namespace Tablebases {
int Cardinality;
- uint64_t Hits;
bool RootInTB;
bool UseRule50;
Depth ProbeDepth;
std::copy(newPv.begin(), newPv.begin() + 3, pv);
StateInfo st[2];
- pos.do_move(newPv[0], st[0], pos.gives_check(newPv[0]));
- pos.do_move(newPv[1], st[1], pos.gives_check(newPv[1]));
+ pos.do_move(newPv[0], st[0]);
+ pos.do_move(newPv[1], st[1]);
expectedPosKey = pos.key();
pos.undo_move(newPv[1]);
pos.undo_move(newPv[0]);
{1, 0, 0, 0, 0, 1, 1 ,1},
};
+ Value bonus(Depth depth) { int d = depth / ONE_PLY ; return Value(d * d + 2 * d - 2); }
+ Value penalty(Depth depth) { int d = depth / ONE_PLY ; return -Value(d * d + 4 * d + 1); }
+
const size_t HalfDensitySize = std::extent<decltype(HalfDensity)>::value;
EasyMoveManager EasyMove;
Value DrawValue[COLOR_NB];
template <NodeType NT>
- Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode);
+ Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode, bool skipEarlyPruning);
template <NodeType NT, bool InCheck>
Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth);
for (int mc = 1; mc < 64; ++mc)
{
double r = log(d) * log(mc) / 2;
- if (r < 0.80)
- continue;
Reductions[NonPV][imp][d][mc] = int(std::round(r));
Reductions[PV][imp][d][mc] = std::max(Reductions[NonPV][imp][d][mc] - 1, 0);
th->counterMoves.clear();
th->fromTo.clear();
th->counterMoveHistory.clear();
+ th->resetCalls = true;
}
Threads.main()->previousScore = VALUE_INFINITE;
cnt = 1, nodes++;
else
{
- pos.do_move(m, st, pos.gives_check(m));
+ pos.do_move(m, st);
cnt = leaf ? MoveList<LEGAL>(pos).size() : perft<false>(pos, depth - ONE_PLY);
nodes += cnt;
pos.undo_move(m);
void Thread::search() {
- Stack stack[MAX_PLY+7], *ss = stack+5; // To allow referencing (ss-5) and (ss+2)
+ Stack stack[MAX_PLY+7], *ss = stack+4; // To allow referencing (ss-4) and (ss+2)
Value bestValue, alpha, beta, delta;
Move easyMove = MOVE_NONE;
MainThread* mainThread = (this == Threads.main() ? Threads.main() : nullptr);
- std::memset(ss-5, 0, 8 * sizeof(Stack));
+ std::memset(ss-4, 0, 7 * sizeof(Stack));
bestValue = delta = alpha = -VALUE_INFINITE;
beta = VALUE_INFINITE;
// high/low anymore.
while (true)
{
- bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false);
+ bestValue = ::search<PV>(rootPos, ss, alpha, beta, rootDepth, false, 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
if (!mainThread)
continue;
- if (Signals.stop)
- sync_cout << "info nodes " << Threads.nodes_searched()
- << " time " << Time.elapsed() << sync_endl;
-
- else if (PVIdx + 1 == multiPV || Time.elapsed() > 3000)
+ if (Signals.stop || PVIdx + 1 == multiPV || Time.elapsed() > 3000)
sync_cout << UCI::pv(rootPos, rootDepth, alpha, beta) << sync_endl;
}
// search<>() is the main search function for both PV and non-PV nodes
template <NodeType NT>
- Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth, bool cutNode) {
+ 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;
Thread* thisThread = pos.this_thread();
inCheck = pos.checkers();
moveCount = quietCount = ss->moveCount = 0;
+ ss->history = VALUE_ZERO;
bestValue = -VALUE_INFINITE;
ss->ply = (ss-1)->ply + 1;
if (thisThread->resetCalls.load(std::memory_order_relaxed))
{
thisThread->resetCalls = false;
- thisThread->callsCnt = 0;
+ // At low node count increase the checking rate to about 0.1% of nodes
+ // otherwise use a default value.
