X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=0b4125fcdd6ccf05279c848c1257eed89c042343;hp=2828ccda35bebb57397034894ce8e434e8de784c;hb=8e45e70e55c42c4750ccb729dcd49cdaafe5af44;hpb=0784bd542bf17679febd9d9d87858fd0fd0424f9 diff --git a/src/search.cpp b/src/search.cpp index 2828ccda..0b4125fc 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -261,19 +261,6 @@ 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 +270,6 @@ 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(); @@ -458,11 +413,6 @@ 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. @@ -541,18 +491,18 @@ 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 @@ -606,9 +556,10 @@ 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 @@ -864,7 +815,9 @@ 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); @@ -910,13 +863,19 @@ 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 + && ( moveCount == 1 + || (!moveCountPruning && pos.see_sign(move) >= VALUE_ZERO))) extension = ONE_PLY; // Singular extension search. If all moves but one fail low on a search of @@ -952,30 +911,23 @@ 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) - { - futilityValue = ss->staticEval + futility_margin(predictedDepth) + 256; - - if (futilityValue <= alpha) - { - bestValue = std::max(bestValue, futilityValue); - continue; - } - } + if ( predictedDepth < 7 * ONE_PLY + && ss->staticEval + futility_margin(predictedDepth) + 256 <= alpha) + continue; // Prune moves with negative SEE at low depths if (predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < VALUE_ZERO) @@ -993,7 +945,7 @@ 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); @@ -1005,31 +957,27 @@ 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)]; - - const CounterMoveStats* fm = (ss - 2)->counterMoves; - const CounterMoveStats* fm2 = (ss - 4)->counterMoves; - Value fmValue = (fm ? (*fm)[pos.piece_on(to_sq(move))][to_sq(move)] : VALUE_ZERO); - Value fm2Value = (fm2 ? (*fm2)[pos.piece_on(to_sq(move))][to_sq(move)] : VALUE_ZERO); + 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); // Increase reduction for cut nodes if (!PvNode && cutNode) - r += ONE_PLY; - - // Decrease/increase reduction for moves with a good/bad history - int rHist = (hValue + cmhValue + fmValue + fm2Value - 10000) / 20000; - r = std::max(DEPTH_ZERO, r - rHist * ONE_PLY); + 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); @@ -1161,7 +1109,7 @@ moves_loop: // When in check search starts from here && !pos.captured_piece_type() && is_ok((ss-1)->currentMove)) { - Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + depth / ONE_PLY - 1); + 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); @@ -1441,7 +1389,7 @@ moves_loop: // When in check search starts from here ss->killers[0] = move; } - Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY) + depth / ONE_PLY - 1); + 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; @@ -1482,13 +1430,13 @@ 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); } } @@ -1611,33 +1559,6 @@ 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, @@ -1663,3 +1584,49 @@ bool RootMove::extract_ponder_from_tt(Position& pos) return false; } + +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; + } + + 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; + } +}