X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=325278fbc95acab4d559b94ae7a1787d2f8b0b9b;hp=2185a3214fc59dd651c3e6639669cbcead83d7df;hb=6e36860554c735775b93f7622806cea90f078480;hpb=e4f8a4fa7f5da8287579c0c74e292974c6acfd8d diff --git a/src/search.cpp b/src/search.cpp index 2185a321..325278fb 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -71,16 +71,6 @@ namespace { return Value((175 - 50 * improving) * d / ONE_PLY); } - // Margin for pruning capturing moves: almost linear in depth - constexpr int CapturePruneMargin[] = { 0, - 1 * PawnValueEg * 1055 / 1000, - 2 * PawnValueEg * 1042 / 1000, - 3 * PawnValueEg * 963 / 1000, - 4 * PawnValueEg * 1038 / 1000, - 5 * PawnValueEg * 950 / 1000, - 6 * PawnValueEg * 930 / 1000 - }; - // Futility and reductions lookup tables, initialized at startup int FutilityMoveCounts[2][16]; // [improving][depth] int Reductions[2][2][64][64]; // [pv][improving][depth][moveNumber] @@ -296,16 +286,17 @@ void Thread::search() { MainThread* mainThread = (this == Threads.main() ? Threads.main() : nullptr); double timeReduction = 1.0; Color us = rootPos.side_to_move(); + bool failedLow; std::memset(ss-4, 0, 7 * sizeof(Stack)); for (int i = 4; i > 0; i--) - (ss-i)->contHistory = this->contHistory[NO_PIECE][0].get(); // Use as sentinel + (ss-i)->continuationHistory = this->continuationHistory[NO_PIECE][0].get(); // Use as sentinel bestValue = delta = alpha = -VALUE_INFINITE; beta = VALUE_INFINITE; if (mainThread) - mainThread->bestMoveChanges = 0, mainThread->failedLow = false; + mainThread->bestMoveChanges = 0, failedLow = false; size_t multiPV = Options["MultiPV"]; Skill skill(Options["Skill Level"]); @@ -340,13 +331,13 @@ void Thread::search() { if (idx > 0) { int i = (idx - 1) % 20; - if (((rootDepth / ONE_PLY + rootPos.game_ply() + SkipPhase[i]) / SkipSize[i]) % 2) + if (((rootDepth / ONE_PLY + SkipPhase[i]) / SkipSize[i]) % 2) continue; // Retry with an incremented rootDepth } // Age out PV variability metric if (mainThread) - mainThread->bestMoveChanges *= 0.517, mainThread->failedLow = false; + mainThread->bestMoveChanges *= 0.517, failedLow = false; // Save the last iteration's scores before first PV line is searched and // all the move scores except the (new) PV are set to -VALUE_INFINITE. @@ -423,7 +414,7 @@ void Thread::search() { if (mainThread) { - mainThread->failedLow = true; + failedLow = true; Threads.stopOnPonderhit = false; } } @@ -471,7 +462,7 @@ void Thread::search() { && !Threads.stop && !Threads.stopOnPonderhit) { - const int F[] = { mainThread->failedLow, + const int F[] = { failedLow, bestValue - mainThread->previousScore }; int improvingFactor = std::max(246, std::min(832, 306 + 119 * F[0] - 6 * F[1])); @@ -522,7 +513,7 @@ namespace { constexpr bool PvNode = NT == PV; const bool rootNode = PvNode && ss->ply == 0; - // Check if we have an upcoming move which draws by repetition, or + // Check if we have an upcoming move which draws by repetition, or // if the opponent had an alternative move earlier to this position. if ( pos.rule50_count() >= 3 && alpha < VALUE_DRAW @@ -596,7 +587,7 @@ namespace { (ss+1)->ply = ss->ply + 1; ss->currentMove = (ss+1)->excludedMove = bestMove = MOVE_NONE; - ss->contHistory = thisThread->contHistory[NO_PIECE][0].get(); + ss->continuationHistory = thisThread->continuationHistory[NO_PIECE][0].get(); (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE; Square prevSq = to_sq((ss-1)->currentMove); @@ -679,7 +670,7 @@ namespace { { 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()); + MOVE_NONE, VALUE_NONE); return value; } @@ -720,7 +711,7 @@ namespace { : -(ss-1)->staticEval + 2 * Eval::Tempo; tte->save(posKey, VALUE_NONE, BOUND_NONE, DEPTH_NONE, MOVE_NONE, - ss->staticEval, TT.generation()); + ss->staticEval); } // Step 7. Razoring (~2 Elo) @@ -760,7 +751,7 @@ namespace { Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY; ss->currentMove = MOVE_NULL; - ss->contHistory = thisThread->contHistory[NO_PIECE][0].get(); + ss->continuationHistory = thisThread->continuationHistory[NO_PIECE][0].get(); pos.do_null_move(st); @@ -811,7 +802,7 @@ namespace { probCutCount++; ss->currentMove = move; - ss->contHistory = thisThread->contHistory[pos.moved_piece(move)][to_sq(move)].get(); + ss->continuationHistory = thisThread->continuationHistory[pos.moved_piece(move)][to_sq(move)].get(); assert(depth >= 5 * ONE_PLY); @@ -844,7 +835,7 @@ namespace { moves_loop: // When in check, search starts from here - const PieceToHistory* contHist[] = { (ss-1)->contHistory, (ss-2)->contHistory, nullptr, (ss-4)->contHistory }; + const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, nullptr, (ss-4)->continuationHistory }; Move countermove = thisThread->counterMoves[pos.piece_on(prevSq)][prevSq]; MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, @@ -944,7 +935,8 @@ moves_loop: // When in check, search starts from here int lmrDepth = std::max(newDepth - reduction(improving, depth, moveCount), DEPTH_ZERO) / ONE_PLY; // Countermoves based pruning (~20 Elo) - if ( lmrDepth < 3 + if ( lmrDepth < 4 + && (lmrDepth < 3 || ((ss - 1)->statScore > 0 && !PvNode)) && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold) continue; @@ -956,13 +948,11 @@ moves_loop: // When in check, search starts from here continue; // Prune moves with negative SEE (~10 Elo) - if ( lmrDepth < 8 - && !pos.see_ge(move, Value(-35 * lmrDepth * lmrDepth))) + if (!pos.see_ge(move, Value(-29 * lmrDepth * lmrDepth))) continue; } - else if ( depth < 7 * ONE_PLY // (~20 Elo) - && !extension - && !pos.see_ge(move, -Value(CapturePruneMargin[depth / ONE_PLY]))) + else if ( !extension // (~20 Elo) + && !pos.see_ge(move, -PawnValueEg * (depth / ONE_PLY))) continue; } @@ -981,7 +971,7 @@ moves_loop: // When in check, search starts from here // Update the current move (this must be done after singular extension search) ss->currentMove = move; - ss->contHistory = thisThread->contHistory[movedPiece][to_sq(move)].get(); + ss->continuationHistory = thisThread->continuationHistory[movedPiece][to_sq(move)].get(); // Step 15. Make the move pos.do_move(move, st, givesCheck); @@ -996,11 +986,9 @@ moves_loop: // When in check, search starts from here if (captureOrPromotion) // (~5 Elo) { - // Increase reduction by comparing opponent's stat score - if ((ss-1)->statScore >= 0) - r += ONE_PLY; - - r -= r ? ONE_PLY : DEPTH_ZERO; + // Decrease reduction by comparing opponent's stat score + if ((ss-1)->statScore < 0) + r -= ONE_PLY; } else { @@ -1041,10 +1029,10 @@ moves_loop: // When in check, search starts from here r += ONE_PLY; // Decrease/increase reduction for moves with a good/bad history (~30 Elo) - r = std::max(DEPTH_ZERO, (r / ONE_PLY - ss->statScore / 20000) * ONE_PLY); + r -= ss->statScore / 20000 * ONE_PLY; } - Depth d = std::max(newDepth - r, ONE_PLY); + Depth d = std::max(newDepth - std::max(r, DEPTH_ZERO), ONE_PLY); value = -search(pos, ss+1, -(alpha+1), -alpha, d, true); @@ -1164,10 +1152,10 @@ moves_loop: // When in check, search starts from here { // Quiet best move: update move sorting heuristics if (!pos.capture_or_promotion(bestMove)) - update_quiet_stats(pos, ss, bestMove, quietsSearched, quietCount, stat_bonus(depth)); - else - update_capture_stats(pos, bestMove, capturesSearched, captureCount, - stat_bonus(depth + (bestValue > beta + KnightValueMg ? ONE_PLY : DEPTH_ZERO))); + update_quiet_stats(pos, ss, bestMove, quietsSearched, quietCount, + stat_bonus(depth + (bestValue > beta + PawnValueMg ? ONE_PLY : DEPTH_ZERO))); + + update_capture_stats(pos, bestMove, capturesSearched, captureCount, stat_bonus(depth + ONE_PLY)); // Extra penalty for a quiet TT move in previous ply when it gets refuted if ((ss-1)->moveCount == 1 && !pos.captured_piece()) @@ -1186,7 +1174,7 @@ moves_loop: // When in check, search starts from here tte->save(posKey, value_to_tt(bestValue, ss->ply), bestValue >= beta ? BOUND_LOWER : PvNode && bestMove ? BOUND_EXACT : BOUND_UPPER, - depth, bestMove, ss->staticEval, TT.generation()); + depth, bestMove, ss->staticEval); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1223,8 +1211,10 @@ moves_loop: // When in check, search starts from here ss->pv[0] = MOVE_NONE; } + Thread* thisThread = pos.this_thread(); (ss+1)->ply = ss->ply + 1; ss->currentMove = bestMove = MOVE_NONE; + ss->continuationHistory = thisThread->continuationHistory[NO_PIECE][0].get(); inCheck = pos.checkers(); moveCount = 0; @@ -1250,8 +1240,8 @@ moves_loop: // When in check, search starts from here && ttHit && tte->depth() >= ttDepth && ttValue != VALUE_NONE // Only in case of TT access race - && (ttValue >= beta ? (tte->bound() & BOUND_LOWER) - : (tte->bound() & BOUND_UPPER))) + && (ttValue >= beta ? (tte->bound() & BOUND_LOWER) + : (tte->bound() & BOUND_UPPER))) return ttValue; // Evaluate the position statically @@ -1269,7 +1259,7 @@ moves_loop: // When in check, search starts from here ss->staticEval = bestValue = evaluate(pos); // Can ttValue be used as a better position evaluation? - if ( ttValue != VALUE_NONE + if ( ttValue != VALUE_NONE && (tte->bound() & (ttValue > bestValue ? BOUND_LOWER : BOUND_UPPER))) bestValue = ttValue; } @@ -1283,7 +1273,7 @@ moves_loop: // When in check, search starts from here { if (!ttHit) tte->save(posKey, value_to_tt(bestValue, ss->ply), BOUND_LOWER, - DEPTH_NONE, MOVE_NONE, ss->staticEval, TT.generation()); + DEPTH_NONE, MOVE_NONE, ss->staticEval); return bestValue; } @@ -1294,12 +1284,15 @@ moves_loop: // When in check, search starts from here futilityBase = bestValue + 128; } + const PieceToHistory* contHist[] = { (ss-1)->continuationHistory, (ss-2)->continuationHistory, nullptr, (ss-4)->continuationHistory }; + // Initialize a MovePicker object for the current position, and prepare // to search the moves. Because the depth is <= 0 here, only captures, // queen promotions and checks (only if depth >= DEPTH_QS_CHECKS) will // be generated. - MovePicker mp(pos, ttMove, depth, &pos.this_thread()->mainHistory, - &pos.this_thread()->captureHistory, + MovePicker mp(pos, ttMove, depth, &thisThread->mainHistory, + &thisThread->captureHistory, + contHist, to_sq((ss-1)->currentMove)); // Loop through the moves until no moves remain or a beta cutoff occurs @@ -1356,6 +1349,7 @@ moves_loop: // When in check, search starts from here } ss->currentMove = move; + ss->continuationHistory = thisThread->continuationHistory[pos.moved_piece(move)][to_sq(move)].get(); // Make and search the move pos.do_move(move, st, givesCheck); @@ -1382,7 +1376,7 @@ moves_loop: // When in check, search starts from here else // Fail high { tte->save(posKey, value_to_tt(value, ss->ply), BOUND_LOWER, - ttDepth, move, ss->staticEval, TT.generation()); + ttDepth, move, ss->staticEval); return value; } @@ -1397,7 +1391,7 @@ moves_loop: // When in check, search starts from here tte->save(posKey, value_to_tt(bestValue, ss->ply), PvNode && bestValue > oldAlpha ? BOUND_EXACT : BOUND_UPPER, - ttDepth, bestMove, ss->staticEval, TT.generation()); + ttDepth, bestMove, ss->staticEval); assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE); @@ -1447,7 +1441,7 @@ moves_loop: // When in check, search starts from here for (int i : {1, 2, 4}) if (is_ok((ss-i)->currentMove)) - (*(ss-i)->contHistory)[pc][to] << bonus; + (*(ss-i)->continuationHistory)[pc][to] << bonus; } @@ -1459,7 +1453,9 @@ moves_loop: // When in check, search starts from here CapturePieceToHistory& captureHistory = pos.this_thread()->captureHistory; Piece moved_piece = pos.moved_piece(move); PieceType captured = type_of(pos.piece_on(to_sq(move))); - captureHistory[moved_piece][to_sq(move)][captured] << bonus; + + if (pos.capture_or_promotion(move)) + captureHistory[moved_piece][to_sq(move)][captured] << bonus; // Decrease all the other played capture moves for (int i = 0; i < captureCnt; ++i)