/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2014 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
const bool FakeSplit = false;
// Different node types, used as template parameter
- enum NodeType { Root, PV, NonPV, SplitPointRoot, SplitPointPV, SplitPointNonPV };
+ enum NodeType { Root, PV, NonPV };
// Dynamic razoring margin based on depth
- inline Value razor_margin(Depth d) { return Value(512 + 16 * int(d)); }
+ inline Value razor_margin(Depth d) { return Value(512 + 16 * d); }
// Futility lookup tables (initialized at startup) and their access functions
int FutilityMoveCounts[2][32]; // [improving][depth]
inline Value futility_margin(Depth d) {
- return Value(100 * int(d));
+ return Value(100 * d);
}
// Reduction lookup tables (initialized at startup) and their access function
return (Depth) Reductions[PvNode][i][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
}
- size_t PVSize, PVIdx;
+ size_t MultiPV, PVIdx;
TimeManager TimeMgr;
double BestMoveChanges;
Value DrawValue[COLOR_NB];
HistoryStats History;
GainsStats Gains;
- CountermovesStats Countermoves;
+ MovesStats Countermoves, Followupmoves;
- template <NodeType NT>
+ template <NodeType NT, bool SpNode>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
template <NodeType NT, bool InCheck>
void id_loop(Position& pos);
Value value_to_tt(Value v, int ply);
Value value_from_tt(Value v, int ply);
+ void update_stats(const Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt);
string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
struct Skill {
// Init reductions array
for (hd = 1; hd < 64; ++hd) for (mc = 1; mc < 64; ++mc)
{
- double pvRed = log(double(hd)) * log(double(mc)) / 3.0;
+ double pvRed = 0.00 + log(double(hd)) * log(double(mc)) / 3.00;
double nonPVRed = 0.33 + log(double(hd)) * log(double(mc)) / 2.25;
- Reductions[1][1][hd][mc] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(ONE_PLY)) : 0);
- Reductions[0][1][hd][mc] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(ONE_PLY)) : 0);
+ Reductions[1][1][hd][mc] = int8_t( pvRed >= 1.0 ? pvRed * int(ONE_PLY) : 0);
+ Reductions[0][1][hd][mc] = int8_t(nonPVRed >= 1.0 ? nonPVRed * int(ONE_PLY) : 0);
Reductions[1][0][hd][mc] = Reductions[1][1][hd][mc];
Reductions[0][0][hd][mc] = Reductions[0][1][hd][mc];
// Init futility move count array
for (d = 0; d < 32; ++d)
{
- FutilityMoveCounts[0][d] = int(2.4 + 0.222 * pow(d + 0.0, 1.8));
- FutilityMoveCounts[1][d] = int(3.0 + 0.3 * pow(d + 0.98, 1.8));
+ FutilityMoveCounts[0][d] = int(2.4 + 0.222 * pow(d + 0.00, 1.8));
+ FutilityMoveCounts[1][d] = int(3.0 + 0.300 * pow(d + 0.98, 1.8));
}
}
/// 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 returned.
