Given number of draws and scalar or array of k's, compute the
relative convergence rate of PSIS estimate RMSE. See Appendix B of
Vehtari et al. (2024). This function is exported to be usable by
other packages. For user-facing diagnostic functions, see
pareto_convergence_rate and pareto_diags.
ps_convergence_rate(k, ndraws, ...)pareto-k values
number of draws
unused
convergence rate
Other helper-functions:
ps_khat_threshold(),
ps_min_ss(),
ps_tail_length()