string uci_pv(const Position& pos, Depth depth, Value alpha, Value beta);
struct Skill {
- Skill(int l) : level(l) {}
- bool enabled() const { return level < 20; }
+ Skill(int l, size_t rootSize) : level(l),
+ candidates(l < 20 ? std::min(4, (int)rootSize) : 0),
+ best(MOVE_NONE) {}
+ ~Skill() {
+ if (candidates) // Swap best PV line with the sub-optimal one
+ std::swap(RootMoves[0], *std::find(RootMoves.begin(),
+ RootMoves.end(), best ? best : pick_move()));
+ }
+
+ size_t candidates_size() const { return candidates; }
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);
+ Move pick_move();
int level;
- Move best = MOVE_NONE;
+ size_t candidates;
+ Move best;
};
} // namespace
CheckInfo ci(pos);
const bool leaf = (depth == 2 * ONE_PLY);
- for (const ExtMove& ms : MoveList<LEGAL>(pos))
+ for (MoveList<LEGAL> it(pos); *it; ++it)
{
if (Root && depth <= ONE_PLY)
cnt = 1, nodes++;
else
{
- pos.do_move(ms.move, st, ci, pos.gives_check(ms.move, ci));
+ pos.do_move(*it, st, pos.gives_check(*it, ci));
cnt = leaf ? MoveList<LEGAL>(pos).size() : perft<false>(pos, depth - ONE_PLY);
nodes += cnt;
- pos.undo_move(ms.move);
+ pos.undo_move(*it);
}
if (Root)
- sync_cout << UCI::move(ms.move, pos.is_chess960()) << ": " << cnt << sync_endl;
+ sync_cout << UCI::move(*it, pos.is_chess960()) << ": " << cnt << sync_endl;
}
return nodes;
}
}
}
- for (Thread* th : Threads)
- th->maxPly = 0;
+ for (size_t i = 0; i < Threads.size(); ++i)
+ Threads[i]->maxPly = 0;
Threads.timer->run = true;
Threads.timer->notify_one(); // Wake up the recurring timer
sync_cout << "bestmove " << UCI::move(RootMoves[0].pv[0], RootPos.is_chess960());
- if (RootMoves[0].pv.size() > 1)
+ 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;
Followupmoves.clear();
size_t multiPV = Options["MultiPV"];
- Skill skill(Options["Skill Level"]);
+ Skill skill(Options["Skill Level"], 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);
-
- multiPV = std::min(multiPV, RootMoves.size());
+ // Do we have to play with skill handicap? In this case enable MultiPV search
+ // that we will use behind the scenes to retrieve a set of possible moves.
+ multiPV = std::max(multiPV, skill.candidates_size());
// Iterative deepening loop until requested to stop or target depth reached
while (++depth < DEPTH_MAX && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
// 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;
+ for (size_t i = 0; i < RootMoves.size(); ++i)
+ RootMoves[i].previousScore = RootMoves[i].score;
// MultiPV loop. We perform a full root search for each PV line
- for (PVIdx = 0; PVIdx < multiPV && !Signals.stop; ++PVIdx)
+ for (PVIdx = 0; PVIdx < std::min(multiPV, RootMoves.size()) && !Signals.stop; ++PVIdx)
{
// Reset aspiration window starting size
if (depth >= 5 * ONE_PLY)
// When failing high/low give some update (without cluttering
// the UI) before a re-search.
- if ( (bestValue <= alpha || bestValue >= beta)
+ if ( multiPV == 1
+ && (bestValue <= alpha || bestValue >= beta)
&& Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
sync_cout << "info nodes " << RootPos.nodes_searched()
<< " time " << Time::now() - SearchTime << sync_endl;
- else if (PVIdx + 1 == multiPV || Time::now() - SearchTime > 3000)
+ else if ( PVIdx + 1 == std::min(multiPV, RootMoves.size())
+ || Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
}
- // 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);
+ // If skill levels are enabled and time is up, pick a sub-optimal best move
+ if (skill.candidates_size() && skill.time_to_pick(depth))
+ skill.pick_move();
// Have we found a "mate in x"?
