X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=6215b083dd22dc3bc2e408d8fbe09c3a076e0bd0;hp=06546f99d038d7942162de2a2bf3d60eeeab3d9a;hb=7ed15af371be19a4d261df87fa33df0a94fdc930;hpb=40f5abba104b411ec5234e2c93b05bba8e6bd3c8 diff --git a/src/search.cpp b/src/search.cpp index 06546f99..6215b083 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -19,17 +19,16 @@ #include #include -#include #include #include #include #include -#include "book.h" #include "evaluate.h" #include "movegen.h" #include "movepick.h" #include "notation.h" +#include "rkiss.h" #include "search.h" #include "timeman.h" #include "thread.h" @@ -52,9 +51,6 @@ using namespace Search; namespace { - // Set to true to force running with one thread. Used for debugging - const bool FakeSplit = false; - // Different node types, used as template parameter enum NodeType { Root, PV, NonPV }; @@ -76,7 +72,7 @@ namespace { return (Depth) Reductions[PvNode][i][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)]; } - size_t MultiPV, PVIdx; + size_t PVIdx; TimeManager TimeMgr; double BestMoveChanges; Value DrawValue[COLOR_NB]; @@ -97,18 +93,21 @@ namespace { string uci_pv(const Position& pos, int depth, Value alpha, Value beta); struct Skill { - Skill(int l) : level(l), best(MOVE_NONE) {} + Skill(int l, size_t rootSize) : level(l), + candidates(l < 20 ? std::min(4, (int)rootSize) : 0), + best(MOVE_NONE) {} ~Skill() { - if (enabled()) // Swap best PV line with the sub-optimal one + 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())); } - bool enabled() const { return level < 20; } + size_t candidates_size() const { return candidates; } bool time_to_pick(int depth) const { return depth == 1 + level; } Move pick_move(); int level; + size_t candidates; Move best; }; @@ -152,26 +151,33 @@ void Search::init() { /// Search::perft() is our utility to verify move generation. All the leaf nodes /// up to the given depth are generated and counted and the sum returned. - -static uint64_t perft(Position& pos, Depth depth) { +template +uint64_t Search::perft(Position& pos, Depth depth) { StateInfo st; - uint64_t cnt = 0; + uint64_t cnt, nodes = 0; CheckInfo ci(pos); const bool leaf = depth == 2 * ONE_PLY; for (MoveList it(pos); *it; ++it) { - pos.do_move(*it, st, ci, pos.gives_check(*it, ci)); - cnt += leaf ? MoveList(pos).size() : ::perft(pos, depth - ONE_PLY); - pos.undo_move(*it); + if (Root && depth <= ONE_PLY) + cnt = 1, nodes++; + else + { + pos.do_move(*it, st, ci, pos.gives_check(*it, ci)); + cnt = leaf ? MoveList(pos).size() : perft(pos, depth - ONE_PLY); + nodes += cnt; + pos.undo_move(*it); + } + if (Root) + sync_cout << move_to_uci(*it, pos.is_chess960()) << ": " << cnt << sync_endl; } - return cnt; + return nodes; } -uint64_t Search::perft(Position& pos, Depth depth) { - return depth > ONE_PLY ? ::perft(pos, depth) : MoveList(pos).size(); -} +template uint64_t Search::perft(Position& pos, Depth depth); + /// Search::think() is the external interface to Stockfish's search, and is /// called by the main thread when the program receives the UCI 'go' command. It @@ -179,11 +185,9 @@ uint64_t Search::perft(Position& pos, Depth depth) { void Search::think() { - static PolyglotBook book; // Defined static to initialize the PRNG only once - TimeMgr.init(Limits, RootPos.game_ply(), RootPos.side_to_move()); - int cf = Options["Contempt Factor"] * PawnValueEg / 100; // From centipawns + int cf = Options["Contempt"] * PawnValueEg / 100; // From centipawns DrawValue[ RootPos.side_to_move()] = VALUE_DRAW - Value(cf); DrawValue[~RootPos.side_to_move()] = VALUE_DRAW + Value(cf); @@ -197,29 +201,6 @@ void Search::think() { goto finalize; } - if (Options["OwnBook"] && !Limits.infinite && !Limits.mate) - { - Move bookMove = book.probe(RootPos, Options["Book File"], Options["Best Book Move"]); - - if (bookMove && std::count(RootMoves.begin(), RootMoves.end(), bookMove)) - { - std::swap(RootMoves[0], *std::find(RootMoves.begin(), RootMoves.end(), bookMove)); - goto finalize; - } - } - - if (Options["Write Search Log"]) - { - Log log(Options["Search Log Filename"]); - log << "\nSearching: " << RootPos.fen() - << "\ninfinite: " << Limits.infinite - << " ponder: " << Limits.ponder - << " time: " << Limits.time[RootPos.side_to_move()] - << " increment: " << Limits.inc[RootPos.side_to_move()] - << " moves to go: " << Limits.movestogo - << "\n" << std::endl; - } - // Reset the threads, still sleeping: will wake up at split time for (size_t i = 0; i < Threads.size(); ++i) Threads[i]->maxPly = 0; @@ -231,21 +212,6 @@ void Search::think() { Threads.timer->run = false; // Stop the timer - if (Options["Write Search Log"]) - { - Time::point elapsed = Time::now() - SearchTime + 1; - - Log log(Options["Search Log Filename"]); - log << "Nodes: " << RootPos.nodes_searched() - << "\nNodes/second: " << RootPos.nodes_searched() * 1000 / elapsed - << "\nBest move: " << move_to_san(RootPos, RootMoves[0].pv[0]); - - StateInfo st; - RootPos.do_move(RootMoves[0].pv[0], st); - log << "\nPonder move: " << move_to_san(RootPos, RootMoves[0].pv[1]) << std::endl; - RootPos.undo_move(RootMoves[0].pv[0]); - } - finalize: // When search is stopped this info is not printed @@ -283,7 +249,6 @@ namespace { Value bestValue, alpha, beta, delta; std::memset(ss-2, 0, 5 * sizeof(Stack)); - (ss-1)->currentMove = MOVE_NULL; // Hack to skip update gains depth = 0; BestMoveChanges = 0; @@ -296,15 +261,12 @@ namespace { Countermoves.clear(); Followupmoves.clear(); - MultiPV = Options["MultiPV"]; - Skill skill(Options["Skill Level"]); + size_t multiPV = Options["MultiPV"]; + Skill skill(Options["Skill Level"], RootMoves.size()); // 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. - if (skill.enabled() && MultiPV < 4) - MultiPV = 4; - - MultiPV = std::min(MultiPV, RootMoves.size()); + multiPV = std::max(multiPV, skill.candidates_size()); // Iterative deepening loop until requested to stop or target depth reached while (++depth <= MAX_PLY && !Signals.stop && (!Limits.depth || depth <= Limits.depth)) @@ -318,7 +280,7 @@ namespace { RootMoves[i].prevScore = RootMoves[i].score; // MultiPV loop. We perform a full root search for each PV line - for (PVIdx = 0; PVIdx < MultiPV && !Signals.stop; ++PVIdx) + for (PVIdx = 0; PVIdx < std::min(multiPV, RootMoves.size()) && !Signals.stop; ++PVIdx) { // Reset aspiration window starting size if (depth >= 5) @@ -375,7 +337,7 @@ namespace { else break; - delta += delta / 2; + delta += 3 * delta / 8; assert(alpha >= -VALUE_INFINITE && beta <= VALUE_INFINITE); } @@ -383,25 +345,14 @@ namespace { // Sort the PV lines searched so far and update the GUI std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1); - if (PVIdx + 1 == MultiPV || Time::now() - SearchTime > 3000) + if (PVIdx + 1 == std::min(multiPV, RootMoves.size()) || 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.enabled() && skill.time_to_pick(depth)) + if (skill.candidates_size() && skill.time_to_pick(depth)) skill.pick_move(); - if (Options["Write Search Log"]) - { - RootMove& rm = RootMoves[0]; - if (skill.best != MOVE_NONE) - rm = *std::find(RootMoves.begin(), RootMoves.end(), skill.best); - - Log log(Options["Search Log Filename"]); - log << pretty_pv(pos, depth, rm.score, Time::now() - SearchTime, &rm.pv[0]) - << std::endl; - } - // Have we found a "mate in x"? if ( Limits.mate && bestValue >= VALUE_MATE_IN_MAX_PLY @@ -412,7 +363,7 @@ namespace { if (Limits.use_time_management() && !Signals.stop && !Signals.stopOnPonderhit) { // Take some extra time