X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=d9543899a0f7844e2b817b3e2095f321a8ca51fc;hp=f1136e3e5b423cfaed45bae25fbc591c341690a7;hb=46ce245763705c89dba60dcfda549dc1f64eb48b;hpb=272936eaba8d3a40f4d2d6649fb9a06912bd162c diff --git a/src/search.cpp b/src/search.cpp index f1136e3e..d9543899 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -71,7 +71,7 @@ namespace { int Reductions[MAX_MOVES]; // [depth or moveNumber] Depth reduction(bool i, Depth d, int mn) { - int r = Reductions[d / ONE_PLY] * Reductions[mn] / 1024; + int r = Reductions[d / ONE_PLY] * Reductions[mn]; return ((r + 512) / 1024 + (!i && r > 1024)) * ONE_PLY; } @@ -149,7 +149,7 @@ namespace { void Search::init() { for (int i = 1; i < MAX_MOVES; ++i) - Reductions[i] = int(733.3 * std::log(i)); + Reductions[i] = int(22.9 * std::log(i)); } @@ -240,17 +240,13 @@ void MainThread::search() { minScore = std::min(minScore, th->rootMoves[0].score); // Vote according to score and depth, and select the best thread - int64_t bestVote = 0; for (Thread* th : Threads) { votes[th->rootMoves[0].pv[0]] += - (th->rootMoves[0].score - minScore + 14) * int(th->completedDepth); + (th->rootMoves[0].score - minScore + 14) * int(th->completedDepth); - if (votes[th->rootMoves[0].pv[0]] > bestVote) - { - bestVote = votes[th->rootMoves[0].pv[0]]; + if (votes[th->rootMoves[0].pv[0]] > votes[bestThread->rootMoves[0].pv[0]]) bestThread = th; - } } } @@ -538,13 +534,13 @@ namespace { bool ttHit, ttPv, inCheck, givesCheck, improving; bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture; Piece movedPiece; - int moveCount, captureCount, quietCount; + int moveCount, captureCount, quietCount, singularLMR; // Step 1. Initialize node Thread* thisThread = pos.this_thread(); inCheck = pos.checkers(); Color us = pos.side_to_move(); - moveCount = captureCount = quietCount = ss->moveCount = 0; + moveCount = captureCount = quietCount = singularLMR = ss->moveCount = 0; bestValue = -VALUE_INFINITE; maxValue = VALUE_INFINITE; @@ -589,10 +585,10 @@ namespace { // starts with statScore = 0. Later grandchildren start with the last calculated // 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; - else - (ss + 2)->statScore = 0; + if (rootNode) + (ss + 4)->statScore = 0; + else + (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 @@ -603,7 +599,7 @@ namespace { ttValue = ttHit ? value_from_tt(tte->value(), ss->ply) : VALUE_NONE; ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE; - ttPv = (ttHit && tte->is_pv()) || (PvNode && depth > 4 * ONE_PLY); + ttPv = PvNode || (ttHit && tte->is_pv()); // At non-PV nodes we check for an early TT cutoff if ( !PvNode @@ -850,7 +846,6 @@ moves_loop: // When in check, search starts from here value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc moveCountPruning = false; ttCapture = ttMove && pos.capture_or_promotion(ttMove); - int singularExtensionLMRmultiplier = 0; // Step 12. Loop through all pseudo-legal moves until no moves remain // or a beta cutoff occurs. @@ -907,12 +902,13 @@ moves_loop: // When in check, search starts from here ss->excludedMove = MOVE_NONE; if (value < singularBeta) - { + { extension = ONE_PLY; - singularExtensionLMRmultiplier++; + singularLMR++; + if (value < singularBeta - std::min(3 * depth / ONE_PLY, 39)) - singularExtensionLMRmultiplier++; - } + singularLMR++; + } // Multi-cut pruning // Our ttMove is assumed to fail high, and now we failed high also on a reduced @@ -958,7 +954,7 @@ 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(~us) > BishopValueMg)) { // Move count based pruning (~30 Elo) if (moveCountPruning) @@ -984,7 +980,8 @@ moves_loop: // When in check, search starts from here if (!pos.see_ge(move, Value(-29 * lmrDepth * lmrDepth))) continue; } - else if (!pos.see_ge(move, -PawnValueEg * (depth / ONE_PLY))) // (~20 Elo) + else if ((!givesCheck || !extension) + && !pos.see_ge(move, -PawnValueEg * (depth / ONE_PLY))) // (~20 Elo) continue; } @@ -1022,8 +1019,9 @@ moves_loop: // When in check, search starts from here // Decrease reduction if opponent's move count is high (~10 Elo) if ((ss-1)->moveCount > 15) r -= ONE_PLY; + // Decrease reduction if move has been singularly extended - r -= singularExtensionLMRmultiplier * ONE_PLY; + r -= singularLMR * ONE_PLY; if (!captureOrPromotion) { @@ -1059,7 +1057,7 @@ moves_loop: // When in check, search starts from here r -= ss->statScore / 20000 * ONE_PLY; } - Depth d = std::max(newDepth - std::max(r, DEPTH_ZERO), ONE_PLY); + Depth d = clamp(newDepth - r, ONE_PLY, newDepth); value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); @@ -1365,6 +1363,7 @@ moves_loop: // When in check, search starts from here // Don't search moves with negative SEE values if ( (!inCheck || evasionPrunable) + && (!givesCheck || !(pos.blockers_for_king(~pos.side_to_move()) & from_sq(move))) && !pos.see_ge(move)) continue; @@ -1475,7 +1474,7 @@ moves_loop: // When in check, search starts from here void update_capture_stats(const Position& pos, Move move, Move* captures, int captureCount, int bonus) { - CapturePieceToHistory& captureHistory = pos.this_thread()->captureHistory; + CapturePieceToHistory& captureHistory = pos.this_thread()->captureHistory; Piece moved_piece = pos.moved_piece(move); PieceType captured = type_of(pos.piece_on(to_sq(move))); @@ -1714,10 +1713,4 @@ void Tablebases::rank_root_moves(Position& pos, Search::RootMoves& rootMoves) { if (dtz_available || rootMoves[0].tbScore <= VALUE_DRAW) Cardinality = 0; } - else - { - // Assign the same rank to all moves - for (auto& m : rootMoves) - m.tbRank = 0; - } }