X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=0d823c8e02425d1cf617d7a7e1939490d4c4b600;hp=266e2db30d0f2516abeb078a894cce3e16136d39;hb=0e1f734b05ee5c67e9a17ae0e2045a64209dee05;hpb=d5f86b63597fdb25b8c670e42ca468c99ca95a74 diff --git a/src/search.cpp b/src/search.cpp index 266e2db3..0d823c8e 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -597,7 +597,7 @@ namespace { Move ttMove, move, excludedMove, bestMove; Depth extension, newDepth; Value bestValue, value, ttValue, eval, maxValue, probCutBeta; - bool ttHit, ttPv, formerPv, givesCheck, improving, didLMR, priorCapture; + bool ttHit, formerPv, givesCheck, improving, didLMR, priorCapture; bool captureOrPromotion, doFullDepthSearch, moveCountPruning, ttCapture, singularQuietLMR; Piece movedPiece; @@ -644,6 +644,7 @@ namespace { assert(0 <= ss->ply && ss->ply < MAX_PLY); (ss+1)->ply = ss->ply + 1; + (ss+1)->ttPv = false; (ss+1)->excludedMove = bestMove = MOVE_NONE; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; Square prevSq = to_sq((ss-1)->currentMove); @@ -667,10 +668,11 @@ namespace { ttValue = ttHit ? value_from_tt(tte->value(), ss->ply, pos.rule50_count()) : VALUE_NONE; ttMove = rootNode ? thisThread->rootMoves[thisThread->pvIdx].pv[0] : ttHit ? tte->move() : MOVE_NONE; - ttPv = PvNode || (ttHit && tte->is_pv()); - formerPv = ttPv && !PvNode; + if (!excludedMove) + ss->ttPv = PvNode || (ttHit && tte->is_pv()); + formerPv = ss->ttPv && !PvNode; - if ( ttPv + if ( ss->ttPv && depth > 12 && ss->ply - 1 < MAX_LPH && !priorCapture @@ -748,7 +750,7 @@ namespace { if ( b == BOUND_EXACT || (b == BOUND_LOWER ? value >= beta : value <= alpha)) { - tte->save(posKey, value_to_tt(value, ss->ply), ttPv, b, + tte->save(posKey, value_to_tt(value, ss->ply), ss->ttPv, b, std::min(MAX_PLY - 1, depth + 6), MOVE_NONE, VALUE_NONE); @@ -798,7 +800,7 @@ namespace { else ss->staticEval = eval = -(ss-1)->staticEval + 2 * Tempo; - tte->save(posKey, VALUE_NONE, ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval); + tte->save(posKey, VALUE_NONE, ss->ttPv, BOUND_NONE, DEPTH_NONE, MOVE_NONE, eval); } // Step 7. Razoring (~1 Elo) @@ -824,7 +826,7 @@ namespace { && (ss-1)->statScore < 22977 && eval >= beta && eval >= ss->staticEval - && ss->staticEval >= beta - 30 * depth - 28 * improving + 84 * ttPv + 182 + && ss->staticEval >= beta - 30 * depth - 28 * improving + 84 * ss->ttPv + 182 && !excludedMove && pos.non_pawn_material(us) && (ss->ply >= thisThread->nmpMinPly || us != thisThread->nmpColor)) @@ -898,6 +900,8 @@ namespace { assert(probCutBeta < VALUE_INFINITE); MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory); int probCutCount = 0; + bool ttPv = ss->ttPv; + ss->ttPv = false; while ( (move = mp.next_move()) != MOVE_NONE && probCutCount < 2 + 2 * cutNode) @@ -938,6 +942,7 @@ namespace { return value; } } + ss->ttPv = ttPv; } // Step 11. If the position is not in TT, decrease depth by 2 @@ -1155,7 +1160,6 @@ moves_loop: // When in check, search starts from here // re-searched at full depth. if ( depth >= 3 && moveCount > 1 + 2 * rootNode + 2 * (PvNode && abs(bestValue) < 2) - && (!rootNode || thisThread->best_move_count(move) == 0) && ( !captureOrPromotion || moveCountPruning || ss->staticEval + PieceValue[EG][pos.captured_piece()] <= alpha @@ -1180,7 +1184,7 @@ moves_loop: // When in check, search starts from here r++; // Decrease reduction if position is or has been on the PV (~10 