arch.univariate.FIGARCH.backcast_transform¶ FIGARCH.backcast_transform(backcast: float | ndarray[tuple[int], dtype[float64]]) → float | ndarray[tuple[int], dtype[float64]][source]¶ Transform user-provided backcast values. Parameters:¶ backcast: float | ndarray[tuple[int], dtype[float64]]¶User-provided backcast that approximates sigma2[0]. Returns:¶ backcast – Backcast transformed to the model-appropriate scale. Return type:¶ float or numpy.ndarray