+ thisThread->callsCnt = Limits.nodes ? std::min((int64_t)4096, Limits.nodes / 1024)
+ : 4096;
}
- if (++thisThread->callsCnt > 4096)
+
+ if (--thisThread->callsCnt <= 0)
{
for (Thread* th : Threads)
th->resetCalls = true;
ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->counterMoves = nullptr;
- (ss+1)->skipEarlyPruning = false;
(ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
+ Square prevSq = to_sq((ss-1)->currentMove);
// Step 4. Transposition table lookup. We don't want the score of a partial
// search to overwrite a previous full search TT value, so we use a different
&& (ttValue >= beta ? (tte->bound() & BOUND_LOWER)
: (tte->bound() & BOUND_UPPER)))
{
- ss->currentMove = ttMove; // Can be MOVE_NONE
-
// If ttMove is quiet, update killers, history, counter move on TT hit
if (ttValue >= beta && ttMove)
{
- int d = depth / ONE_PLY;
-
if (!pos.capture_or_promotion(ttMove))
- {
- Value bonus = Value(d * d + 2 * d - 2);
- update_stats(pos, ss, ttMove, nullptr, 0, bonus);
- }
+ update_stats(pos, ss, ttMove, nullptr, 0, bonus(depth));
// Extra penalty for a quiet TT move in previous ply when it gets refuted
if ((ss-1)->moveCount == 1 && !pos.captured_piece())
- {
- Value penalty = Value(d * d + 4 * d + 1);
- Square prevSq = to_sq((ss-1)->currentMove);
- update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -penalty);
- }
+ update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, penalty(depth));
}
return ttValue;
}
&& pos.rule50_count() == 0
&& !pos.can_castle(ANY_CASTLING))
{
- int found, v = Tablebases::probe_wdl(pos, &found);
+ TB::ProbeState err;
+ TB::WDLScore v = Tablebases::probe_wdl(pos, &err);
- if (found)
+ if (err != TB::ProbeState::FAIL)
{
- TB::Hits++;
+ thisThread->tbHits++;
int drawScore = TB::UseRule50 ? 1 : 0;
ss->staticEval, TT.generation());
}
- if (ss->skipEarlyPruning)
+ if (skipEarlyPruning)
goto moves_loop;
// Step 6. Razoring (skipped when in check)
&& ttMove == MOVE_NONE
&& eval + razor_margin[depth / ONE_PLY] <= alpha)
{
- if ( depth <= ONE_PLY
- && eval + razor_margin[3 * ONE_PLY] <= alpha)
+ if (depth <= ONE_PLY)
return qsearch<NonPV, false>(pos, ss, alpha, beta, DEPTH_ZERO);
Value ralpha = alpha - razor_margin[depth / ONE_PLY];
&& eval - futility_margin(depth) >= beta
&& eval < VALUE_KNOWN_WIN // Do not return unproven wins
&& pos.non_pawn_material(pos.side_to_move()))
- return eval - futility_margin(depth);
+ return eval;
// Step 8. Null move search with verification search (is omitted in PV nodes)
if ( !PvNode
Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY;
pos.do_null_move(st);
- (ss+1)->skipEarlyPruning = true;
nullValue = depth-R < ONE_PLY ? -qsearch<NonPV, false>(pos, ss+1, -beta, -beta+1, DEPTH_ZERO)
- : - search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode);
- (ss+1)->skipEarlyPruning = false;
+ : - search<NonPV>(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true);
pos.undo_null_move();
if (nullValue >= beta)
return nullValue;
// Do verification search at high depths
- ss->skipEarlyPruning = true;
Value v = depth-R < ONE_PLY ? qsearch<NonPV, false>(pos, ss, beta-1, beta, DEPTH_ZERO)
- : search<NonPV>(pos, ss, beta-1, beta, depth-R, false);
- ss->skipEarlyPruning = false;
+ : search<NonPV>(pos, ss, beta-1, beta, depth-R, false, true);
if (v >= beta)
return nullValue;
{
ss->currentMove = move;
ss->counterMoves = &thisThread->counterMoveHistory[pos.moved_piece(move)][to_sq(move)];
- pos.do_move(move, st, pos.gives_check(move));
- value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode);
+ pos.do_move(move, st);
+ value = -search<NonPV>(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode, false);
pos.undo_move(move);
if (value >= rbeta)
return value;
&& (PvNode || ss->staticEval + 256 >= beta))
{
Depth d = (3 * depth / (4 * ONE_PLY) - 2) * ONE_PLY;
- ss->skipEarlyPruning = true;
- search<NT>(pos, ss, alpha, beta, d, cutNode);
- ss->skipEarlyPruning = false;
+ search<NT>(pos, ss, alpha, beta, d, cutNode, true);
