X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=cb16798dc427fcc30162a9f346c0402aac680a95;hp=45f50a6353c649b1eb80eb1ca6b082a509fbfdde;hb=a6d6a2c2fad093a47b575ee4cfb8d346ba037fb3;hpb=d8f683760c9eb6d2c4714ec83e717dd2143de55c diff --git a/src/search.cpp b/src/search.cpp index 45f50a63..cb16798d 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -63,6 +63,10 @@ namespace { // Different node types, used as a template parameter enum NodeType { NonPV, PV }; + // Sizes and phases of the skip-blocks, used for distributing search depths across the threads + const int skipSize[] = { 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4 }; + 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 }; Value futility_margin(Depth d) { return Value(150 * d / ONE_PLY); } @@ -75,6 +79,12 @@ namespace { 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 d = depth / ONE_PLY ; + return Value(d * d + 2 * d - 2); + } + // Skill structure is used to implement strength limit struct Skill { Skill(int l) : level(l) {} @@ -126,38 +136,6 @@ namespace { Move pv[3]; }; - // Set of rows with half bits set to 1 and half to 0. It is used to allocate - // the search depths across the threads. - typedef std::vector Row; - - const Row HalfDensity[] = { - {0, 1}, - {1, 0}, - {0, 0, 1, 1}, - {0, 1, 1, 0}, - {1, 1, 0, 0}, - {1, 0, 0, 1}, - {0, 0, 0, 1, 1, 1}, - {0, 0, 1, 1, 1, 0}, - {0, 1, 1, 1, 0, 0}, - {1, 1, 1, 0, 0, 0}, - {1, 1, 0, 0, 0, 1}, - {1, 0, 0, 0, 1, 1}, - {0, 0, 0, 0, 1, 1, 1, 1}, - {0, 0, 0, 1, 1, 1, 1, 0}, - {0, 0, 1, 1, 1, 1, 0 ,0}, - {0, 1, 1, 1, 1, 0, 0 ,0}, - {1, 1, 1, 1, 0, 0, 0 ,0}, - {1, 1, 1, 0, 0, 0, 0 ,1}, - {1, 1, 0, 0, 0, 0, 1 ,1}, - {1, 0, 0, 0, 0, 1, 1 ,1}, - }; - - const size_t HalfDensitySize = std::extent::value; - - Value bonus(Depth depth) { int d = depth / ONE_PLY ; return Value(d * d + 2 * d - 2); } - Value penalty(Depth depth) { int d = depth / ONE_PLY ; return -Value(d * d + 4 * d + 1); } - EasyMoveManager EasyMove; Value DrawValue[COLOR_NB]; @@ -335,9 +313,9 @@ void MainThread::search() { } -// Thread::search() is the main iterative deepening loop. It calls search() -// repeatedly with increasing depth until the allocated thinking time has been -// consumed, the user stops the search, or the maximum search depth is reached. +/// Thread::search() is the main iterative deepening loop. It calls search() +/// repeatedly with increasing depth until the allocated thinking time has been +/// consumed, the user stops the search, or the maximum search depth is reached. void Thread::search() { @@ -347,6 +325,8 @@ void Thread::search() { MainThread* mainThread = (this == Threads.main() ? Threads.main() : nullptr); 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 bestValue = delta = alpha = -VALUE_INFINITE; beta = VALUE_INFINITE; @@ -376,13 +356,12 @@ void Thread::search() { && !Signals.stop && (!Limits.depth || Threads.main()->rootDepth / ONE_PLY <= Limits.depth)) { - // Set up the new depths for the helper threads skipping on average every - // 2nd ply (using a half-density matrix). - if (!mainThread) + // Distribute search depths across the threads + if (idx) { - const Row& row = HalfDensity[(idx - 1) % HalfDensitySize]; - if (row[(rootDepth / ONE_PLY + rootPos.game_ply()) % row.size()]) - continue; + int i = (idx - 1) % 20; + if (((rootDepth / ONE_PLY + rootPos.game_ply() + skipPhase[i]) / skipSize[i]) % 2) + continue; } // Age out PV variability metric @@ -420,7 +399,7 @@ void Thread::search() { // search the already searched PV lines are preserved. std::stable_sort(rootMoves.begin() + PVIdx, rootMoves.end()); - // If search has been stopped, break immediately. Sorting and + // If search has been stopped, we break immediately. Sorting and // writing PV back to TT is safe because RootMoves is still // valid, although it refers to the previous iteration. if (Signals.stop) @@ -502,7 +481,7 @@ void Thread::search() { bool doEasyMove = rootMoves[0].pv[0] == easyMove && mainThread->bestMoveChanges < 0.03 - && Time.elapsed() > Time.optimum() * 5 / 42; + && Time.elapsed() > Time.optimum() * 5 / 44; if ( rootMoves.size() == 1 || Time.elapsed() > Time.optimum() * unstablePvFactor * improvingFactor / 628 @@ -561,7 +540,7 @@ namespace { Key posKey; Move ttMove, move, excludedMove, bestMove; Depth extension, newDepth; - Value bestValue, value, ttValue, eval, nullValue; + Value bestValue, value, ttValue, eval; bool ttHit, inCheck, givesCheck, singularExtensionNode, improving; bool captureOrPromotion, doFullDepthSearch, moveCountPruning; Piece moved_piece; @@ -619,7 +598,7 @@ namespace { assert(0 <= ss->ply && ss->ply < MAX_PLY); ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE; - ss->counterMoves = nullptr; + ss->counterMoves = &thisThread->counterMoveHistory[NO_PIECE][0]; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; Square prevSq = to_sq((ss-1)->currentMove); @@ -642,14 +621,24 @@ namespace { : (tte->bound() & BOUND_UPPER))) { // If ttMove is quiet, update move sorting heuristics on TT hit - if (ttValue >= beta && ttMove) + if (ttMove) { - if (!pos.capture_or_promotion(ttMove)) - update_stats(pos, ss, ttMove, nullptr, 0, bonus(depth)); + if (ttValue >= beta) + { + if (!pos.capture_or_promotion(ttMove)) + update_stats(pos, ss, ttMove, nullptr, 0, stat_bonus(depth)); - // Extra penalty for a quiet TT move in previous ply when it gets refuted - if ((ss-1)->moveCount == 1 && !pos.captured_piece()) - update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, penalty(depth)); + // Extra penalty for a quiet TT move in previous ply when it gets refuted + if ((ss-1)->moveCount == 1 && !pos.captured_piece()) + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY)); + } + // Penalty for a quiet ttMove that fails low + else if (!pos.capture_or_promotion(ttMove)) + { + Value penalty = -stat_bonus(depth + ONE_PLY); + thisThread->history.update(pos.side_to_move(), ttMove, penalty); + update_cm_stats(ss, pos.moved_piece(ttMove), to_sq(ttMove), penalty); + } } return ttValue; } @@ -657,7 +646,7 @@ namespace { // Step 4a. Tablebase probe if (!rootNode && TB::Cardinality) { - int piecesCount = pos.count(WHITE) + pos.count(BLACK); + int piecesCount = pos.count(); if ( piecesCount <= TB::Cardinality && (piecesCount < TB::Cardinality || depth >= TB::ProbeDepth) @@ -720,7 +709,6 @@ namespace { // Step 6. Razoring (skipped when in check) if ( !PvNode && depth < 4 * ONE_PLY - && ttMove == MOVE_NONE && eval + razor_margin[depth / ONE_PLY] <= alpha) { if (depth <= ONE_PLY) @@ -746,17 +734,18 @@ namespace { && (ss->staticEval >= beta - 35 * (depth / ONE_PLY - 6) || depth >= 13 * ONE_PLY) && pos.non_pawn_material(pos.side_to_move())) { - ss->currentMove = MOVE_NULL; - ss->counterMoves = nullptr; assert(eval - beta >= 0); // Null move dynamic reduction based on depth and value 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]; + pos.do_null_move(st); - nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1) - : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true); + Value nullValue = depth-R < ONE_PLY ? -qsearch(pos, ss+1, -beta, -beta+1) + : - search(pos, ss+1, -beta, -beta+1, depth-R, !cutNode, true); pos.undo_null_move(); if (nullValue >= beta) @@ -788,8 +777,7 @@ namespace { Depth rdepth = depth - 4 * ONE_PLY; assert(rdepth >= ONE_PLY); - assert((ss-1)->currentMove != MOVE_NONE); - assert((ss-1)->currentMove != MOVE_NULL); + assert(is_ok((ss-1)->currentMove)); MovePicker mp(pos, ttMove, rbeta - ss->staticEval); @@ -798,6 +786,7 @@ namespace { { ss->currentMove = move; ss->counterMoves = &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); pos.undo_move(move); @@ -820,9 +809,12 @@ namespace { moves_loop: // When in check search starts from here - const CounterMoveStats* cmh = (ss-1)->counterMoves; - const CounterMoveStats* fmh = (ss-2)->counterMoves; - const CounterMoveStats* fmh2 = (ss-4)->counterMoves; + const CounterMoveStats& cmh = *(ss-1)->counterMoves; + const CounterMoveStats& fmh = *(ss-2)->counterMoves; + const CounterMoveStats& fm2 = *(ss-4)->counterMoves; + const bool cm_ok = is_ok((ss-1)->currentMove); + const bool fm_ok = is_ok((ss-2)->currentMove); + const bool f2_ok = is_ok((ss-4)->currentMove); MovePicker mp(pos, ttMove, depth, ss); value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc @@ -875,7 +867,8 @@ moves_loop: // When in check