/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
void id_loop(Position& pos);
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 check_is_dangerous(const Position& pos, Move move, Value futilityBase, Value beta);
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);
static PolyglotBook book; // Defined static to initialize the PRNG only once
RootColor = RootPos.side_to_move();
- TimeMgr.init(Limits, RootPos.startpos_ply_counter(), RootColor);
+ TimeMgr.init(Limits, RootPos.game_ply(), RootColor);
if (RootMoves.empty())
{
Stack ss[MAX_PLY_PLUS_2];
int depth, prevBestMoveChanges;
Value bestValue, alpha, beta, delta;
- bool bestMoveNeverChanged = true;
memset(ss, 0, 4 * sizeof(Stack));
depth = BestMoveChanges = 0;
// we want to keep the same order for all the moves but the new
// PV that goes to the front. Note that in case of MultiPV search
// the already searched PV lines are preserved.
- sort<RootMove>(RootMoves.begin() + PVIdx, RootMoves.end());
+ 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.
}
// Sort the PV lines searched so far and update the GUI
- sort<RootMove>(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
+ std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
if (PVIdx + 1 == PVSize || Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
<< std::endl;
}
- // Filter out startup noise when monitoring best move stability
- if (depth > 2 && BestMoveChanges)
- bestMoveNeverChanged = false;
-
// Do we have found a "mate in x"?
if ( Limits.mate
&& bestValue >= VALUE_MATE_IN_MAX_PLY
if ( depth >= 12
&& !stop
&& PVSize == 1
- && ( (bestMoveNeverChanged && pos.captured_piece_type())
- || Time::now() - SearchTime > (TimeMgr.available_time() * 40) / 100))
+ && bestValue > VALUE_MATED_IN_MAX_PLY
+ && ( RootMoves.size() == 1
+ || Time::now() - SearchTime > (TimeMgr.available_time() * 20) / 100))
{
Value rBeta = bestValue - 2 * PawnValueMg;
(ss+1)->excludedMove = RootMoves[0].pv[0];
Move movesSearched[64];
StateInfo st;
const TTEntry *tte;
- SplitPoint* sp;
+ SplitPoint* splitPoint;
Key posKey;
Move ttMove, move, excludedMove, bestMove, threatMove;
Depth ext, newDepth;
if (SpNode)
{
- sp = ss->sp;
- bestMove = sp->bestMove;
- threatMove = sp->threatMove;
- bestValue = sp->bestValue;
+ splitPoint = ss->splitPoint;
+ bestMove = splitPoint->bestMove;
+ threatMove = splitPoint->threatMove;
+ bestValue = splitPoint->bestValue;
tte = NULL;
ttMove = excludedMove = MOVE_NONE;
ttValue = VALUE_NONE;
- assert(sp->bestValue > -VALUE_INFINITE && sp->moveCount > 0);
+ assert(splitPoint->bestValue > -VALUE_INFINITE && splitPoint->moveCount > 0);
goto split_point_start;
}
if (!RootNode)
{
// Step 2. Check for aborted search and immediate draw
- if (Signals.stop || pos.is_draw<false>() || ss->ply > MAX_PLY)
+ if (Signals.stop || pos.is_draw() || 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
else if (tte)
{
// Never assume anything on values stored in TT
- if ( (ss->staticEval = eval = tte->static_value()) == VALUE_NONE
- ||(ss->evalMargin = tte->static_value_margin()) == VALUE_NONE)
- eval = ss->staticEval = evaluate(pos, ss->evalMargin);
+ if ( (ss->staticEval = eval = tte->eval_value()) == VALUE_NONE
+ ||(ss->evalMargin = tte->eval_margin()) == VALUE_NONE)
+ eval = ss->staticEval = evaluate(pos, ss->evalMargin, &ss->ei);
// Can ttValue be used as a better position evaluation?