tte = TT.probe(posKey, ttHit);
ttMove = ttHit ? tte->move() : MOVE_NONE;
// Step 12. Extend checks
if ( givesCheck
&& !moveCountPruning
- && pos.see_sign(move) >= VALUE_ZERO)
+ && pos.see_ge(move, VALUE_ZERO))
extension = ONE_PLY;
// Singular extension search. If all moves but one fail low on a search of
Value rBeta = std::max(ttValue - 2 * depth / ONE_PLY, -VALUE_MATE);
Depth d = (depth / (2 * ONE_PLY)) * ONE_PLY;
ss->excludedMove = move;
- ss->skipEarlyPruning = true;
- value = search<NonPV>(pos, ss, rBeta - 1, rBeta, d, cutNode);
- ss->skipEarlyPruning = false;
+ value = search<NonPV>(pos, ss, rBeta - 1, rBeta, d, cutNode, true);
ss->excludedMove = MOVE_NONE;
if (value < rBeta)
// Step 13. Pruning at shallow depth
if ( !rootNode
- && !inCheck
- && bestValue > VALUE_MATED_IN_MAX_PLY)
+ && bestValue > VALUE_MATED_IN_MAX_PLY)
{
if ( !captureOrPromotion
&& !givesCheck
// Futility pruning: parent node
if ( lmrDepth < 7
+ && !inCheck
&& ss->staticEval + 256 + 200 * lmrDepth <= alpha)
continue;
// Prune moves with negative SEE
if ( lmrDepth < 8
- && pos.see_sign(move) < Value(-35 * lmrDepth * lmrDepth))
+ && !pos.see_ge(move, Value(-35 * lmrDepth * lmrDepth)))
continue;
}
- else if ( depth < 7 * ONE_PLY
- && pos.see_sign(move) < Value(-35 * depth / ONE_PLY * depth / ONE_PLY))
+ else if (depth < 7 * ONE_PLY && !extension)
+ {
+ Value v = -Value(400 - 100 * PvNode + 35 * depth / ONE_PLY * depth / ONE_PLY);
+ if (!pos.see_ge(move, v))
continue;
+ }
}
// Speculative prefetch as early as possible
// Decrease reduction for moves that escape a capture. Filter out
// castling moves, because they are coded as "king captures rook" and
- // hence break make_move(). Also use see() instead of see_sign(),
- // because the destination square is empty.
+ // hence break make_move().
else if ( type_of(move) == NORMAL
- && type_of(pos.piece_on(to_sq(move))) != PAWN
- && pos.see(make_move(to_sq(move), from_sq(move))) < VALUE_ZERO)
+ && !pos.see_ge(make_move(to_sq(move), from_sq(move)), VALUE_ZERO))
r -= 2 * ONE_PLY;
+ ss->history = thisThread->history[moved_piece][to_sq(move)]
+ + (cmh ? (*cmh )[moved_piece][to_sq(move)] : VALUE_ZERO)
+ + (fmh ? (*fmh )[moved_piece][to_sq(move)] : VALUE_ZERO)
+ + (fmh2 ? (*fmh2)[moved_piece][to_sq(move)] : VALUE_ZERO)
+ + thisThread->fromTo.get(~pos.side_to_move(), move)
+ - 8000; // Correction factor
+
+ // Decrease/increase reduction by comparing opponent's stat score
+ if (ss->history > VALUE_ZERO && (ss-1)->history < VALUE_ZERO)
+ r -= ONE_PLY;
+
+ else if (ss->history < VALUE_ZERO && (ss-1)->history > VALUE_ZERO)
+ r += ONE_PLY;
+
// Decrease/increase reduction for moves with a good/bad history
- Value val = thisThread->history[moved_piece][to_sq(move)]
- + (cmh ? (*cmh )[moved_piece][to_sq(move)] : VALUE_ZERO)
- + (fmh ? (*fmh )[moved_piece][to_sq(move)] : VALUE_ZERO)
- + (fmh2 ? (*fmh2)[moved_piece][to_sq(move)] : VALUE_ZERO)
- + thisThread->fromTo.get(~pos.side_to_move(), move);
- int rHist = (val - 8000) / 20000;
- r = std::max(DEPTH_ZERO, (r / ONE_PLY - rHist) * ONE_PLY);
+ r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->history / 20000) * ONE_PLY);
}
Depth d = std::max(newDepth - r, ONE_PLY);
- value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true);
+ value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, d, true, false);
doFullDepthSearch = (value > alpha && d != newDepth);
}
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>(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode, false);
// For PV nodes only, do a full PV search on the first move or after a fail
// high (in the latter case search only if value < beta), otherwise let the
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>(pos, ss+1, -beta, -alpha, newDepth, false, false);
}
// Step 17. Undo move
// All legal moves have been searched and if there are no legal moves, it
// must be a mate or a stalemate. If we are in a singular extension search then
// return a fail low score.