search starts from here moveCountPruning = depth < 16 * ONE_PLY && moveCount >= FutilityMoveCounts[improving][depth / ONE_PLY]; - // Step 12. Extend checks + // Step 12. Extensions + // Extend checks if ( givesCheck && !moveCountPruning && pos.see_ge(move, VALUE_ZERO)) @@ -901,7 +894,7 @@ moves_loop: // When in check search starts from here extension = ONE_PLY; } - // Update the current move (this must be done after singular extension search) + // Calculate new depth for this move newDepth = depth - ONE_PLY + extension; // Step 13. Pruning at shallow depth @@ -910,7 +903,7 @@ moves_loop: // When in check search starts from here { if ( !captureOrPromotion && !givesCheck - && !pos.advanced_pawn_push(move)) + && (!pos.advanced_pawn_push(move) || pos.non_pawn_material() >= 5000)) { // Move count based pruning if (moveCountPruning) @@ -921,9 +914,9 @@ moves_loop: // When in check search starts from here // Countermoves based pruning if ( lmrDepth < 3 - && (!cmh || (*cmh )[moved_piece][to_sq(move)] < VALUE_ZERO) - && (!fmh || (*fmh )[moved_piece][to_sq(move)] < VALUE_ZERO) - && (!fmh2 || (*fmh2)[moved_piece][to_sq(move)] < VALUE_ZERO || (cmh && fmh))) + && ((cmh[moved_piece][to_sq(move)] < VALUE_ZERO) || !cm_ok) + && ((fmh[moved_piece][to_sq(move)] < VALUE_ZERO) || !fm_ok) + && ((fm2[moved_piece][to_sq(move)] < VALUE_ZERO) || !f2_ok || (cm_ok && fm_ok))) continue; // Futility pruning: parent node @@ -953,6 +946,7 @@ moves_loop: // When in check search starts from here continue; } + // Update the current move (this must be done after singular extension search) ss->currentMove = move; ss->counterMoves = &thisThread->counterMoveHistory[moved_piece][to_sq(move)]; @@ -982,11 +976,11 @@ moves_loop: // When in check search starts from here && !pos.see_ge(make_move(to_sq(move), from_sq(move)), VALUE_ZERO)) r -= 2 * ONE_PLY; - ss->history = (cmh ? (*cmh )[moved_piece][to_sq(move)] : VALUE_ZERO) - + (fmh ? (*fmh )[moved_piece][to_sq(move)] : VALUE_ZERO) - + (fmh2 ? (*fmh2)[moved_piece][to_sq(move)] : VALUE_ZERO) + 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) - - 8000; // Correction factor + - 4000; // Correction factor // Decrease/increase reduction by comparing opponent's stat score if (ss->history > VALUE_ZERO && (ss-1)->history < VALUE_ZERO) @@ -1118,17 +1112,17 @@ moves_loop: // When in check search starts from here // Quiet best move: update move sorting heuristics if (!pos.capture_or_promotion(bestMove)) - update_stats(pos, ss, bestMove, quietsSearched, quietCount, bonus(depth)); + update_stats(pos, ss, bestMove, quietsSearched, quietCount, stat_bonus(depth)); // Extra penalty for a quiet TT move in previous ply when it gets refuted if ((ss-1)->moveCount == 1 && !pos.captured_piece()) - update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, penalty(depth)); + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY)); } // Bonus for prior countermove that caused the fail low else if ( depth >= 3 * ONE_PLY && !pos.captured_piece() - && is_ok((ss-1)->currentMove)) - update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, bonus(depth)); + && cm_ok) + update_cm_stats(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth)); tte->save(posKey, value_to_tt(bestValue, ss->ply), bestValue >= beta ? BOUND_LOWER : @@ -1387,18 +1381,9 @@ moves_loop: // When in check search starts from here void update_cm_stats(Stack* ss, Piece pc, Square s, Value bonus) { - CounterMoveStats* cmh = (ss-1)->counterMoves; - CounterMoveStats* fmh1 = (ss-2)->counterMoves; - CounterMoveStats* fmh2 = (ss-4)->counterMoves; - - if (cmh) - cmh->update(pc, s, bonus); - - if (fmh1) - fmh1->update(pc, s, bonus); - - if (fmh2) - fmh2->update(pc, s, bonus); + for (int i : {1, 2, 4}) + if (is_ok((ss-i)->currentMove)) + (ss-i)->counterMoves->update(pc, s, bonus); } @@ -1418,7 +1403,7 @@ moves_loop: // When in check search starts from here thisThread->history.update(c, move, bonus); update_cm_stats(ss, pos.moved_piece(move), to_sq(move), bonus); - if ((ss-1)->counterMoves) + if (is_ok((ss-1)->currentMove)) { Square prevSq = to_sq((ss-1)->currentMove); thisThread->counterMoves.update(pos.piece_on(prevSq), prevSq, move);