- && pos.rule50_count() > 18
- && depth < 3 * ONE_PLY
- && ++thisThread->shuffleExts < thisThread->nodes.load(std::memory_order_relaxed) / 4) // To avoid too many extensions
- extension = ONE_PLY;
-
- // Passed pawn extension
- else if ( move == ss->killers[0]
- && pos.advanced_pawn_push(move)
- && pos.pawn_passed(us, to_sq(move)))
- extension = ONE_PLY;
-
- // Calculate new depth for this move
- newDepth = depth - ONE_PLY + extension;
-
- // Step 14. Pruning at shallow depth (~170 Elo)
- if ( !rootNode
- && pos.non_pawn_material(us)
- && bestValue > VALUE_MATED_IN_MAX_PLY)
- {
- // Skip quiet moves if movecount exceeds our FutilityMoveCount threshold
- moveCountPruning = moveCount >= futility_move_count(improving, depth / ONE_PLY);
-
- if ( !captureOrPromotion
- && !givesCheck
- && (!pos.advanced_pawn_push(move) || pos.non_pawn_material(~us) > BishopValueMg))
- {
- // Move count based pruning (~30 Elo)
- if (moveCountPruning)
- continue;
-
- // Reduced depth of the next LMR search
- int lmrDepth = std::max(newDepth - reduction(improving, depth, moveCount), DEPTH_ZERO);
- lmrDepth /= ONE_PLY;
-
- // Countermoves based pruning (~20 Elo)
- if ( lmrDepth < 3 + ((ss-1)->statScore > 0 || (ss-1)->moveCount == 1)
- && (*contHist[0])[movedPiece][to_sq(move)] < CounterMovePruneThreshold
- && (*contHist[1])[movedPiece][to_sq(move)] < CounterMovePruneThreshold)
- continue;
-
- // Futility pruning: parent node (~2 Elo)
- if ( lmrDepth < 7
- && !inCheck
- && ss->staticEval + 256 + 200 * lmrDepth <= alpha)
- continue;