-static size_t perft(Position& pos, Depth depth) {
+static uint64_t perft(Position& pos, Depth depth) {
StateInfo st;
- size_t cnt = 0;
+ uint64_t cnt = 0;
CheckInfo ci(pos);
const bool leaf = depth == 2 * ONE_PLY;
return cnt;
}
-size_t Search::perft(Position& pos, Depth depth) {
+uint64_t Search::perft(Position& pos, Depth depth) {
return depth > ONE_PLY ? ::perft(pos, depth) : MoveList<LEGAL>(pos).size();
}
RootColor = RootPos.side_to_move();
TimeMgr.init(Limits, RootPos.game_ply(), RootColor);
+ int cf = Options["Contempt Factor"] * PawnValueEg / 100; // From centipawns
+ DrawValue[ RootColor] = VALUE_DRAW - Value(cf);
+ DrawValue[~RootColor] = VALUE_DRAW + Value(cf);
+
if (RootMoves.empty())
{
RootMoves.push_back(MOVE_NONE);
}
}
- if (Options["Contempt Factor"] && !Options["UCI_AnalyseMode"])
- {
- int cf = Options["Contempt Factor"] * PawnValueMg / 100; // From centipawns
- cf = cf * Material::game_phase(RootPos) / PHASE_MIDGAME; // Scale down with phase
- DrawValue[ RootColor] = VALUE_DRAW - Value(cf);
- DrawValue[~RootColor] = VALUE_DRAW + Value(cf);
- }
- else
- DrawValue[WHITE] = DrawValue[BLACK] = VALUE_DRAW;
-
if (Options["Write Search Log"])
{
Log log(Options["Search Log Filename"]);
<< " time: " << Limits.time[RootColor]
<< " increment: " << Limits.inc[RootColor]
<< " moves to go: " << Limits.movestogo
- << std::endl;
+ << "\n" << std::endl;
}
// Reset the threads, still sleeping: will wake up at split time
History.clear();
Gains.clear();
Countermoves.clear();
+ Followupmoves.clear();
- PVSize = Options["MultiPV"];
+ MultiPV = Options["MultiPV"];
Skill skill(Options["Skill Level"]);
// 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.
- if (skill.enabled() && PVSize < 4)
- PVSize = 4;
+ if (skill.enabled() && MultiPV < 4)
+ MultiPV = 4;
- PVSize = std::min(PVSize, RootMoves.size());
+ MultiPV = std::min(MultiPV, RootMoves.size());
// Iterative deepening loop until requested to stop or target depth reached
while (++depth <= MAX_PLY && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
{
// Age out PV variability metric
- BestMoveChanges *= 0.8;
+ 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.
RootMoves[i].prevScore = RootMoves[i].score;
// MultiPV loop. We perform a full root search for each PV line
- for (PVIdx = 0; PVIdx < PVSize && !Signals.stop; ++PVIdx)
+ for (PVIdx = 0; PVIdx < MultiPV && !Signals.stop; ++PVIdx)
{
// Reset aspiration window starting size
if (depth >= 5)
// high/low anymore.
while (true)
{
- bestValue = search<Root>(pos, ss, alpha, beta, depth * ONE_PLY, false);
+ bestValue = search<Root, false>(pos, ss, alpha, beta, depth * ONE_PLY, 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
// Sort the PV lines searched so far and update the GUI
std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
- if (PVIdx + 1 == PVSize || Time::now() - SearchTime > 3000)
+ if (PVIdx + 1 == MultiPV || Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
}
// Do we have time for the next iteration? Can we stop searching now?
if (Limits.use_time_management() && !Signals.stop && !Signals.stopOnPonderhit)
{
- bool stop = false; // Local variable, not the volatile Signals.stop
-
// Take some extra time if the best move has changed
- if (depth > 4 && depth < 50 && PVSize == 1)
+ if (depth > 4 && depth < 50 && MultiPV == 1)
TimeMgr.pv_instability(BestMoveChanges);
- // Stop the search if most of the available time has been used. We
- // probably don't have enough time to search the first move at the
- // next iteration anyway.
- if (Time::now() - SearchTime > (TimeMgr.available_time() * 62) / 100)
- stop = true;
-
- // Stop the search early if one move seems to be much better than others
- if ( depth >= 12
- && BestMoveChanges <= DBL_EPSILON
- && !stop
- && PVSize == 1
- && bestValue > VALUE_MATED_IN_MAX_PLY
- && ( RootMoves.size() == 1
- || Time::now() - SearchTime > (TimeMgr.available_time() * 20) / 100))
- {
- Value rBeta = bestValue - 2 * PawnValueMg;
- ss->excludedMove = RootMoves[0].pv[0];
- ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, rBeta - 1, rBeta, (depth - 3) * ONE_PLY, true);
- ss->skipNullMove = false;
- ss->excludedMove = MOVE_NONE;
-
- if (v < rBeta)
- stop = true;
- }
-
- if (stop)
+ // Stop the search if only one legal move is available or all
+ // of the available time has been used.
