X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;ds=sidebyside;f=src%2Fsearch.cpp;h=9d4c6d248c1bac2e39b763d6fce611563f974d92;hb=439aea9ab79373f4520d157ef5feac6cff0ded56;hp=5bf653050df5c2185095c96564df5e581b8c4e22;hpb=b5a4edd86f1a64a6308ea3eaa05d944a7ef817bb;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index 5bf65305..9d4c6d24 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -53,26 +53,6 @@ namespace { /// Types - // IterationInfoType stores search results for each iteration - // - // Because we use relatively small (dynamic) aspiration window, - // there happens many fail highs and fail lows in root. And - // because we don't do researches in those cases, "value" stored - // here is not necessarily exact. Instead in case of fail high/low - // we guess what the right value might be and store our guess - // as a "speculated value" and then move on. Speculated values are - // used just to calculate aspiration window width, so also if are - // not exact is not big a problem. - - struct IterationInfoType { - - IterationInfoType(Value v = Value(0), Value sv = Value(0)) - : value(v), speculatedValue(sv) {} - - Value value, speculatedValue; - }; - - // The BetaCounterType class is used to order moves at ply one. // Apart for the first one that has its score, following moves // normally have score -VALUE_INFINITE, so are ordered according @@ -213,7 +193,7 @@ namespace { BetaCounterType BetaCounter; // Scores and number of times the best move changed for each iteration - IterationInfoType IterationInfo[PLY_MAX_PLUS_2]; + Value ValueByIteration[PLY_MAX_PLUS_2]; int BestMoveChangesByIteration[PLY_MAX_PLUS_2]; // Search window management @@ -716,7 +696,7 @@ namespace { TT.new_search(); H.clear(); init_ss_array(ss); - IterationInfo[1] = IterationInfoType(rml.get_move_score(0), rml.get_move_score(0)); + ValueByIteration[1] = rml.get_move_score(0); Iteration = 1; // Is one move significantly better than others after initial scoring ? @@ -740,16 +720,16 @@ namespace { // Calculate dynamic search window based on previous iterations Value alpha, beta; - if (MultiPV == 1 && Iteration >= 6 && abs(IterationInfo[Iteration - 1].value) < VALUE_KNOWN_WIN) + if (MultiPV == 1 && Iteration >= 6 && abs(ValueByIteration[Iteration - 1]) < VALUE_KNOWN_WIN) { - int prevDelta1 = IterationInfo[Iteration - 1].speculatedValue - IterationInfo[Iteration - 2].speculatedValue; - int prevDelta2 = IterationInfo[Iteration - 2].speculatedValue - IterationInfo[Iteration - 3].speculatedValue; + int prevDelta1 = ValueByIteration[Iteration - 1] - ValueByIteration[Iteration - 2]; + int prevDelta2 = ValueByIteration[Iteration - 2] - ValueByIteration[Iteration - 3]; AspirationDelta = Max(abs(prevDelta1) + abs(prevDelta2) / 2, 16); AspirationDelta = (AspirationDelta + 7) / 8 * 8; // Round to match grainSize - alpha = Max(IterationInfo[Iteration - 1].value - AspirationDelta, -VALUE_INFINITE); - beta = Min(IterationInfo[Iteration - 1].value + AspirationDelta, VALUE_INFINITE); + alpha = Max(ValueByIteration[Iteration - 1] - AspirationDelta, -VALUE_INFINITE); + beta = Min(ValueByIteration[Iteration - 1] + AspirationDelta, VALUE_INFINITE); } else { @@ -768,32 +748,7 @@ namespace { break; // Value cannot be trusted. Break out immediately! //Save info about search result - Value speculatedValue; - bool fHigh = false; - bool fLow = false; - Value delta = value - IterationInfo[Iteration - 1].value; - - if (value >= beta) - { - assert(delta > 0); - - fHigh = true; - speculatedValue = value + delta; - BestMoveChangesByIteration[Iteration] += 2; // Allocate more time - } - else if (value <= alpha) - { - assert(value == alpha); - assert(delta < 0); - - fLow = true; - speculatedValue = value + delta; - BestMoveChangesByIteration[Iteration] += 3; // Allocate more time - } else - speculatedValue = value; - - speculatedValue = Min(Max(speculatedValue, -VALUE_INFINITE), VALUE_INFINITE); - IterationInfo[Iteration] = IterationInfoType(value, speculatedValue); + ValueByIteration[Iteration] = value; // Drop the easy move if it differs from the new best move if (ss[0].pv[0] != EasyMove) @@ -813,15 +768,13 @@ namespace { // Stop search early when the last two iterations returned a mate score if ( Iteration >= 6 - && abs(IterationInfo[Iteration].value) >= abs(VALUE_MATE) - 100 - && abs(IterationInfo[Iteration-1].value) >= abs(VALUE_MATE) - 100) + && abs(ValueByIteration[Iteration]) >= abs(VALUE_MATE) - 100 + && abs(ValueByIteration[Iteration-1]) >= abs(VALUE_MATE) - 100) stopSearch = true; // Stop search early if one move seems to be much better than the rest int64_t nodes = nodes_searched(); if ( Iteration >= 8 - && !fLow - && !fHigh && EasyMove == ss[0].pv[0] && ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100 && current_search_time() > MaxSearchTime / 16) @@ -922,187 +875,120 @@ namespace { while (1) // Fail low loop { - // Loop through all the moves in the root move list - for (int i = 0; i < rml.move_count() && !AbortSearch; i++) - { - if (alpha >= beta) + // Loop through all the moves in the root move list + for (int i = 0; i < rml.move_count() && !AbortSearch; i++) { - // We failed high, invalidate and skip next moves, leave node-counters - // and beta-counters as they are and quickly return, we will try to do - // a research at the next iteration with a bigger aspiration window. - rml.set_move_score(i, -VALUE_INFINITE); - continue; - } + if (alpha >= beta) + { + // We failed high, invalidate and skip next moves, leave node-counters + // and beta-counters as they are and quickly return, we will try to do + // a research at the next iteration with a bigger aspiration window. + rml.set_move_score(i, -VALUE_INFINITE); + continue; + } - RootMoveNumber = i + 1; - FailHigh = false; + RootMoveNumber = i + 1; + FailHigh = false; - // Save the current node count before the move is searched - nodes = nodes_searched(); + // Save the current node count before the move is searched + nodes = nodes_searched(); - // Reset beta cut-off counters - BetaCounter.clear(); + // Reset beta cut-off counters + BetaCounter.clear(); - // Pick the next root move, and print the move and the move number to - // the standard output. - move = ss[0].currentMove = rml.get_move(i); + // Pick the next root move, and print the move and the move number to + // the standard output. + move = ss[0].currentMove = rml.get_move(i); - if (current_search_time() >= 1000) - cout << "info currmove " << move - << " currmovenumber " << RootMoveNumber << endl; + if (current_search_time() >= 1000) + cout << "info currmove " << move + << " currmovenumber " << RootMoveNumber << endl; - // Decide search depth for this move - moveIsCheck = pos.move_is_check(move); - captureOrPromotion = pos.move_is_capture_or_promotion(move); - depth = (Iteration - 2) * OnePly + InitialDepth; - ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous); - newDepth = depth + ext; + // Decide search depth for this move + moveIsCheck = pos.move_is_check(move); + captureOrPromotion = pos.move_is_capture_or_promotion(move); + depth = (Iteration - 2) * OnePly + InitialDepth; + ext = extension(pos, move, true, captureOrPromotion, moveIsCheck, false, false, &dangerous); + newDepth = depth + ext; - value = - VALUE_INFINITE; + value = - VALUE_INFINITE; - // Precalculate reduction parameters - float LogLimit, Gradient, BaseReduction = 0.5; - reduction_parameters(BaseReduction, 6.0, depth, LogLimit, Gradient); + // Precalculate reduction parameters + float LogLimit, Gradient, BaseReduction = 0.5; + reduction_parameters(BaseReduction, 6.0, depth, LogLimit, Gradient); - while (1) // Fail high loop - { + while (1) // Fail high loop + { - // Make the move, and search it - pos.do_move(move, st, ci, moveIsCheck); + // Make