if (ttValue != VALUE_NONE)
}
else
{
- eval = ss->staticEval = evaluate(pos, ss->evalMargin);
+ eval = ss->staticEval = evaluate(pos, ss->evalMargin, &ss->ei);
TT.store(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE,
ss->staticEval, ss->evalMargin);
}
&& !ss->skipNullMove
&& depth < 4 * ONE_PLY
&& !inCheck
- && eval - FutilityMargins[depth][0] >= beta
+ && eval - futility_margin(depth, (ss-1)->futilityMoveCount) >= beta
&& abs(beta) < VALUE_MATE_IN_MAX_PLY
&& pos.non_pawn_material(pos.side_to_move()))
- return eval - FutilityMargins[depth][0];
+ return eval - futility_margin(depth, (ss-1)->futilityMoveCount);
// Step 8. Null move search with verification search (is omitted in PV nodes)
if ( !PvNode
if (nullValue >= VALUE_MATE_IN_MAX_PLY)
nullValue = beta;
- if (depth < 6 * ONE_PLY)
+ if (depth < 12 * ONE_PLY)
return nullValue;
// Do verification search at high depths
&& ttMove == MOVE_NONE
&& (PvNode || (!inCheck && ss->staticEval + Value(256) >= beta)))
{
- Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2);
+ Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
ss->skipNullMove = true;
search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d);
if (!pos.pl_move_is_legal(move, ci.pinned))
continue;
- moveCount = ++sp->moveCount;
- sp->mutex.unlock();
+ moveCount = ++splitPoint->moveCount;
+ splitPoint->mutex.unlock();
}
else
moveCount++;
<< " currmovenumber " << moveCount + PVIdx << sync_endl;
}
+ ss->futilityMoveCount = 0;
ext = DEPTH_ZERO;
captureOrPromotion = pos.is_capture_or_promotion(move);
givesCheck = pos.move_gives_check(move, ci);
&& !captureOrPromotion
&& !inCheck
&& !dangerous
- && move != ttMove
- && (bestValue > VALUE_MATED_IN_MAX_PLY || ( bestValue == -VALUE_INFINITE
- && alpha > VALUE_MATED_IN_MAX_PLY)))
+ /* && move != ttMove Already implicit in the next condition */
+ && bestValue > VALUE_MATED_IN_MAX_PLY)
{
// Move count based pruning
if ( depth < 16 * ONE_PLY
&& (!threatMove || !refutes(pos, move, threatMove)))
{
if (SpNode)
- sp->mutex.lock();
+ splitPoint->mutex.lock();
continue;
}
if (futilityValue < beta)
{
- if (SpNode)
- sp->mutex.lock();
+ bestValue = std::max(bestValue, futilityValue);
+ if (SpNode)
+ {
+ splitPoint->mutex.lock();
+ if (bestValue > splitPoint->bestValue)
+ splitPoint->bestValue = bestValue;
+ }
continue;
}
// Prune moves with negative SEE at low depths
- if ( predictedDepth < 2 * ONE_PLY
+ if ( predictedDepth < 4 * ONE_PLY
&& pos.see_sign(move) < 0)
{
if (SpNode)
- sp->mutex.lock();
+ splitPoint->mutex.lock();
continue;
}
+
+ // We have not pruned the move that will be searched, but remember how
+ // far in the move list we are to be more aggressive in the child node.
+ ss->futilityMoveCount = moveCount;
}
// Check for legality only before to do the move
{
ss->reduction = reduction<PvNode>(depth, moveCount);
Depth d = std::max(newDepth - ss->reduction, ONE_PLY);
- alpha = SpNode ? sp->alpha : alpha;
+ if (SpNode)
+ alpha = splitPoint->alpha;
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d);
// Step 16. Full depth search, when LMR is skipped or fails high
if (doFullDepthSearch)
{
- alpha = SpNode ? sp->alpha : alpha;
+ 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)
// Step 18. Check for new best move
if (SpNode)
{
- sp->mutex.lock();
- bestValue = sp->bestValue;
- alpha = sp->alpha;
+ splitPoint->mutex.lock();
+ bestValue = splitPoint->bestValue;
+ alpha = splitPoint->alpha;
}
// Finished searching the move. If Signals.stop is true, the search
if (value > bestValue)
{
- bestValue = SpNode ? sp->bestValue = value : value;
+ bestValue = SpNode ? splitPoint->bestValue = value : value;
if (value > alpha)
{
- bestMove = SpNode ? sp->bestMove = move : move;
+ bestMove = SpNode ? splitPoint->bestMove = move : move;
if (PvNode && value < beta) // Update alpha! Always alpha < beta
- alpha = SpNode ? sp->alpha = value : value;
+ alpha = SpNode ? splitPoint->alpha = value : value;
else
{
assert(value >= beta); // Fail high
if (SpNode)
- sp->cutoff = true;
+ splitPoint->cutoff = true;
break;
}
// Step 19. Check for splitting the search
if ( !SpNode
&& depth >= Threads.minimumSplitDepth
- && Threads.slave_available(thisThread)
+ && Threads.available_slave(thisThread)
&& thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
{
assert(bestValue < beta);
- bestValue = thisThread->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;
}
ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
- if (pos.is_draw<true>() || ss->ply > MAX_PLY)
+ if (pos.is_draw() || ss->ply > MAX_PLY)
return DrawValue[pos.side_to_move()];
+ // Decide whether or not to include checks, this fixes also the type of
+ // TT entry depth that we are going to use. Note that in qsearch we use
+ // 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. At PV nodes, we don't use the TT for
// pruning, but only for move ordering.