+ if ( RootMoves.size() == 1
+ || Time::now() - SearchTime > TimeMgr.available_time())
{
// If we are allowed to ponder do not stop the search now but
// keep pondering until the GUI sends "ponderhit" or "stop".
// 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>
+ template <NodeType NT, bool SpNode>
Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
- const bool PvNode = (NT == PV || NT == Root || NT == SplitPointPV || NT == SplitPointRoot);
- const bool SpNode = (NT == SplitPointPV || NT == SplitPointNonPV || NT == SplitPointRoot);
- const bool RootNode = (NT == Root || NT == SplitPointRoot);
+ const bool RootNode = NT == Root;
+ const bool PvNode = NT == PV || NT == Root;
- assert(alpha >= -VALUE_INFINITE && alpha < beta && beta <= VALUE_INFINITE);
+ assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE);
assert(PvNode || (alpha == beta - 1));
assert(depth > DEPTH_ZERO);
moveCount = quietCount = 0;
bestValue = -VALUE_INFINITE;
- ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
+ ss->currentMove = ss->ttMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
(ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
{
// Step 2. Check for aborted search and immediate draw
if (Signals.stop || pos.is_draw() || ss->ply > MAX_PLY)
- return DrawValue[pos.side_to_move()];
+ return ss->ply > MAX_PLY && !inCheck ? evaluate(pos) : DrawValue[pos.side_to_move()];
// Step 3. Mate distance pruning. Even if we mate at the next move our score
// would be at best mate_in(ss->ply+1), but if alpha is already bigger because
excludedMove = ss->excludedMove;
posKey = excludedMove ? pos.exclusion_key() : pos.key();
tte = TT.probe(posKey);
- ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
+ ss->ttMove = ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE;
ttValue = tte ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE;
// At PV nodes we check for exact scores, whilst at non-PV nodes we check for
: ttValue >= beta ? (tte->bound() & BOUND_LOWER)
: (tte->bound() & BOUND_UPPER)))
{
- TT.refresh(tte);
ss->currentMove = ttMove; // Can be MOVE_NONE
- // Update killers, history, and counter move on TT hit
- if ( ttValue >= beta
- && ttMove
- && !pos.capture_or_promotion(ttMove)
- && !inCheck)
- {
- if (ss->killers[0] != ttMove)
- {
- ss->killers[1] = ss->killers[0];
- ss->killers[0] = ttMove;
- }
-
- Value bonus = Value(int(depth) * int(depth));
- History.update(pos.moved_piece(ttMove), to_sq(ttMove), bonus);
+ // 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, NULL, 0);
- if (is_ok((ss-1)->currentMove))
- {
- Square prevMoveSq = to_sq((ss-1)->currentMove);
- Countermoves.update(pos.piece_on(prevMoveSq), prevMoveSq, ttMove);
- }
- }
return ttValue;
}
// Step 6. Razoring (skipped when in check)
if ( !PvNode
&& depth < 4 * ONE_PLY
- && eval + razor_margin(depth) < beta
+ && eval + razor_margin(depth) <= alpha
&& ttMove == MOVE_NONE
&& abs(beta) < VALUE_MATE_IN_MAX_PLY
&& !pos.pawn_on_7th(pos.side_to_move()))
{
- Value rbeta = beta - razor_margin(depth);
- Value v = qsearch<NonPV, false>(pos, ss, rbeta-1, rbeta, DEPTH_ZERO);
- if (v < rbeta)
- // Logically we should return (v + razor_margin(depth)), but
- // surprisingly this performed slightly weaker in tests.
