X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=01de12a4cea99b662ce0134349be1b3c3dadaeb5;hp=98419b20fc75b9ee7bde88ce952da472719fff34;hb=3a3ca6af0390d74427c218f29cb5fe1a913efb42;hpb=fcee0ce6a39a28ffdfa4b1ed438b353a895edb6b diff --git a/src/search.cpp b/src/search.cpp index 98419b20..01de12a4 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -64,7 +64,7 @@ namespace { // Razor and futility margins constexpr int RazorMargin = 661; Value futility_margin(Depth d, bool improving) { - return Value((168 - 51 * improving) * d / ONE_PLY); + return Value(198 * (d / ONE_PLY - improving)); } // Reductions lookup table, initialized at startup @@ -102,15 +102,16 @@ namespace { Move best = MOVE_NONE; }; - // Breadcrumbs are used to mark nodes as being searched by a given thread. + // Breadcrumbs are used to mark nodes as being searched by a given thread struct Breadcrumb { std::atomic thread; std::atomic key; }; std::array breadcrumbs; - // ThreadHolding keeps track of which thread left breadcrumbs at the given node for potential reductions. - // A free node will be marked upon entering the moves loop, and unmarked upon leaving that loop, by the ctor/dtor of this struct. + // ThreadHolding structure keeps track of which thread left breadcrumbs at the given + // node for potential reductions. A free node will be marked upon entering the moves + // loop by the constructor, and unmarked upon leaving that loop by the destructor. struct ThreadHolding { explicit ThreadHolding(Thread* thisThread, Key posKey, int ply) { location = ply < 8 ? &breadcrumbs[posKey & (breadcrumbs.size() - 1)] : nullptr; @@ -118,7 +119,7 @@ namespace { owning = false; if (location) { - // see if another already marked this location, if not, mark it ourselves. + // See if another already marked this location, if not, mark it ourselves Thread* tmp = (*location).thread.load(std::memory_order_relaxed); if (tmp == nullptr) { @@ -133,7 +134,7 @@ namespace { } ~ThreadHolding() { - if (owning) // free the marked location. + if (owning) // Free the marked location (*location).thread.store(nullptr, std::memory_order_relaxed); } @@ -471,7 +472,10 @@ void Thread::search() { ++failedHighCnt; } else + { + ++rootMoves[pvIdx].bestMoveCount; break; + } delta += delta / 4 + 5; @@ -647,9 +651,9 @@ namespace { // statScore of the previous grandchild. This influences the reduction rules in // LMR which are based on the statScore of parent position. if (rootNode) - (ss + 4)->statScore = 0; + (ss+4)->statScore = 0; else - (ss + 2)->statScore = 0; + (ss+2)->statScore = 0; // Step 4. Transposition table lookup. We don't want the score of a partial // search to overwrite a previous full search TT value, so we use a different @@ -680,7 +684,7 @@ namespace { // Extra penalty for early quiet moves of the previous ply if ((ss-1)->moveCount <= 2 && !pos.captured_piece()) - update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, -stat_bonus(depth + ONE_PLY)); + update_continuation_histories(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)) @@ -758,6 +762,9 @@ namespace { if (eval == VALUE_NONE) ss->staticEval = eval = evaluate(pos); + if (eval == VALUE_DRAW) + eval = value_draw(depth, thisThread); + // Can ttValue be used as a better position evaluation? if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > eval ? BOUND_LOWER : BOUND_UPPER))) @@ -798,7 +805,8 @@ namespace { && (ss-1)->currentMove != MOVE_NULL && (ss-1)->statScore < 22661 && eval >= beta - && ss->staticEval >= beta - 33 * depth / ONE_PLY + 299 + && eval >= ss->staticEval + && ss->staticEval >= beta - 33 * depth / ONE_PLY + 299 - improving * 30 && !excludedMove && pos.non_pawn_material(us) && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor)) @@ -908,7 +916,7 @@ moves_loop: // When in check, search starts from here moveCountPruning = false; ttCapture = ttMove && pos.capture_or_promotion(ttMove); - // Mark this node as being searched. + // Mark this node as being searched ThreadHolding th(thisThread, posKey, ss->ply); // Step 12. Loop through all pseudo-legal moves until no moves remain @@ -989,10 +997,6 @@ moves_loop: // When in check, search starts from here && (pos.is_discovery_check_on_king(~us, move) || pos.see_ge(move))) extension = ONE_PLY; - // Castling extension - else if (type_of(move) == CASTLING) - extension = ONE_PLY; - // Shuffle extension else if ( PvNode && pos.rule50_count() > 18 @@ -1005,6 +1009,10 @@ moves_loop: // When in check, search starts from here && pos.advanced_pawn_push(move) && pos.pawn_passed(us, to_sq(move))) extension = ONE_PLY; + + // Castling extension + if (type_of(move) == CASTLING) + extension = ONE_PLY; // Calculate new depth for this move newDepth = depth - ONE_PLY + extension; @@ -1045,7 +1053,7 @@ moves_loop: // When in check, search starts from here if (!pos.see_ge(move, Value(-(31 - std::min(lmrDepth, 18)) * lmrDepth * lmrDepth))) continue; } - else if ( (!givesCheck || !extension) + else if ( !(givesCheck && extension) && !pos.see_ge(move, Value(-199) * (depth / ONE_PLY))) // (~20 Elo) continue; } @@ -1070,10 +1078,12 @@ moves_loop: // When in check, search starts from here // Step 16. Reduced depth search (LMR). If the move fails high it will be // re-searched at full depth. if ( depth >= 3 * ONE_PLY - && moveCount > 1 + 3 * rootNode + && moveCount > 1 + 2 * rootNode + && (!rootNode || thisThread->best_move_count(move) == 0) && ( !captureOrPromotion || moveCountPruning - || ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha)) + || ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha + || cutNode)) { Depth r = reduction(improving, depth, moveCount); @@ -1089,7 +1099,7 @@ moves_loop: // When in check, search starts from here if ((ss-1)->moveCount > 15) r -= ONE_PLY; - // Decrease reduction if move has been singularly extended + // Decrease reduction if ttMove has been singularly extended r -= singularLMR * ONE_PLY; if (!captureOrPromotion) @@ -1106,7 +1116,7 @@ moves_loop: // When in check, search starts from here // castling moves, because they are coded as "king captures rook" and // hence break make_move(). (~5 Elo) else if ( type_of(move) == NORMAL - && !pos.see_ge(make_move(to_sq(move), from_sq(move)))) + && !pos.see_ge(reverse_move(move))) r -= 2 * ONE_PLY; ss->statScore = thisThread->mainHistory[us][from_to(move)] @@ -1596,6 +1606,9 @@ moves_loop: // When in check, search starts from here thisThread->mainHistory[us][from_to(move)] << bonus; update_continuation_histories(ss, pos.moved_piece(move), to_sq(move), bonus); + if (type_of(pos.moved_piece(move)) != PAWN) + thisThread->mainHistory[us][from_to(reverse_move(move))] << -bonus; + if (is_ok((ss-1)->currentMove)) { Square prevSq = to_sq((ss-1)->currentMove);