X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=43a3175bfe83e309b219f116c8bcc3aded3a0d1b;hp=5c22e512b233d5af808538993d01fce556fdafab;hb=9369f4963d9376820cb5ca4bad66b86e67b0a010;hpb=c30eb4c9c9f875a8302056ddd9612003bc21c023 diff --git a/src/search.cpp b/src/search.cpp index 5c22e512..43a3175b 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -20,14 +20,14 @@ #include #include #include -#include +#include // For std::memset #include #include #include "evaluate.h" +#include "misc.h" #include "movegen.h" #include "movepick.h" -#include "rkiss.h" #include "search.h" #include "timeman.h" #include "thread.h" @@ -39,18 +39,24 @@ 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; @@ -167,13 +173,13 @@ uint64_t Search::perft(Position& pos, Depth depth) { cnt = 1, nodes++; else { - pos.do_move(*it, st, ci, pos.gives_check(*it, ci)); + pos.do_move(*it, st, 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 << UCI::format_move(*it, pos.is_chess960()) << ": " << cnt << sync_endl; + sync_cout << UCI::move(*it, pos.is_chess960()) << ": " << cnt << sync_endl; } return nodes; } @@ -187,62 +193,62 @@ template uint64_t Search::perft(Position& pos, Depth depth); void Search::think() { - TimeMgr.init(Limits, RootPos.game_ply(), RootPos.side_to_move()); + TimeMgr.init(Limits, RootPos.side_to_move(), RootPos.game_ply()); - 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); - TBHits = 0; - RootInTB = false; - TBProbeDepth = Options["SyzygyProbeDepth"] * ONE_PLY; - TB50MoveRule = Options["Syzygy50MoveRule"]; - TBCardinality = Options["SyzygyProbeLimit"]; + 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 -> !TBCardinality - if (TBCardinality > Tablebases::TBLargest) + // Skip TB probing when no TB found: !TBLargest -> !TB::Cardinality + if (TB::Cardinality > TB::MaxCardinality) { - TBCardinality = Tablebases::TBLargest; - TBProbeDepth = DEPTH_ZERO; + TB::Cardinality = TB::MaxCardinality; + TB::ProbeDepth = DEPTH_ZERO; } if (RootMoves.empty()) { RootMoves.push_back(MOVE_NONE); sync_cout << "info depth 0 score " - << UCI::format_value(RootPos.checkers() ? -VALUE_MATE : VALUE_DRAW) + << UCI::value(RootPos.checkers() ? -VALUE_MATE : VALUE_DRAW) << sync_endl; } else { - if (TBCardinality >= RootPos.count(WHITE) - + RootPos.count(BLACK)) + if (TB::Cardinality >= RootPos.count(WHITE) + + RootPos.count(BLACK)) { // 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 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) + if (TB::RootInTB) { - TBHits = RootMoves.size(); + TB::Hits = RootMoves.size(); - if (!TB50MoveRule) - TBScore = TBScore > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 - : TBScore < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1 - : VALUE_DRAW; + 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; } } @@ -268,10 +274,10 @@ void Search::think() { RootPos.this_thread()->wait_for(Signals.stop); } - sync_cout << "bestmove " << UCI::format_move(RootMoves[0].pv[0], RootPos.is_chess960()); + sync_cout << "bestmove " << UCI::move(RootMoves[0].pv[0], RootPos.is_chess960()); - if (RootMoves[0].pv.size() > 1) - std::cout << " ponder " << UCI::format_move(RootMoves[0].pv[1], RootPos.is_chess960()); + if (RootMoves[0].pv.size() > 1 || RootMoves[0].extract_ponder_from_tt(RootPos)) + std::cout << " ponder " << UCI::move(RootMoves[0].pv[1], RootPos.is_chess960()); std::cout << sync_endl; } @@ -318,7 +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) @@ -327,8 +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 @@ -359,7 +365,8 @@ namespace { // When failing high/low give some update (without cluttering // the UI) before a re-search. - if ( (bestValue <= alpha || bestValue >= beta) + if ( multiPV == 1 + && (bestValue <= alpha || bestValue >= beta) && Time::now() - SearchTime > 3000) sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl; @@ -451,13 +458,13 @@ namespace { Move pv[MAX_PLY+1], quietsSearched[64]; StateInfo