What is the `ints` type mentioned in the Stan Functions Reference

What is the ints type used the example code in the Stan Functions Reference document. One place it appears is:


I’ve tried using it myself when specifying a Stan model, but it doesn’t appear to be valid Stan code.

Is it just a synonym for an array of integers (int[])?

ints means that both int and int[] arrray are supported. The full list of supported signatures for the poisson_lpmf function is:

poisson_lpmf(int, real) => real
poisson_lpmf(int, vector) => real
poisson_lpmf(int, row_vector) => real
poisson_lpmf(int, array[] real) => real
poisson_lpmf(array[] int, real) => real
poisson_lpmf(array[] int, vector) => real
poisson_lpmf(array[] int, row_vector) => real
poisson_lpmf(array[] int, array[] real) => real

So this is just a shorthand so that we dont need to write eight signatures in the documentation. reals similarlly mean that real, real[], vector and row_vector are supported.

You can use my web app to check for exact lists of signatures supported: Stan supported functions and signatures