X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=61475a2f3f3be641fc19b2222d5665cc85d1f214;hp=695d4ae540ee432412de71c7791b564c0b717459;hb=cd4604b05c2d61928b26ab50c5864c36ef1d3785;hpb=5c20f59788c30cdfc5b1d16dae125ab394c5145c diff --git a/src/search.cpp b/src/search.cpp index 695d4ae5..61475a2f 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -28,6 +28,7 @@ #include #include +#include "bitcount.h" #include "book.h" #include "evaluate.h" #include "history.h" @@ -195,6 +196,16 @@ namespace { /// Variables initialized by UCI options + // Adjustable playing strength + int Slowdown = 0; + const int SlowdownArray[32] = { + 19, 41, 70, 110, 160, 230, 320, 430, 570, 756, 1000, 1300, 1690, 2197, + 2834, 3600, 4573, 5809, 7700, 9863, 12633, 16181, 20726, 26584, 34005, + 43557, 55792, 71463, 91536, 117247, 150180, 192363 + }; + int Strength; + const int MaxStrength = 25; + // Minimum number of full depth (i.e. non-reduced) moves at PV and non-PV nodes int LMRPVMoves, LMRNonPVMoves; // heavy SMP read access for the latter @@ -281,7 +292,7 @@ namespace { Value qsearch(Position& pos, SearchStack ss[], Value alpha, Value beta, Depth depth, int ply, int threadID); void sp_search(SplitPoint* sp, int threadID); void sp_search_pv(SplitPoint* sp, int threadID); - void init_node(SearchStack ss[], int ply, int threadID); + void init_node(const Position& pos, SearchStack ss[], int ply, int threadID); void update_pv(SearchStack ss[], int ply); void sp_update_pv(SearchStack* pss, SearchStack ss[], int ply); bool connected_moves(const Position& pos, Move m1, Move m2); @@ -294,6 +305,7 @@ namespace { bool ok_to_history(const Position& pos, Move m); void update_history(const Position& pos, Move m, Depth depth, Move movesSearched[], int moveCount); void update_killers(Move m, SearchStack& ss); + void slowdown(const Position& pos); bool fail_high_ply_1(); int current_search_time(); @@ -414,7 +426,10 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, read_weights(pos.side_to_move()); - int newActiveThreads = get_option_value_int("Threads"); + // Set the number of active threads. If UCI_LimitStrength is enabled, never + // use more than one thread. + int newActiveThreads = + get_option_value_bool("UCI_LimitStrength")? 1 : get_option_value_int("Threads"); if (newActiveThreads != ActiveThreads) { ActiveThreads = newActiveThreads; @@ -427,6 +442,19 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, for (int i = 1; i < ActiveThreads; i++) assert(thread_is_available(i, 0)); + // Set playing strength + if (get_option_value_bool("UCI_LimitStrength")) + { + Strength = (get_option_value_int("UCI_Elo") - 2100) / 25; + Slowdown = + (Strength == MaxStrength)? 0 : SlowdownArray[Max(0, 31-Strength)]; + } + else + { + Strength = MaxStrength; + Slowdown = 0; + } + // Set thinking time int myTime = time[side_to_move]; int myIncrement = increment[side_to_move]; @@ -471,10 +499,16 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move, NodesBetweenPolls = Min(MaxNodes, 30000); InfiniteSearch = true; // HACK } + else if (Slowdown) { + if (Slowdown > 50000) NodesBetweenPolls = 30; + else if (Slowdown > 10000) NodesBetweenPolls = 100; + else if (Slowdown > 1000) NodesBetweenPolls = 500; + else if (Slowdown > 100) NodesBetweenPolls = 3000; + else NodesBetweenPolls = 15000; + } else NodesBetweenPolls = 30000; - // Write information to search log file if (UseLogFile) LogFile << "Searching: " << pos.to_fen() << std::endl @@ -858,8 +892,9 @@ namespace { << " currmovenumber " << i + 1 << std::endl; // Decide search depth for this move + bool moveIsCapture = pos.move_is_capture(move); bool dangerous; - ext = extension(pos, move, true, pos.move_is_capture(move), pos.move_is_check(move), false, false, &dangerous); + ext = extension(pos, move, true, moveIsCapture, pos.move_is_check(move), false, false, &dangerous); newDepth = (Iteration - 2) * OnePly + ext + InitialDepth; // Make the move, and search it @@ -883,15 +918,30 @@ namespace { } else { - value = -search(pos, ss, -alpha, newDepth, 1, true, 0); + if ( newDepth >= 3*OnePly + && i >= MultiPV + LMRPVMoves - 2 // Remove -2 and decrease LMRPVMoves instead ? + && !dangerous + && !moveIsCapture + && !move_is_promotion(move) + && !move_is_castle(move)) + { + ss[0].reduction = OnePly; + value = -search(pos, ss, -alpha, newDepth-OnePly, 1, true, 0); + } else + value = alpha + 1; // Just to trigger next condition + if (value > alpha) { - // Fail high! Set the boolean variable FailHigh to true, and - // re-search the move with a big window. The variable FailHigh is - // used for time managment: We try to avoid aborting the search - // prematurely during a fail high research. - FailHigh = true; - value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); + value = -search(pos, ss, -alpha, newDepth, 1, true, 0); + if (value > alpha) + { + // Fail high! Set the boolean variable FailHigh to true, and + // re-search the move with a big window. The variable FailHigh is + // used for time managment: We try to avoid aborting the search + // prematurely during a fail high research. + FailHigh = true; + value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); + } } } @@ -925,6 +975,7 @@ namespace { // Update PV rml.set_move_score(i, value); update_pv(ss, 0); + TT.extract_pv(pos, ss[0].pv); rml.set_move_pv(i, ss[0].pv); if (MultiPV == 1) @@ -938,6 +989,8 @@ namespace { // Print search information to the standard output std::cout << "info depth " << Iteration << " score " << value_to_string(value) + << ((value >= beta)? + " lowerbound" : ((value <= alpha)? " upperbound" : "")) << " time " << current_search_time() << " nodes " << nodes_searched() << " nps " << nps() @@ -1006,7 +1059,7 @@ namespace { // Initialize, and make an early exit in case of an aborted search, // an instant draw, maximum ply reached, etc. - init_node(ss, ply, threadID); + init_node(pos, ss, ply, threadID); // After init_node() that calls poll() if (AbortSearch || thread_should_stop(threadID)) @@ -1073,6 +1126,7 @@ namespace { // Make and search the move StateInfo st; pos.do_move(move, st, dcCandidates); + TT.prefetch(pos.get_key()); if (moveCount == 1) // The first move in list is the PV value = -search_pv(pos, ss, -beta, -alpha, newDepth, ply+1, threadID); @@ -1080,7 +1134,7 @@ namespace { { // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. - if ( depth >= 2*OnePly + if ( depth >= 3*OnePly && moveCount >= LMRPVMoves && !dangerous && !moveIsCapture @@ -1196,7 +1250,7 @@ namespace { // Initialize, and make an early exit in case of an aborted search, // an instant draw, maximum ply reached, etc. - init_node(ss, ply, threadID); + init_node(pos, ss, ply, threadID); // After init_node() that calls poll() if (AbortSearch || thread_should_stop(threadID)) @@ -1243,17 +1297,15 @@ namespace { StateInfo st; pos.do_null_move(st); + TT.prefetch(pos.get_key()); + int R = (depth >= 5 * OnePly ? 4 : 3); // Null move dynamic reduction Value nullValue = -search(pos, ss, -(beta-1), depth-R*OnePly, ply+1, false, threadID); pos.undo_null_move(); - if (value_is_mate(nullValue)) - { - /* Do not return unproven mates */ - } - else if (nullValue >= beta) + if (nullValue >= beta) { if (depth < 6 * OnePly) return beta; @@ -1361,10 +1413,11 @@ namespace { // Make and search the move StateInfo st; pos.do_move(move, st, dcCandidates); + TT.prefetch(pos.get_key()); // Try to reduce non-pv search depth by one ply if move seems not problematic, // if the move fails high will be re-searched at full depth. - if ( depth >= 2*OnePly + if ( depth >= 3*OnePly && moveCount >= LMRNonPVMoves && !dangerous && !moveIsCapture @@ -1456,7 +1509,7 @@ namespace { // Initialize, and make an early exit in case of an aborted search, // an instant draw, maximum ply reached, etc. - init_node(ss, ply, threadID); + init_node(pos, ss, ply, threadID); // After init_node() that calls poll() if (AbortSearch || thread_should_stop(threadID)) @@ -1492,7 +1545,6 @@ namespace { else if (tte && tte->type() == VALUE_TYPE_EVAL) { // Use the cached evaluation score if possible - assert(tte->value() == evaluate(pos, ei, threadID)); assert(ei.futilityMargin == Value(0)); staticValue = tte->value(); @@ -1571,6 +1623,7 @@ namespace { // Make and search the move. StateInfo st; pos.do_move(move, st, dcCandidates); + TT.prefetch(pos.get_key()); Value value = -qsearch(pos, ss, -beta, -alpha, depth-OnePly, ply+1, threadID); pos.undo_move(move); @@ -2044,11 +2097,14 @@ namespace { // NodesBetweenPolls nodes, init_node() also calls poll(), which polls // for user input and checks whether it is time to stop the search. - void init_node(SearchStack ss[], int ply, int threadID) { + void init_node(const Position& pos, SearchStack ss[], int ply, int threadID) { assert(ply >= 0 && ply < PLY_MAX); assert(threadID >= 0 && threadID < ActiveThreads); + if (Slowdown && Iteration >= 3) + slowdown(pos); + Threads[threadID].nodes++; if (threadID == 0) @@ -2203,16 +2259,19 @@ namespace { assert(m != MOVE_NONE); Depth result = Depth(0); - *dangerous = check || singleReply || mateThreat; + *dangerous = check | singleReply | mateThreat; - if (check) - result += CheckExtension[pvNode]; + if (*dangerous) + { + if (check) + result += CheckExtension[pvNode]; - if (singleReply) - result += SingleReplyExtension[pvNode]; + if (singleReply) + result += SingleReplyExtension[pvNode]; - if (mateThreat) - result += MateThreatExtension[pvNode]; + if (mateThreat) + result += MateThreatExtension[pvNode]; + } if (pos.type_of_piece_on(move_from(m)) == PAWN) { @@ -2378,6 +2437,21 @@ namespace { ss.killers[0] = m; } + + // slowdown() simply wastes CPU cycles doing nothing useful. It's used + // in strength handicap mode. + + void slowdown(const Position &pos) { + int i, n; + n = Slowdown; + for (i = 0; i < n; i++) { + Square s = Square(i&63); + if (count_1s(pos.attacks_to(s)) > 63) + std::cout << "This can't happen, but I put this string here anyway, in order to prevent the compiler from optimizing away the useless computation." << std::endl; + } + } + + // fail_high_ply_1() checks if some thread is currently resolving a fail // high at ply 1 at the node below the first root node. This information // is used for time managment.