Get observation indices used in subsampling
obs_idx(x, rep = TRUE)A psis_loo_ss object.
If sampling with replacement is used, an observation can have
multiple samples and these are then repeated in the returned object if
rep=TRUE (e.g., a vector c(1,1,2) indicates that observation 1 has been
subampled two times). If rep=FALSE only the unique indices are returned.
An integer vector.