#include "book.h"
#include "evaluate.h"
-#include "history.h"
#include "movegen.h"
#include "movepick.h"
#include "notation.h"
TimeManager TimeMgr;
int BestMoveChanges;
Value DrawValue[COLOR_NB];
- History H;
+ History Hist;
+ Gains Gain;
template <NodeType NT>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta);
- bool prevents_move(const Position& pos, Move first, Move second);
+ bool allows(const Position& pos, Move first, Move second);
+ bool refutes(const Position& pos, Move first, Move second);
string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
struct Skill {
// Reset the threads, still sleeping: will be wake up at split time
for (size_t i = 0; i < Threads.size(); i++)
- Threads[i].maxPly = 0;
+ Threads[i]->maxPly = 0;
Threads.sleepWhileIdle = Options["Use Sleeping Threads"];
// Set best timer interval to avoid lagging under time pressure. Timer is
// used to check for remaining available thinking time.
- Threads.timer_thread()->msec =
+ Threads.timer->msec =
Limits.use_time_management() ? std::min(100, std::max(TimeMgr.available_time() / 16, TimerResolution)) :
Limits.nodes ? 2 * TimerResolution
: 100;
- Threads.timer_thread()->notify_one(); // Wake up the recurring timer
+ Threads.timer->notify_one(); // Wake up the recurring timer
id_loop(RootPos); // Let's start searching !
- Threads.timer_thread()->msec = 0; // Stop the timer
+ Threads.timer->msec = 0; // Stop the timer
Threads.sleepWhileIdle = true; // Send idle threads to sleep
if (Options["Use Search Log"])
bestValue = delta = -VALUE_INFINITE;
ss->currentMove = MOVE_NULL; // Hack to skip update gains
TT.new_search();
- H.clear();
+ Hist.clear();
+ Gain.clear();
PVSize = Options["MultiPV"];
Skill skill(Options["Skill Level"]);
// Sort the PV lines searched so far and update the GUI
sort<RootMove>(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
+
if (PVIdx + 1 == PVSize || Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
}
if (!RootNode)
{
// Step 2. Check for aborted search and immediate draw
- if (Signals.stop || pos.is_draw<true, PvNode>() || ss->ply > MAX_PLY)
+ if (Signals.stop || pos.is_draw<false>() || ss->ply > MAX_PLY)
return DrawValue[pos.side_to_move()];
// Step 3. Mate distance pruning. Even if we mate at the next move our score
&& type_of(move) == NORMAL)
{
Square to = to_sq(move);
- H.update_gain(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
+ Gain.update(pos.piece_on(to), to, -(ss-1)->staticEval - ss->staticEval);
}
// Step 6. Razoring (is omitted in PV nodes)
if (eval - PawnValueMg > beta)
R += ONE_PLY;
- pos.do_null_move<true>(st);
+ pos.do_null_move(st);
(ss+1)->skipNullMove = true;
nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -alpha, DEPTH_ZERO)
: - search<NonPV>(pos, ss+1, -beta, -alpha, depth-R);
(ss+1)->skipNullMove = false;
- pos.do_null_move<false>(st);
+ pos.undo_null_move();
if (nullValue >= beta)
{
return nullValue;
}
else
+ {
// The null move failed low, which means that we may be faced with
- // some kind of threat.
+ // some kind of threat. If the previous move was reduced, check if
+ // the move that refuted the null move was somehow connected to the
+ // move which was reduced. If a connection is found, return a fail
+ // low score (which will cause the reduced move to fail high in the
+ // parent node, which will trigger a re-search with full depth).
