hierarchical_gp.ipynb

In case anyone else is exploring using this as part of a linear model, I've forked it to show a version using prior_linearized instead: https://gist.github.com/kforeman/692542430469d016f84a17f230d8500b

From there @theorashid might be able to change the size of beta_f to (n_gps, gp_f._m_star) to use the same basis function but independent coefficients for each of the child GPs. I haven't yet worked out how to get the delta deterministic working yet, though - I imagine it may have to first construct a sparse matrix (kronecker of a 3x3 identity matrix with phi_f or something like that based on @bwengals comment)?

Yup that's right @kforeman. I have it implemented but it's slower, I think I'm doing something wrong but haven't looked into it more yet.

Interesting, I am currently using that approach but didn't actually benchmark - will find some time to see if it's actually faster or I've just slowed myself down.