int FutilityMoveCounts[2][16]; // [improving][depth]
int Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber]
- // Threshold used for countermoves based pruning
- const int CounterMovePruneThreshold = 0;
-
template <bool PvNode> Depth reduction(bool i, Depth d, int mn) {
return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY;
}
// Skill structure is used to implement strength limit
struct Skill {
- Skill(int l) : level(l) {}
+ explicit Skill(int l) : level(l) {}
bool enabled() const { return level < 20; }
bool time_to_pick(Depth depth) const { return depth / ONE_PLY == 1 + level; }
- Move best_move(size_t multiPV) { return best ? best : pick_best(multiPV); }
Move pick_best(size_t multiPV);
int level;
}
}
- int stableCnt;
Key expectedPosKey;
+ int stableCnt;
Move pv[3];
};
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 update_cm_stats(Stack* ss, Piece pc, Square s, int bonus);
+ void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus);
void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, int bonus);
+ bool pv_is_draw(Position& pos);
+
+ // perft() is our utility to verify move generation. All the leaf nodes up
+ // to the given depth are generated and counted, and the sum is returned.
+ template<bool Root>
+ uint64_t perft(Position& pos, Depth depth) {
+
+ StateInfo st;
+ uint64_t cnt, nodes = 0;
+ const bool leaf = (depth == 2 * ONE_PLY);
+
+ for (const auto& m : MoveList<LEGAL>(pos))
+ {
+ if (Root && depth <= ONE_PLY)
+ cnt = 1, nodes++;
+ else
+ {
+ pos.do_move(m, st);
+ cnt = leaf ? MoveList<LEGAL>(pos).size() : perft<false>(pos, depth - ONE_PLY);
+ nodes += cnt;
+ pos.undo_move(m);
+ }
+ if (Root)
+ sync_cout << UCI::move(m, pos.is_chess960()) << ": " << cnt << sync_endl;
+ }
+ return nodes;
+ }
} // namespace
}
-/// Search::clear() resets search state to its initial value, to obtain reproducible results
+/// Search::clear() resets search state to its initial value
void Search::clear() {
+ Threads.main()->wait_for_search_finished();
+
+ Time.availableNodes = 0;
TT.clear();
for (Thread* th : Threads)
- {
- th->counterMoves.fill(MOVE_NONE);
- th->history.fill(0);
-
- for (auto& to : th->counterMoveHistory)
- for (auto& h : to)
- h.fill(0);
-
- th->counterMoveHistory[NO_PIECE][0].fill(CounterMovePruneThreshold - 1);
- }
+ th->clear();
Threads.main()->callsCnt = 0;
Threads.main()->previousScore = VALUE_INFINITE;
}
-/// Search::perft() is our utility to verify move generation. All the leaf nodes
-/// up to the given depth are generated and counted, and the sum is returned.
-template<bool Root>
-uint64_t Search::perft(Position& pos, Depth depth) {
-
- StateInfo st;
- uint64_t cnt, nodes = 0;
- const bool leaf = (depth == 2 * ONE_PLY);
-
- for (const auto& m : MoveList<LEGAL>(pos))
- {
- if (Root && depth <= ONE_PLY)
- cnt = 1, nodes++;
- else
- {
- pos.do_move(m, st);
- cnt = leaf ? MoveList<LEGAL>(pos).size() : perft<false>(pos, depth - ONE_PLY);
- nodes += cnt;
- pos.undo_move(m);
- }
- if (Root)
- sync_cout << UCI::move(m, pos.is_chess960()) << ": " << cnt << sync_endl;
- }
- return nodes;
-}
-
-template uint64_t Search::perft<true>(Position&, Depth);
-
-
/// MainThread::search() is called by the main thread when the program receives
/// the UCI 'go' command. It searches from the root position and outputs the "bestmove".
void MainThread::search() {
+ if (Limits.perft)
+ {
+ nodes = perft<true>(rootPos, Limits.perft * ONE_PLY);
+ sync_cout << "\nNodes searched: " << nodes << "\n" << sync_endl;
+ return;
+ }
+
Color us = rootPos.side_to_move();
Time.init(Limits, us, rootPos.game_ply());
TT.new_search();
if (rootMoves.empty())
{
- rootMoves.push_back(RootMove(MOVE_NONE));
+ rootMoves.emplace_back(MOVE_NONE);
sync_cout << "info depth 0 score "
<< UCI::value(rootPos.checkers() ? -VALUE_MATE : VALUE_DRAW)
<< sync_endl;
Thread::search(); // Let's start searching!
