Time Series Forecasting, Fourier, Ensemble Method, Data Science, Signal Processing.
order=trend_order).in_sample() X = trend_year.copy() X = X.join(seasonal_year) const trend trend_squared s(1,4) s(2,4) s(3,4) s(4,4) time 1956Q1 1.0 1.0 1.0 1.0 0.0 0.0 0.0 1956Q2 1.0 2.0 4.0 0.0 1.0 0.0 0.0 1956Q3 1.0 3.0 9.0 0.0 0.0 1.0 0.0 1956Q4 1.0 4.0 16.0 0.0 0.0 0.0 1.0 1957Q1 1.0 5.0 25.0