Monthly Math development meeting: 03/18/2021, 10 am EDT (2 pm UTC)

Hey all, we’ve been having monthly Math meetings on the third Thursday of the month. The next one is tomorrow, March 18, 2021, at 10 am EDT! (It’s 2 PM UTC… just in case the time zone conversion isn’t straightforward.)

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.


tagging: @bbbales2, @rok_cesnovar, @stevebronder , @storopoli, @charlesm93


forgot to tag @spinkney too.

@bbbales2 joined. We’ll wait a few minutes to get started.

@bbbales2 is walking through the expression generation in python.

@storopoli joined!

@charlesm93 is here too!

@stevebronder is here too!

New topic:

@stevebronder brought up Remove v_vari by SteveBronder · Pull Request #2422 · stan-dev/math · GitHub. Asked about setting NaN for the adjoints when the value is NaN. We had a discussion… it’s ok to remove that… it was checked when we were being general about the use case where we could be friendly to non-Stan use cases. Since this is applied so inconsistently, it makes sense to just remove that.

New topic:

@storopoli brought up pattern matching for Python 3.10 and “seeing the bunch of if and elif I think once python 3.10 is on production we can use the pattern matching to replace that”. Thanks!

New topic:

@bbbales2 is asking @charlesm93 questions about the algebra solver. (It’s going over my head.)

Oh man, this is embarrassing, US is on summer time already and we are not… :)

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New Topic:

@bbbales2 is talking about distribution tests. They’re shorter now on PR.

New Topic:

@charlesm93 is talking about an embedded laplace approximation. We’re talking about autodiff and using forward and mix mode.

Meeting adjourned.

@rok_cesnovar, sorry we missed you!

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