}
- // When playing in 'nodes as time' mode, subtract the searched nodes from
- // the available ones before exiting.
- if (Limits.npmsec)
- Time.availableNodes += Limits.inc[us] - Threads.nodes_searched();
-
// When we reach the maximum depth, we can arrive here without a raise of
// Threads.stop. However, if we are pondering or in an infinite search,
// the UCI protocol states that we shouldn't print the best move before the
// GUI sends a "stop" or "ponderhit" command. We therefore simply wait here
// until the GUI sends one of those commands (which also raises Threads.stop).
- if (!Threads.stop && (Limits.ponder || Limits.infinite))
- {
- Threads.stopOnPonderhit = true;
- wait(Threads.stop);
- }
+ Threads.stopOnPonderhit = true;
+
+ while (!Threads.stop && (Threads.ponder || Limits.infinite))
+ {} // Busy wait for a stop or a ponder reset
- // Stop the threads if not already stopped
+ // Stop the threads if not already stopped (also raise the stop if
+ // "ponderhit" just reset Threads.ponder).
Threads.stop = true;
// Wait until all threads have finished
if (th != this)
th->wait_for_search_finished();
+ // When playing in 'nodes as time' mode, subtract the searched nodes from
+ // the available ones before exiting.
+ if (Limits.npmsec)
+ Time.availableNodes += Limits.inc[us] - Threads.nodes_searched();
+
// Check if there are threads with a better score than main thread
Thread* bestThread = this;
if ( !this->easyMovePlayed
Depth depthDiff = th->completedDepth - bestThread->completedDepth;
Value scoreDiff = th->rootMoves[0].score - bestThread->rootMoves[0].score;
- if (scoreDiff > 0 && depthDiff >= 0)
+ // Select the thread with the best score, always if it is a mate
+ if ( scoreDiff > 0
+ && (depthDiff >= 0 || th->rootMoves[0].score >= VALUE_MATE_IN_MAX_PLY))
bestThread = th;
}
}
void Thread::search() {
- Stack stack[MAX_PLY+7], *ss = stack+4; // To allow referencing (ss-4) and (ss+2)
+ Stack stack[MAX_PLY+7], *ss = stack+4; // To reference from (ss-4) to (ss+2)
Value bestValue, alpha, beta, delta;
Move easyMove = MOVE_NONE;
MainThread* mainThread = (this == Threads.main() ? Threads.main() : nullptr);
std::memset(ss-4, 0, 7 * sizeof(Stack));
for (int i = 4; i > 0; i--)
- (ss-i)->history = &this->counterMoveHistory[NO_PIECE][0]; // Use as sentinel
+ (ss-i)->contHistory = &this->contHistory[NO_PIECE][0]; // Use as sentinel
bestValue = delta = alpha = -VALUE_INFINITE;
beta = VALUE_INFINITE;
- completedDepth = DEPTH_ZERO;
if (mainThread)
{
// Sort the PV lines searched so far and update the GUI
std::stable_sort(rootMoves.begin(), rootMoves.begin() + PVIdx + 1);
- if (!mainThread)
- continue;
-
- if (Threads.stop || PVIdx + 1 == multiPV || Time.elapsed() > 3000)
+ if ( mainThread
+ && (Threads.stop || PVIdx + 1 == multiPV || Time.elapsed() > 3000))
sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl;
}
if (!Threads.stop)
completedDepth = rootDepth;
+ // Have we found a "mate in x"?
+ if ( Limits.mate
+ && bestValue >= VALUE_MATE_IN_MAX_PLY
+ && VALUE_MATE - bestValue <= 2 * Limits.mate)
+ Threads.stop = true;
+
if (!mainThread)
continue;
if (skill.enabled() && skill.time_to_pick(rootDepth))
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)
- Threads.stop = true;
-
// Do we have time for the next iteration? Can we stop searching now?
if (Limits.use_time_management())
{
// from the previous search and just did a fast verification.
