R: Extract Diagnostic Quantities of 'brms' Models

diagnostic-quantities {brms} | R Documentation

## 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)

[Package brms version 2.17.0 Index]