brms: diagnostic-quantities – R documentation

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diagnostic-quantities

Extract Diagnostic Quantities of brms Models

Description

Extract quantities that can be used to diagnose sampling behavior of the algorithms applied by Stan at the back-end of brms.

Usage

## S3 method for class 'brmsfit'
log_posterior(object, ...)

## S3 method for class 'brmsfit'
nuts_params(object, pars = NULL, ...)

## S3 method for class 'brmsfit'
rhat(object, pars = NULL, ...)

## S3 method for class 'brmsfit'
neff_ratio(object, pars = NULL, ...)

Arguments

`object`	A `brmsfit` object.
`...`	Arguments passed to individual methods.
`pars`	An optional character vector of parameter names. For `nuts_params` these will be NUTS sampler parameter names rather than model parameters. If pars is omitted all parameters are included.

Details

For more details see bayesplot-extractors.

Value

The exact form of the output depends on the method.

Examples

## Not run: 
fit <- brm(time ~ age * sex, data = kidney)

lp <- log_posterior(fit)
head(lp)

np <- nuts_params(fit)
str(np)
# extract the number of divergence transitions
sum(subset(np, Parameter == "divergent__")$Value)

head(rhat(fit))
head(neff_ratio(fit))

## End(Not run)

brms

Bayesian Regression Models using 'Stan'

v2.15.0

GPL-2

Authors

Paul-Christian Bürkner [aut, cre], Jonah Gabry [ctb], Sebastian Weber [ctb], Andrew Johnson [ctb], Martin Modrak [ctb]

Initial release

2021-03-10