X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=9d3734b89365c670415c0a9f8070526ea1e4bc90;hp=7970a393d003848a537f9e4c18650266fd12580d;hb=8a61b030a6cbfa70b7a473e31ae2662f1b8f39b9;hpb=ccf4ec6768b17f47b48a296978bc19e3eaaa70ba diff --git a/src/search.cpp b/src/search.cpp index 7970a393..9d3734b8 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -88,6 +88,7 @@ namespace { Value DrawValue[COLOR_NB]; History Hist; Gains Gain; + RefutationTable Refutation; template Value search(Position& pos, Stack* ss, Value alpha, Value beta, Depth depth); @@ -145,7 +146,7 @@ void Search::init() { // Init futility move count array for (d = 0; d < 32; d++) - FutilityMoveCounts[d] = int(3.001 + 0.25 * pow(double(d), 2.0)); + FutilityMoveCounts[d] = int(3.001 + 0.3 * pow(double(d), 1.8)); } @@ -264,6 +265,10 @@ void Search::think() { finalize: + // When search is stopped this info is not printed + sync_cout << "info nodes " << RootPos.nodes_searched() + << " time " << Time::now() - SearchTime + 1 << sync_endl; + // When we reach max depth we arrive here even without Signals.stop is raised, // but if we are pondering or in infinite search, according to UCI protocol, // we shouldn't print the best move before the GUI sends a "stop" or "ponderhit" @@ -293,7 +298,6 @@ namespace { Stack ss[MAX_PLY_PLUS_2]; int depth, prevBestMoveChanges; Value bestValue, alpha, beta, delta; - bool triedEasyMove = false; memset(ss, 0, 4 * sizeof(Stack)); depth = BestMoveChanges = 0; @@ -302,6 +306,7 @@ namespace { TT.new_search(); Hist.clear(); Gain.clear(); + Refutation.clear(); PVSize = Options["MultiPV"]; Skill skill(Options["Skill Level"]); @@ -440,12 +445,11 @@ namespace { // Stop search early if one move seems to be much better than others if ( depth >= 12 && !stop - && !triedEasyMove && PVSize == 1 + && bestValue > VALUE_MATED_IN_MAX_PLY && ( RootMoves.size() == 1 || Time::now() - SearchTime > (TimeMgr.available_time() * 20) / 100)) { - triedEasyMove = true; Value rBeta = bestValue - 2 * PawnValueMg; (ss+1)->excludedMove = RootMoves[0].pv[0]; (ss+1)->skipNullMove = true; @@ -525,6 +529,7 @@ namespace { bestValue = -VALUE_INFINITE; ss->currentMove = threatMove = (ss+1)->excludedMove = bestMove = MOVE_NONE; ss->ply = (ss-1)->ply + 1; + ss->futilityMoveCount = 0; (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO; (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; @@ -535,7 +540,7 @@ namespace { if (!RootNode) { // Step 2. Check for aborted search and immediate draw - if (Signals.stop || pos.is_draw() || ss->ply > MAX_PLY) + if (Signals.stop || pos.is_draw() || ss->ply > MAX_PLY) return DrawValue[pos.side_to_move()]; // Step 3. Mate distance pruning. Even if we mate at the next move our score @@ -645,10 +650,11 @@ namespace { && !ss->skipNullMove && depth < 4 * ONE_PLY && !inCheck - && eval - FutilityMargins[depth][0] >= beta + && eval - futility_margin(depth, (ss-1)->futilityMoveCount) >= beta && abs(beta) < VALUE_MATE_IN_MAX_PLY + && abs(eval) < VALUE_KNOWN_WIN && pos.non_pawn_material(pos.side_to_move())) - return eval - FutilityMargins[depth][0]; + return eval - futility_margin(depth, (ss-1)->futilityMoveCount); // Step 8. Null move search with verification search (is omitted in PV nodes) if ( !PvNode @@ -681,7 +687,7 @@ namespace { if (nullValue >= VALUE_MATE_IN_MAX_PLY) nullValue = beta; - if (depth < 6 * ONE_PLY) + if (depth < 12 * ONE_PLY) return nullValue; // Do verification search at high depths @@ -748,7 +754,7 @@ namespace { && ttMove == MOVE_NONE && (PvNode || (!inCheck && ss->staticEval + Value(256) >= beta))) { - Depth