Takes the nonparametric delays and the PMF group boundaries and
returns the ragged-array fields that Stan needs to map a
normalised Dirichlet draw back into delay_np_pmf.
Usage
build_np_est_data(np_delays, np_pmf_groups)
Arguments
- np_delays
A list of nonparametric dist_spec objects in
their original order. Each estimated entry must carry an
$alpha numeric vector aligned with its PMF.
- np_pmf_groups
Integer vector of 1-indexed PMF group
boundaries (output of create_stan_delays()).
Value
A named list with n_np_est, np_est_which,
np_est_alpha, np_est_pos, np_est_groups, and
np_est_length. Empty arrays are returned when no delays are
estimated.
Details
Structural zeros (entries where the prior alpha is zero, e.g. the
t = 0 generation-time bin) are dropped from the estimated
parameter vector so Stan never sees a Gamma(0, 1) rate. Their
positions are still held by the fixed delay_np_pmf entries and
are left untouched at sampling time.