threatMove = (ss+1)->currentMove;
+
+ if ( depth < 5 * ONE_PLY
+ && (ss-1)->reduction
+ && threatMove != MOVE_NONE
+ && allows(pos, (ss-1)->currentMove, threatMove))
+ return beta - 1;
+ }
}
// Step 9. ProbCut (is omitted in PV nodes)
assert((ss-1)->currentMove != MOVE_NONE);
assert((ss-1)->currentMove != MOVE_NULL);
- MovePicker mp(pos, ttMove, H, pos.captured_piece_type());
+ MovePicker mp(pos, ttMove, Hist, pos.captured_piece_type());
CheckInfo ci(pos);
while ((move = mp.next_move<false>()) != MOVE_NONE)
split_point_start: // At split points actual search starts from here
- MovePicker mp(pos, ttMove, depth, H, ss, PvNode ? -VALUE_INFINITE : beta);
+ MovePicker mp(pos, ttMove, depth, Hist, ss, PvNode ? -VALUE_INFINITE : beta);
CheckInfo ci(pos);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
singularExtensionNode = !RootNode
ss->excludedMove = MOVE_NONE;
if (value < rBeta)
- ext = rBeta >= beta ? ONE_PLY + ONE_PLY / 2 : ONE_PLY;
+ ext = ONE_PLY;
}
// Update current move (this must be done after singular extension search)
&& !inCheck
&& !dangerous
&& move != ttMove
- && (!threatMove || !prevents_move(pos, move, threatMove))
&& (bestValue > VALUE_MATED_IN_MAX_PLY || ( bestValue == -VALUE_INFINITE
&& alpha > VALUE_MATED_IN_MAX_PLY)))
{
// Move count based pruning
- if (depth < 16 * ONE_PLY && moveCount >= FutilityMoveCounts[depth])
+ if ( depth < 16 * ONE_PLY
+ && moveCount >= FutilityMoveCounts[depth]
+ && (!threatMove || !refutes(pos, move, threatMove)))
{
if (SpNode)
sp->mutex.lock();
// but fixing this made program slightly weaker.
Depth predictedDepth = newDepth - reduction<PvNode>(depth, moveCount);
futilityValue = ss->staticEval + ss->evalMargin + futility_margin(predictedDepth, moveCount)
- + H.gain(pos.piece_moved(move), to_sq(move));
+ + Gain[pos.piece_moved(move)][to_sq(move)];
if (futilityValue < beta)
{
&& !pvMove
&& !captureOrPromotion
&& !dangerous
- && ss->killers[0] != move
- && ss->killers[1] != move)
+ && move != ttMove
+ && move != ss->killers[0]
+ && move != ss->killers[1])
{
ss->reduction = reduction<PvNode>(depth, moveCount);
Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
// Step 19. Check for splitting the search
if ( !SpNode
- && depth >= Threads.min_split_depth()
- && Threads.available_slave_exists(thisThread))
+ && depth >= Threads.minimumSplitDepth
+ && Threads.slave_available(thisThread)
+ && thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
{
assert(bestValue < beta);
- bestValue = Threads.split<FakeSplit>(pos, ss, alpha, beta, bestValue, &bestMove,
- depth, threatMove, moveCount, mp, NT);
+ thisThread->split<FakeSplit>(pos, ss, alpha, beta, &bestValue, &bestMove,
+ depth, threatMove, moveCount, &mp, NT);
if (bestValue >= beta)
break;
}
// Increase history value of the cut-off move
Value bonus = Value(int(depth) * int(depth));
- H.add(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
+ Hist.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus);
// Decrease history of all the other played non-capture moves
for (int i = 0; i < playedMoveCount - 1; i++)
{
Move m = movesSearched[i];
- H.add(pos.piece_moved(m), to_sq(m), -bonus);
+ Hist.update(pos.piece_moved(m), to_sq(m), -bonus);
}
}
}
ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
- if (pos.is_draw<false, false>() || ss->ply > MAX_PLY)
+ if (pos.is_draw<true>() || ss->ply > MAX_PLY)
return DrawValue[pos.side_to_move()];
// Transposition table lookup. At PV nodes, we don't use the TT for
// 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, H, to_sq((ss-1)->currentMove));
+ MovePicker mp(pos, ttMove, depth, Hist, to_sq((ss-1)->currentMove));
CheckInfo ci(pos);
// Loop through the moves until no moves remain or a beta cutoff occurs
}
- // prevents_move() tests whether a move (first) is able to defend against an
- // opponent's move (second). In this case will not be pruned. Normally the
- // second move is the threat move (the best move returned from a null search
- // that fails low).
