Periodicity Impacts

Motivation

• Sometimes the rise in sales is observed earlier than the months of summers in our data and the dip in sales is also observed earlier than actual time of winters.
• In other cases, the rise and fall in sales aligns perfectly with the summer and winter months.
• The magnitude of how the summer and winters are received in terms of sales also varies from one wholesaler, brand combination to another.
• This necessitates the need for modeling these seasonal patterns based on the data rather than when the actual summers/ winters happen.

Periodic Layer

• The purpose of periodic layer is to allow the model to learn the phase shifts of the 52 week seasonal pattern for the sales.
• Also, it enables the model to learn the amplitude of the rise and fall in sales in different regions.

NOTE: Instead of using the periodic_layer, we can also use the derivative of temperature signal as input and model that as a mixed effect.