I’m using Rstan. I have something like this:

```
simplex[K] theta[Q];
```

And I can use Rstan’s `rstan::plot(input, pars = c("theta"))`

. But, this is not good when any dimension of theta gets large, and I’d like to do comparisons.

Is there any way I can get a similar “boxplot” for, in R: `theta[,3]`

where I index later? What about for a range of indices (i.e. `theta[,1:3,c(2,4)]`

)?

So it would be great if I could do `plot(input, pars = c("theta[,2]")`

, or something similar

Edit: fixed typo