Add JAX implementation for `MultinomialRV`

[rlouf]

[GStechschulte]

Hey @rlouf and others, I will give this PR a go. I am following #1335 and #1284 for more explanations on the implementations. Likewise, I will comment here on progress and questions.

[brandonwillard]

Much appreciated, @GStechschulte!

[rlouf]

Here is an explanation of how to go about adding an implementation: https://github.com/aesara-devs/aesara/issues/1335#issuecomment-1344510169

[GStechschulte]

After using NumPyro, I remembered that they have a JAX implementation of the Multinomial distribution, albeit following the design of the PyTorch distributions module. Therefore, I adapted the code to align with the parameters argument passed into the respective RV's __call__ function in this file.

I still need to add the tests. As this is my first time contributing, how should I/we handle "using" a code snippet from another library? In this case, I have used 3 functions from the NumPyro library to meet the needs of this PR. My idea is to add a reference in a doc string? Thanks!

Here is the link to my branch of the JAX implementation of MultinomialRV.

[brandonwillard]

Here is the link to my branch of the JAX implementation of MultinomialRV.

Feel free to create a PR for that branch. If you're still working on it, no worries; you can make it a draft PR.

[brandonwillard]

I still need to add the tests. As this is my first time contributing, how should I/we handle "using" a code snippet from another library? In this case, I have used 3 functions from the NumPyro library to meet the needs of this PR. My idea is to add a reference in a doc string? Thanks!

We'll need to make sure that the licenses are compatible and see what they require.