Firedrake meeting 2026 07 07

Date and time 2026-07-07 1600 UTC+1

Action Items

1. Pick Chair and Minuter (AC to pick)
2. ALL: (ongoing) triage the open issues and confirm if they are indeed still open (and perhaps provide labels)
3. ALL: do things with SV's branches
4. DH: Email to Andreas to have 2 (+ others!!!) loopy PRs merged TODO: FIND OUT WHICH PRS THESE ARE
5. DH: Talk to GregVernon about PR#2116.
6. JHC: New manual release

Agenda

Present: CW, JHC, IM, PB, DH, AC, LC, NW

Apologies:

CW: pyop3

I need some help getting this done.

https://github.com/firedrakeproject/firedrake/pull/3318

https://github.com/orgs/firedrakeproject/projects/12/views/1 (see description)

Plan: Next Monday 13th July 10am meet Get everyone set up on pyop3 and started looking at bugs/profiling.

AC/LC: Nested interpolates

https://github.com/firedrakeproject/firedrake/pull/5097

AC: My particle time steppers define their update expressions as nested interpolate expressions. I currently have a way of making this work using a two step approach: 1) rewrite the interpolation expression by traversing the UFL DAG and substituting every inner interpolate node with a placeholder Function and returning a mapping {placeholder Function -> Interpolator} 2) using CompositeInterpolator which wraps the outer interpolator together with the mapping from 1). CompositeInterpolator builds one callable per inner interpolator each writing its result directly into the placeholder Function and finally building one callable for the outer interpolation. This mechanism ensures the inner-most interpolations run first and the outer callable runs last always picking up the updated coefficients data that it relies on.

I would like to review this implementation and get people's ideas on whether there's a better way to do this.

Minutes:

• This should happen during the traversal, ensuring that the interpolates are visited in the correct order to ensure they are not assembled in advance and holding old data.

DH Allow in-place modification of coordinates via infix operators.

https://github.com/firedrakeproject/firedrake/pull/5214

Minutes: Approved, will merge once things are passing.

PB AGENTS.md

https://github.com/firedrakeproject/firedrake/pull/5219

Comments made on PR.

PB prolongation MatAIJ

https://github.com/firedrakeproject/firedrake/pull/5206

Comments made on PR.

DirichletBC.coefficients()

Happy to retarget to main https://github.com/firedrakeproject/firedrake/pull/5127

Minutes:

• Review added, add Adjoint test to trigger bug we think is there (taping interpolates). Fix bug if it exists!

Team catch up (if time)

Date of next meeting

1600 UTC+0100 2026-07-14