Covariance between random effects in lme4/glmmTMB

[davidnfisher]

Hi folks,

Does anyone know how to code a covariance between two random effects that use the same set of levels in lme4 or glmmTMB? I would do it in MCMCglmm like this:

random=~str(focal + partner)

while the prior includes G1 as a 2x2 matrix.

Any help appreciated!