X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=aafbf80f94aef804009883e41bbfc8d28b96c3b6;hp=8d8d700114153d7642b91876b9f196ec2a58e379;hb=ecd3218b6b24bb54509dbe6e9b24517b7df7390d;hpb=ced29248c93de7fc5a4e284807f8f052006e647c diff --git a/src/search.cpp b/src/search.cpp index 8d8d7001..aafbf80f 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -68,24 +68,25 @@ namespace { const int skipPhase[] = { 0, 1, 0, 1, 2, 3, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 6, 7 }; // Razoring and futility margin based on depth - const int razor_margin[4] = { 483, 570, 603, 554 }; + // razor_margin[0] is unused as long as depth >= ONE_PLY in search + const int razor_margin[] = { 0, 570, 603, 554 }; Value futility_margin(Depth d) { return Value(150 * d / ONE_PLY); } // Futility and reductions lookup tables, initialized at startup int FutilityMoveCounts[2][16]; // [improving][depth] int Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber] - // Threshold used for countermoves based pruning. - const int CounterMovePruneThreshold = VALUE_ZERO; + // Threshold used for countermoves based pruning + const int CounterMovePruneThreshold = 0; template Depth reduction(bool i, Depth d, int mn) { return Reductions[PvNode][i][std::min(d / ONE_PLY, 63)][std::min(mn, 63)] * ONE_PLY; } // History and stats update bonus, based on depth - Value stat_bonus(Depth depth) { + int stat_bonus(Depth depth) { int d = depth / ONE_PLY ; - return d > 17 ? VALUE_ZERO : Value(d * d + 2 * d - 2); + return d > 17 ? 0 : d * d + 2 * d - 2; } // Skill structure is used to implement strength limit @@ -151,8 +152,8 @@ namespace { Value value_to_tt(Value v, int ply); Value value_from_tt(Value v, int ply); void update_pv(Move* pv, Move move, Move* childPv); - void update_cm_stats(Stack* ss, Piece pc, Square s, Value bonus); - void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, Value bonus); + void update_cm_stats(Stack* ss, Piece pc, Square s, int bonus); + void update_stats(const Position& pos, Stack* ss, Move move, Move* quiets, int quietsCnt, int bonus); void check_time(); } // namespace @@ -184,7 +185,7 @@ void Search::init() { } -/// Search::clear() resets search state to zero, to obtain reproducible results +/// Search::clear() resets search state to its initial value, to obtain reproducible results void Search::clear() { @@ -192,11 +193,15 @@ void Search::clear() { for (Thread* th : Threads) { - th->counterMoves.clear(); - th->history.clear(); - th->counterMoveHistory.clear(); - th->counterMoveHistory[NO_PIECE][0].fill(Value(CounterMovePruneThreshold-1)); th->resetCalls = true; + th->counterMoves.fill(MOVE_NONE); + th->history.fill(0); + + for (auto& to : th->counterMoveHistory) + for (auto& h : to) + h.fill(0); + + th->counterMoveHistory[NO_PIECE][0].fill(CounterMovePruneThreshold - 1); } Threads.main()->previousScore = VALUE_INFINITE; @@ -330,7 +335,7 @@ void Thread::search() { std::memset(ss-4, 0, 7 * sizeof(Stack)); for(int i = 4; i > 0; i--) - (ss-i)->counterMoves = &this->counterMoveHistory[NO_PIECE][0]; // Use as sentinel + (ss-i)->history = &this->counterMoveHistory[NO_PIECE][0]; // Use as sentinel bestValue = delta = alpha = -VALUE_INFINITE; beta = VALUE_INFINITE; @@ -553,8 +558,8 @@ namespace { // Step 1. Initialize node Thread* thisThread = pos.this_thread(); inCheck = pos.checkers(); - moveCount = quietCount = ss->moveCount = 0; - ss->history = VALUE_ZERO; + moveCount = quietCount = ss->moveCount = 0; + ss->statScore = 0; bestValue = -VALUE_INFINITE; ss->ply = (ss-1)->ply + 1; @@ -562,9 +567,10 @@ namespace { if (thisThread->resetCalls.load(std::memory_order_relaxed)) { thisThread->resetCalls = false; + // At low node count increase the checking rate to about 0.1% of nodes // otherwise use a default value. - thisThread->callsCnt = Limits.nodes ? std::min((int64_t)4096, Limits.nodes / 1024) + thisThread->callsCnt = Limits.nodes ? std::min(4096, int(Limits.nodes / 1024)) : 4096; } @@ -602,7 +608,7 @@ namespace { assert(0 <= ss->ply && ss->ply < MAX_PLY); ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE; - ss->counterMoves = &thisThread->counterMoveHistory[NO_PIECE][0]; + ss->history = &thisThread->counterMoveHistory[NO_PIECE][0]; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; Square prevSq = to_sq((ss-1)->currentMove); @@ -639,7 +645,7 @@ namespace { // Penalty for a quiet ttMove that fails low else if (!pos.capture_or_promotion(ttMove)) { - Value penalty = -stat_bonus(depth); + int penalty = -stat_bonus(depth); thisThread->history.update(pos.side_to_move(), ttMove, penalty); update_cm_stats(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty); } @@ -745,7 +751,7 @@ namespace { Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; ss->currentMove = MOVE_NULL; - ss->counterMoves = &thisThread->counterMoveHistory[NO_PIECE][0]; + ss->history = &thisThread->counterMoveHistory[NO_PIECE][0]; pos.do_null_move(st); Value nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1) @@ -789,7 +795,7 @@ namespace { if (pos.legal(move)) { ss->currentMove = move; - ss->counterMoves = &thisThread->counterMoveHistory[pos.moved_piece(move)][to_sq(move)]; + ss->history = &thisThread->counterMoveHistory[pos.moved_piece(move)][to_sq(move)]; pos.do_move(move, st); value = -search(pos, ss+1, -rbeta, -rbeta+1, rdepth, !cutNode, false); @@ -813,9 +819,9 @@ namespace { moves_loop: // When in check search starts from here - const CounterMoveStats& cmh = *(ss-1)->counterMoves; - const CounterMoveStats& fmh = *(ss-2)->counterMoves; - const CounterMoveStats& fm2 = *(ss-4)->counterMoves; + const PieceToHistory& cmh = *(ss-1)->history; + const PieceToHistory& fmh = *(ss-2)->history; + const PieceToHistory& fm2 = *(ss-4)->history; MovePicker mp(pos, ttMove, depth, ss); value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc @@ -875,7 +881,7 @@ moves_loop: // When in check search starts from here // (alpha-s, beta-s), and just one fails high on (alpha, beta), then that move // is singular and should be extended. To verify this we do a reduced search // on all the other moves but the ttMove and if the result is lower than - // ttValue minus a margin then we extend the ttMove. + // ttValue minus a margin then we will extend the ttMove. if ( singularExtensionNode && move == ttMove && pos.legal(move)) @@ -889,9 +895,9 @@ moves_loop: // When in check search starts from here if (value < rBeta) extension = ONE_PLY; } - else if ( givesCheck + else if ( givesCheck && !moveCountPruning - && pos.see_ge(move, VALUE_ZERO)) + && pos.see_ge(move)) extension = ONE_PLY; // Calculate new depth for this move @@ -904,10 +910,11 @@ moves_loop: // When in check search starts from here { if ( !captureOrPromotion && !givesCheck - && (!pos.advanced_pawn_push(move) || pos.non_pawn_material() >= 5000)) + && (!pos.advanced_pawn_push(move) || pos.non_pawn_material() >= Value(5000))) { // Move count based pruning - if (moveCountPruning) { + if (moveCountPruning) + { skipQuiets = true; continue; } @@ -950,7 +957,7 @@ moves_loop: // When in check search starts from here // Update the current move (this must be done after singular extension search) ss->currentMove = move; - ss->counterMoves = &thisThread->counterMoveHistory[moved_piece][to_sq(move)]; + ss->history = &thisThread->counterMoveHistory[moved_piece][to_sq(move)]; // Step 14. Make the move pos.do_move(move, st, givesCheck); @@ -974,25 +981,25 @@ moves_loop: // When in check search starts from here // Decrease reduction for moves that escape a capture. Filter out // castling moves, because they are coded as "king captures rook" and // hence break make_move(). - else if ( type_of(move) == NORMAL - && !pos.see_ge(make_move(to_sq(move), from_sq(move)), VALUE_ZERO)) + else if ( type_of(move) == NORMAL + && !pos.see_ge(make_move(to_sq(move), from_sq(move)))) r -= 2 * ONE_PLY; - ss->history = cmh[moved_piece][to_sq(move)] - + fmh[moved_piece][to_sq(move)] - + fm2[moved_piece][to_sq(move)] - + thisThread->history.get(~pos.side_to_move(), move) - - 4000; // Correction factor + ss->statScore = cmh[moved_piece][to_sq(move)] + + fmh[moved_piece][to_sq(move)] + + fm2[moved_piece][to_sq(move)] + + thisThread->history[~pos.side_to_move()][from_to(move)] + - 4000; // Correction factor // Decrease/increase reduction