Requiremed Number of Covariates

[ErikKusch]

Hiya,

just partook in a workshop organised by the IBS and am pretty stoked on your package here. Wanting to run an example as simple as possible during the workshop, I opted for a model with only two environmental covariates to my binary outcome of species-presence/absence.

Unfortunately, that caused a few issues in particular with the variable.step function which seems to accommodate exclusively models with three or more covariates. I propose a check to be implemented in this function that alerts users to this fact.

Cheers,
Erik

[cjcarlson]

Great idea! I'll work on implementing that. I would definitely not suggest using a regression tree approach with only one or two variables so a warning message is a good thought