Closed mitchelloharawild closed 4 years ago
It's a perfect fit, so R^2 should be 1. Therefore return 1.
Thought as much.
I also noticed that the condition is length(x) <= 13
, shouldn't this be lag+1
? This is something copied over from tsfeatures.
Further, do you think a better handling of default lags would be useful for small sample sizes?
Yes, that it should be lags+1
. I'm not familiar with this test (and I didn't write the code) so I'm not sure what is recommended for small sample sizes. I'm also not sure where the default of 12 came from. The original paper is Engle (1982) [https://www.jstor.org/stable/1912773].
@robjhyndman What would you expect from this feature's output?
Issue with this series is that it drops to zero after 12 observations.
Created on 2020-01-06 by the reprex package (v0.3.0)