private void ensureLowpassFilter(double kmax) { if (_lpf==null || _kmax!=kmax) { _kmax = kmax; double kdelta = 0.5-kmax; double kupper = kmax+0.5*kdelta; _lpf = new BandPassFilter(0.0,kupper,kdelta,0.01); _lpf.setExtrapolation(BandPassFilter.Extrapolation.ZERO_SLOPE); _lpf.setFilterCaching(false); } }