by comparing opponent's stat score - if (ss->history > VALUE_ZERO && (ss-1)->history < VALUE_ZERO) + if (ss->statScore > 0 && (ss-1)->statScore < 0) r -= ONE_PLY; - else if (ss->history < VALUE_ZERO && (ss-1)->history > VALUE_ZERO) + else if (ss->statScore < 0 && (ss-1)->statScore > 0) r += ONE_PLY; // Decrease/increase reduction for moves with a good/bad history - r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->history / 20000) * ONE_PLY); + r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->statScore / 20000) * ONE_PLY); } Depth d = std::max(newDepth - r, ONE_PLY); @@ -1111,7 +1118,6 @@ moves_loop: // When in check search starts from here : inCheck ? mated_in(ss->ply) : DrawValue[pos.side_to_move()]; else if (bestMove) { - // Quiet best move: update move sorting heuristics if (!pos.capture_or_promotion(bestMove)) update_stats(pos, ss, bestMove, quietsSearched, quietCount, stat_bonus(depth)); @@ -1126,11 +1132,11 @@ moves_loop: // When in check search starts from here && is_ok((ss-1)->currentMove)) update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth)); - if(!excludedMove) + if (!excludedMove) 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()); + bestValue >= beta ? BOUND_LOWER : + PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER, + depth, bestMove, ss->staticEval, TT.generation()); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1160,6 +1166,7 @@ moves_loop: // When in check search starts from here Value bestValue, value, ttValue, futilityValue, futilityBase, oldAlpha; bool ttHit, givesCheck, evasionPrunable; Depth ttDepth; + int moveCount; if (PvNode) { @@ -1170,6 +1177,7 @@ moves_loop: // When in check search starts from here ss->currentMove = bestMove = MOVE_NONE; ss->ply = (ss-1)->ply + 1; + moveCount = 0; // Check for an instant draw or if the maximum ply has been reached if (pos.is_draw(ss->ply) || ss->ply >= MAX_PLY) @@ -1253,6 +1261,8 @@ moves_loop: // When in check search starts from here ? pos.check_squares(type_of(pos.piece_on(from_sq(move)))) & to_sq(move) : pos.gives_check(move); + moveCount++; + // Futility pruning if ( !InCheck && !givesCheck @@ -1278,13 +1288,14 @@ moves_loop: // When in check search starts from here // Detect non-capture evasions that are candidates to be pruned evasionPrunable = InCheck + && (depth != DEPTH_ZERO || moveCount > 2) && bestValue > VALUE_MATED_IN_MAX_PLY && !pos.capture(move); // Don't search moves with negative SEE values if ( (!InCheck || evasionPrunable) && type_of(move) != PROMOTION - && !pos.see_ge(move, VALUE_ZERO)) + && !pos.see_ge(move)) continue; // Speculative prefetch as early as possible @@ -1292,7 +1303,10 @@ moves_loop: // When in check search starts from here // Check for legality just before making the move if (!pos.legal(move)) + { + moveCount--; continue; + } ss->currentMove = move; @@ -1382,18 +1396,18 @@ moves_loop: // When in check search starts from here // update_cm_stats() updates countermove and follow-up move history - void update_cm_stats(Stack* ss, Piece pc, Square s, Value bonus) { + void update_cm_stats(Stack* ss, Piece pc, Square s, int bonus) { for (int i : {1, 2, 4}) if (is_ok((ss-i)->currentMove)) - (ss-i)->counterMoves->update(pc, s, bonus); + (ss-i)->history->update(pc, s, bonus); } // update_stats() updates move sorting heuristics when a new quiet best move is found void update_stats(const Position& pos, Stack* ss, Move move, - Move* quiets, int quietsCnt, Value bonus) { + Move* quiets, int quietsCnt, int bonus) { if (ss->killers[0] != move) { @@ -1409,7 +1423,7 @@ moves_loop: // When in check search starts from here if (is_ok((ss-1)->currentMove)) { Square prevSq = to_sq((ss-1)->currentMove); - thisThread->counterMoves.update(pos.piece_on(prevSq), prevSq, move); + thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]=move; } // Decrease all the other played quiet moves @@ -1499,7 +1513,7 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { for (size_t i = 0; i < multiPV; ++i) { - bool updated = (i <= PVIdx); + bool updated = (i <= PVIdx && rootMoves[i].score != -VALUE_INFINITE); if (depth == ONE_PLY && !updated) continue;