posKey = pos.key();
ttMove = tte ? tte->move() : MOVE_NONE;
ttValue = tte ? value_from_tt(tte->value(),ss->ply) : VALUE_NONE;
- // Decide whether or not to include checks, this fixes also the type of
- // TT entry depth that we are going to use. Note that in qsearch we use
- // 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;
if ( tte
&& tte->depth() >= ttDepth
&& ttValue != VALUE_NONE // Only in case of TT access race
if (tte)
{
// Never assume anything on values stored in TT
- if ( (ss->staticEval = bestValue = tte->static_value()) == VALUE_NONE
- ||(ss->evalMargin = tte->static_value_margin()) == VALUE_NONE)
- ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
+ if ( (ss->staticEval = bestValue = tte->eval_value()) == VALUE_NONE
+ ||(ss->evalMargin = tte->eval_margin()) == VALUE_NONE)
+ ss->staticEval = bestValue = evaluate(pos, ss->evalMargin, &ss->ei);
}
else
- ss->staticEval = bestValue = evaluate(pos, ss->evalMargin);
+ ss->staticEval = bestValue = evaluate(pos, ss->evalMargin, &ss->ei);
// Stand pat. Return immediately if static value is at least beta
if (bestValue >= beta)
continue;
}
- // Prune moves with negative or equal SEE
+ // Prune moves with negative or equal SEE and also moves with positive
+ // SEE where capturing piece loses a tempo and SEE < beta - futilityBase.
if ( futilityBase < beta
&& depth < DEPTH_ZERO
- && pos.see(move) <= 0)
+ && pos.see(move, beta - futilityBase) <= 0)
{
bestValue = std::max(bestValue, futilityBase);
continue;
// check_is_dangerous() tests if a checking move can be pruned in qsearch()
- bool check_is_dangerous(Position& pos, Move move, Value futilityBase, Value beta)
+ bool check_is_dangerous(const Position& pos, Move move, Value futilityBase, Value beta)
{
Piece pc = pos.piece_moved(move);
Square from = from_sq(move);
&& 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<false>() || ply < 2));
+ && (!pos.is_draw() || ply < 2));
pv.push_back(MOVE_NONE); // Must be zero-terminating
// 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;
+ SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : NULL;
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 (!this_sp || this_sp->slavesMask)
+ while (true)
{
// If we are not searching, wait for a condition to be signaled instead of
// wasting CPU time polling for work.
Position pos(*sp->pos, this);
memcpy(ss, sp->ss - 1, 4 * sizeof(Stack));
- (ss+1)->sp = sp;
+ (ss+1)->splitPoint = sp;
sp->mutex.lock();
- assert(sp->slavesPositions[idx] == NULL);
+ assert(activePosition == NULL);
- sp->slavesPositions[idx] = &pos;
+ activePosition = &pos;
switch (sp->nodeType) {
case Root:
assert(searching);
searching = false;
- sp->slavesPositions[idx] = NULL;
+ activePosition = NULL;
sp->slavesMask &= ~(1ULL << idx);
sp->nodes += pos.nodes_searched();
// unsafe because if we are exiting there is a chance are already freed.
sp->mutex.unlock();
}
+
+ // 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.
+ if (this_sp && !this_sp->slavesMask)
+ {
+ this_sp->mutex.lock();
+ bool finished = !this_sp->slavesMask; // Retest under lock protection
+ this_sp->mutex.unlock();
+ if (finished)
+ return;
+ }
}
}
nodes = RootPos.nodes_searched();
// Loop across all split points and sum accumulated SplitPoint nodes plus
- // all the currently active slaves positions.
+ // all the currently active positions nodes.
for (size_t i = 0; i < Threads.size(); i++)
for (int j = 0; j < Threads[i]->splitPointsSize; j++)
{
Bitboard sm = sp.slavesMask;
while (sm)
{
- Position* pos = sp.slavesPositions[pop_lsb(&sm)];
- nodes += pos ? pos->nodes_searched() : 0;
+ Position* pos = Threads[pop_lsb(&sm)]->activePosition;
+ if (pos)
+ nodes += pos->nodes_searched();
}
sp.mutex.unlock();
projects / stockfish / blobdiff