- Operating System: Mac-OS
- brms Version: 2.6

Hi there,

I was wondering if there is any equivalent of the at.level function in brms, or in Stan? This function is handy for multivariate hierarchical models, in which the residual covariance should be estimated for some (but not all) combinations of variables. Basically I want to do a model like in which I estimate the residual covariance between a pair of male traits, and a pair of female traits, but not between male and female traits (since individual in my dataset never have a mixture of male and female traits, so Iâ€™d like to fix the residual covariance to zero and â€śtellâ€ť brms not to estimate it).

I wrote a full post, with some reproducible code, when I asked the same question on SO in reference to another R package called sommer that is used for (frequentist) mixed modelling: https://stackoverflow.com/questions/53146684/dealing-with-separate-sexes-in-the-sommer-package/53162974#53162974

Hope that makes sense, please let me know if now.

Many thanks,

Luke