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ZVCV (version 1.0.0)

evidence: Evidence estimation with ZV-CV

Description

The function evidence_CTI uses ZV-CV on the controlled thermodynamic integration estimator for the normalising constant.

Usage

evidence_CTI(samples, loglike, der_loglike, der_logprior, temperatures,
  temperatures_all, most_recent, obs_estim_choose, obs_estim, options)

evidence_SMC(samples, loglike, der_loglike, der_logprior, temperatures, temperatures_all, most_recent, obs_estim_choose, obs_estim, options)

Arguments

samples

An \(N\) by \(d\) by \(T\) matrix of samples from the \(T\) power posteriors, where \(N\) is the number of samples and \(d\) is the dimension of the target distribution

loglike

An \(N\) by \(T\) matrix of log likelihood values corresponding to samples

der_loglike

An \(N\) by \(d\) by \(T\) matrix of the derivatives of the log likelihood with respect to the parameters, with parameter values corresponding to samples

der_logprior

An \(N\) by \(d\) by \(T\) matrix of the derivatives of the log prior with respect to the parameters, with parameter values corresponding to samples

temperatures

A vector of length \(T\) of temperatures for the power posterior temperatures

temperatures_all

An adjusted vector of length \(tau\) of temperatures. Better performance should be obtained with a more conservative temperature schedule. See Expand_Temperatures for a function to adjust the temperatures.

most_recent

A vector of length \(tau\) which gives the indices in the original temperatures that the new temperatures correspond to.

obs_estim_choose

See zvcv.

obs_estim

See zvcv.

options

See zvcv.

Value

The function evidence_CTI returns a list, containing the following components:

  • log_evidence_PS1: The 1st order quadrature estimate for the log normalising constant

  • log_evidence_PS2: The 2nd order quadrature estimate for the log normalising constant

  • regression_LL: The set of \(tau\) zvcv type returns for the 1st order quadrature expectations

  • regression_vLL: The set of \(tau\) zvcv type returns for the 2nd order quadrature expectations

The function evidence_SMC returns a list, containing the following components:

  • log_evidence: The logged SMC estimate for the normalising constant

  • regression_SMC: The set of \(tau\) zvcv type returns for the expectations

References

Mira, A., Solgi, R., & Imparato, D. (2013). Zero variance Markov chain Monte Carlo for Bayesian estimators. Statistics and Computing, 23(5), 653-662.

South, L. F., Oates, C. J., Mira, A., & Drovandi, C. (2019). Regularised zero variance control variates for high-dimensional variance reduction. https://arxiv.org/abs/1811.05073

See Also

See Expand_Temperatures for a function that can be used to find stricter (or less stricter) temperature schedules based on the conditional effective sample size. See an example at VDP and see ZVCV for more package details.