the move, and search it + pos.do_move(move, st, ci, moveIsCheck); - if (i < MultiPV || value > alpha) - { - // Aspiration window is disabled in multi-pv case - if (MultiPV > 1) - alpha = -VALUE_INFINITE; + if (i < MultiPV || value > alpha) + { + // Aspiration window is disabled in multi-pv case + if (MultiPV > 1) + alpha = -VALUE_INFINITE; - value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); + value = -search_pv(pos, ss, -beta, -alpha, newDepth, 1, 0); - // If the value has dropped a lot compared to the last iteration, - // set the boolean variable Problem to true. This variable is used - // for time managment: When Problem is true, we try to complete the - // current iteration before playing a move. - Problem = ( Iteration >= 2 - && value <= IterationInfo[Iteration - 1].value - ProblemMargin); + // If the value has dropped a lot compared to the last iteration, + // set the boolean variable Problem to true. This variable is used + // for time managment: When Problem is true, we try to complete the + // current iteration before playing a move. + Problem = ( Iteration >= 2 + && value <= ValueByIteration[Iteration - 1] - ProblemMargin); - if (Problem && StopOnPonderhit) - StopOnPonderhit = false; - } - else - { - // 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. - bool doFullDepthSearch = true; - - if ( depth >= 3*OnePly // FIXME was newDepth - && !dangerous - && !captureOrPromotion - && !move_is_castle(move)) - { - ss[0].reduction = reduction(RootMoveNumber - MultiPV + 1, LogLimit, BaseReduction, Gradient); - if (ss[0].reduction) - { - value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0); - doFullDepthSearch = (value > alpha); + if (Problem && StopOnPonderhit) + StopOnPonderhit = false; } - } - - if (doFullDepthSearch) - { - ss[0].reduction = Depth(0); - value = -search(pos, ss, -alpha, newDepth, 1, true, 0); - - if (value > alpha) + else { - // Fail high! Set the boolean variable FailHigh to true, and - // re-search the move using a PV search. 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); + // 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. + bool doFullDepthSearch = true; + + if ( depth >= 3*OnePly // FIXME was newDepth + && !dangerous + && !captureOrPromotion + && !move_is_castle(move)) + { + ss[0].reduction = reduction(RootMoveNumber - MultiPV + 1, LogLimit, BaseReduction, Gradient); + if (ss[0].reduction) + { + value = -search(pos, ss, -alpha, newDepth-ss[0].reduction, 1, true, 0); + doFullDepthSearch = (value > alpha); + } + } + + if (doFullDepthSearch) + { + ss[0].reduction = Depth(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 using a PV search. 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); + } + } } - } - } - - pos.undo_move(move); - - // Can we exit fail high loop ? - if (AbortSearch || value < beta) - break; - // We are failing high and going to do a research. It's important to update score - // before research in case we run out of time while researching. - rml.set_move_score(i, value); - update_pv(ss, 0); - TT.extract_pv(pos, ss[0].pv, PLY_MAX); - rml.set_move_pv(i, ss[0].pv); - - // Print search information to the standard output - cout << "info depth " << Iteration - << " score " << value_to_string(value) - << ((value >= beta) ? " lowerbound" : - ((value <= alpha)? " upperbound" : "")) - << " time " << current_search_time() - << " nodes " << nodes_searched() - << " nps " << nps() - << " pv "; - - for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++) - cout << ss[0].pv[j] << " "; + pos.undo_move(move); - cout << endl; - - if (UseLogFile) - { - ValueType type = (value >= beta ? VALUE_TYPE_LOWER - : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT)); - - LogFile << pretty_pv(pos, current_search_time(), Iteration, - nodes_searched(), value, type, ss[0].pv) << endl; - } - - // Prepare for a research after a fail