X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fsearch.cpp;h=425c2c65d7e098d18b07e9d459c23511f6a2a701;hb=1b947aafbf19fb35c71eb2201ad32ae072ab6658;hp=3c32c4bb762a45ee1ae35f14a02aa119ff654418;hpb=ce0a95c2c013f4aa9d41a80b8f12f005fe162fcb;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index 3c32c4bb..425c2c65 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -66,22 +66,29 @@ namespace { // Different node types, used as template parameter enum NodeType { Root, PV, NonPV }; - // Dynamic razoring margin based on depth + // Razoring and futility margin based on depth inline Value razor_margin(Depth d) { return Value(512 + 32 * d); } + inline Value futility_margin(Depth d) { return Value(200 * d); } - // Futility lookup tables (initialized at startup) and their access functions - int FutilityMoveCounts[2][16]; // [improving][depth] + // Futility and reductions lookup tables, initialized at startup + int FutilityMoveCounts[2][16]; // [improving][depth] + Depth Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber] - inline Value futility_margin(Depth d) { - return Value(200 * d); + template inline Depth reduction(bool i, Depth d, int mn) { + return Reductions[PvNode][i][std::min(d, 63 * ONE_PLY)][std::min(mn, 63)]; } - // Reduction lookup tables (initialized at startup) and their access function - int8_t Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber] + // Skill struct is used to implement strength limiting + struct Skill { + Skill(int l) : level(l) {} + bool enabled() const { return level < 20; } + bool time_to_pick(Depth depth) const { return depth / ONE_PLY == 1 + level; } + Move best_move(size_t multiPV) { return best ? best : pick_best(multiPV); } + Move pick_best(size_t multiPV); - template inline Depth reduction(bool i, Depth d, int mn) { - return (Depth) Reductions[PvNode][i][std::min(int(d), 63)][std::min(mn, 63)]; - } + int level; + Move best = MOVE_NONE; + }; size_t PVIdx; TimeManager TimeMgr; @@ -104,25 +111,6 @@ namespace { void update_stats(const Position& pos, Stack* ss, Move move, Depth depth, Move* quiets, int quietsCnt); string uci_pv(const Position& pos, Depth depth, Value alpha, Value beta); - struct Skill { - Skill(int l, size_t rootSize) : level(l), - candidates(l < 20 ? std::min(4, (int)rootSize) : 0), - best(MOVE_NONE) {} - ~Skill() { - if (candidates) // Swap best PV line with the sub-optimal one - std::swap(RootMoves[0], *std::find(RootMoves.begin(), - RootMoves.end(), best ? best : pick_move())); - } - - size_t candidates_size() const { return candidates; } - bool time_to_pick(Depth depth) const { return depth / ONE_PLY == 1 + level; } - Move pick_move(); - - int level; - size_t candidates; - Move best; - }; - } // namespace @@ -130,25 +118,23 @@ namespace { void Search::init() { - // Init reductions array - for (int d = 1; d < 64; ++d) - for (int mc = 1; mc < 64; ++mc) - { - double pvRed = 0.00 + log(double(d)) * log(double(mc)) / 3.00; - double nonPVRed = 0.33 + log(double(d)) * log(double(mc)) / 2.25; + const double K[][2] = {{ 0.83, 2.25 }, { 0.50, 3.00 }}; - Reductions[1][1][d][mc] = int8_t( pvRed >= 1.0 ? pvRed + 0.5: 0); - Reductions[0][1][d][mc] = int8_t(nonPVRed >= 1.0 ? nonPVRed + 0.5: 0); + for (int pv = 0; pv <= 1; ++pv) + for (int imp = 0; imp <= 1; ++imp) + for (int d = 1; d < 64; ++d) + for (int mc = 1; mc < 64; ++mc) + { + double r = K[pv][0] + log(d) * log(mc) / K[pv][1]; - Reductions[1][0][d][mc] = Reductions[1][1][d][mc]; - Reductions[0][0][d][mc] = Reductions[0][1][d][mc]; + if (r >= 1.5) + Reductions[pv][imp][d][mc] = int(r) * ONE_PLY; - // Increase reduction when eval is not improving - if (Reductions[0][0][d][mc] >= 2) - Reductions[0][0][d][mc] += 1; - } + // Increase reduction when eval is not improving + if (!pv && !imp && Reductions[pv][imp][d][mc] >= 2 * ONE_PLY) + Reductions[pv][imp][d][mc] += ONE_PLY; + } - // Init futility move count array for (int d = 0; d < 16; ++d) { FutilityMoveCounts[0][d] = int(2.4 + 0.773 * pow(d + 0.00, 1.8)); @@ -167,19 +153,19 @@ uint64_t Search::perft(Position& pos, Depth depth) { CheckInfo ci(pos); const bool leaf = (depth == 2 * ONE_PLY); - for (MoveList it(pos); *it; ++it) + for (const ExtMove& ms : MoveList(pos)) { if (Root && depth <= ONE_PLY) cnt = 1, nodes++; else { - pos.do_move(*it, st, ci, pos.gives_check(*it, ci)); + pos.do_move(ms.move, st, ci, pos.gives_check(ms.move, ci)); cnt = leaf ? MoveList(pos).size() : perft(pos, depth - ONE_PLY); nodes += cnt; - pos.undo_move(*it); + pos.undo_move(ms.move); } if (Root) - sync_cout << UCI::move(*it, pos.is_chess960()) << ": " << cnt << sync_endl; + sync_cout << UCI::move(ms.move, pos.is_chess960()) << ": " << cnt << sync_endl; } return nodes; } @@ -252,8 +238,8 @@ void Search::think() { } } - for (size_t i = 0; i < Threads.size(); ++i) - Threads[i]->maxPly = 0; + for (Thread* th : Threads) + th->maxPly = 0; Threads.timer->run = true; Threads.timer->notify_one(); // Wake up the recurring timer @@ -309,11 +295,14 @@ namespace { Followupmoves.clear(); size_t multiPV = Options["MultiPV"]; - Skill skill(Options["Skill Level"], RootMoves.size()); + Skill skill(Options["Skill Level"]); + + // When playing with strength handicap enable MultiPV search that we will + // use behind the scenes to retrieve a set of possible moves. + if (skill.enabled()) + multiPV = std::max(multiPV, (size_t)4); - // 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. - multiPV = std::max(multiPV, skill.candidates_size()); + multiPV = std::min(multiPV, RootMoves.size()); // Iterative deepening loop until requested to stop or target depth reached while (++depth < DEPTH_MAX && !Signals.stop && (!Limits.depth || depth <= Limits.depth)) @@ -323,11 +312,11 @@ namespace { // 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. - for (size_t i = 0; i < RootMoves.size(); ++i) - RootMoves[i].previousScore = RootMoves[i].score; + for (RootMove& rm : RootMoves) + rm.previousScore = rm.score; // MultiPV loop. We perform a full root search for each PV line - for (PVIdx = 0; PVIdx < std::min(multiPV, RootMoves.size()) && !Signals.stop; ++PVIdx) + for (PVIdx = 0; PVIdx < multiPV && !Signals.stop; ++PVIdx) { // Reset aspiration window starting size if (depth >= 5 * ONE_PLY) @@ -400,14 +389,13 @@ namespace { sync_cout << "info nodes " << RootPos.nodes_searched() << " time " << Time::now() - SearchTime << sync_endl; - else if ( PVIdx + 1 == std::min(multiPV, RootMoves.size()) - || Time::now() - SearchTime > 3000) + else if (PVIdx + 1 == multiPV || Time::now() - SearchTime > 3000) sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl; } - // If skill levels are enabled and time is up, pick a sub-optimal best move - if (skill.candidates_size() && skill.time_to_pick(depth)) - skill.pick_move(); + // If skill level is enabled and time is up, pick a sub-optimal best move + if (skill.enabled() && skill.time_to_pick(depth)) + skill.pick_best(multiPV); // Have we found a "mate in x"? if ( Limits.mate @@ -436,6 +424,11 @@ namespace { } } } + + // If skill level is enabled, swap best PV line with the sub-optimal one + if (skill.enabled()) + std::swap(RootMoves[0], *std::find(RootMoves.begin(), + RootMoves.end(), skill.best_move(multiPV))); } @@ -477,7 +470,7 @@ namespace { splitPoint = ss->splitPoint; bestMove = splitPoint->bestMove; bestValue = splitPoint->bestValue; - tte = NULL; + tte = nullptr; ttHit = false; ttMove = excludedMove = MOVE_NONE; ttValue = VALUE_NONE; @@ -540,7 +533,7 @@ namespace { // 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); + update_stats(pos, ss, ttMove, depth, nullptr, 0); return ttValue; } @@ -789,7 +782,7 @@ moves_loop: // When in check and at SpNode search starts from here } if (PvNode) - (ss+1)->pv = NULL; + (ss+1)->pv = nullptr; extension = DEPTH_ZERO; captureOrPromotion = pos.capture_or_promotion(move); @@ -1352,6 +1345,7 @@ moves_loop: // When in check and at SpNode search starts