tsa
statsmodels.tsa.arima_process.
lpol_sdiff
return coefficients for seasonal difference (1-L^s)
just a trivial convenience function
s : int
number of periods in season
sdiff : list, length s+1
statsmodels.tsa.arima_process.lpol_fima
statsmodels.sandbox.tsa.fftarma.ArmaFft