if ( Limits.mate
}
}
}
-
- // 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)));
}
splitPoint = ss->splitPoint;
bestMove = splitPoint->bestMove;
bestValue = splitPoint->bestValue;
- tte = nullptr;
+ tte = NULL;
ttHit = false;
ttMove = excludedMove = MOVE_NONE;
ttValue = VALUE_NONE;
// If ttMove is quiet, update killers, history, counter move and followup move on TT hit
if (ttValue >= beta && ttMove && !pos.capture_or_promotion(ttMove) && !inCheck)
- update_stats(pos, ss, ttMove, depth, nullptr, 0);
+ update_stats(pos, ss, ttMove, depth, NULL, 0);
return ttValue;
}
if (pos.legal(move, ci.pinned))
{
ss->currentMove = move;
- pos.do_move(move, st, ci, pos.gives_check(move, ci));
+ pos.do_move(move, st, pos.gives_check(move, ci));
value = -search<NonPV, false>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
pos.undo_move(move);
if (value >= rbeta)
}
if (PvNode)
- (ss+1)->pv = nullptr;
+ (ss+1)->pv = NULL;
extension = DEPTH_ZERO;
captureOrPromotion = pos.capture_or_promotion(move);
newDepth = depth - ONE_PLY + extension;
// Step 13. Pruning at shallow depth
- if ( !captureOrPromotion
+ if ( !RootNode
+ && !captureOrPromotion
&& !inCheck
&& !dangerous
&& bestValue > VALUE_MATED_IN_MAX_PLY)
quietsSearched[quietCount++] = move;
// Step 14. Make the move
- pos.do_move(move, st, ci, givesCheck);
+ pos.do_move(move, st, givesCheck);
// Step 15. Reduced depth search (LMR). If the move fails high it will be
// re-searched at full depth.
&& Threads.size() >= 2
&& depth >= Threads.minimumSplitDepth
&& ( !thisThread->activeSplitPoint
- || !thisThread->activeSplitPoint->allSlavesSearching)
+ || !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);
ss->currentMove = move;
// Make and search the move
- pos.do_move(move, st, ci, givesCheck);
+ pos.do_move(move, st, givesCheck);
value = givesCheck ? -qsearch<NT, true>(pos, ss+1, -beta, -alpha, depth - ONE_PLY)
: -qsearch<NT, false>(pos, ss+1, -beta, -alpha, depth - ONE_PLY);
pos.undo_move(move);
}
- // 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.
+ // When playing with a strength handicap, choose best move among the first 'candidates'
+ // RootMoves using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
- Move Skill::pick_best(size_t multiPV) {
+ Move Skill::pick_move() {
// PRNG sequence should be non-deterministic, so we seed it with the time at init
static PRNG rng(Time::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[candidates - 1].score, PawnValueMg);
int weakness = 120 - 2 * level;
int maxScore = -VALUE_INFINITE;
+ best = MOVE_NONE;
// Choose best move. For each move score we add two terms both dependent on
- // weakness. One deterministic and bigger for weaker levels, and one random,
+ // weakness. One deterministic and bigger for weaker moves, and one random,
// then we choose the move with the resulting highest score.
- for (size_t i = 0; i < multiPV; ++i)
+ for (size_t i = 0; i < candidates; ++i)
{
int score = RootMoves[i].score;
- // Don't allow crazy blunders even at very low skills
- if (i > 0 && RootMoves[i - 1].score > score + 2 * PawnValueMg)
- break;
-
// This is our magic formula
score += ( weakness * int(RootMoves[0].score - score)
+ variance * (rng.rand<unsigned>() % weakness)) / 128;
size_t uciPVSize = std::min((size_t)Options["MultiPV"], RootMoves.size());
int selDepth = 0;
- for (Thread* th : Threads)
- if (th->maxPly > selDepth)
- selDepth = th->maxPly;
+ for (size_t i = 0; i < Threads.size(); ++i)
+ if (Threads[i]->maxPly > selDepth)
+ selDepth = Threads[i]->maxPly;
for (size_t i = 0; i < uciPVSize; ++i)
{
ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
ss << " nodes " << pos.nodes_searched()
- << " nps " << pos.nodes_searched() * 1000 / elapsed
- << " tbhits " << TB::Hits
+ << " nps " << pos.nodes_searched() * 1000 / elapsed;
+
+ if (elapsed > 1000) // Earlier makes little sense
+ ss << " hashfull " << TT.hashfull();
+
+ ss << " tbhits " << TB::Hits
<< " time " << elapsed
<< " pv";
}
+/// RootMove::extract_ponder_from_tt() is called in case we have no ponder move before
+/// exiting the search, for instance in case we stop the search during a fail high at
+/// root. We try hard to have a ponder move to return to the GUI, otherwise in case of
+/// 'ponder on' we have nothing to think on.
