X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=8b6e1690404bf5317f3dab7bf8fde61c4fc802d7;hp=847fc762e53644abb7959622e211a1c3966b3f03;hb=b3525fa9ea88e230a38d72351826cbc16c282938;hpb=ec6aab01366ba1d2de27084d3cc7415a31aa5a24 diff --git a/src/search.cpp b/src/search.cpp index 847fc762..8b6e1690 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -65,7 +65,7 @@ namespace { // Razoring and futility margin based on depth const int razor_margin[4] = { 483, 570, 603, 554 }; - Value futility_margin(Depth d) { return Value(200 * d); } + Value futility_margin(Depth d) { return Value(150 * d); } // Futility and reductions lookup tables, initialized at startup int FutilityMoveCounts[2][16]; // [improving][depth] @@ -213,6 +213,7 @@ void Search::clear() { { th->history.clear(); th->counterMoves.clear(); + th->fromTo.clear(); } Threads.main()->previousScore = VALUE_INFINITE; @@ -261,19 +262,6 @@ void MainThread::search() { DrawValue[ us] = VALUE_DRAW - Value(contempt); DrawValue[~us] = VALUE_DRAW + Value(contempt); - TB::Hits = 0; - TB::RootInTB = false; - TB::UseRule50 = Options["Syzygy50MoveRule"]; - TB::ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY; - TB::Cardinality = Options["SyzygyProbeLimit"]; - - // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality - if (TB::Cardinality > TB::MaxCardinality) - { - TB::Cardinality = TB::MaxCardinality; - TB::ProbeDepth = DEPTH_ZERO; - } - if (rootMoves.empty()) { rootMoves.push_back(RootMove(MOVE_NONE)); @@ -283,38 +271,6 @@ void MainThread::search() { } else { - if ( TB::Cardinality >= rootPos.count(WHITE) - + rootPos.count(BLACK) - && !rootPos.can_castle(ANY_CASTLING)) - { - // If the current root position is in the tablebases, then RootMoves - // contains only moves that preserve the draw or the win. - TB::RootInTB = Tablebases::root_probe(rootPos, rootMoves, TB::Score); - - if (TB::RootInTB) - TB::Cardinality = 0; // Do not probe tablebases during the search - - else // If DTZ tables are missing, use WDL tables as a fallback - { - // Filter out moves that do not preserve the draw or the win. - TB::RootInTB = Tablebases::root_probe_wdl(rootPos, rootMoves, TB::Score); - - // Only probe during search if winning - if (TB::Score <= VALUE_DRAW) - TB::Cardinality = 0; - } - - if (TB::RootInTB) - { - TB::Hits = rootMoves.size(); - - if (!TB::UseRule50) - TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 - : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1 - : VALUE_DRAW; - } - } - for (Thread* th : Threads) if (th != this) th->start_searching(); @@ -350,6 +306,7 @@ void MainThread::search() { Thread* bestThread = this; if ( !this->easyMovePlayed && Options["MultiPV"] == 1 + && !Limits.depth && !Skill(Options["Skill Level"]).enabled() && rootMoves[0].pv[0] != MOVE_NONE) { @@ -411,7 +368,7 @@ void Thread::search() { multiPV = std::min(multiPV, rootMoves.size()); // Iterative deepening loop until requested to stop or the target depth is reached. - while (++rootDepth < DEPTH_MAX && !Signals.stop && (!Limits.depth || rootDepth <= Limits.depth)) + while (++rootDepth < DEPTH_MAX && !Signals.stop && (!Limits.depth || Threads.main()->rootDepth <= Limits.depth)) { // Set up the new depths for the helper threads skipping on average every // 2nd ply (using a half-density matrix). @@ -457,11 +414,6 @@ void Thread::search() { // search the already searched PV lines are preserved. std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.end()); - // Write PV back to the transposition table in case the relevant - // entries have been overwritten during the search. - for (size_t i = 0; i <= PVIdx; ++i) - rootMoves[i].insert_pv_in_tt(rootPos); - // If search has been stopped, break immediately. Sorting and // writing PV back to TT is safe because RootMoves is still // valid, although it refers to the previous iteration. @@ -506,7 +458,7 @@ void Thread::search() { std::stable_sort(rootMoves.begin(), rootMoves.begin() + PVIdx + 1); if (!mainThread) - break; + continue; if (Signals.stop) sync_cout << "info nodes " << Threads.nodes_searched() @@ -540,18 +492,18 @@ void Thread::search() { // Stop the search if only one legal move is available, or if all // of the available time has been used, or if we matched an easyMove // from the previous search and just did a fast verification. - const bool F[] = { !mainThread->failedLow, - bestValue >= mainThread->previousScore }; + const int F[] = { mainThread->failedLow, + bestValue - mainThread->previousScore }; - int improvingFactor = 640 - 160*F[0] - 126*F[1] - 124*F[0]*F[1]; + int improvingFactor = std::max(229, std::min(715, 357 + 119 * F[0] - 6 * F[1])); double unstablePvFactor = 1 + mainThread->bestMoveChanges; bool doEasyMove = rootMoves[0].pv[0] == easyMove && mainThread->bestMoveChanges < 0.03 - && Time.elapsed() > Time.optimum() * 25 / 204; + && Time.elapsed() > Time.optimum() * 5 / 42; if ( rootMoves.size() == 1 - || Time.elapsed() > Time.optimum() * unstablePvFactor * improvingFactor / 634 + || Time.elapsed() > Time.optimum() * unstablePvFactor * improvingFactor / 628 || (mainThread->easyMovePlayed = doEasyMove)) { // If we are allowed to ponder do not stop the search now but @@ -598,6 +550,7 @@ namespace { assert(-VALUE_INFINITE <= alpha && alpha < beta && beta <= VALUE_INFINITE); assert(PvNode || (alpha == beta - 1)); assert(DEPTH_ZERO < depth && depth < DEPTH_MAX); + assert(!(PvNode && cutNode)); Move pv[MAX_PLY+1], quietsSearched[64]; StateInfo st; @@ -605,9 +558,10 @@ namespace { Key posKey; Move ttMove, move, excludedMove, bestMove; Depth extension, newDepth, predictedDepth; - Value bestValue, value, ttValue, eval, nullValue, futilityValue; + Value bestValue, value, ttValue, eval, nullValue; bool ttHit, inCheck, givesCheck, singularExtensionNode, improving; - bool captureOrPromotion, doFullDepthSearch; + bool captureOrPromotion, doFullDepthSearch, moveCountPruning; + Piece moved_piece; int moveCount, quietCount; // Step 1. Initialize node @@ -776,8 +730,8 @@ namespace { // Step 8. Null move search with verification search (is omitted in PV nodes) if ( !PvNode - && depth >= 2 * ONE_PLY && eval >= beta + && (ss->staticEval >= beta - 35 * (depth / ONE_PLY - 6) || depth >= 13 * ONE_PLY) && pos.non_pawn_material(pos.side_to_move())) { ss->currentMove = MOVE_NULL; @@ -853,7 +807,7 @@ namespace { { Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4); ss->skipEarlyPruning = true; - search(pos, ss, alpha, beta, d, true); + search(pos, ss, alpha, beta, d, cutNode); ss->skipEarlyPruning = false; tte = TT.probe(posKey, ttHit); @@ -862,14 +816,15 @@ namespace { moves_loop: // When in check search starts from here - Square prevSq = to_sq((ss-1)->currentMove); - const CounterMoveStats& cmh = CounterMoveHistory[pos.piece_on(prevSq)][prevSq]; + const CounterMoveStats* cmh = (ss-1)->counterMoves; + const CounterMoveStats* fmh = (ss-2)->counterMoves; + const CounterMoveStats* fmh2 = (ss-4)->counterMoves; MovePicker mp(pos, ttMove, depth, ss); CheckInfo ci(pos); value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc improving = ss->staticEval >= (ss-2)->staticEval - || ss->staticEval == VALUE_NONE + /* || ss->staticEval == VALUE_NONE Already implicit in the previous condition */ ||(ss-2)->staticEval == VALUE_NONE; singularExtensionNode = !rootNode @@ -909,13 +864,19 @@ moves_loop: // When in check search starts from here extension = DEPTH_ZERO; captureOrPromotion = pos.capture_or_promotion(move); + moved_piece = pos.moved_piece(move); givesCheck = type_of(move) == NORMAL && !ci.dcCandidates ? ci.checkSquares[type_of(pos.piece_on(from_sq(move)))] & to_sq(move) : pos.gives_check(move, ci); + moveCountPruning = depth < 16 * ONE_PLY + && moveCount >= FutilityMoveCounts[improving][depth]; + // Step 12. Extend checks - if (givesCheck && pos.see_sign(move) >= VALUE_ZERO) + if ( givesCheck + && !moveCountPruning + && pos.see_sign(move) >= VALUE_ZERO) extension = ONE_PLY; // Singular extension search. If all moves but one fail low on a search of @@ -951,34 +912,34 @@ moves_loop: // When in check search starts from here && bestValue > VALUE_MATED_IN_MAX_PLY) { // Move count based pruning - if ( depth < 16 * ONE_PLY - && moveCount >= FutilityMoveCounts[improving][depth]) + if (moveCountPruning) continue; - // History based pruning + // Countermoves based pruning if ( depth <= 4 * ONE_PLY && move != ss->killers[0] - && thisThread->history[pos.moved_piece(move)][to_sq(move)] < VALUE_ZERO - && cmh[pos.moved_piece(move)][to_sq(move)] < VALUE_ZERO) + && (!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 || (cmh && fmh))) continue; predictedDepth = std::max(newDepth - reduction(improving, depth, moveCount), DEPTH_ZERO); // Futility pruning: parent node - if (predictedDepth < 7 * ONE_PLY) + if ( predictedDepth < 7 * ONE_PLY + && ss->staticEval + 256 + 200 * predictedDepth / ONE_PLY <= alpha) + continue; + + // Prune moves with negative SEE at low depths and below a decreasing + // threshold at higher depths. + if (predictedDepth < 8 * ONE_PLY) { - futilityValue = ss->staticEval + futility_margin(predictedDepth) + 256; + Value see_v = predictedDepth < 4 * ONE_PLY ? VALUE_ZERO + : -PawnValueMg * 2 * int(predictedDepth - 3 * ONE_PLY); - if (futilityValue <= alpha) - { - bestValue = std::max(bestValue, futilityValue); + if (pos.see_sign(move) < see_v) continue; - } } - - // Prune moves with negative SEE at low depths - if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO) - continue; } // Speculative prefetch as early as possible @@ -992,7 +953,7 @@ moves_loop: // When in check search starts from here } ss->currentMove = move; - ss->counterMoves = &CounterMoveHistory[pos.moved_piece(move)][to_sq(move)]; + ss->counterMoves = &CounterMoveHistory[moved_piece][to_sq(move)]; // Step 14. Make the move pos.do_move(move, st, givesCheck); @@ -1004,27 +965,28 @@ moves_loop: // When in check search starts from here && !captureOrPromotion) { Depth r = reduction(improving, depth, moveCount); - Value hValue = thisThread->history[pos.piece_on(to_sq(move))][to_sq(move)]; - Value cmhValue = cmh[pos.piece_on(to_sq(move))][to_sq(move)]; - - // Increase reduction for cut nodes and moves with a bad history - if ( (!PvNode && cutNode) - || (hValue < VALUE_ZERO && cmhValue <= VALUE_ZERO)) - r += ONE_PLY; + 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); - // Decrease/increase reduction for moves with a good/bad history - int rHist = (hValue + cmhValue) / 14980; - r = std::max(DEPTH_ZERO, r - rHist * ONE_PLY); + // Increase reduction for cut nodes + if (cutNode) + r += 2 * ONE_PLY; // 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. - if ( r - && 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) - r = std::max(DEPTH_ZERO, r - ONE_PLY); + 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) + r -= 2 * ONE_PLY; + + // Decrease/increase reduction for moves with a good/bad history + int rHist = (val - 10000) / 20000; + r = std::max(DEPTH_ZERO, r - rHist * ONE_PLY); Depth d = std::max(newDepth - r, ONE_PLY); @@ -1152,11 +1114,11 @@ moves_loop: // When in check search starts from here // Bonus for prior countermove that caused the fail low else if ( depth >= 3 * ONE_PLY && !bestMove - && !inCheck && !pos.captured_piece_type() && is_ok((ss-1)->currentMove)) { - Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + depth / ONE_PLY - 1); + Square prevSq = to_sq((ss-1)->currentMove); + Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + 2 * depth / ONE_PLY - 2); if ((ss-2)->counterMoves) (ss-2)->counterMoves->update(pos.piece_on(prevSq), prevSq, bonus); @@ -1435,8 +1397,9 @@ moves_loop: // When in check search starts from here ss->killers[1] = ss->killers[0]; ss->killers[0] = move; } - - Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + depth / ONE_PLY - 1); + + Color c = pos.side_to_move(); + Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + 2 * depth / ONE_PLY - 2); Square prevSq = to_sq((ss-1)->currentMove); CounterMoveStats* cmh = (ss-1)->counterMoves; @@ -1445,6 +1408,7 @@ moves_loop: // When in check search starts from here Thread* thisThread = pos.this_thread(); thisThread->history.update(pos.moved_piece(move), to_sq(move), bonus); + thisThread->fromTo.update(c, move, bonus); if (cmh) { @@ -1462,6 +1426,7 @@ moves_loop: // When in check search starts from here for (int i = 0; i < quietsCnt; ++i) { thisThread->history.update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); + thisThread->fromTo.update(c, quiets[i], -bonus); if (cmh) cmh->update(pos.moved_piece(quiets[i]), to_sq(quiets[i]), -bonus); @@ -1477,13 +1442,13 @@ moves_loop: // When in check search starts from here if ((ss-1)->moveCount == 1 && !pos.captured_piece_type()) { if ((ss-2)->counterMoves) - (ss-2)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY); + (ss-2)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1); if ((ss-3)->counterMoves) - (ss-3)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY); + (ss-3)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1); if ((ss-5)->counterMoves) - (ss-5)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY); + (ss-5)->counterMoves->update(pos.piece_on(prevSq), prevSq, -bonus - 2 * (depth + 1) / ONE_PLY - 1); } } @@ -1606,33 +1571,6 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { } -/// RootMove::insert_pv_in_tt() is called at the end of a search iteration, and -/// inserts the PV back into the TT. This makes sure the old PV moves are searched -/// first, even if the old TT entries have been overwritten. - -void RootMove::insert_pv_in_tt(Position& pos) { - - StateInfo state[MAX_PLY], *st = state; - bool ttHit; - - for (Move m : pv) - { - assert(MoveList(pos).contains(m)); - - TTEntry* tte = TT.probe(pos.key(), ttHit); - - if (!ttHit || tte->move() != m) // Don't overwrite correct entries - tte->save(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, - m, VALUE_NONE, TT.generation()); - - pos.do_move(m, *st++, pos.gives_check(m, CheckInfo(pos))); - } - - for (size_t i = pv.size(); i > 0; ) - pos.undo_move(pv[--i]); -} - - /// 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, @@ -1647,14 +1585,60 @@ bool RootMove::extract_ponder_from_tt(Position& pos) pos.do_move(pv[0], st, pos.gives_check(pv[0], CheckInfo(pos))); TTEntry* tte = TT.probe(pos.key(), ttHit); - pos.undo_move(pv[0]); if (ttHit) { Move m = tte->move(); // Local copy to be SMP safe if (MoveList(pos).contains(m)) - return pv.push_back(m), true; + pv.push_back(m); + } + + pos.undo_move(pv[0]); + return pv.size() > 1; +} + +void Tablebases::filter_root_moves(Position& pos, Search::RootMoves& rootMoves) { + + Hits = 0; + RootInTB = false; + UseRule50 = Options["Syzygy50MoveRule"]; + ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY; + Cardinality = Options["SyzygyProbeLimit"]; + + // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality + if (Cardinality > MaxCardinality) + { + Cardinality = MaxCardinality; + ProbeDepth = DEPTH_ZERO; + } + + if (Cardinality < popcount(pos.pieces()) || pos.can_castle(ANY_CASTLING)) + return; + + // If the current root position is in the tablebases, then RootMoves + // contains only moves that preserve the draw or the win. + RootInTB = root_probe(pos, rootMoves, TB::Score); + + if (RootInTB) + Cardinality = 0; // Do not probe tablebases during the search + + else // If DTZ tables are missing, use WDL tables as a fallback + { + // Filter out moves that do not preserve the draw or the win. + RootInTB = root_probe_wdl(pos, rootMoves, TB::Score); + + // Only probe during search if winning + if (TB::Score <= VALUE_DRAW) + Cardinality = 0; } - return false; + 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; + } }