Discrete uniform distribution

General
1

Hi, stan users,

I wonder if there is a discrete uniform distribution in stan. If not, how to build it?

Thanks.

2

Not sure if this is helpful, because the context is not clear.
Anyhow, you could use the categorical distribution:

or the Dirichlet distribution for the multivariate case:

3

These are great. Many thanks for your reply.

4

We’re going to be making this even easier by building in a symmetric simplex constructor, so uniform with K variables will look something like

y ~ categorical(uniform_simplex(K));

But we should probably just add a discrete uniform distribution with inclusive upper and lower bounds.

1 Like
5

I think this is the relevant issue: https://github.com/stan-dev/math/issues/719
I was going to have a go at it in the coming release cycle, so since there’s interest I might really try it.

6

Hi, I’m trying to implement a discrete uniform prior in Stan. Is it still recommended to use the categorical distribution? I don’t think the uniform_simplex was added so I’m not 100% sure how to do this. I took a look at the github issue you linked to and saw that the discrete_range was implemented. Is it possible to use with the ‘distributed as’ notation: y ~ discrete_range(lower, upper)? Any info would be appreciated. Thanks!

7

The main implementation is complete, but it was never exposed to the compiler, so at the moment this will not work. I’ve now opened https://github.com/stan-dev/stanc3/issues/750 to track the final part of this work, sorry we didn’t get it finished a few months ago.

8

Oh great, thanks for the info! I’ll keep an eye on that issue.