Elo) - if (ttPv) + if (ss->ttPv) r -= 2; if (moveCountPruning && !formerPv) @@ -1209,7 +1213,7 @@ moves_loop: // When in check, search starts from here // hence break make_move(). (~2 Elo) else if ( type_of(move) == NORMAL && !pos.see_ge(reverse_move(move))) - r -= 2 + ttPv - (type_of(movedPiece) == PAWN); + r -= 2 + ss->ttPv - (type_of(movedPiece) == PAWN); ss->statScore = thisThread->mainHistory[us][from_to(move)] + (*contHist[0])[movedPiece][to_sq(move)] @@ -1387,8 +1391,17 @@ moves_loop: // When in check, search starts from here if (PvNode) bestValue = std::min(bestValue, maxValue); + // If no good move is found and the previous position was ttPv, then the previous + // opponent move is probably good and the new position is added to the search tree. + if (bestValue <= alpha) + ss->ttPv = ss->ttPv || ((ss-1)->ttPv && depth > 3); + // Otherwise, a counter move has been found and if the position is the last leaf + // in the search tree, remove the position from the search tree. + else if (depth > 3) + ss->ttPv = ss->ttPv && (ss+1)->ttPv; + if (!excludedMove && !(rootNode && thisThread->pvIdx)) - tte->save(posKey, value_to_tt(bestValue, ss->ply), ttPv, + tte->save(posKey, value_to_tt(bestValue, ss->ply), ss->ttPv, bestValue >= beta ? BOUND_LOWER : PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER, depth, bestMove, ss->staticEval); @@ -1532,7 +1545,7 @@ moves_loop: // When in check, search starts from here assert(type_of(move) != ENPASSANT); // Due to !pos.advanced_pawn_push // moveCount pruning - if (moveCount > abs(depth) + 2) + if (moveCount > 2) continue; futilityValue = futilityBase + PieceValue[EG][pos.piece_on(to_sq(move))]; @@ -1551,7 +1564,9 @@ moves_loop: // When in check, search starts from here } // Do not search moves with negative SEE values - if (!ss->inCheck && !pos.see_ge(move)) + if ( !ss->inCheck + && !(givesCheck && pos.is_discovery_check_on_king(~pos.side_to_move(), move)) + && !pos.see_ge(move)) continue; // Speculative prefetch as early as possible @@ -1570,6 +1585,12 @@ moves_loop: // When in check, search starts from here [pos.moved_piece(move)] [to_sq(move)]; + if ( !captureOrPromotion + && moveCount + && (*contHist[0])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold + && (*contHist[1])[pos.moved_piece(move)][to_sq(move)] < CounterMovePruneThreshold) + continue; + // Make and search the move pos.do_move(move, st, givesCheck); value = -qsearch(pos, ss+1, -beta, -alpha, depth - 1); @@ -1841,12 +1862,15 @@ string UCI::pv(const Position& pos, Depth depth, Value alpha, Value beta) { { bool updated = rootMoves[i].score != -VALUE_INFINITE; - if (depth == 1 && !updated) + if (depth == 1 && !updated && i > 0) continue; - Depth d = updated ? depth : depth - 1; + Depth d = updated ? depth : std::max(1, depth - 1); Value v = updated ? rootMoves[i].score : rootMoves[i].previousScore; + if (v == -VALUE_INFINITE) + v = VALUE_ZERO; + bool tb = TB::RootInTB && abs(v) < VALUE_MATE_IN_MAX_PLY; v = tb ? rootMoves[i].tbScore : v; @@ -1944,7 +1968,7 @@ void Tablebases::rank_root_moves(Position& pos, Search::RootMoves& rootMoves) { if (RootInTB) { // Sort moves according to TB rank - std::sort(rootMoves.begin(), rootMoves.end(), + std::stable_sort(rootMoves.begin(), rootMoves.end(), [](const RootMove &a, const RootMove &b) { return a.tbRank > b.tbRank; } ); // Probe during search only if DTZ is not available and we are winning