+ Value ralpha = alpha - razor_margin(depth);
+ Value v = qsearch<NonPV, false>(pos, ss, ralpha, ralpha+1, DEPTH_ZERO);
+ if (v <= ralpha)
return v;
}
{
ss->currentMove = MOVE_NULL;
- // Null move dynamic reduction based on depth
- Depth R = 3 * ONE_PLY + depth / 4;
+ assert(eval - beta >= 0);
- // Null move dynamic reduction based on value
- if (eval - PawnValueMg > beta)
- R += ONE_PLY;
+ // Null move dynamic reduction based on depth and value
+ Depth R = 3 * ONE_PLY
+ + depth / 4
+ + int(eval - beta) / PawnValueMg * ONE_PLY;
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, !cutNode);
+ 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);
(ss+1)->skipNullMove = false;
pos.undo_null_move();
// Do verification search at high depths
ss->skipNullMove = true;
- Value v = search<NonPV>(pos, ss, alpha, beta, depth-R, false);
+ 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);
ss->skipNullMove = false;
if (v >= beta)
&& !ss->skipNullMove
&& abs(beta) < VALUE_MATE_IN_MAX_PLY)
{
- Value rbeta = beta + 200;
- Depth rdepth = depth - ONE_PLY - 3 * ONE_PLY;
+ Value rbeta = std::min(beta + 200, VALUE_INFINITE);
+ Depth rdepth = depth - 4 * ONE_PLY;
assert(rdepth >= ONE_PLY);
assert((ss-1)->currentMove != MOVE_NONE);
{
ss->currentMove = move;
pos.do_move(move, st, ci, pos.gives_check(move, ci));
- value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
+ value = -search<NonPV, false>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
pos.undo_move(move);
if (value >= rbeta)
return value;
}
// Step 10. Internal iterative deepening (skipped when in check)
- if ( depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY)
- && ttMove == MOVE_NONE
- && (PvNode || ss->staticEval + Value(256) >= beta))
+ if ( depth >= (PvNode ? 5 * ONE_PLY : 8 * ONE_PLY)
+ && !ttMove
+ && (PvNode || ss->staticEval + 256 >= beta))
{
Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4);
ss->skipNullMove = true;
- search<PvNode ? PV : NonPV>(pos, ss, alpha, beta, d, true);
+ search<PvNode ? PV : NonPV, false>(pos, ss, alpha, beta, d, true);
ss->skipNullMove = false;
tte = TT.probe(posKey);
Move countermoves[] = { Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].first,
Countermoves[pos.piece_on(prevMoveSq)][prevMoveSq].second };
- MovePicker mp(pos, ttMove, depth, History, countermoves, ss);
+ Square prevOwnMoveSq = to_sq((ss-2)->currentMove);
+ Move followupmoves[] = { Followupmoves[pos.piece_on(prevOwnMoveSq)][prevOwnMoveSq].first,
+ Followupmoves[pos.piece_on(prevOwnMoveSq)][prevOwnMoveSq].second };
+
+ MovePicker mp(pos, ttMove, depth, History, countermoves, followupmoves, ss);
CheckInfo ci(pos);
value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc
improving = ss->staticEval >= (ss-2)->staticEval
ext = DEPTH_ZERO;
captureOrPromotion = pos.capture_or_promotion(move);
- givesCheck = pos.gives_check(move, ci);
+
+ givesCheck = type_of(move) == NORMAL && !ci.dcCandidates
+ ? ci.checkSq[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
+ : pos.gives_check(move, ci);
+
dangerous = givesCheck
|| type_of(move) != NORMAL
|| pos.advanced_pawn_push(move);
// Step 12. Extend checks
- if (givesCheck && pos.see_sign(move) >= 0)
+ if (givesCheck && pos.see_sign(move) >= VALUE_ZERO)
ext = ONE_PLY;
// Singular extension search. If all moves but one fail low on a search of
Value rBeta = ttValue - int(depth);
ss->excludedMove = move;
ss->skipNullMove = true;
- value = search<NonPV>(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode);
+ value = search<NonPV, false>(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode);
ss->skipNullMove = false;
ss->excludedMove = MOVE_NONE;
if (predictedDepth < 7 * ONE_PLY)
{
futilityValue = ss->staticEval + futility_margin(predictedDepth)
- + Value(128) + Gains[pos.moved_piece(move)][to_sq(move)];