const int F[] = { mainThread->failedLow,
bestValue - mainThread->previousScore };
-
int improvingFactor = std::max(229, std::min(715, 357 + 119 * F[0] - 6 * F[1]));
- double unstablePvFactor = 1 + mainThread->bestMoveChanges;
+
+ Color us = rootPos.side_to_move();
+ bool thinkHard = DrawValue[us] == bestValue
+ && Limits.time[us] - Time.elapsed() > Limits.time[~us]
+ && ::pv_is_draw(rootPos);
+
+ double unstablePvFactor = 1 + mainThread->bestMoveChanges + thinkHard;
bool doEasyMove = rootMoves[0].pv[0] == easyMove
+ && !thinkHard
&& mainThread->bestMoveChanges < 0.03
&& Time.elapsed() > Time.optimum() * 5 / 44;
{
// 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)
+ if (Threads.ponder)
Threads.stopOnPonderhit = true;
else
Threads.stop = true;
// 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)));
+ std::swap(rootMoves[0], *std::find(rootMoves.begin(), rootMoves.end(),
+ skill.best ? skill.best : skill.pick_best(multiPV)));
}
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning) {
const bool PvNode = NT == PV;
- const bool rootNode = PvNode && (ss-1)->ply == 0;
+ const bool rootNode = PvNode && ss->ply == 0;
assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE);
assert(PvNode || (alpha == beta - 1));
Depth extension, newDepth;
Value bestValue, value, ttValue, eval;
bool ttHit, inCheck, givesCheck, singularExtensionNode, improving;
- bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture;
- Piece moved_piece;
+ bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture, pvExact;
+ Piece movedPiece;
int moveCount, quietCount;
// Step 1. Initialize node
moveCount = quietCount = ss->moveCount = 0;
ss->statScore = 0;
bestValue = -VALUE_INFINITE;
- ss->ply = (ss-1)->ply + 1;
// Check for the available remaining time
if (thisThread == Threads.main())
static_cast<MainThread*>(thisThread)->check_time();
- // Used to send selDepth info to GUI
- if (PvNode && thisThread->selDepth < ss->ply)
- thisThread->selDepth = ss->ply;
+ // Used to send selDepth info to GUI (selDepth counts from 1, ply from 0)
+ if (PvNode && thisThread->selDepth < ss->ply + 1)
+ thisThread->selDepth = ss->ply + 1;
if (!rootNode)
{
assert(0 <= ss->ply && ss->ply < MAX_PLY);
+ (ss+1)->ply = ss->ply + 1;
ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
- ss->history = &thisThread->counterMoveHistory[NO_PIECE][0];
+ ss->contHistory = &thisThread->contHistory[NO_PIECE][0];
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
Square prevSq = to_sq((ss-1)->currentMove);
// Extra penalty for a quiet TT move in previous ply when it gets refuted
if ((ss-1)->moveCount == 1 && !pos.captured_piece())
- update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY));
+ update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY));
}
// Penalty for a quiet ttMove that fails low
else if (!pos.capture_or_promotion(ttMove))
{
int penalty = -stat_bonus(depth);
- thisThread->history.update(pos.side_to_move(), ttMove, penalty);
- update_cm_stats(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
+ thisThread->mainHistory.update(pos.side_to_move(), ttMove, penalty);
+ update_continuation_histories(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty);
}
}
return ttValue;
int drawScore = TB::UseRule50 ? 1 : 0;
- value = v < -drawScore ? -VALUE_MATE + MAX_PLY + ss->ply
- : v > drawScore ? VALUE_MATE - MAX_PLY - ss->ply
+ value = v < -drawScore ? -VALUE_MATE + MAX_PLY + ss->ply + 1
+ : v > drawScore ? VALUE_MATE - MAX_PLY - ss->ply - 1
: VALUE_DRAW + 2 * v * drawScore;
tte->save(posKey, value_to_tt(value, ss->ply), BOUND_EXACT,
eval = ss->staticEval = evaluate(pos);
// Can ttValue be used as a better position evaluation?
