X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=a9fc1c6d4c80b41aec8c20c4b6b2e7c070760050;hp=e4c903a598587bf3ed02a9ed31094b6afba39665;hb=d39ffbeea6ad54c90123a352d50b65c5bda1561b;hpb=ca677526452823d1fe89543762edb66684e7bdc7 diff --git a/src/search.cpp b/src/search.cpp index e4c903a5..a9fc1c6d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -113,8 +113,8 @@ namespace { 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]); @@ -155,14 +155,17 @@ namespace { const size_t HalfDensitySize = std::extent::value; + 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); } + EasyMoveManager EasyMove; Value DrawValue[COLOR_NB]; template - 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 - Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); + Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth = DEPTH_ZERO); Value value_to_tt(Value v, int ply); Value value_from_tt(Value v, int ply); @@ -183,8 +186,6 @@ void Search::init() { 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); @@ -214,6 +215,7 @@ void Search::clear() { th->counterMoves.clear(); th->fromTo.clear(); th->counterMoveHistory.clear(); + th->resetCalls = true; } Threads.main()->previousScore = VALUE_INFINITE; @@ -235,7 +237,7 @@ uint64_t Search::perft(Position& pos, Depth depth) { cnt = 1, nodes++; else { - pos.do_move(m, st, pos.gives_check(m)); + pos.do_move(m, st); cnt = leaf ? MoveList(pos).size() : perft(pos, depth - ONE_PLY); nodes += cnt; pos.undo_move(m); @@ -310,9 +312,13 @@ void MainThread::search() { && rootMoves[0].pv[0] != MOVE_NONE) { for (Thread* th : Threads) - if ( th->completedDepth > bestThread->completedDepth - && th->rootMoves[0].score > bestThread->rootMoves[0].score) + { + Depth depthDiff = th->completedDepth - bestThread->completedDepth; + Value scoreDiff = th->rootMoves[0].score - bestThread->rootMoves[0].score; + + if (scoreDiff > 0 && depthDiff >= 0) bestThread = th; + } } previousScore = bestThread->rootMoves[0].score; @@ -336,12 +342,12 @@ void MainThread::search() { 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; @@ -405,7 +411,7 @@ void Thread::search() { // high/low anymore. while (true) { - bestValue = ::search(rootPos, ss, alpha, beta, rootDepth, false); + bestValue = ::search(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 @@ -461,11 +467,7 @@ void Thread::search() { 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; } @@ -543,7 +545,7 @@ namespace { // search<>() is the main search function for both PV and non-PV nodes template - 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; @@ -570,6 +572,7 @@ namespace { 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; @@ -577,9 +580,13 @@ namespace { 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; @@ -594,7 +601,7 @@ namespace { if (!rootNode) { // Step 2. Check for aborted search and immediate draw - if (Signals.stop.load(std::memory_order_relaxed) || pos.is_draw() || ss->ply >= MAX_PLY) + if (Signals.stop.load(std::memory_order_relaxed) || pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) return ss->ply >= MAX_PLY && !inCheck ? evaluate(pos) : DrawValue[pos.side_to_move()]; @@ -614,8 +621,8 @@ namespace { 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 @@ -638,21 +645,12 @@ namespace { // 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; } @@ -660,16 +658,17 @@ namespace { // Step 4a. Tablebase probe if (!rootNode && TB::Cardinality) { - int piecesCnt = pos.count(WHITE) + pos.count(BLACK); + int piecesCount = pos.count(WHITE) + pos.count(BLACK); - if ( piecesCnt <= TB::Cardinality - && (piecesCnt < TB::Cardinality || depth >= TB::ProbeDepth) + if ( piecesCount <= TB::Cardinality + && (piecesCount < TB::Cardinality || depth >= TB::ProbeDepth) && 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) { thisThread->tbHits++; @@ -716,7 +715,7 @@ namespace { ss->staticEval, TT.generation()); } - if (ss->skipEarlyPruning) + if (skipEarlyPruning) goto moves_loop; // Step 6. Razoring (skipped when in check) @@ -726,10 +725,10 @@ namespace { && eval + razor_margin[depth / ONE_PLY] <= alpha) { if (depth <= ONE_PLY) - return qsearch(pos, ss, alpha, beta, DEPTH_ZERO); + return qsearch(pos, ss, alpha, alpha+1); Value ralpha = alpha - razor_margin[depth / ONE_PLY]; - Value v = qsearch(pos, ss, ralpha, ralpha+1, DEPTH_ZERO); + Value v = qsearch(pos, ss, ralpha, ralpha+1); if (v <= ralpha) return v; } @@ -757,10 +756,8 @@ namespace { 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(pos, ss+1, -beta, -beta+1, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode); - (ss+1)->skipEarlyPruning = false; + nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1) + : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true); pos.undo_null_move(); if (nullValue >= beta) @@ -773,10 +770,8 @@ namespace { return nullValue; // Do verification search at high depths - ss->skipEarlyPruning = true; - Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta, DEPTH_ZERO) - : search(pos, ss, beta-1, beta, depth-R, false); - ss->skipEarlyPruning = false; + Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta) + : search(pos, ss, beta-1, beta, depth-R, false, true); if (v >= beta) return nullValue; @@ -804,8 +799,8 @@ namespace { { 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(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode); + pos.do_move(move, st); + value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode, false); pos.undo_move(move); if (value >= rbeta) return value; @@ -818,9 +813,7 @@ namespace { && (PvNode || ss->staticEval + 256 >= beta)) { Depth d = (3 * depth / (4 * ONE_PLY) - 2) * ONE_PLY; - ss->skipEarlyPruning = true; - search(pos, ss, alpha, beta, d, cutNode); - ss->skipEarlyPruning = false; + search(pos, ss, alpha, beta, d, cutNode, true); tte = TT.probe(posKey, ttHit); ttMove = ttHit ? tte->move() : MOVE_NONE; @@ -902,9 +895,7 @@ moves_loop: // When in check search starts from here 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(pos, ss, rBeta - 1, rBeta, d, cutNode); - ss->skipEarlyPruning = false; + value = search(pos, ss, rBeta - 1, rBeta, d, cutNode, true); ss->excludedMove = MOVE_NONE; if (value < rBeta) @@ -947,9 +938,9 @@ moves_loop: // When in check search starts from here && !pos.see_ge(move, Value(-35 * lmrDepth * lmrDepth))) continue; } - else if ( depth < 7 * ONE_PLY + else if ( depth < 7 * ONE_PLY && !extension - && !pos.see_ge(move, Value(-35 * depth / ONE_PLY * depth / ONE_PLY))) + && !pos.see_ge(move, -PawnValueEg * (depth / ONE_PLY))) continue; } @@ -987,26 +978,32 @@ moves_loop: // When in check search starts from here // 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_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(pos, ss+1, -(alpha+1), -alpha, d, true); + value = -search(pos, ss+1, -(alpha+1), -alpha, d, true, false); doFullDepthSearch = (value > alpha && d != newDepth); } @@ -1016,9 +1013,9 @@ moves_loop: // When in check search starts from here // Step 16. Full depth search when LMR is skipped or fails high if (doFullDepthSearch) value = newDepth < ONE_PLY ? - givesCheck ? -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : -qsearch(pos, ss+1, -(alpha+1), -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); + givesCheck ? -qsearch(pos, ss+1, -(alpha+1), -alpha) + : -qsearch(pos, ss+1, -(alpha+1), -alpha) + : - search(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 @@ -1029,9 +1026,9 @@ moves_loop: // When in check search starts from here (ss+1)->pv[0] = MOVE_NONE; value = newDepth < ONE_PLY ? - givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : -qsearch(pos, ss+1, -beta, -alpha, DEPTH_ZERO) - : - search(pos, ss+1, -beta, -alpha, newDepth, false); + givesCheck ? -qsearch(pos, ss+1, -beta, -alpha) + : -qsearch(pos, ss+1, -beta, -alpha) + : - search(pos, ss+1, -beta, -alpha, newDepth, false, false); } // Step 17. Undo move @@ -1081,13 +1078,6 @@ moves_loop: // When in check search starts from here if (value > alpha) { - // If there is an easy move for this position, clear it if unstable - if ( PvNode - && thisThread == Threads.main() - && EasyMove.get(pos.key()) - && (move != EasyMove.get(pos.key()) || moveCount > 1)) - EasyMove.clear(); - bestMove = move; if (PvNode && !rootNode) // Update pv even in fail-high case @@ -1127,33 +1117,20 @@ moves_loop: // When in check search starts from here : 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 : @@ -1167,8 +1144,7 @@ moves_loop: // When in check search starts from here // qsearch() is the quiescence search function, which is called by the main - // search function when the remaining depth is zero (or, to be more precise, - // less than ONE_PLY). + // search function with depth zero, or recursively with depth less than ONE_PLY. template Value qsearch(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth) { @@ -1201,7 +1177,7 @@ moves_loop: // When in check search starts from here ss->ply = (ss-1)->ply + 1; // Check for an instant draw or if the maximum ply has been reached - if (pos.is_draw() || ss->ply >= MAX_PLY) + if (pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) return ss->ply >= MAX_PLY && !InCheck ? evaluate(pos) : DrawValue[pos.side_to_move()]; @@ -1596,7 +1572,7 @@ bool RootMove::extract_ponder_from_tt(Position& pos) { 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)