I have made python code for exponential smoothing (ES) that takes in about 15 different cases including:
- Simple Exponential Smoothing (SES)
- Simple Seasonal models (both multiplicative and additive)
- Brown's Linear Exponential Smoothing
- Holt's Double Exponential Smoothing
- Exponential trend method
- Damped-Trend Linear Exponential Smoothing
- Multiplicative damped trend (Taylor, 2003)
- Holt-Winters Exponential Smoothing: multiplicative trend, additive trend, multiplicative season, additive season, and damped models for all four variations
14 of these cases can be found in page 8 of Exponential smoothing: The state of the art Part II.
What values are commonly used for the initial values for the different ES models? What methods are used to determine points at time 0 and 1? (I am using
Nan (not a number) to substitute in the code right now).