Storing nested sampling results

ernest_rcrd is a [vctrs::new_rcrd] class that stores metadata for all samples drawn from the nested sampling algorithm, tracking the history of replacements in the live set and each point's contribution to evidence estimation.

Details

This object is designed to be used internally within the ernest_run class to track the history of samples generated during a nested sampling run. Generally, users will not interact with ernest_rcrd objects directly, and instead will call methods on ernest_run objects which, internally, manipulate the ernest_rcrd object.

Fields

unit

[double(nvar)] The sample's coordinates within the unit hypercube (prior to transformation via the prior distribution).

id

[integer(1)] A unique identifier for each sample in the sequence of live points.

nlive

[integer(1)] The number of effective live points remaining when the sample was removed from the live set. Generally corresponds to the nlive of the ernest_run, but can be lower if the sample found within a plateau in the log-likelihood function (see References) or if the sample is still in the live set at termination.

neval

[integer(1)] The number of likelihood evaluations required by the sampler to generate this replacement point, reflecting the difficulty of sampling from the likelihood-restricted prior. Equal to 0 for points remaining in the live set at termination.

log_lik

[double(1)] The log-likelihood at the sample.

birth_lik

[double(1)] The log-likelihood threshold that this sample exceeded; the minimum likelihood constraint applied when generating it. Equals -Inf for samples in the initial live set.

References

Fowlie, A., Handley, W., Su, L., Nested Sampling with Plateaus, Monthly Notices of the Royal Astronomical Society, 503(1), 1199–1205, doi:10.1093/mnras/stab590