X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=e6e53e7c59d147d16aaa588670dd989f7ad66f76;hp=ba13680cecbb1e4ade4f3a6264218a2d9679e740;hb=e0bafa1911ede61b9268e0b461a5d8856d6cd6be;hpb=e64b957274b94e89ad1a6e3ec4571c9082246a0a diff --git a/src/search.cpp b/src/search.cpp index ba13680c..e6e53e7c 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -335,7 +335,7 @@ void Thread::search() { // for match (TC 60+0.6) results spanning a wide range of k values. PRNG rng(now()); double floatLevel = Options["UCI_LimitStrength"] ? - Utility::clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) : + std::clamp(std::pow((Options["UCI_Elo"] - 1346.6) / 143.4, 1 / 0.806), 0.0, 20.0) : double(Options["Skill Level"]); int intLevel = int(floatLevel) + ((floatLevel - int(floatLevel)) * 1024 > rng.rand() % 1024 ? 1 : 0); @@ -508,7 +508,7 @@ void Thread::search() { { double fallingEval = (318 + 6 * (mainThread->bestPreviousScore - bestValue) + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0; - fallingEval = Utility::clamp(fallingEval, 0.5, 1.5); + fallingEval = std::clamp(fallingEval, 0.5, 1.5); // If the bestMove is stable over several iterations, reduce time accordingly timeReduction = lastBestMoveDepth + 9 < completedDepth ? 1.92 : 0.95; @@ -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) @@ -807,8 +809,9 @@ namespace { && eval <= alpha - RazorMargin) return qsearch(pos, ss, alpha, beta); - improving = (ss-2)->staticEval == VALUE_NONE ? (ss->staticEval > (ss-4)->staticEval - || (ss-4)->staticEval == VALUE_NONE) : ss->staticEval > (ss-2)->staticEval; + improving = (ss-2)->staticEval == VALUE_NONE + ? ss->staticEval > (ss-4)->staticEval || (ss-4)->staticEval == VALUE_NONE + : ss->staticEval > (ss-2)->staticEval; // Step 8. Futility pruning: child node (~50 Elo) if ( !PvNode @@ -823,7 +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)) @@ -879,8 +882,8 @@ namespace { // there and in further interactions with transposition table cutoff depth is set to depth - 3 // because probCut search has depth set to depth - 4 but we also do a move before it // so effective depth is equal to depth - 3 - && !( ttHit - && tte->depth() >= depth - 3 + && !( ttHit + && tte->depth() >= depth - 3 && ttValue != VALUE_NONE && ttValue < probCutBeta)) { @@ -897,6 +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) @@ -937,6 +942,7 @@ namespace { return value; } } + ss->ttPv = ttPv; } // Step 11. If the position is not in TT, decrease depth by 2 @@ -1179,7 +1185,7 @@ 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) @@ -1208,7 +1214,7 @@ 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)] @@ -1238,7 +1244,7 @@ moves_loop: // When in check, search starts from here r++; } - Depth d = Utility::clamp(newDepth - r, 1, newDepth); + Depth d = std::clamp(newDepth - r, 1, newDepth); value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); @@ -1386,8 +1392,17 @@ 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); @@ -1530,6 +1545,10 @@ moves_loop: // When in check, search starts from here { assert(type_of(move) != ENPASSANT); // Due to !pos.advanced_pawn_push + // moveCount pruning + if (moveCount > 2) + continue; + futilityValue = futilityBase + PieceValue[EG][pos.piece_on(to_sq(move))]; if (futilityValue <= alpha) @@ -1546,7 +1565,7 @@ 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 && !pos.see_ge(move)) continue; // Speculative prefetch as early as possible @@ -1565,6 +1584,12 @@ 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);