X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsearch.cpp;h=cded8614ad9d6c77851b5b71db034ec96baa0e38;hb=8e8234593190804babd36b8a8862e2bb1fc65bb7;hp=92ec9eca77dae75a800adf0f719c753288a233a4;hpb=092b27a6d0174f619fff9a53099ac9fdc5c2cb4e;p=stockfish diff --git a/src/search.cpp b/src/search.cpp index 92ec9eca..cded8614 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -260,6 +260,7 @@ void MainThread::search() { bestThread = Threads.get_best_thread(); bestPreviousScore = bestThread->rootMoves[0].score; + bestPreviousAverageScore = bestThread->rootMoves[0].averageScore; // Send again PV info if we have a new best thread if (bestThread != this) @@ -477,25 +478,26 @@ void Thread::search() { if (skill.enabled() && skill.time_to_pick(rootDepth)) skill.pick_best(multiPV); + // Use part of the gained time from a previous stable move for the current move + for (Thread* th : Threads) + { + totBestMoveChanges += th->bestMoveChanges; + th->bestMoveChanges = 0; + } + // Do we have time for the next iteration? Can we stop searching now? if ( Limits.use_time_management() && !Threads.stop && !mainThread->stopOnPonderhit) { - double fallingEval = (318 + 6 * (mainThread->bestPreviousScore - bestValue) + double fallingEval = (142 + 6 * (mainThread->bestPreviousScore - bestValue) + + 6 * (mainThread->bestPreviousAverageScore - bestValue) + 6 * (mainThread->iterValue[iterIdx] - bestValue)) / 825.0; 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; double reduction = (1.47 + mainThread->previousTimeReduction) / (2.32 * timeReduction); - - // Use part of the gained time from a previous stable move for the current move - for (Thread* th : Threads) - { - totBestMoveChanges += th->bestMoveChanges; - th->bestMoveChanges = 0; - } double bestMoveInstability = 1.073 + std::max(1.0, 2.25 - 9.9 / rootDepth) * totBestMoveChanges / Threads.size(); double totalTime = Time.optimum() * fallingEval * reduction * bestMoveInstability; @@ -801,7 +803,7 @@ namespace { // Use static evaluation difference to improve quiet move ordering if (is_ok((ss-1)->currentMove) && !(ss-1)->inCheck && !priorCapture) { - int bonus = std::clamp(-depth * 4 * int((ss-1)->staticEval + ss->staticEval), -1000, 1000); + int bonus = std::clamp(-16 * int((ss-1)->staticEval + ss->staticEval), -2000, 2000); thisThread->mainHistory[~us][from_to((ss-1)->currentMove)] << bonus; } @@ -1054,17 +1056,23 @@ moves_loop: // When in check, search starts here } else { + int history = (*contHist[0])[movedPiece][to_sq(move)] + + (*contHist[1])[movedPiece][to_sq(move)] + + (*contHist[3])[movedPiece][to_sq(move)]; + // Continuation history based pruning (~20 Elo) - if (lmrDepth < 5 - && (*contHist[0])[movedPiece][to_sq(move)] - + (*contHist[1])[movedPiece][to_sq(move)] - + (*contHist[3])[movedPiece][to_sq(move)] < -3000 * depth + 3000) + if ( lmrDepth < 5 + && history < -3000 * depth + 3000) continue; + history += thisThread->mainHistory[us][from_to(move)]; + + lmrDepth = std::max(0, lmrDepth - (beta - alpha < thisThread->rootDelta / 4)); + // Futility pruning: parent node (~5 Elo) if ( !ss->inCheck && lmrDepth < 8 - && ss->staticEval + 172 + 145 * lmrDepth <= alpha) + && ss->staticEval + 142 + 139 * lmrDepth + history / 64 <= alpha) continue; // Prune moves with negative SEE (~20 Elo) @@ -1081,7 +1089,7 @@ moves_loop: // When in check, search starts here // a reduced search on all the other moves but the ttMove and if the // result is lower than ttValue minus a margin, then we will extend the ttMove. if ( !rootNode - && depth >= 7 + && depth >= 6 + 2 * (PvNode && tte->is_pv()) && move == ttMove && !excludedMove // Avoid recursive singular search /* && ttValue != VALUE_NONE Already implicit in the next condition */ @@ -1157,6 +1165,8 @@ moves_loop: // When in check, search starts here // Step 15. Make the move pos.do_move(move, st, givesCheck); + bool doDeeperSearch = false; + // Step 16. Late moves reduction / extension (LMR, ~200 Elo) // We use various heuristics for the sons of a node after the first son has // been searched. In general we would like to reduce them, but there are many @@ -1181,9 +1191,8 @@ moves_loop: // When in check, search starts here && !likelyFailLow) r -= 2; - // Increase reduction at root and non-PV nodes when the best move does not change frequently - if ( (rootNode || !PvNode) - && thisThread->bestMoveChanges <= 2) + // Increase reduction at non-PV nodes + if (!PvNode) r++; // Decrease reduction if opponent's move count is high (~1 Elo) @@ -1230,6 +1239,7 @@ moves_loop: // When in check, search starts here // If the son is reduced and fails high it will be re-searched at full depth doFullDepthSearch = value > alpha && d < newDepth; + doDeeperSearch = value > alpha + 88; didLMR = true; } else @@ -1241,7 +1251,7 @@ moves_loop: // When in check, search starts here // Step 17. Full depth search when LMR is skipped or fails high if (doFullDepthSearch) { - value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth, !cutNode); + value = -search(pos, ss+1, -(alpha+1), -alpha, newDepth + doDeeperSearch, !cutNode); // If the move passed LMR update its stats if (didLMR && !captureOrPromotion) @@ -1373,7 +1383,15 @@ moves_loop: // When in check, search starts here // Bonus for prior countermove that caused the fail low else if ( (depth >= 3 || PvNode) && !priorCapture) - update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + (PvNode || cutNode))); + { + //Assign extra bonus if current node is PvNode or cutNode + //or fail low was really bad + bool extraBonus = PvNode + || cutNode + || bestValue < alpha - 94 * depth; + + update_continuation_histories(ss-1, pos.piece_on(prevSq), prevSq, stat_bonus(depth) * (1 + extraBonus)); + } if (PvNode) bestValue = std::min(bestValue, maxValue);