arch.univariate.ConstantVariance.backcast¶

ConstantVariance.backcast(resids: ndarray[tuple[int], dtype[float64]] | Series) → float | ndarray[tuple[int], dtype[float64]][source]¶

Construct values for backcasting to start the recursion

Parameters:¶

resids: ndarray[tuple[int], dtype[float64]] | Series¶

Vector of (approximate) residuals

Returns:¶

backcast – Value to use in backcasting in the volatility recursion

Return type:¶

float