- if (ttValue != VALUE_NONE)
- if (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER))
- eval = ttValue;
+ if ( ttValue != VALUE_NONE
+ && (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER)))
+ eval = ttValue;
}
else
{
Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY;
ss->currentMove = MOVE_NULL;
- ss->history = &thisThread->counterMoveHistory[NO_PIECE][0];
+ ss->contHistory = &thisThread->contHistory[NO_PIECE][0];
pos.do_null_move(st);
Value nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -beta+1)
if (pos.legal(move))
{
ss->currentMove = move;
- ss->history = &thisThread->counterMoveHistory[pos.moved_piece(move)][to_sq(move)];
+ ss->contHistory = &thisThread->contHistory[pos.moved_piece(move)][to_sq(move)];
assert(depth >= 5 * ONE_PLY);
pos.do_move(move, st);
moves_loop: // When in check search starts from here
- const PieceToHistory& cmh = *(ss-1)->history;
- const PieceToHistory& fmh = *(ss-2)->history;
- const PieceToHistory& fm2 = *(ss-4)->history;
+ const PieceToHistory* contHist[] = { (ss-1)->contHistory, (ss-2)->contHistory, nullptr, (ss-4)->contHistory };
+ Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq];
- MovePicker mp(pos, ttMove, depth, ss);
+ MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, contHist, countermove, ss->killers);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
improving = ss->staticEval >= (ss-2)->staticEval
/* || ss->staticEval == VALUE_NONE Already implicit in the previous condition */
&& tte->depth() >= depth - 3 * ONE_PLY;
skipQuiets = false;
ttCapture = false;
+ pvExact = PvNode && ttHit && tte->bound() == BOUND_EXACT;
// Step 11. Loop through moves
// Loop through all pseudo-legal moves until no moves remain or a beta cutoff occurs
extension = DEPTH_ZERO;
captureOrPromotion = pos.capture_or_promotion(move);
- moved_piece = pos.moved_piece(move);
+ movedPiece = pos.moved_piece(move);
givesCheck = type_of(move) == NORMAL && !pos.discovered_check_candidates()
? pos.check_squares(type_of(pos.piece_on(from_sq(move)))) & to_sq(move)
// Countermoves based pruning
if ( lmrDepth < 3
- && (cmh[moved_piece][to_sq(move)] < CounterMovePruneThreshold)
- && (fmh[moved_piece][to_sq(move)] < CounterMovePruneThreshold))
+ && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold
+ && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
continue;
// Futility pruning: parent node
// Update the current move (this must be done after singular extension search)
ss->currentMove = move;
- ss->history = &thisThread->counterMoveHistory[moved_piece][to_sq(move)];
+ ss->contHistory = &thisThread->contHistory[movedPiece][to_sq(move)];
// Step 14. Make the move
pos.do_move(move, st, givesCheck);
r -= r ? ONE_PLY : DEPTH_ZERO;
else
{
+ // Decrease reduction if opponent's move count is high
+ if ((ss-1)->moveCount > 15)
+ r -= ONE_PLY;
+
+ // Decrease reduction for exact PV nodes
+ if (pvExact)
+ r -= ONE_PLY;
+
// Increase reduction if ttMove is a capture
if (ttCapture)
r += ONE_PLY;
&& !pos.see_ge(make_move(to_sq(move), from_sq(move))))
r -= 2 * ONE_PLY;
- ss->statScore = cmh[moved_piece][to_sq(move)]
- + fmh[moved_piece][to_sq(move)]
- + fm2[moved_piece][to_sq(move)]
- + thisThread->history[~pos.side_to_move()][from_to(move)]
- - 4000; // Correction factor
+ ss->statScore = thisThread->mainHistory[~pos.side_to_move()][from_to(move)]
+ + (*contHist[0])[movedPiece][to_sq(move)]
+ + (*contHist[1])[movedPiece][to_sq(move)]
+ + (*contHist[3])[movedPiece][to_sq(move)]
+ - 4000;
// Decrease/increase reduction by comparing opponent's stat score
- if (ss->statScore > 0 && (ss-1)->statScore < 0)
+ if (ss->statScore >= 0 && (ss-1)->statScore < 0)
r -= ONE_PLY;
- else if (ss->statScore < 0 && (ss-1)->statScore > 0)
+ else if ((ss-1)->statScore >= 0 && ss->statScore < 0)
r += ONE_PLY;
// Decrease/increase reduction for moves with a good/bad history
// Extra penalty for a quiet TT move in previous ply when it gets refuted
if ((ss-1)->moveCount == 1 && !pos.captured_piece())
- update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY));
+ update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY));
}
// Bonus for prior countermove that caused the fail low
else if ( depth >= 3 * ONE_PLY
&& !pos.captured_piece()
&& is_ok((ss-1)->currentMove))
- update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth));
+ update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth));
if (!excludedMove)
tte->save(posKey, value_to_tt(bestValue, ss->ply),
}
ss->currentMove = bestMove = MOVE_NONE;
- ss->ply = (ss-1)->ply + 1;
+ (ss+1)->ply = ss->ply + 1;
moveCount = 0;
// Check for an instant draw or if the maximum ply has been reached
// only two types of depth in TT: DEPTH_QS_CHECKS or DEPTH_QS_NO_CHECKS.