st; - const TTEntry *tte; + TTEntry* tte; 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 ttHit, inCheck, givesCheck, singularExtensionNode, improving; bool captureOrPromotion, dangerous, doFullDepthSearch; int moveCount, quietCount; @@ -471,6 +478,7 @@ namespace { bestMove = splitPoint->bestMove; bestValue = splitPoint->bestValue; tte = NULL; + ttHit = false; ttMove = excludedMove = MOVE_NONE; ttValue = VALUE_NONE; @@ -508,7 +516,7 @@ namespace { assert(0 <= ss->ply && ss->ply < MAX_PLY); ss->currentMove = ss->ttMove = (ss+1)->excludedMove = bestMove = MOVE_NONE; - (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO; + (ss+1)->skipEarlyPruning = false; (ss+1)->reduction = DEPTH_ZERO; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; // Step 4. Transposition table lookup @@ -516,13 +524,13 @@ namespace { // TT value, so we use a different position key in case of an excluded move. excludedMove = ss->excludedMove; posKey = excludedMove ? pos.exclusion_key() : pos.key(); - tte = TT.probe(posKey); - ss->ttMove = ttMove = RootNode ? RootMoves[PVIdx].pv[0] : tte ? tte->move() : MOVE_NONE; - ttValue = tte ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE; + tte = TT.probe(posKey, ttHit); + ss->ttMove = ttMove = RootNode ? RootMoves[PVIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE; + ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE; // At non-PV nodes we check for a fail high/low. We don't probe at PV nodes if ( !PvNode - && tte + && ttHit && tte->depth() >= depth && ttValue != VALUE_NONE // Only in case of TT access race && (ttValue >= beta ? (tte->bound() & BOUND_LOWER) @@ -538,34 +546,29 @@ namespace { } // Step 4a. Tablebase probe - if (!RootNode && TBCardinality) + if (!RootNode && TB::Cardinality) { int piecesCnt = pos.count(WHITE) + pos.count(BLACK); - if ( piecesCnt <= TBCardinality - && (piecesCnt < TBCardinality || depth >= TBProbeDepth) + if ( piecesCnt <= TB::Cardinality + && (piecesCnt < TB::Cardinality || depth >= TB::ProbeDepth) && pos.rule50_count() == 0) { int found, v = Tablebases::probe_wdl(pos, &found); if (found) { - TBHits++; + TB::Hits++; - if (TB50MoveRule) { - value = v < -1 ? -VALUE_MATE + MAX_PLY + ss->ply - : v > 1 ? VALUE_MATE - MAX_PLY - ss->ply - : VALUE_DRAW + 2 * v; - } - else - { - value = v < 0 ? -VALUE_MATE + MAX_PLY + ss->ply - : v > 0 ? VALUE_MATE - MAX_PLY - ss->ply - : VALUE_DRAW; - } + int drawScore = TB::UseRule50 ? 1 : 0; + + 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); + tte->save(posKey, value_to_tt(value, ss->ply), BOUND_EXACT, + std::min(DEPTH_MAX - ONE_PLY, depth + 6 * ONE_PLY), + MOVE_NONE, VALUE_NONE, TT.generation()); return value; } @@ -579,10 +582,10 @@ namespace { goto moves_loop; } - else if (tte) + else if (ttHit) { // Never assume anything on values stored in TT - if ((ss->staticEval = eval = tte->eval_value()) == VALUE_NONE) + if ((ss->staticEval = eval = tte->eval()) == VALUE_NONE) eval = ss->staticEval = evaluate(pos); // Can ttValue be used as a better position evaluation? @@ -595,9 +598,12 @@ namespace { 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); + tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, ss->staticEval, TT.generation()); } + if (ss->skipEarlyPruning) + goto moves_loop; + if ( !pos.captured_piece_type() && ss->staticEval != VALUE_NONE && (ss-1)->staticEval != VALUE_NONE @@ -627,8 +633,7 @@ namespace { } // Step 7. Futility pruning: child node (skipped when in check) - if ( !PvNode - && !ss->skipNullMove + if ( !RootNode && depth < 7 * ONE_PLY && eval - futility_margin(depth) >= beta && eval < VALUE_KNOWN_WIN // Do not return unproven wins @@ -637,7 +642,6 @@ namespace { // Step 8. Null move search with verification search (is omitted in PV nodes) if ( !PvNode - && !ss->skipNullMove && depth >= 2 * ONE_PLY && eval >= beta && pos.non_pawn_material(pos.side_to_move())) @@ -647,13 +651,13 @@ namespace { assert(eval - beta >= 0); // Null move dynamic reduction based on depth and value - Depth R = (3 + depth / 4 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; + Depth R = ((823 + 67 * depth) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; pos.do_null_move(st); - (ss+1)->skipNullMove = true; + (ss+1)->skipEarlyPruning = true; nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1, DEPTH_ZERO) : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode); - (ss+1)->skipNullMove = false; + (ss+1)->skipEarlyPruning = false; pos.undo_null_move(); if (nullValue >= beta) @@ -666,10 +670,10 @@ namespace { return nullValue; // Do verification search at high depths - ss->skipNullMove = true; + ss->skipEarlyPruning = true; Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta, DEPTH_ZERO) : search(pos, ss, beta-1, beta, depth-R, false); - ss->skipNullMove = false; + ss->skipEarlyPruning = false; if (v >= beta) return nullValue; @@ -682,7 +686,6 @@ namespace { // prune the previous move. if ( !PvNode && depth >= 5 * ONE_PLY - && !ss->skipNullMove && abs(beta) < VALUE_MATE_IN_MAX_PLY) { Value rbeta = std::min(beta + 200, VALUE_INFINITE); @@ -699,7 +702,7 @@ namespace { if (pos.legal(move, ci.pinned)) { ss->currentMove = move; - pos.do_move(move, st, ci, pos.gives_check(move, ci)); + pos.do_move(move, st, pos.gives_check(move, ci)); value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode); pos.undo_move(move); if (value >= rbeta) @@ -713,12 +716,12 @@ namespace { && (PvNode || ss->staticEval + 256 >= beta)) { Depth d = 2 * (depth - 2 * ONE_PLY) - (PvNode ? DEPTH_ZERO : depth / 2); - ss->skipNullMove = true; + ss->skipEarlyPruning = true; search(pos, ss, alpha, beta, d / 2, true); - ss->skipNullMove = false; + ss->skipEarlyPruning = false; - tte = TT.probe(posKey); - ttMove = tte ? tte->move() : MOVE_NONE; + tte = TT.probe(posKey, ttHit); + ttMove = ttHit ? tte->move() : MOVE_NONE; } moves_loop: // When in check and at SpNode search starts from here @@ -781,14 +784,14 @@ moves_loop: // When in check and at SpNode search starts from here if (thisThread == Threads.main() && Time::now() - SearchTime > 3000) sync_cout << "info depth " << depth / ONE_PLY - << " currmove " << UCI::format_move(move, pos.is_chess960()) + << " currmove " << UCI::move(move, pos.is_chess960()) << " currmovenumber " << moveCount + PVIdx << sync_endl; } 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 @@ -801,7 +804,7 @@ 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 @@ -810,25 +813,25 @@ 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 - 2 * depth / ONE_PLY; ss->excludedMove = move; - ss->skipNullMove = true; + ss->skipEarlyPruning = true; value = search(pos, ss, rBeta - 1, rBeta, depth / 2, cutNode); - ss->skipNullMove = false; + ss->skipEarlyPruning = false; 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 + // Step 13. Pruning at shallow depth + if ( !RootNode && !captureOrPromotion && !inCheck && !dangerous @@ -891,7 +894,7 @@ moves_loop: // When in check and at SpNode search starts from here quietsSearched[quietCount++] = move; // Step 14. Make the move - pos.do_move(move, st, ci, givesCheck); + pos.do_move(move, st, givesCheck); // Step 15. Reduced depth search (LMR). If the move fails high it will be // re-searched at full depth. @@ -904,7 +907,7 @@ moves_loop: // When in check and at SpNode search starts from here ss->reduction = reduction(improving, depth, moveCount); if ( (!PvNode && cutNode) - || History[pos.piece_on(to_sq(move))][to_sq(move)] < 0) + || History[pos.piece_on(to_sq(move))][to_sq(move)] < VALUE_ZERO) ss->reduction += ONE_PLY; if (move == countermoves[0] || move == countermoves[1]) @@ -914,7 +917,7 @@ moves_loop: // When in check and at SpNode search starts from here 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) + && pos.see(make_move(to_sq(move), from_sq(move))) < VALUE_ZERO) ss->reduction = std::max(DEPTH_ZERO, ss->reduction - ONE_PLY); Depth d = std::max(newDepth - ss->reduction, ONE_PLY); @@ -1039,7 +1042,9 @@ moves_loop: // When in check and at SpNode search starts from here && Threads.size() >= 2 && depth >= Threads.minimumSplitDepth && ( !thisThread->activeSplitPoint - || !thisThread->activeSplitPoint->allSlavesSearching) + || !thisThread->activeSplitPoint->allSlavesSearching + || ( Threads.size() > MAX_SLAVES_PER_SPLITPOINT + && thisThread->activeSplitPoint->slavesMask.count() == MAX_SLAVES_PER_SPLITPOINT)) && thisThread->splitPointsSize < MAX_SPLITPOINTS_PER_THREAD) { assert(bestValue > -VALUE_INFINITE && bestValue < beta); @@ -1078,10 +1083,10 @@ moves_loop: // When in check and at SpNode search starts from here else if (bestValue >= beta && !pos.capture_or_promotion(bestMove) && !inCheck) update_stats(pos, ss, bestMove, depth, quietsSearched, quietCount - 1); - TT.store(posKey, value_to_tt(bestValue, ss->ply), - bestValue >= beta ? BOUND_LOWER : - PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER, - depth, bestMove, ss->staticEval); + tte->save(posKey, value_to_tt(bestValue, ss->ply), + bestValue >= beta ? BOUND_LOWER : + PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER, + depth, bestMove, ss->staticEval, TT.generation()); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1106,11 +1111,11 @@ moves_loop: // When in check and at SpNode search starts from here Move pv[MAX_PLY+1]; StateInfo st; - const TTEntry* tte; + TTEntry* tte; Key posKey; Move ttMove, move, bestMove; Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha; - bool givesCheck, evasionPrunable; + bool ttHit, givesCheck, evasionPrunable; Depth ttDepth; if (PvNode) @@ -1137,12 +1142,12 @@ moves_loop: // When in check and at SpNode search starts from here // Transposition table lookup posKey = pos.key(); - tte = TT.probe(posKey); - ttMove = tte ? tte->move() : MOVE_NONE; - ttValue = tte ? value_from_tt(tte->value(),ss->ply) : VALUE_NONE; + tte = TT.probe(posKey, ttHit); + ttMove = ttHit ? tte->move() : MOVE_NONE; + ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE; if ( !PvNode - && tte + && ttHit && tte->depth() >= ttDepth && ttValue != VALUE_NONE // Only in case of TT access race && (ttValue >= beta ? (tte->bound() & BOUND_LOWER) @@ -1160,10 +1165,10 @@ moves_loop: // When in check and at SpNode search starts from here } else { - if (tte) + if (ttHit) { // Never assume anything on values stored in TT - if ((ss->staticEval = bestValue = tte->eval_value()) == VALUE_NONE) + if ((ss->staticEval = bestValue = tte->eval()) == VALUE_NONE) ss->staticEval = bestValue = evaluate(pos); // Can ttValue be used as a better position evaluation? @@ -1178,9 +1183,9 @@ moves_loop: // When in check and at SpNode search starts from here // Stand pat. Return immediately if static value is at least beta if (bestValue >= beta) { - if (!tte) - TT.store(pos.key(), value_to_tt(bestValue, ss->ply), BOUND_LOWER, - DEPTH_NONE, MOVE_NONE, ss->staticEval); + if (!ttHit) + tte->save(pos.key(), value_to_tt(bestValue, ss->ply), BOUND_LOWER, + DEPTH_NONE, MOVE_NONE, ss->staticEval, TT.generation()); return bestValue; } @@ -1208,8 +1213,7 @@ moves_loop: // When in check and at SpNode search starts from here : pos.gives_check(move, ci); // Futility pruning - if ( !PvNode - && !InCheck + if ( !InCheck && !givesCheck && futilityBase > -VALUE_KNOWN_WIN && !pos.advanced_pawn_push(move)) @@ -1218,13 +1222,13 @@ moves_loop: // When in check and at SpNode search starts from here futilityValue = futilityBase + PieceValue[EG][pos.piece_on(to_sq(move))]; - if (futilityValue < beta) + if (futilityValue <= alpha) { bestValue = std::max(bestValue, futilityValue); continue; } - if (futilityBase < beta && pos.see(move) <= VALUE_ZERO) + if (futilityBase <= alpha && pos.see(move) <= VALUE_ZERO) { bestValue = std::max(bestValue, futilityBase); continue; @@ -1238,8 +1242,7 @@ moves_loop: // When in check and at SpNode search starts from here && !pos.can_castle(pos.side_to_move()); // Don't search moves with negative SEE values - if ( !PvNode - && (!InCheck || evasionPrunable) + if ( (!InCheck || evasionPrunable) && type_of(move) != PROMOTION && pos.see_sign(move) < VALUE_ZERO) continue; @@ -1254,7 +1257,7 @@ moves_loop: // When in check and at SpNode search starts from here ss->currentMove = move; // Make and search the move - pos.do_move(move, st, ci, givesCheck); + pos.do_move(move, st, givesCheck); value = givesCheck ? -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY) : -qsearch(pos, ss+1, -beta, -alpha, depth - ONE_PLY); pos.undo_move(move); @@ -1278,8 +1281,8 @@ moves_loop: // When in check and at SpNode search starts from here } else // Fail high { - TT.store(posKey, value_to_tt(value, ss->ply), BOUND_LOWER, - ttDepth, move, ss->staticEval); + tte->save(posKey, value_to_tt(value, ss->ply), BOUND_LOWER, + ttDepth, move, ss->staticEval, TT.generation()); return value; } @@ -1292,9 +1295,9 @@ moves_loop: // When in check and at SpNode search starts from here if (InCheck && bestValue == -VALUE_INFINITE) return mated_in(ss->ply); // Plies to mate from the root - TT.store(posKey, value_to_tt(bestValue, ss->ply), - PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER, - ttDepth, bestMove, ss->staticEval); + tte->save(posKey, value_to_tt(bestValue, ss->ply), + PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER, + ttDepth, bestMove, ss->staticEval, TT.generation()); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1376,16 +1379,13 @@ 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 @@ -1393,19 +1393,15 @@ 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; - - // Don't allow crazy blunders even at very low skills - if (i > 0 && RootMoves[i - 1].score > s + 2 * PawnValueMg) - break; + int score = RootMoves[i].score; // 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]; } } @@ -1436,10 +1432,10 @@ moves_loop: // When in check and at SpNode search starts from here 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 && abs(v) < VALUE_MATE - MAX_PLY; - v = tb ? TBScore : v; + 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"; @@ -1447,15 +1443,23 @@ moves_loop: // When in check and at SpNode search starts from here ss << "info depth " << d / ONE_PLY << " seldepth " << selDepth << " multipv " << i + 1 - << " 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 + << " score " << UCI::value(v); + + if (!tb && i == PVIdx) + ss << (v >= beta ? " lowerbound" : v <= alpha ? " upperbound" : ""); + + ss << " nodes " << pos.nodes_searched() + << " nps " << pos.nodes_searched() * 1000 / elapsed; + + if (elapsed > 1000) // Earlier makes little sense + ss << " hashfull " << TT.hashfull(); + + ss << " tbhits " << TB::Hits << " time " << elapsed << " pv"; for (size_t j = 0; j < RootMoves[i].pv.size(); ++j) - ss << " " << UCI::format_move(RootMoves[i].pv[j], pos.is_chess960()); + ss << " " << UCI::move(RootMoves[i].pv[j], pos.is_chess960()); } return ss.str(); @@ -1471,15 +1475,15 @@ moves_loop: // When in check and at SpNode search starts from here void RootMove::insert_pv_in_tt(Position& pos) { StateInfo state[MAX_PLY], *st = state; - const TTEntry* tte; size_t idx = 0; for ( ; idx < pv.size(); ++idx) { - tte = TT.probe(pos.key()); + bool ttHit; + TTEntry* tte = TT.probe(pos.key(), ttHit); - if (!tte || tte->move() != pv[idx]) // Don't overwrite correct entries - TT.store(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[idx], VALUE_NONE); + if (!ttHit || tte->move() != pv[idx]) // Don't overwrite correct entries + tte->save(pos.key(), VALUE_NONE, BOUND_NONE, DEPTH_NONE, pv[idx], VALUE_NONE, TT.generation()); assert(MoveList(pos).contains(pv[idx])); @@ -1490,15 +1494,39 @@ void RootMove::insert_pv_in_tt(Position& pos) { } +/// RootMove::extract_ponder_from_tt() is