Monthly Math development meeting: 04/16/2020, 10 am EDT

Hey all,

We have our monthly Math meetings on the third Thursday of the month. The next Math meeting is Thursday, April 16, 2020, 10 am Eastern time. This will last no more than one hour; if we need more time, we will schedule additional time.

This meeting is open to all those that currently contribute to the Math library or that would like to contribute to the Math library. If you’d like an invite to the Google Calendar event, please DM me with your Google handle. If you’d like to just have a copy of the event on your calendar, please use this link:

Direct Google Meet link:


  • this is a chance to collaborate and coordinate efforts. We’re expecting everyone to be kind and courteous. And patient. We have a team with diverse backgrounds.
  • impactful decisions will not be made at these meetings. That will continue to be done online on these forums. The meetings are a good time to discuss and get on the same page, but the decision making will be done online where we can include the opinions of others that can’t make the meeting.
  • important discussions that happen at the meeting will be communicated back online on these forums. If they don’t make it back here, it wasn’t important. No one will be penalized for not being present at a meeting.

If there’s anything you know you want to talk about, please post here. This is a good time to request help from others if there’s expertise that you need.

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tagging @wds15, @bbbales2, @rok_cesnovar, @stevebronder.

Sorry about missing the last one.

I will try to make it this time also. Lets check on the release if anyone has comments on the release notes


I am afraid that I have a conflict tomorrow. Maybe I can join at the end, not sure.

If you could do post stan meeting I’d be fine with moving it to later. Though whatever is fine for me

Uhh… my memory served me wrong and Outlook is telling me that I can join the first 30min. So let’s do that.

Let’s quickly settle on reduce_sum stuff before we merge. @rok_cesnovar already filed a PR - thanks - and I think we should just merge this and change all the doc.

Hey all… I’m gonna try to do a different thing with notes. I’m going to keep them live.

We started the meeting. Attendees so far (10:02 am):
me, @mitzimorris, @bbbales2, @wds15.

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@Bob_Carpenter, @rok_cesnovar joined.

We’re talking about reduce_sum now as our first agenda item. Argument order is changing.

New topic. Discussing PR: The von mises cdf.

For consistency in Math, we want to limit the support from -pi to pi. We discussed options for doing this.


  1. new function called von_mises_2 and deprecate von_mises.
  2. change the implementation of von_mises… this will break backwards compatibility. we discussed different options here including rolling it into a major change.

New topic: Makefile issues.

@mitzimorris described the problem. Difficulty with Intel TBB.

@stevebronder just joined.

@mitzimorris will start a discourse thread discussing the current Makefile issues and how to proceed.

New topic: MPI caching.

@rok_cesnovar asked if it’s ok to move MPI caching to the compiler instead of Math… we discussed it and it’s not breaking backward compatibility, so ok.

This idea comes out of this discussion

New topic: GitHub Actions.

We talked about what it is and where we can use it. We’ll start talking about uses on Discourse.

Meeting adjourned. Thanks, all!


For CI see

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