from here // played quiet moves. Value bonus = Value((depth / ONE_PLY) * (depth / ONE_PLY)); History.update(pos.moved_piece(move), to_sq(move), bonus); + for (int i = 0; i < quietsCnt; ++i) { Move m = quiets[i]; @@ -1372,24 +1366,23 @@ moves_loop: // When in check and at SpNode search starts from here } - // When playing with a strength handicap, choose best move among the first 'candidates' - // RootMoves using a statistical rule dependent on 'level'. Idea by Heinz van Saanen. + // When playing with strength handicap, choose best move among a set of RootMoves + // using a statistical rule dependent on 'level'. Idea by Heinz van Saanen. - Move Skill::pick_move() { + Move Skill::pick_best(size_t multiPV) { // PRNG sequence should be non-deterministic, so we seed it with the time at init static PRNG rng(Time::now()); // RootMoves are already sorted by score in descending order - int variance = std::min(RootMoves[0].score - RootMoves[candidates - 1].score, PawnValueMg); + int variance = std::min(RootMoves[0].score - RootMoves[multiPV - 1].score, PawnValueMg); int weakness = 120 - 2 * level; int maxScore = -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, + // weakness. One deterministic and bigger for weaker levels, and one random, // then we choose the move with the resulting highest score. - for (size_t i = 0; i < candidates; ++i) + for (size_t i = 0; i < multiPV; ++i) { int score = RootMoves[i].score; @@ -1418,9 +1411,9 @@ moves_loop: // When in check and at SpNode search starts from here size_t uciPVSize = std::min((size_t)Options["MultiPV"], RootMoves.size()); int selDepth = 0; - for (size_t i = 0; i < Threads.size(); ++i) - if (Threads[i]->maxPly > selDepth) - selDepth = Threads[i]->maxPly; + for (Thread* th : Threads) + if (th->maxPly > selDepth) + selDepth = th->maxPly; for (size_t i = 0; i < uciPVSize; ++i) { @@ -1518,7 +1511,7 @@ void Thread::idle_loop() { // Pointer 'this_sp' is not null only if we are called from split(), and not // at the thread creation. This means we are the split point's master. - SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : NULL; + SplitPoint* this_sp = splitPointsSize ? activeSplitPoint : nullptr; assert(!this_sp || (this_sp->masterThread == this && searching)); @@ -1542,7 +1535,7 @@ void Thread::idle_loop() { sp->mutex.lock(); - assert(activePosition == NULL); + assert(activePosition == nullptr); activePosition = &pos; @@ -1561,7 +1554,7 @@ void Thread::idle_loop() { assert(searching); searching = false; - activePosition = NULL; + activePosition = nullptr; sp->slavesMask.reset(idx); sp->allSlavesSearching = false; sp->nodes += pos.nodes_searched(); @@ -1586,7 +1579,7 @@ void Thread::idle_loop() { for (size_t i = 0; i < Threads.size(); ++i) { const int size = Threads[i]->splitPointsSize; // Local copy - sp = size ? &Threads[i]->splitPoints[size - 1] : NULL; + sp = size ? &Threads[i]->splitPoints[size - 1] : nullptr; if ( sp && sp->allSlavesSearching @@ -1613,22 +1606,19 @@ void Thread::idle_loop() { } // Grab the lock to avoid races with Thread::notify_one() - mutex.lock(); + std::unique_lock lk(mutex); // If we are master and all slaves have finished then exit idle_loop if (this_sp && this_sp->slavesMask.none()) { assert(!searching); - mutex.unlock(); break; } // If we are not searching, wait for a condition to be signaled instead of // wasting CPU time polling for work. if (!searching && !exit) - sleepCondition.wait(mutex); - - mutex.unlock(); + sleepCondition.wait(lk); } } @@ -1673,10 +1663,10 @@ void check_time() { // Loop across all split points and sum accumulated SplitPoint nodes plus // all the currently active positions nodes. - for (size_t i = 0; i < Threads.size(); ++i) - for (int j = 0; j < Threads[i]->splitPointsSize; ++j) + for (Thread* th : Threads) + for (int i = 0; i < th->splitPointsSize; ++i) { - SplitPoint& sp = Threads[i]->splitPoints[j]; + SplitPoint& sp = th->splitPoints[i]; sp.mutex.lock();