called in case we have no ponder move before +/// exiting the search, for instance in case we stop the search during a fail high at +/// root. We try hard to have a ponder move to return to the GUI, otherwise in case of +/// 'ponder on' we have nothing to think on. + +Move RootMove::extract_ponder_from_tt(Position& pos) +{ + StateInfo st; + bool found; + + assert(pv.size() == 1); + + pos.do_move(pv[0], st); + TTEntry* tte = TT.probe(pos.key(), found); + Move m = found ? tte->move() : MOVE_NONE; + if (!MoveList(pos).contains(m)) + m = MOVE_NONE; + + pos.undo_move(pv[0]); + pv.push_back(m); + return m; +} + + /// Thread::idle_loop() is where the thread is parked when it has no work to do 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 = activeSplitPoint; - assert(!this_sp || (this_sp->masterThread == this && searching)); + assert(!this_sp || (this_sp->master == this && searching)); while (!exit) { @@ -1508,6 +1536,7 @@ void Thread::idle_loop() { Threads.mutex.lock(); assert(activeSplitPoint); + SplitPoint* sp = activeSplitPoint; Threads.mutex.unlock(); @@ -1546,11 +1575,11 @@ void Thread::idle_loop() { // Wake up the master thread so to allow it to return from the idle // loop in case we are the last slave of the split point. - if ( this != sp->masterThread - && sp->slavesMask.none()) + if (this != sp->master && sp->slavesMask.none()) { - assert(!sp->masterThread->searching); - sp->masterThread->notify_one(); + assert(!sp->master->searching); + + sp->master->notify_one(); } // After releasing the lock we can't access any SplitPoint related data @@ -1560,37 +1589,60 @@ void Thread::idle_loop() { // Try to late join to another split point if none of its slaves has // already finished. - if (Threads.size() > 2) - for (size_t i = 0; i < Threads.size(); ++i) + SplitPoint* bestSp = NULL; + int minLevel = INT_MAX; + + for (size_t i = 0; i < Threads.size(); ++i) + { + const size_t size = Threads[i]->splitPointsSize; // Local copy + sp = size ? &Threads[i]->splitPoints[size - 1] : NULL; + + if ( sp + && sp->allSlavesSearching + && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT + && available_to(Threads[i])) { - const int size = Threads[i]->splitPointsSize; // Local copy - sp = size ? &Threads[i]->splitPoints[size - 1] : NULL; + assert(this != Threads[i]); + assert(!(this_sp && this_sp->slavesMask.none())); + assert(Threads.size() > 2); - if ( sp - && sp->allSlavesSearching - && available_to(Threads[i])) + // Prefer to join to SP with few parents to reduce the probability + // that a cut-off occurs above us, and hence we waste our work. + int level = 0; + for (SplitPoint* p = Threads[i]->activeSplitPoint; p; p = p->parentSplitPoint) + level++; + + if (level < minLevel) { - // Recheck the conditions under lock protection - Threads.mutex.lock(); - sp->mutex.lock(); - - if ( sp->allSlavesSearching - && available_to(Threads[i])) - { - sp->slavesMask.set(idx); - activeSplitPoint = sp; - searching = true; - } - - sp->mutex.unlock(); - Threads.mutex.unlock(); - - break; // Just a single attempt + bestSp = sp; + minLevel = level; } } + } + + if (bestSp) + { + sp = bestSp; + + // Recheck the conditions under lock protection + Threads.mutex.lock(); + sp->mutex.lock(); + + if ( sp->allSlavesSearching + && sp->slavesMask.count() < MAX_SLAVES_PER_SPLITPOINT + && available_to(sp->master)) + { + sp->slavesMask.set(idx); + activeSplitPoint = sp; + searching = true; + } + + sp->mutex.unlock(); + Threads.mutex.unlock(); + } } - // Grab the lock to avoid races with Thread::notify_one() + // Avoid races with notify_one() fired from last slave of the split point mutex.lock(); // If we are master and all slaves have finished then exit idle_loop @@ -1652,7 +1704,7 @@ 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 (size_t j = 0; j < Threads[i]->splitPointsSize; ++j) { SplitPoint& sp = Threads[i]->splitPoints[j];