+
+ assert(moveCount || !inCheck || excludedMove || !MoveList<LEGAL>(pos).size());
+
if (!moveCount)
bestValue = excludedMove ? alpha
: inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()];
else if (bestMove)
{
- int d = depth / ONE_PLY;
// Quiet best move: update killers, history and countermoves
if (!pos.capture_or_promotion(bestMove))
- {
- Value bonus = Value(d * d + 2 * d - 2);
- update_stats(pos, ss, bestMove, quietsSearched, quietCount, bonus);
- }
+ update_stats(pos, ss, bestMove, quietsSearched, quietCount, bonus(depth));
// Extra penalty for a quiet TT move in previous ply when it gets refuted
if ((ss-1)->moveCount == 1 && !pos.captured_piece())
- {
- Value penalty = Value(d * d + 4 * d + 1);
- Square prevSq = to_sq((ss-1)->currentMove);
- update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -penalty);
- }
+ update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, penalty(depth));
}
// Bonus for prior countermove that caused the fail low
else if ( depth >= 3 * ONE_PLY
&& !pos.captured_piece()
&& is_ok((ss-1)->currentMove))
- {
- int d = depth / ONE_PLY;
- Value bonus = Value(d * d + 2 * d - 2);
- Square prevSq = to_sq((ss-1)->currentMove);
- update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, bonus);
- }
+ update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, bonus(depth));
tte->save(posKey, value_to_tt(bestValue, ss->ply),
bestValue >= beta ? BOUND_LOWER :
&& ttValue != VALUE_NONE // Only in case of TT access race
&& (ttValue >= beta ? (tte->bound() & BOUND_LOWER)
: (tte->bound() & BOUND_UPPER)))
- {
- ss->currentMove = ttMove; // Can be MOVE_NONE
return ttValue;
- }
// Evaluate the position statically
if (InCheck)
continue;
}
- if (futilityBase <= alpha && pos.see(move) <= VALUE_ZERO)
+ if (futilityBase <= alpha && !pos.see_ge(move, VALUE_ZERO + 1))
{
bestValue = std::max(bestValue, futilityBase);
continue;
// Don't search moves with negative SEE values
if ( (!InCheck || evasionPrunable)
&& type_of(move) != PROMOTION
- && pos.see_sign(move) < VALUE_ZERO)
+ && !pos.see_ge(move, VALUE_ZERO))
continue;
// Speculative prefetch as early as possible
if ( (Limits.use_time_management() && elapsed > Time.maximum() - 10)
|| (Limits.movetime && elapsed >= Limits.movetime)
- || (Limits.nodes && Threads.nodes_searched() >= Limits.nodes))
+ || (Limits.nodes && Threads.nodes_searched() >= (uint64_t)Limits.nodes))
Signals.stop = true;
}
const RootMoves& rootMoves = pos.this_thread()->rootMoves;
size_t PVIdx = pos.this_thread()->PVIdx;
size_t multiPV = std::min((size_t)Options["MultiPV"], rootMoves.size());
- uint64_t nodes_searched = Threads.nodes_searched();
+ uint64_t nodesSearched = Threads.nodes_searched();
+ uint64_t tbHits = Threads.tb_hits() + (TB::RootInTB ? rootMoves.size() : 0);
for (size_t i = 0; i < multiPV; ++i)
{
if (!tb && i == PVIdx)
ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : "");
- ss << " nodes " << nodes_searched
- << " nps " << nodes_searched * 1000 / elapsed;
+ ss << " nodes " << nodesSearched
+ << " nps " << nodesSearched * 1000 / elapsed;
if (elapsed > 1000) // Earlier makes little sense
ss << " hashfull " << TT.hashfull();
- ss << " tbhits " << TB::Hits
+ ss << " tbhits " << tbHits
<< " time " << elapsed
<< " pv";
/// 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.
-bool RootMove::extract_ponder_from_tt(Position& pos)
-{
+bool RootMove::extract_ponder_from_tt(Position& pos) {
+
StateInfo st;
bool ttHit;
if (!pv[0])
return false;
- pos.do_move(pv[0], st, pos.gives_check(pv[0]));
+ pos.do_move(pv[0], st);
TTEntry* tte = TT.probe(pos.key(), ttHit);
if (ttHit)
void Tablebases::filter_root_moves(Position& pos, Search::RootMoves& rootMoves) {
- Hits = 0;
RootInTB = false;
UseRule50 = Options["Syzygy50MoveRule"];
ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY;
Cardinality = 0;
}
- if (RootInTB)
- {
- Hits = rootMoves.size();
-
- if (!UseRule50)
- TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1
- : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1
- : VALUE_DRAW;
- }
+ if (RootInTB && !UseRule50)
+ TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1
+ : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1
+ : VALUE_DRAW;
}
projects / stockfish / blobdiff