if the best move has changed - if (depth > 4 && depth < 50 && MultiPV == 1) + if (depth > 4 && multiPV == 1) TimeMgr.pv_instability(BestMoveChanges); // Stop the search if only one legal move is available or all @@ -558,7 +509,9 @@ namespace { } else { - eval = ss->staticEval = evaluate(pos); + eval = ss->staticEval = + (ss-1)->currentMove != MOVE_NULL ? evaluate(pos) : -(ss-1)->staticEval + 2 * Eval::Tempo; + TT.store(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, ss->staticEval); } @@ -566,6 +519,7 @@ namespace { && ss->staticEval != VALUE_NONE && (ss-1)->staticEval != VALUE_NONE && (move = (ss-1)->currentMove) != MOVE_NULL + && move != MOVE_NONE && type_of(move) == NORMAL) { Square to = to_sq(move); @@ -577,7 +531,6 @@ namespace { && depth < 4 * ONE_PLY && eval + razor_margin(depth) <= alpha && ttMove == MOVE_NONE - && abs(beta) < VALUE_MATE_IN_MAX_PLY && !pos.pawn_on_7th(pos.side_to_move())) { if ( depth <= ONE_PLY @@ -605,7 +558,6 @@ namespace { && !ss->skipNullMove && depth >= 2 * ONE_PLY && eval >= beta - && abs(beta) < VALUE_MATE_IN_MAX_PLY && pos.non_pawn_material(pos.side_to_move())) { ss->currentMove = MOVE_NULL; @@ -615,7 +567,7 @@ namespace { // Null move dynamic reduction based on depth and value Depth R = 3 * ONE_PLY + depth / 4 - + int(eval - beta) / PawnValueMg * ONE_PLY; + + std::min(int(eval - beta) / PawnValueMg, 3) * ONE_PLY; pos.do_null_move(st); (ss+1)->skipNullMove = true; @@ -630,7 +582,7 @@ namespace { if (nullValue >= VALUE_MATE_IN_MAX_PLY) nullValue = beta; - if (depth < 12 * ONE_PLY) + if (depth < 12 * ONE_PLY && abs(beta) < VALUE_KNOWN_WIN) return nullValue; // Do verification search at high depths @@ -710,7 +662,10 @@ moves_loop: // When in check and at SpNode search starts from here singularExtensionNode = !RootNode && !SpNode && depth >= 8 * ONE_PLY + && abs(beta) < VALUE_KNOWN_WIN && ttMove != MOVE_NONE + /* && ttValue != VALUE_NONE Already implicit in the next condition */ + && abs(ttValue) < VALUE_KNOWN_WIN && !excludedMove // Recursive singular search is not allowed && (tte->bound() & BOUND_LOWER) && tte->depth() >= depth - 3 * ONE_PLY; @@ -775,11 +730,8 @@ moves_loop: // When in check and at SpNode search starts from here if ( singularExtensionNode && move == ttMove && !ext - && pos.legal(move, ci.pinned) - && abs(ttValue) < VALUE_KNOWN_WIN) + && pos.legal(move, ci.pinned)) { - assert(ttValue != VALUE_NONE); - Value rBeta = ttValue - int(depth); ss->excludedMove = move; ss->skipNullMove = true; @@ -870,15 +822,20 @@ moves_loop: // When in check and at SpNode search starts from here { ss->reduction = reduction(improving, depth, moveCount); - if (!PvNode && cutNode) + if ( (!PvNode && cutNode) + || History[pos.piece_on(to_sq(move))][to_sq(move)] < 0) ss->reduction += ONE_PLY; - else if (History[pos.piece_on(to_sq(move))][to_sq(move)] < 0) - ss->reduction += ONE_PLY / 2; - if (move == countermoves[0] || move == countermoves[1]) ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY); + // Decrease reduction for moves that escape a capture + if ( ss->reduction + && type_of(move) == NORMAL + && type_of(pos.piece_on(to_sq(move))) != PAWN + && pos.see(make_move(to_sq(move), from_sq(move))) < 0) + ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY); + Depth d = std::max(newDepth - ss->reduction, ONE_PLY); if (SpNode) alpha = splitPoint->alpha; @@ -992,8 +949,8 @@ moves_loop: // When in check and at SpNode search starts from here { assert(bestValue > -VALUE_INFINITE && bestValue < beta); - thisThread->split(pos, ss, alpha, beta, &bestValue, &bestMove, - depth, moveCount, &mp, NT, cutNode); + thisThread->split(pos, ss, alpha, beta, &bestValue, &bestMove, + depth, moveCount, &mp, NT, cutNode); if (Signals.stop || thisThread->cutoff_occurred()) return