+ + 128 + Gains[pos.moved_piece(move)][to_sq(move)];
if (futilityValue <= alpha)
{
}
// Prune moves with negative SEE at low depths
- if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < 0)
+ if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO)
{
if (SpNode)
splitPoint->mutex.lock();
if (SpNode)
alpha = splitPoint->alpha;
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
+ value = -search<NonPV, false>(pos, ss+1, -(alpha+1), -alpha, d, true);
- // Research at intermediate depth if reduction is very high
+ // Re-search at intermediate depth if reduction is very high
if (value > alpha && ss->reduction >= 4 * ONE_PLY)
{
Depth d2 = std::max(newDepth - 2 * ONE_PLY, ONE_PLY);
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d2, true);
+ value = -search<NonPV, false>(pos, ss+1, -(alpha+1), -alpha, d2, true);
}
doFullDepthSearch = (value > alpha && ss->reduction != DEPTH_ZERO);
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>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode);
+ : - search<NonPV, false>(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
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>(pos, ss+1, -beta, -alpha, newDepth, false);
+ : - search<PV, false>(pos, ss+1, -beta, -alpha, newDepth, false);
// Step 17. Undo move
pos.undo_move(move);
alpha = splitPoint->alpha;
}
- // Finished searching the move. If Signals.stop is true, the search
- // was aborted because the user interrupted the search or because we
- // ran out of time. In this case, the return value of the search cannot
- // be trusted, and we don't update the best move and/or PV.
+ // 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
+ // updating best move, PV and TT.
if (Signals.stop || thisThread->cutoff_occurred())
- return value; // To avoid returning VALUE_INFINITE
+ return VALUE_ZERO;
if (RootNode)
{
// Step 19. Check for splitting the search
if ( !SpNode
+ && Threads.size() >= 2
&& depth >= Threads.minimumSplitDepth
- && Threads.available_slave(thisThread)
+ && ( !thisThread->activeSplitPoint
+ || !thisThread->activeSplitPoint->allSlavesSearching)
&& thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD)
{
- assert(bestValue < beta);
+ assert(bestValue > -VALUE_INFINITE && bestValue < beta);
thisThread->split<FakeSplit>(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.
+ /*
+ if (Signals.stop || thisThread->cutoff_occurred())
+ return VALUE_DRAW;
+ */
+
// Step 20. Check for mate and stalemate
// All legal moves have been searched and if there are no legal moves, it
- // must be mate or stalemate. Note that we can have a false positive in
- // case of Signals.stop or thread.cutoff_occurred() are set, but this is
- // harmless because return value is discarded anyhow in the parent nodes.
- // If we are in a singular extension search then return a fail low score.
- // A split node has at least one move - the one tried before to be splitted.
+ // must be mate or stalemate. If we are in a singular extension search then
+ // return a fail low score.
if (!moveCount)
return excludedMove ? alpha
: inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()];
- // If we have pruned all the moves without searching return a fail-low score
- if (bestValue == -VALUE_INFINITE)
- bestValue = alpha;
-
TT.store(posKey, value_to_tt(bestValue, ss->ply),
bestValue >= beta ? BOUND_LOWER :
PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER,
depth, bestMove, ss->staticEval);
- // Quiet best move: update killers, history and countermoves
- if ( bestValue >= beta
- && !pos.capture_or_promotion(bestMove)
- && !inCheck)
- {
- if (ss->killers[0] != bestMove)
- {
- ss->killers[1] = ss->killers[0];
- ss->killers[0] = bestMove;
- }
-
- // Increase history value of the cut-off move and decrease all the other
- // played non-capture moves.