+ // allows() tests whether the 'first' move at previous ply somehow makes the
+ // 'second' move possible, for instance if the moving piece is the same in
+ // both moves. Normally the second move is the threat (the best move returned
+ // from a null search that fails low).
- bool prevents_move(const Position& pos, Move first, Move second) {
+ bool allows(const Position& pos, Move first, Move second) {
+
+ assert(is_ok(first));
+ assert(is_ok(second));
+ assert(color_of(pos.piece_on(from_sq(second))) == ~pos.side_to_move());
+ assert(color_of(pos.piece_on(to_sq(first))) == ~pos.side_to_move());
+
+ Square m1from = from_sq(first);
+ Square m2from = from_sq(second);
+ Square m1to = to_sq(first);
+ Square m2to = to_sq(second);
+
+ // The piece is the same or second's destination was vacated by the first move
+ if (m1to == m2from || m2to == m1from)
+ return true;
+
+ // Second one moves through the square vacated by first one
+ if (between_bb(m2from, m2to) & m1from)
+ return true;
+
+ // Second's destination is defended by the first move's piece
+ Bitboard m1att = pos.attacks_from(pos.piece_on(m1to), m1to, pos.pieces() ^ m2from);
+ if (m1att & m2to)
+ return true;
+
+ // Second move gives a discovered check through the first's checking piece
+ if (m1att & pos.king_square(pos.side_to_move()))
+ {
+ assert(between_bb(m1to, pos.king_square(pos.side_to_move())) & m2from);
+ return true;
+ }
+
+ return false;
+ }
+
+
+ // refutes() tests whether a 'first' move is able to defend against a 'second'
+ // opponent's move. In this case will not be pruned. Normally the second move
+ // is the threat (the best move returned from a null search that fails low).
+
+ bool refutes(const Position& pos, Move first, Move second) {
assert(is_ok(first));
assert(is_ok(second));
int selDepth = 0;
for (size_t i = 0; i < Threads.size(); i++)
- if (Threads[i].maxPly > selDepth)
- selDepth = Threads[i].maxPly;
+ if (Threads[i]->maxPly > selDepth)
+ selDepth = Threads[i]->maxPly;
for (size_t i = 0; i < uciPVSize; i++)
{
&& pos.is_pseudo_legal(m = tte->move()) // Local copy, TT could change
&& pos.pl_move_is_legal(m, pos.pinned_pieces())
&& ply < MAX_PLY
- && (!pos.is_draw<true, true>() || ply < 2));
+ && (!pos.is_draw<false>() || ply < 2));
pv.push_back(MOVE_NONE); // Must be zero-terminating
void Thread::idle_loop() {
- // Pointer 'sp_master', if non-NULL, points to the active SplitPoint
- // object for which the thread is the master.
- const SplitPoint* sp_master = splitPointsCnt ? curSplitPoint : NULL;
+ // Pointer 'this_sp' is not null only if we are called from split(), and not
+ // at the thread creation. So it means we are the split point's master.
+ const SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : NULL;
- assert(!sp_master || (sp_master->master == this && is_searching));
+ assert(!this_sp || (this_sp->masterThread == this && searching));
- // If this thread is the master of a split point and all slaves have
- // finished their work at this split point, return from the idle loop.
- while (!sp_master || sp_master->slavesMask)
+ // If this thread is the master of a split point and all slaves have finished
+ // their work at this split point, return from the idle loop.
+ while (!this_sp || this_sp->slavesMask)
{
- // If we are not searching, wait for a condition to be signaled
- // instead of wasting CPU time polling for work.