d = (PvNode ? depth - 2 * ONE_PLY : depth / 2); + Depth d = depth - 2 * ONE_PLY - (PvNode ? DEPTH_ZERO : depth / 4); ss->skipNullMove = true; search(pos, ss, alpha, beta, d); @@ -760,7 +766,12 @@ namespace { split_point_start: // At split points actual search starts from here - MovePicker mp(pos, ttMove, depth, Hist, ss, PvNode ? -VALUE_INFINITE : beta); + Move prevMove = (ss-1)->currentMove; + Square prevSq = to_sq(prevMove); + Piece prevP = pos.piece_on(prevSq); + Move refutationMove = Refutation.get(prevP, prevSq); + + MovePicker mp(pos, ttMove, depth, Hist, ss, refutationMove, PvNode ? -VALUE_INFINITE : beta); CheckInfo ci(pos); value = bestValue; // Workaround a bogus 'uninitialized' warning under gcc singularExtensionNode = !RootNode @@ -859,7 +870,8 @@ split_point_start: // At split points actual search starts from here && !captureOrPromotion && !inCheck && !dangerous - && move != ttMove) + /* && move != ttMove Already implicit in the next condition */ + && bestValue > VALUE_MATED_IN_MAX_PLY) { // Move count based pruning if ( depth < 16 * ONE_PLY @@ -881,14 +893,19 @@ split_point_start: // At split points actual search starts from here if (futilityValue < beta) { + bestValue = std::max(bestValue, futilityValue); + if (SpNode) + { splitPoint->mutex.lock(); - + if (bestValue > splitPoint->bestValue) + splitPoint->bestValue = bestValue; + } continue; } // Prune moves with negative SEE at low depths - if ( predictedDepth < 3 * ONE_PLY + if ( predictedDepth < 4 * ONE_PLY && pos.see_sign(move) < 0) { if (SpNode) @@ -896,7 +913,13 @@ split_point_start: // At split points actual search starts from here continue; } + + // We have not pruned the move that will be searched, but remember how + // far in the move list we are to be more aggressive in the child node. + ss->futilityMoveCount = moveCount; } + else + ss->futilityMoveCount = 0; // Check for legality only before to do the move if (!RootNode && !SpNode && !pos.pl_move_is_legal(move, ci.pinned)) @@ -1074,6 +1097,7 @@ split_point_start: // At split points actual search starts from here // Increase history value of the cut-off move Value bonus = Value(int(depth) * int(depth)); Hist.update(pos.piece_moved(bestMove), to_sq(bestMove), bonus); + Refutation.update(prevP, prevSq, bestMove); // Decrease history of all the other played non-capture moves for (int i = 0; i < playedMoveCount - 1; i++) @@ -1125,7 +1149,7 @@ split_point_start: // At split points actual search starts from here ss->ply = (ss-1)->ply + 1; // Check for an instant draw or maximum ply reached - if (pos.is_draw() || ss->ply > MAX_PLY) + if (pos.is_draw() || ss->ply > MAX_PLY) return DrawValue[pos.side_to_move()]; // Decide whether or not to include checks, this fixes also the type of @@ -1221,10 +1245,11 @@ split_point_start: // At split points actual search starts from here continue; } - // Prune moves with negative or equal SEE + // Prune moves with negative or equal SEE and also moves with positive + // SEE where capturing piece loses a tempo and SEE < beta - futilityBase. if ( futilityBase < beta && depth < DEPTH_ZERO - && pos.see(move) <= 0) + && pos.see(move, beta - futilityBase) <= 0) { bestValue = std::max(bestValue, futilityBase); continue; @@ -1574,7 +1599,7 @@ void RootMove::extract_pv_from_tt(Position& pos) { && pos.is_pseudo_legal(m = tte->move()) // Local copy, TT could change && pos.pl_move_is_legal(m, pos.pinned_pieces()) && ply < MAX_PLY - && (!pos.is_draw() || ply < 2)); + && (!pos.is_draw() || ply < 2)); pv.push_back(MOVE_NONE); // Must be zero-terminating