ttDepth = InCheck || depth >= DEPTH_QS_CHECKS ? DEPTH_QS_CHECKS
: DEPTH_QS_NO_CHECKS;
-
// Transposition table lookup
posKey = pos.key();
tte = TT.probe(posKey, ttHit);
ss->staticEval = bestValue = evaluate(pos);
// Can ttValue be used as a better position evaluation?
- if (ttValue != VALUE_NONE)
- if (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))
- bestValue = ttValue;
+ if ( ttValue != VALUE_NONE
+ && (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER)))
+ bestValue = ttValue;
}
else
ss->staticEval = bestValue =
// 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, to_sq((ss-1)->currentMove));
+ MovePicker mp(pos, ttMove, depth, &pos.this_thread()->mainHistory, to_sq((ss-1)->currentMove));
// Loop through the moves until no moves remain or a beta cutoff occurs
while ((move = mp.next_move()) != MOVE_NONE)
}
- // update_cm_stats() updates countermove and follow-up move history
+ // update_continuation_histories() updates histories of the move pairs formed
+ // by moves at ply -1, -2, and -4 with current move.
- void update_cm_stats(Stack* ss, Piece pc, Square s, int bonus) {
+ void update_continuation_histories(Stack* ss, Piece pc, Square to, int bonus) {
for (int i : {1, 2, 4})
if (is_ok((ss-i)->currentMove))
- (ss-i)->history->update(pc, s, bonus);
+ (ss-i)->contHistory->update(pc, to, bonus);
}
Color c = pos.side_to_move();
Thread* thisThread = pos.this_thread();
- thisThread->history.update(c, move, bonus);
- update_cm_stats(ss, pos.moved_piece(move), to_sq(move), bonus);
+ thisThread->mainHistory.update(c, move, bonus);
+ update_continuation_histories(ss, pos.moved_piece(move), to_sq(move), bonus);
if (is_ok((ss-1)->currentMove))
{
Square prevSq = to_sq((ss-1)->currentMove);
- thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]=move;
+ thisThread->counterMoves[pos.piece_on(prevSq)][prevSq] = move;
}
// Decrease all the other played quiet moves
for (int i = 0; i < quietsCnt; ++i)
{
- thisThread->history.update(c, quiets[i], -bonus);
- update_cm_stats(ss, pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
+ thisThread->mainHistory.update(c, quiets[i], -bonus);
+ update_continuation_histories(ss, pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus);
}
}
+ // Is the PV leading to a draw position? Assumes all pv moves are legal
+ bool pv_is_draw(Position& pos) {
+
+ StateInfo st[MAX_PLY];
+ auto& pv = pos.this_thread()->rootMoves[0].pv;
+
+ for (size_t i = 0; i < pv.size(); ++i)
+ pos.do_move(pv[i], st[i]);
+
+ bool isDraw = pos.is_draw(pv.size());
+
+ for (size_t i = pv.size(); i > 0; --i)
+ pos.undo_move(pv[i-1]);
+
+ return isDraw;
+ }
+
+
// When playing with strength handicap, choose best move among a set of RootMoves
// using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
int push = ( weakness * int(topScore - rootMoves[i].score)
+ delta * (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];
}
// An engine may not stop pondering until told so by the GUI
- if (Limits.ponder)
+ if (Threads.ponder)
return;
- if ( (Limits.use_time_management() && elapsed > Time.maximum() - 10)
+ if ( (Limits.use_time_management() && elapsed > Time.maximum())
|| (Limits.movetime && elapsed >= Limits.movetime)
|| (Limits.nodes && Threads.nodes_searched() >= (uint64_t)Limits.nodes))
Threads.stop = true;
ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY;
Cardinality = Options["SyzygyProbeLimit"];
+ // Don't filter any moves if the user requested analysis on multiple
+ if (Options["MultiPV"] != 1)
+ return;
+
// Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality
if (Cardinality > MaxCardinality)
{
projects / stockfish / blobdiff