Summarize the distributions of estimated parameters and derived quantities
using the posterior draws.

```
# S4 method for stanfit
summary(object, pars, probs = c(0.025, 0.25, 0.50, 0.75, 0.975),
use_cache = TRUE, ...)
```

## Arguments

- object
An instance of class `stanfit`

.

- pars
A character vector of parameter names. Defaults to all parameters
as well as the log-posterior (`lp__`

).

- probs
A numeric vector of `quantile`

s of interest.
The default is `c(0.025,0.25,0.5,0.75,0.975)`

.

- use_cache
Logical, defaulting to `TRUE`

. When `use_cache=TRUE`

the summary quantities for all parameters are computed and cached for future
use. Setting `use_cache=FALSE`

can be used to avoid performing the
summary computations for all parameters if `pars`

is given as some
specific parameters.

- ...
Currently unused.

## Value

The `summary`

method returns a named list with elements `summary`

and `c_summary`

, which contain summaries for for all chains merged and
individual chains, respectively.
Included in the summaries are quantiles, means, standard deviations (sd),
effective sample sizes (n_eff), and split Rhats (the potential scale
reduction derived from all chains after splitting each chain in half and
treating the halves as chains). For the summary of all chains merged,
Monte Carlo standard errors (se_mean) are also reported.

## See also

`monitor`

, which computes similar summaries but accepts an
array of MCMC draws as its input rather than a `stanfit`

object.

The RStan vignettes for more example usage.

## Examples

```
if (FALSE) {
ecode <- '
parameters {
real<lower=0> y[2];
}
model {
y ~ exponential(1);
}
'
fit <- stan(model_code = ecode)
s <- summary(fit, probs = c(0.1, 0.9))
s$summary # all chaines merged
s$c_summary # individual chains
}
```