X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=7cf4a8a3b583054b651d17b7c422564e859a7296;hp=711680818a2ba4cbb61c7ee3a8d25338a34af07f;hb=158864270a055fe20dca4a87f4b7a8aa9cedfeb9;hpb=7caa6cd3383cf90189a1947c9bdf9c6fea1172a6 diff --git a/src/search.cpp b/src/search.cpp index 71168081..7cf4a8a3 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -27,33 +27,36 @@ #include "evaluate.h" #include "movegen.h" #include "movepick.h" -#include "rkiss.h" +#include "misc.h" #include "search.h" #include "timeman.h" #include "thread.h" #include "tt.h" #include "uci.h" - -#ifdef SYZYGY #include "syzygy/tbprobe.h" -#endif namespace Search { volatile SignalsType Signals; LimitsType Limits; - std::vector RootMoves; + RootMoveVector RootMoves; Position RootPos; Time::point SearchTime; StateStackPtr SetupStates; - int TBCardinality; - uint64_t TBHits; +} + +namespace Tablebases { + + int Cardinality; + uint64_t Hits; bool RootInTB; - bool TB50MoveRule; - Depth TBProbeDepth; - Value TBScore; + bool UseRule50; + Depth ProbeDepth; + Value Score; } +namespace TB = Tablebases; + using std::string; using Eval::evaluate; using namespace Search; @@ -112,7 +115,7 @@ namespace { } size_t candidates_size() const { return candidates; } - bool time_to_pick(Depth depth) const { return depth == 1 + level; } + bool time_to_pick(Depth depth) const { return depth / ONE_PLY == 1 + level; } Move pick_move(); int level; @@ -191,12 +194,23 @@ template uint64_t Search::perft(Position& pos, Depth depth); void Search::think() { TimeMgr.init(Limits, RootPos.game_ply(), RootPos.side_to_move()); - TBHits = TBCardinality = 0; - RootInTB = false; - 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); + int contempt = Options["Contempt"] * PawnValueEg / 100; // From centipawns + DrawValue[ RootPos.side_to_move()] = VALUE_DRAW - Value(contempt); + DrawValue[~RootPos.side_to_move()] = VALUE_DRAW + Value(contempt); + + TB::Hits = 0; + TB::RootInTB = false; + TB::UseRule50 = Options["Syzygy50MoveRule"]; + TB::ProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY; + TB::Cardinality = Options["SyzygyProbeLimit"]; + + // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality + if (TB::Cardinality > TB::MaxCardinality) + { + TB::Cardinality = TB::MaxCardinality; + TB::ProbeDepth = DEPTH_ZERO; + } if (RootMoves.empty()) { @@ -207,59 +221,36 @@ void Search::think() { } else { -#ifdef SYZYGY - // Check Tablebases at root - int piecesCnt = RootPos.total_piece_count(); - TBCardinality = Options["SyzygyProbeLimit"]; - TBProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY; - if (TBCardinality > Tablebases::TBLargest) + if (TB::Cardinality >= RootPos.count(WHITE) + + RootPos.count(BLACK)) { - TBCardinality = Tablebases::TBLargest; - TBProbeDepth = 0 * ONE_PLY; - } - TB50MoveRule = Options["Syzygy50MoveRule"]; - - if (piecesCnt <= TBCardinality) - { - TBHits = RootMoves.size(); - // If the current root position is in the tablebases then RootMoves // contains only moves that preserve the draw or win. - RootInTB = Tablebases::root_probe(RootPos, TBScore); + TB::RootInTB = Tablebases::root_probe(RootPos, RootMoves, TB::Score); - if (RootInTB) - { - TBCardinality = 0; // Do not probe tablebases during the search + if (TB::RootInTB) + TB::Cardinality = 0; // Do not probe tablebases during the search - // It might be a good idea to mangle the hash key (xor it - // with a fixed value) in order to "clear" the hash table of - // the results of previous probes. However, that would have to - // be done from within the Position class, so we skip it for now. - - // Optional: decrease target time. - } else // If DTZ tables are missing, use WDL tables as a fallback { // Filter out moves that do not preserve a draw or win - RootInTB = Tablebases::root_probe_wdl(RootPos, TBScore); + TB::RootInTB = Tablebases::root_probe_wdl(RootPos, RootMoves, TB::Score); // Only probe during search if winning - if (TBScore <= VALUE_DRAW) - TBCardinality = 0; + if (TB::Score <= VALUE_DRAW) + TB::Cardinality = 0; } - if (!RootInTB) - { - TBHits = 0; - } - else if (!TB50MoveRule) + if (TB::RootInTB) { - TBScore = TBScore > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 - : TBScore < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1 - : TBScore; + TB::Hits = RootMoves.size(); + + if (!TB::UseRule50) + TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 + : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1 + : VALUE_DRAW; } } -#endif for (size_t i = 0; i < Threads.size(); ++i) Threads[i]->maxPly = 0; @@ -333,7 +324,7 @@ 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].prevScore = RootMoves[i].score; + RootMoves[i].previousScore = RootMoves[i].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) @@ -342,8 +333,8 @@ namespace { if (depth >= 5 * ONE_PLY) { delta = Value(16); - alpha = std::max(RootMoves[PVIdx].prevScore - delta,-VALUE_INFINITE); - beta = std::min(RootMoves[PVIdx].prevScore + delta, VALUE_INFINITE); + alpha = std::max(RootMoves[PVIdx].previousScore - delta,-VALUE_INFINITE); + beta = std::min(RootMoves[PVIdx].previousScore + delta, VALUE_INFINITE); } // Start with a small aspiration window and, in the case of a fail @@ -470,7 +461,7 @@ namespace { SplitPoint* splitPoint; Key posKey; Move ttMove, move, excludedMove, bestMove; - Depth ext, newDepth, predictedDepth; + Depth extension, newDepth, predictedDepth; Value bestValue, value, ttValue, eval, nullValue, futilityValue; bool inCheck, givesCheck, singularExtensionNode, improving; bool captureOrPromotion, dangerous, doFullDepthSearch; @@ -552,38 +543,35 @@ namespace { return ttValue; } -#ifdef SYZYGY // Step 4a. Tablebase probe - if ( !RootNode - && pos.total_piece_count() <= TBCardinality - && ( pos.total_piece_count() < TBCardinality || depth >= TBProbeDepth ) - && pos.rule50_count() == 0) + if (!RootNode && TB::Cardinality) { - int found, v = Tablebases::probe_wdl(pos, &found); + int piecesCnt = pos.count(WHITE) + pos.count(BLACK); - if (found) + if ( piecesCnt <= TB::Cardinality + && (piecesCnt < TB::Cardinality || depth >= TB::ProbeDepth) + && pos.rule50_count() == 0) { - TBHits++; + int found, v = Tablebases::probe_wdl(pos, &found); - if (TB50MoveRule) { - value = v < -1 ? -VALUE_MATE + MAX_PLY + ss->ply - : v > 1 ? VALUE_MATE - MAX_PLY - ss->ply - : VALUE_DRAW + 2 * v; - } - else + if (found) { - value = v < 0 ? -VALUE_MATE + MAX_PLY + ss->ply - : v > 0 ? VALUE_MATE - MAX_PLY - ss->ply - : VALUE_DRAW; - } + TB::Hits++; - TT.store(posKey, value_to_tt(value, ss->ply), BOUND_EXACT, - std::min(DEPTH_MAX - ONE_PLY, depth + 6 * ONE_PLY), MOVE_NONE, VALUE_NONE); + int drawScore = TB::UseRule50 ? 1 : 0; - return value; + value = v < -drawScore ? -VALUE_MATE + MAX_PLY + ss->ply + : v > drawScore ? VALUE_MATE - MAX_PLY - ss->ply + : VALUE_DRAW + 2 * v * drawScore; + + TT.store(posKey, value_to_tt(value, ss->ply), BOUND_EXACT, + std::min(DEPTH_MAX - ONE_PLY, depth + 6 * ONE_PLY), + MOVE_NONE, VALUE_NONE); + + return value; + } } } -#endif // Step 5. Evaluate the position statically and update parent's gain statistics if (inCheck) @@ -660,7 +648,7 @@ namespace { assert(eval - beta >= 0); // Null move dynamic reduction based on depth and value - Depth R = (3 + depth / 4 + std::min(int(eval - beta) / PawnValueMg, 3)) * ONE_PLY; + Depth R = (3 + depth / 4 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; pos.do_null_move(st); (ss+1)->skipNullMove = true; @@ -793,7 +781,7 @@ moves_loop: // When in check and at SpNode search starts from here Signals.firstRootMove = (moveCount == 1); if (thisThread == Threads.main() && Time::now() - SearchTime > 3000) - sync_cout << "info depth " << depth + sync_cout << "info depth " << depth / ONE_PLY << " currmove " << UCI::format_move(move, pos.is_chess960()) << " currmovenumber " << moveCount + PVIdx << sync_endl; } @@ -801,7 +789,7 @@ moves_loop: // When in check and at SpNode search starts from here if (PvNode) (ss+1)->pv = NULL; - ext = DEPTH_ZERO; + extension = DEPTH_ZERO; captureOrPromotion = pos.capture_or_promotion(move); givesCheck = type_of(move) == NORMAL && !ci.dcCandidates @@ -814,7 +802,7 @@ moves_loop: // When in check and at SpNode search starts from here // Step 12. Extend checks if (givesCheck && pos.see_sign(move) >= VALUE_ZERO) - ext = ONE_PLY; + extension = ONE_PLY; // Singular extension search. If all moves but one fail low on a search of // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move @@ -823,10 +811,10 @@ moves_loop: // When in check and at SpNode search starts from here // ttValue minus a margin then we extend the ttMove. if ( singularExtensionNode && move == ttMove - && !ext + && !extension && pos.legal(move, ci.pinned)) { - Value rBeta = ttValue - int(2 * depth); + Value rBeta = ttValue - 2 * depth / ONE_PLY; ss->excludedMove = move; ss->skipNullMove = true; value = search(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode); @@ -834,11 +822,11 @@ moves_loop: // When in check and at SpNode search starts from here ss->excludedMove = MOVE_NONE; if (value < rBeta) - ext = ONE_PLY; + extension = ONE_PLY; } // Update the current move (this must be done after singular extension search) - newDepth = depth - ONE_PLY + ext; + newDepth = depth - ONE_PLY + extension; // Step 13. Pruning at shallow depth (exclude PV nodes) if ( !PvNode @@ -1362,7 +1350,7 @@ moves_loop: // When in check and at SpNode search starts from here // Increase history value of the cut-off move and decrease all the other // played quiet moves. - Value bonus = Value(int(depth) * int(depth)); + 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) { @@ -1389,16 +1377,13 @@ moves_loop: // When in check and at SpNode search starts from here Move Skill::pick_move() { - static RKISS rk; - - // PRNG sequence should be not deterministic - for (int i = Time::now() % 50; i > 0; --i) - rk.rand(); + // 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 weakness = 120 - 2 * level; - int max_s = -VALUE_INFINITE; + int maxScore = -VALUE_INFINITE; best = MOVE_NONE; // Choose best move. For each move score we add two terms both dependent on @@ -1406,19 +1391,19 @@ moves_loop: // When in check and at SpNode search starts from here // then we choose the move with the resulting highest score. for (size_t i = 0; i < candidates; ++i) { - int s = RootMoves[i].score; + int score = 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 > score + 2 * PawnValueMg) break; // This is our magic formula - s += ( weakness * int(RootMoves[0].score - s) - + variance * (rk.rand() % weakness)) / 128; + score += ( weakness * int(RootMoves[0].score - score) + + variance * (rng.rand() % weakness)) / 128; - if (s > max_s) + if (score > maxScore) { - max_s = s; + maxScore = score; best = RootMoves[i].pv[0]; } } @@ -1445,20 +1430,14 @@ moves_loop: // When in check and at SpNode search starts from here { bool updated = (i <= PVIdx); - if (depth == 1 && !updated) + if (depth == ONE_PLY && !updated) continue; Depth d = updated ? depth : depth - ONE_PLY; - Value v = updated ? RootMoves[i].score : RootMoves[i].prevScore; + Value v = updated ? RootMoves[i].score : RootMoves[i].previousScore; - bool tb = RootInTB; - if (tb) - { - if (abs(v) >= VALUE_MATE - MAX_PLY) - tb = false; - else - v = TBScore; - } + bool tb = TB::RootInTB && abs(v) < VALUE_MATE - MAX_PLY; + v = tb ? TB::Score : v; if (ss.rdbuf()->in_avail()) // Not at first line ss << "\n"; @@ -1469,7 +1448,7 @@ moves_loop: // When in check and at SpNode search starts from here << " score " << ((!tb && i == PVIdx) ? UCI::format_value(v, alpha, beta) : UCI::format_value(v)) << " nodes " << pos.nodes_searched() << " nps " << pos.nodes_searched() * 1000 / elapsed - << " tbhits " << TBHits + << " tbhits " << TB::Hits << " time " << elapsed << " pv";