Failure to fit with only intercept model

[bgerber123]

I noticed that intercept only type models with no slope/offset parameters are not currently possible. Using the example code/data- this model -

ord_fit_mean <- ordbetareg(formula=therm ~ 1 + (1|region),
data=model_data,
cores=2,chains=2)

returns this error -

Error: The following priors do not correspond to any model parameter:
b ~ normal(0,5)
Function 'default_prior' might be helpful to you.

Seems like a possible backend code fix for not pre-specifying b priors without checking the design matrix.

I would be interested in this being fixed to be able to fit a model using ordbetreg.

Thanks!
cheers, Brian

[saudiwin]

This will require a new option to allow for formulas with only intercepts. In the meantime, it's relatively easy to get around this restriction, just add a covariate to the formula equal to 0, as in the following code:

model_data$zero_cov <- 0
ord_fit_mean <- ordbetareg(formula=therm ~ zero_cov + (1|region),
data=model_data,
cores=2,chains=2)

[saudiwin]

Just an fYI, I hope to be able to fix this issue soon-ish, but also know that I have a working version of ordbetareg in brms proper:

https://github.com/saudiwin/brms/blob/feature/ordbeta-family/ordbeta_example.R

Which shouldn't have any of these issues.