Dear Tomas,

It sounds like what is happening is that the grid function in question only has 1 time level, but multiple active refinement levels. Because of sub cycling in time, not all refinement levels will be at the same cctk_time during a simulation. Therefore, if you request, for example, output_every = 1, then the toolkit tries to perform time interpolations when outputting the data (I think). Since the grid function only has 1 time level active, the toolkit can’t do that for the interpolation method selected (likely some default parameter in the thorn), hence the error.

The easiest, and likely most useful, way to fix this is to only output data when all time levels are aligned. For example, you can achieve this by requesting to output the data on iterations that are multiple of 2^(max_refinement_levels).

Alternatively, you can look at the param.ccl file of the Extract thorn and see if there a way to change the number of active time levels.

Hope this helps!

Cheers, Leo

------ Leonardo R. Werneck, Ph.D. Postdoctoral researcher Office EP 314 | Department of Physics | University of Idaho 875 Perimeter Dr. MS 0903 Moscow, ID 83844-0903, USA leonardo@uidaho.edu mailto:leonardo@uidaho.edu https://leowerneck.github.io https://leowerneck.github.io/

On Oct 2, 2023, at 3:50 AM, users-request@einsteintoolkit.org wrote:

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Today's Topics:

1. Today: NR community call at 9am Pacific / noon NYC / 5pm London / 6pm Berlin (Nils Vu)
2. Einstein Toolkit Meeting Reminder (rhaas@illinois.edu)
3. meeting minutes for 2023-09-28 (Roland Haas)
4. thorn Extract (Tomas Andrade)

---

Message: 1 Date: Mon, 11 Sep 2023 07:51:34 -0700 From: Nils Vu nils.vu@black-holes.org To: nr-community-call@black-holes.org Subject: [Users] Today: NR community call at 9am Pacific / noon NYC / 5pm London / 6pm Berlin Message-ID: 42ED8340-ED86-442E-9231-591AF9B2B619@black-holes.org Content-Type: text/plain; charset="utf-8"

??Dear Numerical Relativists,

We?ll have our NR community call today, Monday Sep 11, 9am LA / noon NYC / 5pm London / 6pm Berlin in this Zoom room:

https://caltech.zoom.us/j/87114806411

Our speakers today will be Deborah Ferguson (UT Austin / UIUC) and Jaime Redondo Yuste (NBI).

• Feel free to circulate this information within the NR community.
• Please subscribe to our mailing list https://groups.google.com/u/1/a/black-holes.org/g/nr-community-call/ to receive info on the community calls in the future (or send a short message to nr-community-call+subscribe@black-holes.org mailto:nr-community-call+subscribe@black-holes.org to subscribe) and join our Slack https://join.slack.com/t/generalrelativity/shared_invite/zt-dl4gqb6v-aAuw~post8OOMGCS2i~VkA for discussions (channel: #nr-community-call https://generalrelativity.slack.com/archives/C021LLTLK37).
• Please sign up for a slot https://docs.google.com/forms/d/e/1FAIpQLSfoCnnCJve7J7Jzrpdlqw7nAbwWS_iuX_evuTiajI-m9nstKA/viewform?usp=sf_link in the schedule to speak at one of the community calls: https://github.com/sxs-collaboration/nr-community-call/wiki

Looking forward to seeing you all later, Nils

? Nils Vu, Ph.D. (he/him) Sherman Fairchild Postdoctoral Fellow in Theoretical Astrophysics California Institute of Technology