nodes_searched * 1000 / elapsed;
if (elapsed > 1000) // Earlier makes little sense
ss << " hashfull " << TT.hashfull();
<< " time " << elapsed
<< " pv";
- for (Move m : RootMoves[i].pv)
+ for (Move m : rootMoves[i].pv)
ss << " " << UCI::move(m, pos.is_chess960());
}
}
-/// Thread::idle_loop() is where the thread is parked when it has no work to do
-
-void Thread::idle_loop() {
-
- // Pointer 'this_sp' is not null only if we are called from split(), and not
- // at the thread creation. This means we are the split point's master.
- SplitPoint* this_sp = activeSplitPoint;
-
- assert(!this_sp || (this_sp->master == this && searching));
-
- while (!exit && !(this_sp && this_sp->slavesMask.none()))
- {
- // If this thread has been assigned work, launch a search
- while (searching)
- {
- spinlock.acquire();
-
- assert(activeSplitPoint);
- SplitPoint* sp = activeSplitPoint;
-
- spinlock.release();
-
- Stack stack[MAX_PLY+4], *ss = stack+2; // To allow referencing (ss-2) and (ss+2)
- Position pos(*sp->pos, this);
-
- std::memcpy(ss-2, sp->ss-2, 5 * sizeof(Stack));
- ss->splitPoint = sp;
-
- sp->spinlock.acquire();
-
- assert(activePosition == nullptr);
-
- activePosition = &pos;
-
- if (sp->nodeType == NonPV)
- search<NonPV, true>(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode);
-
- else if (sp->nodeType == PV)
- search<PV, true>(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode);
-
- else if (sp->nodeType == Root)
- search<Root, true>(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode);
-
- else
- assert(false);
-
- assert(searching);
-
- spinlock.acquire();
-
- searching = false;
- activePosition = nullptr;
-
- spinlock.release();
-
- sp->slavesMask.reset(idx);
- sp->allSlavesSearching = false;
- sp->nodes += pos.nodes_searched();
-
- // After releasing the lock we can't access any SplitPoint related data
- // in a safe way because it could have been released under our feet by
- // the sp master.
- sp->spinlock.release();
-
- // Try to late join to another split point if none of its slaves has
- // already finished.
- SplitPoint* bestSp = NULL;
- int minLevel = INT_MAX;
-
- for (Thread* th : Threads)
- {
- const size_t size = th->splitPointsSize; // Local copy
- sp = size ? &th->splitPoints[size - 1] : nullptr;
-
- if ( sp
- && sp->allSlavesSearching
- && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
- && can_join(sp))
- {
- assert(this != th);
- assert(!(this_sp && this_sp->slavesMask.none()));
- assert(Threads.size() > 2);
-
- // Prefer to join to SP with few parents to reduce the probability
- // that a cut-off occurs above us, and hence we waste our work.
- int level = 0;
- for (SplitPoint* p = th->activeSplitPoint; p; p = p->parentSplitPoint)
- level++;
-
- if (level < minLevel)
- {
- bestSp = sp;
- minLevel = level;
- }
- }
- }
-
- if (bestSp)
- {
- sp = bestSp;
-
- // Recheck the conditions under lock protection
- sp->spinlock.acquire();
-
- if ( sp->allSlavesSearching
- && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT)
- {
- spinlock.acquire();
-
- if (can_join(sp))
- {
- sp->slavesMask.set(idx);
- activeSplitPoint = sp;
- searching = true;
- }
-
- spinlock.release();
- }
-
- sp->spinlock.release();
- }
- }
-
- // If search is finished then sleep, otherwise just yield
- if (!Threads.main()->thinking)
- {
- assert(!this_sp);
-
- std::unique_lock<Mutex> lk(mutex);
- while (!exit && !Threads.main()->thinking)
- sleepCondition.wait(lk);
- }
- else
- std::this_thread::yield(); // Wait for a new job or for our slaves to finish
- }
-}
-
-
/// check_time() is called by the timer thread when the timer triggers. It is
/// used to print debug info and, more importantly, to detect when we are out of
/// available time and thus stop the search.
else if (Limits.movetime && elapsed >= Limits.movetime)
Signals.stop = true;
- else if (Limits.nodes)
- {
- int64_t nodes = RootPos.nodes_searched();
-
- // Loop across all split points and sum accumulated SplitPoint nodes plus
- // all the currently active positions nodes.
- // FIXME: Racy...
- for (Thread* th : Threads)
- for (size_t i = 0; i < th->splitPointsSize; ++i)
- {
- SplitPoint& sp = th->splitPoints[i];
-
- sp.spinlock.acquire();
-
- nodes += sp.nodes;
-
- for (size_t idx = 0; idx < Threads.size(); ++idx)
- if (sp.slavesMask.test(idx) && Threads[idx]->activePosition)
- nodes += Threads[idx]->activePosition->nodes_searched();
-
- sp.spinlock.release();
- }
-
- if (nodes >= Limits.nodes)
+ else if (Limits.nodes && Threads.nodes_searched() >= Limits.nodes)
Signals.stop = true;
- }
}
projects / stockfish / commitdiff