- Value bonus = Value(int(depth) * int(depth));
- History.update(pos.moved_piece(bestMove), to_sq(bestMove), bonus);
- for (int i = 0; i < quietCount - 1; ++i)
- {
- Move m = quietsSearched[i];
- History.update(pos.moved_piece(m), to_sq(m), -bonus);
- }
-
- if (is_ok((ss-1)->currentMove))
- Countermoves.update(pos.piece_on(prevMoveSq), prevMoveSq, bestMove);
- }
+ // Quiet best move: update killers, history, countermoves and followupmoves
+ if (bestValue >= beta && !pos.capture_or_promotion(bestMove) && !inCheck)
+ update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount - 1);
assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
template <NodeType NT, bool InCheck>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) {
- const bool PvNode = (NT == PV);
+ const bool PvNode = NT == PV;
assert(NT == PV || NT == NonPV);
assert(InCheck == !!pos.checkers());
// Check for an instant draw or if the maximum ply has been reached
if (pos.is_draw() || ss->ply > MAX_PLY)
- return DrawValue[pos.side_to_move()];
+ return ss->ply > MAX_PLY && !InCheck ? evaluate(pos) : 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
if (PvNode && bestValue > alpha)
alpha = bestValue;
- futilityBase = bestValue + Value(128);
+ futilityBase = bestValue + 128;
}
// Initialize a MovePicker object for the current position, and prepare
{
assert(is_ok(move));
- givesCheck = pos.gives_check(move, ci);
+ givesCheck = type_of(move) == NORMAL && !ci.dcCandidates
+ ? ci.checkSq[type_of(pos.piece_on(from_sq(move)))] & to_sq(move)
+ : pos.gives_check(move, ci);
// Futility pruning
if ( !PvNode
continue;
}
- // 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
- && pos.see(move, beta - futilityBase) <= 0)
+ if (futilityBase < beta && pos.see(move) <= VALUE_ZERO)
{
bestValue = std::max(bestValue, futilityBase);
continue;
&& (!InCheck || evasionPrunable)
&& move != ttMove
&& type_of(move) != PROMOTION
- && pos.see_sign(move) < 0)
+ && pos.see_sign(move) < VALUE_ZERO)
continue;
// Check for legality just before making the move
}
+ // update_stats() updates killers, history, countermoves and followupmoves stats after a fail-high
+ // of a quiet move.
+
+ void update_stats(const Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt) {
+
+ if (ss->killers[0] != move)
+ {
+ ss->killers[1] = ss->killers[0];
+ ss->killers[0] = move;
+ }
+
+ // Increase history value of the cut-off move and decrease all the other
+ // played quiet moves.
+ Value bonus = Value(int(depth) * int(depth));
+ History.update(pos.moved_piece(move), to_sq(move), bonus);
+ for (int i = 0; i < quietsCnt; ++i)
+ {
+ Move m = quiets[i];
+ History.update(pos.moved_piece(m), to_sq(m), -bonus);
+ }
+
+ if (is_ok((ss-1)->currentMove))
+ {
+ Square prevMoveSq = to_sq((ss-1)->currentMove);
+ Countermoves.update(pos.piece_on(prevMoveSq), prevMoveSq, move);
+ }
+
+ if (is_ok((ss-2)->currentMove) && (ss-1)->currentMove == (ss-1)->ttMove)
+ {
+ Square prevOwnMoveSq = to_sq((ss-2)->currentMove);
+ Followupmoves.update(pos.piece_on(prevOwnMoveSq), prevOwnMoveSq, move);
+ }
+ }
+
+
// When playing with a strength handicap, choose best move among the MultiPV
// set using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
rk.rand<unsigned>();
// RootMoves are already sorted by score in descending order
- int variance = std::min(RootMoves[0].score - RootMoves[PVSize - 1].score, PawnValueMg);
+ int variance = std::min(RootMoves[0].score - RootMoves[MultiPV - 1].score, PawnValueMg);
int weakness = 120 - 2 * level;
int max_s = -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 moves, and one random,
// then we choose the move with the resulting highest score.