VALUE_ZERO; @@ -1114,7 +1071,8 @@ moves_loop: // When in check and at SpNode search starts from here bestValue = ttValue; } else - ss->staticEval = bestValue = evaluate(pos); + ss->staticEval = bestValue = + (ss-1)->currentMove != MOVE_NULL ? evaluate(pos) : -(ss-1)->staticEval + 2 * Eval::Tempo; // Stand pat. Return immediately if static value is at least beta if (bestValue >= beta) @@ -1299,8 +1257,8 @@ moves_loop: // When in check and at SpNode search starts from here } - // When playing with a strength handicap, choose best move among the MultiPV - // set using a statistical rule dependent on 'level'. Idea by Heinz van Saanen. + // 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. Move Skill::pick_move() { @@ -1311,7 +1269,7 @@ moves_loop: // When in check and at SpNode search starts from here rk.rand(); // RootMoves are already sorted by score in descending order - int variance = std::min(RootMoves[0].score - RootMoves[MultiPV - 1].score, PawnValueMg); + int variance = std::min(RootMoves[0].score - RootMoves[candidates - 1].score, PawnValueMg); int weakness = 120 - 2 * level; int max_s = -VALUE_INFINITE; best = MOVE_NONE; @@ -1319,12 +1277,12 @@ moves_loop: // When in check and at SpNode search starts from here // 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, // then we choose the move with the resulting highest score. - for (size_t i = 0; i < MultiPV; ++i) + for (size_t i = 0; i < candidates; ++i) { int s = RootMoves[i].score; // Don't allow crazy blunders even at very low skills - if (i > 0 && RootMoves[i-1].score > s + 2 * PawnValueMg) + if (i > 0 && RootMoves[i - 1].score > s + 2 * PawnValueMg) break; // This is our magic formula @@ -1461,46 +1419,13 @@ void Thread::idle_loop() { assert(!this_sp || (this_sp->masterThread == this && searching)); - while (true) + while (!exit) { - // If we are not searching, wait for a condition to be signaled instead of - // wasting CPU time polling for work. - while (!searching || exit) - { - if (exit) - { - assert(!this_sp); - return; - } - - // Grab the lock to avoid races with Thread::notify_one() - mutex.lock(); - - // If we are master and all slaves have finished then exit idle_loop - if (this_sp && this_sp->slavesMask.none()) - { - mutex.unlock(); - break; - } - - // Do sleep after retesting sleep conditions under lock protection. In - // particular we need to avoid a deadlock in case a master thread has, - // in the meanwhile, allocated us and sent the notify_one() call before - // we had the chance to grab the lock. - if (!searching && !exit) - sleepCondition.wait(mutex); - - mutex.unlock(); - } - // If this thread has been assigned work, launch a search - if (searching) + while (searching) { - assert(!exit); - Threads.mutex.lock(); - assert(searching); assert(activeSplitPoint); SplitPoint* sp = activeSplitPoint; @@ -1557,7 +1482,7 @@ void Thread::idle_loop() { if (Threads.size() > 2) for (size_t i = 0; i < Threads.size(); ++i) { - int size = Threads[i]->splitPointsSize; // Local copy + const int size = Threads[i]->splitPointsSize; // Local copy sp = size ? &Threads[i]->splitPoints[size - 1] : NULL; if ( sp @@ -1584,16 +1509,23 @@ void Thread::idle_loop() { } } - // If this thread is the master of a split point and all slaves have finished - // their work at this split point, return from the idle loop. + // Grab the lock to avoid races with Thread::notify_one() + mutex.lock(); + + // If we are master and all slaves have finished then exit idle_loop if (this_sp && this_sp->slavesMask.none()) { - this_sp->mutex.lock(); - bool finished = this_sp->slavesMask.none(); // Retest under lock protection - this_sp->mutex.unlock(); - if (finished) - return; + 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(); } }