+
+Move RootMove::extract_ponder_from_tt(Position& pos)
+{
+ StateInfo st;
+ bool found;
+
+ assert(pv.size() == 1);
+
+ pos.do_move(pv[0], st);
+ TTEntry* tte = TT.probe(pos.key(), found);
+ Move m = found ? tte->move() : MOVE_NONE;
+ if (!MoveList<LEGAL>(pos).contains(m))
+ m = MOVE_NONE;
+
+ pos.undo_move(pv[0]);
+ pv.push_back(m);
+ return m;
+}
+
+
/// 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 = splitPointsSize ? activeSplitPoint : nullptr;
+ SplitPoint* this_sp = activeSplitPoint;
- assert(!this_sp || (this_sp->masterThread == this && searching));
+ assert(!this_sp || (this_sp->master == this && searching));
while (!exit)
{
Threads.mutex.lock();
assert(activeSplitPoint);
+
SplitPoint* sp = activeSplitPoint;
Threads.mutex.unlock();
sp->mutex.lock();
- assert(activePosition == nullptr);
+ assert(activePosition == NULL);
activePosition = &pos;
assert(searching);
searching = false;
- activePosition = nullptr;
+ activePosition = NULL;
sp->slavesMask.reset(idx);
sp->allSlavesSearching = false;
sp->nodes += pos.nodes_searched();
// Wake up the master thread so to allow it to return from the idle
// loop in case we are the last slave of the split point.
- if ( this != sp->masterThread
- && sp->slavesMask.none())
+ if (this != sp->master && sp->slavesMask.none())
{
- assert(!sp->masterThread->searching);
- sp->masterThread->notify_one();
+ assert(!sp->master->searching);
+
+ sp->master->notify_one();
}
// After releasing the lock we can't access any SplitPoint related data
// Try to late join to another split point if none of its slaves has
// already finished.
- if (Threads.size() > 2)
- for (size_t i = 0; i < Threads.size(); ++i)
+ SplitPoint* bestSp = NULL;
+ int minLevel = INT_MAX;
+
+ for (size_t i = 0; i < Threads.size(); ++i)
+ {
+ const size_t size = Threads[i]->splitPointsSize; // Local copy
+ sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
+
+ if ( sp
+ && sp->allSlavesSearching
+ && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
+ && available_to(Threads[i]))
{
- const int size = Threads[i]->splitPointsSize; // Local copy
- sp = size ? &Threads[i]->splitPoints[size - 1] : nullptr;
+ assert(this != Threads[i]);
+ 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 = Threads[i]->activeSplitPoint; p; p = p->parentSplitPoint)
+ level++;
- if ( sp
- && sp->allSlavesSearching
- && available_to(Threads[i]))
+ if (level < minLevel)
{
- // Recheck the conditions under lock protection
- Threads.mutex.lock();
- sp->mutex.lock();
-
- if ( sp->allSlavesSearching
- && available_to(Threads[i]))
- {
- sp->slavesMask.set(idx);
- activeSplitPoint = sp;
- searching = true;
- }
-
- sp->mutex.unlock();
- Threads.mutex.unlock();
-
- break; // Just a single attempt
+ bestSp = sp;
+ minLevel = level;
}
}
+ }
+
+ if (bestSp)
+ {
+ sp = bestSp;
+
+ // Recheck the conditions under lock protection
+ Threads.mutex.lock();
+ sp->mutex.lock();
+
+ if ( sp->allSlavesSearching
+ && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT
+ && available_to(sp->master))
+ {
+ sp->slavesMask.set(idx);
+ activeSplitPoint = sp;
+ searching = true;
+ }
+
+ sp->mutex.unlock();
+ Threads.mutex.unlock();
+ }
}
- // Grab the lock to avoid races with Thread::notify_one()
- std::unique_lock<std::mutex> lk(mutex);
+ // Avoid races with notify_one() fired from last slave of the split point
+ mutex.lock();
// If we are master and all slaves have finished then exit idle_loop
if (this_sp && this_sp->slavesMask.none())
{
assert(!searching);
+ mutex.unlock();
break;
}
// If we are not searching, wait for a condition to be signaled instead of
// wasting CPU time polling for work.
if (!searching && !exit)
- sleepCondition.wait(lk);
+ sleepCondition.wait(mutex);
+
+ mutex.unlock();
}
}
// Loop across all split points and sum accumulated SplitPoint nodes plus
// all the currently active positions nodes.
- for (Thread* th : Threads)
- for (int i = 0; i < th->splitPointsSize; ++i)
+ for (size_t i = 0; i < Threads.size(); ++i)
+ for (size_t j = 0; j < Threads[i]->splitPointsSize; ++j)
{
- SplitPoint& sp = th->splitPoints[i];
+ SplitPoint& sp = Threads[i]->splitPoints[j];
sp.mutex.lock();
projects / stockfish / blobdiff