X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=b9ce9a621175023d284ea8ba90c47ce3e29c881a;hp=66c432fc823c51bc7e780c18c4cc3119055a0499;hb=414a3e6ee3ab38215f9eba69939773ba62a9766e;hpb=9afa1d73306cb98e95acec5daf4efd65e592ceff diff --git a/src/search.cpp b/src/search.cpp index 66c432fc..b9ce9a62 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -67,8 +67,7 @@ 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 - // razor_margin[0] is unused as long as depth >= ONE_PLY in search - const int razor_margin[] = { 0, 570, 603, 554 }; + const int razor_margin = 600; Value futility_margin(Depth d) { return Value(150 * d / ONE_PLY); } // Futility and reductions lookup tables, initialized at startup @@ -500,7 +499,7 @@ namespace { Key posKey; Move ttMove, move, excludedMove, bestMove; Depth extension, newDepth; - Value bestValue, value, ttValue, eval; + Value bestValue, value, ttValue, eval, maxValue; bool ttHit, inCheck, givesCheck, singularExtensionNode, improving; bool captureOrPromotion, doFullDepthSearch, moveCountPruning, skipQuiets, ttCapture, pvExact; Piece movedPiece; @@ -512,6 +511,7 @@ namespace { moveCount = captureCount = quietCount = ss->moveCount = 0; ss->statScore = 0; bestValue = -VALUE_INFINITE; + maxValue = VALUE_INFINITE; // Check for the available remaining time if (thisThread == Threads.main()) @@ -599,7 +599,7 @@ namespace { && !pos.can_castle(ANY_CASTLING)) { TB::ProbeState err; - TB::WDLScore v = Tablebases::probe_wdl(pos, &err); + TB::WDLScore wdl = Tablebases::probe_wdl(pos, &err); if (err != TB::ProbeState::FAIL) { @@ -607,15 +607,30 @@ namespace { int drawScore = TB::UseRule50 ? 1 : 0; - value = v < -drawScore ? -VALUE_MATE + MAX_PLY + ss->ply + 1 - : v > drawScore ? VALUE_MATE - MAX_PLY - ss->ply - 1 - : VALUE_DRAW + 2 * v * drawScore; + value = wdl < -drawScore ? -VALUE_MATE + MAX_PLY + ss->ply + 1 + : wdl > drawScore ? VALUE_MATE - MAX_PLY - ss->ply - 1 + : VALUE_DRAW + 2 * wdl * drawScore; - tte->save(posKey, value_to_tt(value, ss->ply), BOUND_EXACT, - std::min(DEPTH_MAX - ONE_PLY, depth + 6 * ONE_PLY), - MOVE_NONE, VALUE_NONE, TT.generation()); + Bound b = wdl < -drawScore ? BOUND_UPPER + : wdl > drawScore ? BOUND_LOWER : BOUND_EXACT; - return value; + if ( b == BOUND_EXACT + || (b == BOUND_LOWER ? value >= beta : value <= alpha)) + { + tte->save(posKey, value_to_tt(value, ss->ply), b, + std::min(DEPTH_MAX - ONE_PLY, depth + 6 * ONE_PLY), + MOVE_NONE, VALUE_NONE, TT.generation()); + + return value; + } + + if (PvNode) + { + if (b == BOUND_LOWER) + bestValue = value, alpha = std::max(alpha, bestValue); + else + maxValue = value; + } } } } @@ -654,12 +669,12 @@ namespace { // Step 6. Razoring (skipped when in check) if ( !PvNode && depth < 4 * ONE_PLY - && eval + razor_margin[depth / ONE_PLY] <= alpha) + && eval + razor_margin <= alpha) { if (depth <= ONE_PLY) return qsearch(pos, ss, alpha, alpha+1); - Value ralpha = alpha - razor_margin[depth / ONE_PLY]; + Value ralpha = alpha - razor_margin; Value v = qsearch(pos, ss, ralpha, ralpha+1); if (v <= ralpha) return v; @@ -676,7 +691,7 @@ namespace { if ( !PvNode && eval >= beta && ss->staticEval >= beta - 36 * depth / ONE_PLY + 225 - && (ss->ply >= thisThread->nmp_ply || ss->ply % 2 == thisThread->pair)) + && (ss->ply >= thisThread->nmp_ply || ss->ply % 2 != thisThread->nmp_odd)) { assert(eval - beta >= 0); @@ -698,21 +713,18 @@ namespace { if (nullValue >= VALUE_MATE_IN_MAX_PLY) nullValue = beta; - if (depth < 12 * ONE_PLY && abs(beta) < VALUE_KNOWN_WIN) + if (abs(beta) < VALUE_KNOWN_WIN && (depth < 12 * ONE_PLY || thisThread->nmp_ply)) return nullValue; // Do verification search at high depths - R += ONE_PLY; // disable null move pruning for side to move for the first part of the remaining search tree - int nmp_ply = thisThread->nmp_ply; - int pair = thisThread->pair; thisThread->nmp_ply = ss->ply + 3 * (depth-R) / 4; - thisThread->pair = (ss->ply % 2) == 0; + thisThread->nmp_odd = ss->ply % 2; Value v = depth-R < ONE_PLY ? qsearch(pos, ss, beta-1, beta) : search(pos, ss, beta-1, beta, depth-R, false, true); - thisThread->pair = pair; - thisThread->nmp_ply = nmp_ply; + + thisThread->nmp_odd = thisThread->nmp_ply = 0; if (v >= beta) return nullValue; @@ -1095,6 +1107,9 @@ moves_loop: // When in check search starts from here && is_ok((ss-1)->currentMove)) update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth)); + if (PvNode) + bestValue = std::min(bestValue, maxValue); + if (!excludedMove) tte->save(posKey, value_to_tt(bestValue, ss->ply), bestValue >= beta ? BOUND_LOWER : @@ -1255,7 +1270,6 @@ moves_loop: // When in check search starts from here // Don't search moves with negative SEE values if ( (!InCheck || evasionPrunable) - && type_of(move) != PROMOTION && !pos.see_ge(move)) continue; @@ -1497,7 +1511,7 @@ moves_loop: // When in check search starts from here if (Threads.ponder) return; - if ( (Limits.use_time_management() && elapsed > Time.maximum()) + if ( (Limits.use_time_management() && elapsed > Time.maximum() - 10) || (Limits.movetime && elapsed >= Limits.movetime) || (Limits.nodes && Threads.nodes_searched() >= (uint64_t)Limits.nodes)) Threads.stop = true; @@ -1631,4 +1645,9 @@ void Tablebases::filter_root_moves(Position& pos, Search::RootMoves& rootMoves) TB::Score = TB::Score > VALUE_DRAW ? VALUE_MATE - MAX_PLY - 1 : TB::Score < VALUE_DRAW ? -VALUE_MATE + MAX_PLY + 1 : VALUE_DRAW; + + // Since root_probe() and root_probe_wdl() dirty the root move scores, + // we reset them to -VALUE_INFINITE + for (RootMove& rm : rootMoves) + rm.score = -VALUE_INFINITE; }