Rstanarm output

Hi, I have a couple concerns.

First, rstanarm (and rstan in general) spews out a ton of output, every 10% of iterations in each chain, the elapsed time, just lots of crap which as a user I’d rather not see. Maybe if it’s gonna take more than a few seconds it would be good to have one or two lines of output so that the user won’t freak out. But all these screenfuls, that too much.

Second, I wonder if we could change the header of print output to be more similar to what lm/glm does.

Here’s an example.

From lm:
lm(formula = post_test ~ treatment, data=electric, subset=(grade==4))

From stan_glm:
family: gaussian [identity]
formula: post_test ~ treatment

I prefer the way lm does it, because sometimes we’re just looking at the print output and it’s very helpful to see the name of the data frame and any subsetting.

It is refresh = BIG_NUMBER in rstanarm <= 2.17.x and refresh = 0 in rstan{arm} >= 2.18.x to curtail the progress output. My PR to do time-based updating is still in limbo.

To print out the relevant part(s) of the call in one line, we have to decide what is relevant.

Also there’s a problem when we ask rstanarm to print out the priors it was using. It doesn’t give the full priors on the original data scale.