minor change to wevar

[microprediction]

Hi are you still developing this project?

I might have someone (and maybe myself) to add a few little things, maybe starting with this...
online-ml/river#1619

[AdilZouitine]

Yes we maintain the project! What do you want to add ?

[microprediction]

I've found myself using fewvar.py in place of ewvar.py because the answers make more sense (to me) during the burn-in period and it converges to var.py as we vary the fading_factor. In contrast ewvar.py is highly sensitive to the first value and will take a long time to converge, potentially. Similar comments apply to the EWMean.

[microprediction]

I'm not fixated on names btw just trying to conform to river. Also not a rust guy yet but that should probably change!