high, each time with a wider window - researchCount++; - beta = Min(beta + AspirationDelta * (1 << researchCount), VALUE_INFINITE); - - } // End of fail high loop - - // Finished searching the move. If AbortSearch is true, the search - // was aborted because the user interrupted the search or because we - // ran out of time. In this case, the return value of the search cannot - // be trusted, and we break out of the loop without updating the best - // move and/or PV. - if (AbortSearch) - break; - - // Remember beta-cutoff and searched nodes counts for this move. The - // info is used to sort the root moves at the next iteration. - int64_t our, their; - BetaCounter.read(pos.side_to_move(), our, their); - rml.set_beta_counters(i, our, their); - rml.set_move_nodes(i, nodes_searched() - nodes); - - assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE); - - if (value <= alpha && i >= MultiPV) - rml.set_move_score(i, -VALUE_INFINITE); - else - { - // PV move or new best move! - - // Update PV - rml.set_move_score(i, value); - update_pv(ss, 0); - TT.extract_pv(pos, ss[0].pv, PLY_MAX); - rml.set_move_pv(i, ss[0].pv); + // Can we exit fail high loop ? + if (AbortSearch || value < beta) + break; - if (MultiPV == 1) - { - // We record how often the best move has been changed in each - // iteration. This information is used for time managment: When - // the best move changes frequently, we allocate some more time. - if (i > 0) - BestMoveChangesByIteration[Iteration]++; + // We are failing high and going to do a research. It's important to update score + // before research in case we run out of time while researching. + rml.set_move_score(i, value); + update_pv(ss, 0); + TT.extract_pv(pos, ss[0].pv, PLY_MAX); + rml.set_move_pv(i, ss[0].pv); // Print search information to the standard output cout << "info depth " << Iteration @@ -1127,49 +1013,116 @@ namespace { LogFile << pretty_pv(pos, current_search_time(), Iteration, nodes_searched(), value, type, ss[0].pv) << endl; } - if (value > alpha) - alpha = value; - // Reset the global variable Problem to false if the value isn't too - // far below the final value from the last iteration. - if (value > IterationInfo[Iteration - 1].value - NoProblemMargin) - Problem = false; - } - else // MultiPV > 1 + // Prepare for a research after a fail high, each time with a wider window + researchCount++; + beta = Min(beta + AspirationDelta * (1 << researchCount), VALUE_INFINITE); + + } // End of fail high loop + + // Finished searching the move. If AbortSearch is true, the search + // was aborted because the user interrupted the search or because we + // ran out of time. In this case, the return value of the search cannot + // be trusted, and we break out of the loop without updating the best + // move and/or PV. + if (AbortSearch) + break; + + // Remember beta-cutoff and searched nodes counts for this move. The + // info is used to sort the root moves at the next iteration. + int64_t our, their; + BetaCounter.read(pos.side_to_move(), our, their); + rml.set_beta_counters(i, our, their); + rml.set_move_nodes(i, nodes_searched() - nodes); + + assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE); + + if (value <= alpha && i >= MultiPV) + rml.set_move_score(i, -VALUE_INFINITE); + else { - rml.sort_multipv(i); - for (int j = 0; j < Min(MultiPV, rml.move_count()); j++) + // PV move or new best move! + + // Update PV + rml.set_move_score(i, value); + update_pv(ss, 0); + TT.extract_pv(pos, ss[0].pv, PLY_MAX); + rml.set_move_pv(i, ss[0].pv); + + if (MultiPV == 1) { - cout << "info multipv " << j + 1 - << " score " << value_to_string(rml.get_move_score(j)) - << " depth " << ((j <= i)? Iteration : Iteration - 1) - << " time " << current_search_time() + // We record how often the best move has been changed in each + // iteration. This information is used for time managment: When + // the best move changes frequently, we allocate some more time. + if (i > 0) + BestMoveChangesByIteration[Iteration]++; + + // Print search information to the standard output + cout << "info depth " << Iteration + << " score " << value_to_string(value) + << ((value >= beta) ? " lowerbound" : + ((value <= alpha)? " upperbound" : "")) + << " time " << current_search_time() << " nodes " << nodes_searched() - << " nps " << nps() + << " nps " << nps() << " pv "; - for (int k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++) - cout << rml.get_move_pv(j, k) << " "; + for (int j = 0; ss[0].pv[j] != MOVE_NONE && j < PLY_MAX; j++) + cout << ss[0].pv[j] << " "; cout << endl; + + if (UseLogFile) + { + ValueType type = (value >= beta ? VALUE_TYPE_LOWER + : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT)); + + LogFile << pretty_pv(pos, current_search_time(), Iteration, + nodes_searched(), value, type, ss[0].pv) << endl; + } + if (value > alpha) + alpha = value; + + // Reset the global variable Problem to false if the value isn't too + // far below the final value from the last iteration. + if (value > ValueByIteration[Iteration - 1] - NoProblemMargin) + Problem = false; } - alpha = rml.get_move_score(Min(i, MultiPV-1)); - } - } // PV move or new best move + else // MultiPV > 1 + { + rml.sort_multipv(i); + for (int j = 0; j < Min(MultiPV, rml.move_count()); j++) + { + cout << "info multipv " << j + 1 + << " score " << value_to_string(rml.get_move_score(j)) + << " depth " << ((j <= i)? Iteration : Iteration - 1) + << " time " << current_search_time() + << " nodes " << nodes_searched() + << " nps " << nps() + << " pv "; + + for (int k = 0; rml.get_move_pv(j, k) != MOVE_NONE && k < PLY_MAX; k++) + cout << rml.get_move_pv(j, k) << " "; + + cout << endl; + } + alpha = rml.get_move_score(Min(i, MultiPV-1)); + } + } // PV move or new best move - assert(alpha >= oldAlpha); + assert(alpha >= oldAlpha); - FailLow = (alpha == oldAlpha); - } + FailLow = (alpha == oldAlpha); + } - // Can we exit fail low loop ? - if (AbortSearch || alpha > oldAlpha) - break; + // Can we exit fail low loop ? + if (AbortSearch || alpha > oldAlpha) + break; - // Prepare for a research after a fail low, each time with a wider window - researchCount++; - alpha = Max(alpha - AspirationDelta * (1 << researchCount), -VALUE_INFINITE); - oldAlpha = alpha; + // Prepare for a research after a fail low, each time with a wider window + researchCount++; + alpha = Max(alpha - AspirationDelta * (1 << researchCount), -VALUE_INFINITE); + oldAlpha = alpha; } // Fail low loop @@ -1366,7 +1319,7 @@ namespace { // (from the computer's point of view) since the previous iteration. if ( ply == 1 && Iteration >= 2 - && -value <= IterationInfo[Iteration-1].value - ProblemMargin) + && -value <= ValueByIteration[Iteration-1] - ProblemMargin) Problem = true; } @@ -1654,7 +1607,7 @@ namespace { if (predictedDepth >= OnePly) preFutilityValueMargin = FutilityMargins[int(predictedDepth)]; - preFutilityValueMargin += H.gain(pos.piece_on(move_from(move)), move_from(move), move_to(move)) + 45; + preFutilityValueMargin += H.gain(pos.piece_on(move_from(move)), move_to(move)) + 45; futilityValueScaled = ss[ply].eval + preFutilityValueMargin - moveCount * IncrementalFutilityMargin; @@ -2224,7 +2177,7 @@ namespace { // (from the computer's point of view) since the previous iteration. if ( sp->ply == 1 && Iteration >= 2 - && -value <= IterationInfo[Iteration-1].value - ProblemMargin) + && -value <= ValueByIteration[Iteration-1] - ProblemMargin) Problem = true; } lock_release(&(sp->lock)); @@ -2751,7 +2704,7 @@ namespace { && pos.captured_piece() == NO_PIECE_TYPE && !move_is_castle(m) && !move_is_promotion(m)) - H.set_gain(pos.piece_on(move_to(m)), move_from(m), move_to(m), -(before + after)); + H.set_gain(pos.piece_on(move_to(m)), move_to(m), -(before + after)); }