RDF - Preprocessing calculation doubt

Hi,

I'd like to understand how the preprocessing calculates future velocity when there's not enough data points to fulfill the NFUT periods setup.

For example, let's say we have the following preprocessing parameters setup:

NFUT is 4.

Envent flag is checked on July 20th.

Preprocessing is run on July 23rd.

In this case, preprocessing will have only 2 data point for future velocity calculation (July 21st and 22nd).

How does it calculate the future velocity?

Thank you,

Cesar