- for (size_t i = 0; i < PVSize; ++i)
+ for (size_t i = 0; i < MultiPV; ++i)
{
int s = RootMoves[i].score;
string uci_pv(const Position& pos, int depth, Value alpha, Value beta) {
- std::stringstream s;
+ std::stringstream ss;
Time::point elapsed = Time::now() - SearchTime + 1;
size_t uciPVSize = std::min((size_t)Options["MultiPV"], RootMoves.size());
int selDepth = 0;
int d = updated ? depth : depth - 1;
Value v = updated ? RootMoves[i].score : RootMoves[i].prevScore;
- if (s.rdbuf()->in_avail()) // Not at first line
- s << "\n";
+ if (ss.rdbuf()->in_avail()) // Not at first line
+ ss << "\n";
- s << "info depth " << d
- << " seldepth " << selDepth
- << " score " << (i == PVIdx ? score_to_uci(v, alpha, beta) : score_to_uci(v))
- << " nodes " << pos.nodes_searched()
- << " nps " << pos.nodes_searched() * 1000 / elapsed
- << " time " << elapsed
- << " multipv " << i + 1
- << " pv";
+ ss << "info depth " << d
+ << " seldepth " << selDepth
+ << " score " << (i == PVIdx ? score_to_uci(v, alpha, beta) : score_to_uci(v))
+ << " nodes " << pos.nodes_searched()
+ << " nps " << pos.nodes_searched() * 1000 / elapsed
+ << " time " << elapsed
+ << " multipv " << i + 1
+ << " pv";
for (size_t j = 0; RootMoves[i].pv[j] != MOVE_NONE; ++j)
- s << " " << move_to_uci(RootMoves[i].pv[j], pos.is_chess960());
+ ss << " " << move_to_uci(RootMoves[i].pv[j], pos.is_chess960());
}
- return s.str();
+ return ss.str();
}
} // namespace
mutex.lock();
// If we are master and all slaves have finished then exit idle_loop
- if (this_sp && !this_sp->slavesMask)
+ if (this_sp && this_sp->slavesMask.none())
{
mutex.unlock();
break;
activePosition = &pos;
- switch (sp->nodeType) {
- case Root:
- search<SplitPointRoot>(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode);
- break;
- case PV:
- search<SplitPointPV>(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode);
- break;
- case NonPV:
- search<SplitPointNonPV>(pos, ss, sp->alpha, sp->beta, sp->depth, sp->cutNode);
- break;
- default:
+ 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);
searching = false;
activePosition = NULL;
- sp->slavesMask &= ~(1ULL << idx);
+ 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 ( Threads.sleepWhileIdle
&& this != sp->masterThread
- && !sp->slavesMask)
+ && sp->slavesMask.none())
{
assert(!sp->masterThread->searching);
sp->masterThread->notify_one();
// 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. Also accessing other Thread objects is unsafe because
- // if we are exiting there is a chance that they are already freed.
+ // the sp master.
sp->mutex.unlock();
+
+ // 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)
+ {
+ int size = Threads[i]->splitPointsSize; // Local copy
+ sp = size ? &Threads[i]->splitPoints[size - 1] : NULL;
+
+ if ( sp
+ && sp->allSlavesSearching
+ && available_to(Threads[i]))
+ {
+ // 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
+ }
+ }
}
// 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)
+ if (this_sp && this_sp->slavesMask.none())
{
this_sp->mutex.lock();
- bool finished = !this_sp->slavesMask; // Retest under lock protection
+ bool finished = this_sp->slavesMask.none(); // Retest under lock protection
this_sp->mutex.unlock();
if (finished)
return;
sp.mutex.lock();
nodes += sp.nodes;
- Bitboard sm = sp.slavesMask;
- while (sm)
- {
- Position* pos = Threads[pop_lsb(&sm)]->activePosition;
- if (pos)
- nodes += pos->nodes_searched();
- }
+
+ for (size_t idx = 0; idx < Threads.size(); ++idx)
+ if (sp.slavesMask.test(idx) && Threads[idx]->activePosition)
+ nodes += Threads[idx]->activePosition->nodes_searched();
sp.mutex.unlock();
}
Time::point elapsed = Time::now() - SearchTime;
bool stillAtFirstMove = Signals.firstRootMove
&& !Signals.failedLowAtRoot
- && elapsed > TimeMgr.available_time();
+ && elapsed > TimeMgr.available_time() * 75 / 100;
bool noMoreTime = elapsed > TimeMgr.maximum_time() - 2 * TimerThread::Resolution
|| stillAtFirstMove;
projects / stockfish / blobdiff