# Technical review meeting for reintroduction of tabulated non-bonded potentials **URL:** \ **Category:** Developers discussions\ **Created:** [August 3, 2026, 7:55am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639 "2026-08-03T07:55:50Z")\ **Posts on this page:** 19\ **Page:** 1
**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\ **Post date:** [August 3, 2026, 7:55am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/1 "2026-08-03T07:55:50Z")
The removal of the user-tabulated non-bonded interactions with the removal of the group scheme has left quite a few users with the options to keep using the 2018 or switch simulation package. Thus this is a rather important issue. Gregory Lazarski har reimplemented this feature in a much cleaner fashion in the Verlet kernel scheme, also with more options. The change is rather large (although more than half test reference data): [Draft: Modernize tabulated potentials (!6086) · Merge requests · GROMACS / GROMACS · GitLab](https://gitlab.com/gromacs/gromacs/-/merge_requests/6086) We need to have a technical review for this code. Gregory will shortly present the features of this MR and the code organization. We need to decide which are the minimum features required and which can be added later. We also need to decide whether the current organization of the code is suitable. And Gregory wants feedback on one technical issue. I think we should allocate three hours for this, but hopefully we can do it in less time, I would suggest a time next week, August 10-14. I can also do the week after. I am available most of the time. Who is willing to participate? And what is your avaibility next week (or the week after)? ---
**Author:** ![pbauer](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/pbauer/32/13_2.png) [@pbauer](https://gromacs.bioexcel.eu/u/pbauer)\ **Post date:** [August 3, 2026, 8:11am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/2 "2026-08-03T08:11:26Z")
I should be available on those dates on Zoom, but don’t know if I could make it to Stockholm for an in person meeting. I would like to participate and can also be available for review afterwards. ---
**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\ **Post date:** [August 3, 2026, 8:28am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/3 "2026-08-03T08:28:26Z")
The meeting will be on Zoom, as Gregory is not in Stockholm. We could organize for the Stockholm people to sit in the same room. ---
**Author:** ![vedran](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/vedran/32/1784_2.png) [@vedran](https://gromacs.bioexcel.eu/u/vedran)\ **Post date:** [August 3, 2026, 6:10pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/4 "2026-08-03T18:10:02Z")
I can do it as well, preferably afternoons. ---
**Author:** ![lmullender](https://avatars.discourse-cdn.com/v4/letter/l/8dc957/32.png) [@lmullender](https://gromacs.bioexcel.eu/u/lmullender)\ **Post date:** [August 4, 2026, 11:25am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/5 "2026-08-04T11:25:50Z")
I would be interested in joining as well. I’m flexible regarding the time. ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 5, 2026, 9:07am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/6 "2026-08-05T09:07:22Z")
Any of these dates are fine with me, but on the 10th I would be available only after 9 AM UTC. ---
**Author:** ![pszilard](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/pszilard/32/21_2.png) [@pszilard](https://gromacs.bioexcel.eu/u/pszilard)\ **Post date:** [August 7, 2026, 2:06pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/7 "2026-08-07T14:06:35Z")
Hi! I have some availability the next two weeks, but it’s quite spotty. A poll would help pick the time. On the length: I’d prefer (and suggest) keeping the meeting shorter rather than taking a whole afternoon. ---
**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\ **Post date:** [August 10, 2026, 9:16am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/8 "2026-08-10T09:16:05Z")
It seems that the others can do any time in the afternoon. Can you suggest one or two days? We could do 14:00 or 15:00. ---
**Author:** ![pszilard](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/pszilard/32/21_2.png) [@pszilard](https://gromacs.bioexcel.eu/u/pszilard)\ **Post date:** [August 10, 2026, 2:30pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/9 "2026-08-10T14:30:30Z")
This week’s relevant time-slots are quite full I realize, I might be able to Join Wed after 15:00 but I can’t promise. Next week, 21st 14:00 could work. However, since that might delay things quite a bit and there seem to be others who can attend, I suggest to schedule it whenever works best for others. ---
