Spatial gaussian covariance

[danielinteractive]

Discussed in #500

^{Originally posted by TobyHauge April 2, 2025}
Dear mmrm community and editors,

I have been given the task to perform a mmrm as a spatial gaussian model with a Kenward-Roger correction. I have found no way to do this in R, an I have to do it in SAS instead. However, the mmrm package come closest to making it possible. So I'm wondering whether sp_gauss() will be a reality someday?

All the best,
Tobias

[danielinteractive]

Similar as #256