RStan Diagnostic plots
Diagnostic plots for HMC and NUTS using ggplot2.
stan_diag(object, information = c("sample","stepsize", "treedepth","divergence"), chain = 0, ...) stan_par(object, par, chain = 0, ...) stan_rhat(object, pars, ...) stan_ess(object, pars, ...) stan_mcse(object, pars, ...)
object |
A stanfit or stanreg object. |
information |
The information to be contained in the diagnostic plot. |
par,pars |
The name of a single scalar parameter ( |
chain |
If |
... |
For |
stan_rhat
,stan_ess
,stan_mcse
Respectively, these plots show the distribution of the Rhat statistic, the ratio of effective sample size to total sample size, and the ratio of Monte Carlo standard error to posterior standard deviation for the estimated parameters. These plots are not intended to identify individual parameters, but rather to allow for quickly identifying if the estimated values of these quantities are desireable for all parameters.
stan_par
Calling stan_par
generates three plots:
(i) a scatterplot of par
vs. the accumulated log-posterior (lp__
),
(ii) a scatterplot of par
vs. the average Metropolis acceptance rate
(accept_stat
), and
(iii) a violin plot showing the distribution of par
at each of the
sampled step sizes (one per chain).
For the scatterplots, red points are superimposed to indicate which
(if any) iterations encountered a divergent transition. Yellow points indicate
a transition that hit the maximum treedepth rather than terminated its
evolution normally.
stan_diag
The information
argument is used to specify which
plots stan_diag
should generate:
information='sample'
Histograms of lp__
and accept_stat
, as well as a scatterplot showing their
joint distribution.
information='stepsize'
Violin plots showing the
distributions of lp__
and accept_stat
at each of the sampled
step sizes (one per chain).
information='treedepth'
Histogram of treedepth
and
violin plots showing the distributions of lp__
and
accept_stat
for each value of treedepth
.
information='divergence'
Violin plots showing the
distributions of lp__
and accept_stat
for iterations that
encountered divergent transitions (divergent=1
) and those that
did not (divergent=0
).
For stan_diag
and stan_par
, a list containing the ggplot objects for
each of the displayed plots. For stan_rhat
, stan_ess
,
and stan_mcse
, a single ggplot object.
For details about the individual diagnostics and sampler parameters and their interpretations see the Stan Modeling Language User's Guide and Reference Manual at http://mc-stan.org/documentation/.
## Not run: fit <- stan_demo("eight_schools") stan_diag(fit, info = 'sample') # shows three plots together samp_info <- stan_diag(fit, info = 'sample') # saves the three plots in a list samp_info[[3]] # access just the third plot stan_diag(fit, info = 'sample', chain = 1) # overlay chain 1 stan_par(fit, par = "mu") ## End(Not run)
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