generate_datasets fails with nonlinear brms models

[hrlai]

Hi devs, I have a brms model fitted with the set_nl(TRUE) formula setting. Then I got the following error from generate_datasets:

Error in UseMethod("brms_response_sequence") : 
  no applicable method for 'brms_response_sequence' applied to an object of class "btnl"

Could they be related? Thanks.

[martinmodrak]

Unfortunately, automatic datset generation for non-linear brms models is not currently supported (the error should be clearer on that). For most use cases, I'd strongly suggest writing your own generator anyway - if your model specification does something different than what you'd like the automatic generator will replicate the issue and you will not notice any problems, despite the model being incorrect...

[hrlai]

Thanks for the quick reply. I'll explore the custom generator. Gonna close this for now since it isn't an immediate fix. :)

[martinmodrak]

I'll keep it open - we definitely should at least improve the error message. It is also possible that supporting non-linear models won't be that hard - we never really tried doing that.