**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\ **Post date:** [August 10, 2026, 2:46pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/10 "2026-08-10T14:46:04Z")
Shall we do Wednesday 15:00 then? ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 10, 2026, 2:53pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/11 "2026-08-10T14:53:35Z")
Sounds good to me. I’ll post the presentation in a few hours. ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 11, 2026, 2:53am UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/12 "2026-08-11T02:53:46Z")
The materials for the technical review can be found here: [Google Slides](https://docs.google.com/presentation/d/14s1H9I3hS6zrjjLiwMNkxnARBYgyTpOx/edit?usp=sharing&ouid=105849527668766982988&rtpof=true&sd=true), [Downloadable PDF](https://drive.google.com/file/d/1F7CwuVqyxv-8K5ffQYVRrT2HVLcESBam/view?usp=share_link) If you have any questions or need me to expand on anything, please post a comment either here or on the document itself before the meeting. ---
**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\ **Post date:** [August 11, 2026, 2:58pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/13 "2026-08-11T14:58:21Z")
I think it would be useful to show a, simple, example of a topology file with tabulated interactions. ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 11, 2026, 2:59pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/14 "2026-08-11T14:59:17Z")
This is available in both the first (outdated) and the latest merge request. There, I include input files for the same system simulated using analytical 12-6 LJ and all 4 cases for the tabulated potential. Direct link: [https://gitlab.com/-/project/17679574/uploads/912b2c56b143b2a22464f317db47ca6a/CHARMMWater.tar.gz](https://gitlab.com/-/project/17679574/uploads/912b2c56b143b2a22464f317db47ca6a/CHARMMWater.tar.gz) ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 11, 2026, 3:08pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/15 "2026-08-11T15:08:43Z")
More information on the syntax can be found in the following merge requests and comments: > **[Support parsing tabulated potential-related data in topology files. (!5194) ·...](https://gitlab.com/gromacs/gromacs/-/merge_requests/5194)** > > Refs #1347 In this MR,... > **[Support parsing tabulated potential-related data in topology files. (!5194) ·...](https://gitlab.com/gromacs/gromacs/-/merge_requests/5194#note_2572768048)** > > Refs #1347 In this MR,... > **[Draft: Modernize tabulated potentials (!6086) · Merge requests · GROMACS /...](https://gitlab.com/gromacs/gromacs/-/merge_requests/6086)** > > Refs #1347 This merge request... ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 12, 2026, 12:53pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/16 "2026-08-12T12:53:00Z")
@hess Could you please prepare and post the meeting link? ---
**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\ **Post date:** [August 12, 2026, 1:16pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/17 "2026-08-12T13:16:54Z")
Sorry, I have stomach issues and had fallen asleep. I started the meeting now. ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 12, 2026, 1:21pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/18 "2026-08-12T13:21:42Z")
Meeting link: [Launch Meeting - Zoom](https://kth-se.zoom.us/j/69277089234?pwd=V2MwM0JJaGJOK3dDUWlhcWx6YUM5QT09) @pszilard @pbauer @lmullender @vedran ---
**Author:** ![Golui](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/golui/32/3962_2.png) [@Golui](https://gromacs.bioexcel.eu/u/Golui)\ **Post date:** [August 12, 2026, 3:24pm UTC](https://gromacs.bioexcel.eu/t/technical-review-meeting-for-reintroduction-of-tabulated-non-bonded-potentials/13639/19 "2026-08-12T15:24:26Z")
Thanks to everybody who participated in the meeting. Key takeaways: - The Draft MR will be split into parts, roughly in line with how the materials are split. - Besides the changes mentioned in the presentation, no major changes to the functionality will be introduced. Some minor ITP/MDP syntax and TPR format adjustments are likely. - We will do our best _not_ to alter the SIMD layer, likely using the approach from this proposal: [Slow CPU SIMD nbnxm kernel code path for non-geometric force fields due to gather loads (#5662) · Issues · GROMACS / GROMACS · GitLab](https://gitlab.com/gromacs/gromacs/-/work_items/5662) If anyone has further questions, or wants to have a more in-depth technical discussion, please post it here.