- while (do_exit || (!is_searching && Threads.sleepWhileIdle))
+ // If we are not searching, wait for a condition to be signaled instead of
+ // wasting CPU time polling for work.
+ while ((!searching && Threads.sleepWhileIdle) || exit)
{
- if (do_exit)
+ if (exit)
{
- assert(!sp_master);
+ assert(!this_sp);
return;
}
- // Grab the lock to avoid races with Thread::wake_up()
+ // Grab the lock to avoid races with Thread::notify_one()
mutex.lock();
- // If we are master and all slaves have finished don't go to sleep
- if (sp_master && !sp_master->slavesMask)
+ // If we are master and all slaves have finished then exit idle_loop
+ if (this_sp && !this_sp->slavesMask)
{
mutex.unlock();
break;
// Do sleep after retesting sleep conditions under lock protection, in
// particular we need to avoid a deadlock in case a master thread has,
- // in the meanwhile, allocated us and sent the wake_up() call before we
- // had the chance to grab the lock.
- if (!is_searching && Threads.sleepWhileIdle)
+ // in the meanwhile, allocated us and sent the notify_one() call before
+ // we had the chance to grab the lock.
+ if (!searching && !exit)
sleepCondition.wait(mutex);
mutex.unlock();
}
// If this thread has been assigned work, launch a search
- if (is_searching)
+ if (searching)
{
- assert(!do_exit);
+ assert(!exit);
Threads.mutex.lock();
- assert(is_searching);
- SplitPoint* sp = curSplitPoint;
+ assert(searching);
+ SplitPoint* sp = activeSplitPoint;
Threads.mutex.unlock();
sp->mutex.lock();
- assert(sp->activePositions[idx] == NULL);
+ assert(sp->slavesPositions[idx] == NULL);
- sp->activePositions[idx] = &pos;
+ sp->slavesPositions[idx] = &pos;
- if (sp->nodeType == Root)
+ switch (sp->nodeType) {
+ case Root:
search<SplitPointRoot>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
- else if (sp->nodeType == PV)
+ break;
+ case PV:
search<SplitPointPV>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
- else if (sp->nodeType == NonPV)
+ break;
+ case NonPV:
search<SplitPointNonPV>(pos, ss+1, sp->alpha, sp->beta, sp->depth);
- else
+ break;
+ default:
assert(false);
+ }
- assert(is_searching);
+ assert(searching);
- is_searching = false;
- sp->activePositions[idx] = NULL;
+ searching = false;
+ sp->slavesPositions[idx] = NULL;
sp->slavesMask &= ~(1ULL << idx);
sp->nodes += pos.nodes_searched();
- // Wake up master thread so to allow it to return from the idle loop in
- // case we are the last slave of the split point.
+ // Wake up master thread so to allow it to return from the idle loop
+ // in case we are the last slave of the split point.
if ( Threads.sleepWhileIdle
- && this != sp->master
+ && this != sp->masterThread
&& !sp->slavesMask)
{
- assert(!sp->master->is_searching);
- sp->master->notify_one();
+ assert(!sp->masterThread->searching);
+ sp->masterThread->notify_one();
}
// After releasing the lock we cannot access anymore any SplitPoint
// Loop across all split points and sum accumulated SplitPoint nodes plus
// all the currently active slaves positions.
for (size_t i = 0; i < Threads.size(); i++)
- for (int j = 0; j < Threads[i].splitPointsCnt; j++)
+ for (int j = 0; j < Threads[i]->splitPointsSize; j++)
{
- SplitPoint& sp = Threads[i].splitPoints[j];
+ SplitPoint& sp = Threads[i]->splitPoints[j];
sp.mutex.lock();
Bitboard sm = sp.slavesMask;
while (sm)
{
- Position* pos = sp.activePositions[pop_lsb(&sm)];
+ Position* pos = sp.slavesPositions[pop_lsb(&sm)];
nodes += pos ? pos->nodes_searched() : 0;
}
projects / stockfish / blobdiff