2026-02-05

2026-02-05
James Kermode
Draft for approval

1. Attendance

Present

  • Adam Jackson (AJJ)
  • Alin-Marin Elena (AE)
  • Andrew Peterson (AP)
  • Ask Hjorth Larsen (AHL)
  • Elena Gelžinytė (EG)
  • Gábor Csányi (GC)
  • Hanna Türk (HT)
  • James Kermode (JK) — Chair
  • Karsten Wedel Jacobsen (KWJ)
  • Kristian Thygesen (KT)
  • Lars Pastewka (LP)
  • Michael Herbst (MH)
  • Paul Erhart (PE)
  • Xing Wang (XW)
  • Yuji Ikeda (YI)

Apologies

  • Andrew Rosen
  • Bjørk Hammer
  • Michele Ceriotti

2. Opening

The Chair welcomed attendees and noted the meeting was being recorded for the purpose of preparing minutes. Adam Jackson agreed to take notes.

3. Approval of Minutes from Previous Meeting

The minutes from Meeting #1 (20 August 2025) were approved without amendment.

4. Actions from Previous Meeting

The committee reviewed the action list from Meeting #1. The following updates were noted:

Completed actions:

  • A1, A2: Governance documents drafted and circulated
  • A3, A4, A5: Committee email list, GitLab repo, and meeting minutes established
  • A6: Contact email in pyproject.toml now updated
  • A7, A9: CECAM workshop report circulated; documentation sprint publicised
  • A8: Domain redirect to ase-lib.org in place — marked as complete
  • A10, A11, A13: Documentation group assembled; milestone created; ASEv4 working group meeting held
  • A16: Support request redirection to MatSci.org implemented via issue template
  • A18, A19: Foundation options paper prepared; this meeting scheduled

Outstanding actions:

  • A12: Top-level landing page still in early stages. AHL has started a repository and opened a merge request listing committee members.
  • A14, A15, A17: Documentation guidance items remain pending. The committee agreed these should be addressed as part of a broader overhaul of developer documentation.

New action: All committee members to provide a web link or email address to AHL for inclusion on the website.

5. Terms of Reference

The committee reviewed the draft Terms of Reference (Paper 1).

Key consensus points:

  • The document was well received and considered suitable for adoption.
  • The Terms of Reference should be published on the ASE website once finalised.
  • Six-monthly meeting frequency was confirmed as appropriate.

Term limits and membership rotation:

  • Five-year terms renewable once (maximum 10 years continuous service) were endorsed.
  • Initial terms for founding members will be randomly assigned between 3, 4, and 5 years to ensure staggered rotation. Members wishing to volunteer for shorter initial terms may indicate this privately to the Chair.
  • Technical Sub-Committee (TSC) members will have no fixed term limit, recognising their essential ongoing role as code maintainers.
  • It was clarified that TSC members are full Steering Committee members for the duration of their TSC role. The Terms of Reference will be updated to make this explicit.
  • The existing provision regarding non-participation (contact after two consecutive missed meetings without apology) was noted. Members may propose additional text to strengthen automatic removal procedures if desired.

New action: JK to update the Terms of Reference to clarify that TSC members are also full Steering Committee members.

6. ASE Foundation

The committee discussed foundation options (Paper 2) for establishing a legal entity to receive funds.

Key discussion points:

  • NumFOCUS remains the ideal fit for scientific Python projects but is not currently accepting new projects due to US funding constraints. The committee will continue to monitor this.
  • The Open Molecular Software Foundation (OMSF) was discussed but received limited enthusiasm, partly due to uncertainty about ease of exit and alignment with ASE’s needs.
  • A German gGmbH was considered but the €25,000 capital requirement was seen as disproportionate to current needs. LP offered to investigate alternative German structures that may be relevant.
  • A Danish Forening was noted as simpler but potentially less familiar to international funders.
  • A UK Community Interest Company (CIC) emerged as the leading option, offering EU funding eligibility (UK is a Horizon Europe associated country), low setup costs, and strong committee representation willing to serve as directors.

Consensus:

No final decision was made at this meeting. The committee expressed equal interest in pursuing both a UK CIC and a German legal structure (such as a Verein or alternative to gGmbH). Both options will be developed further with a view to making a decision at the June meeting.

Volunteer directors: AJJ, AE, JK, and GC indicated willingness in principle to serve as directors of a UK legal entity.

New actions:

  • JK to investigate the UK CIC option in more detail.
  • LP to investigate German legal structures (Verein or alternatives) and report back.
  • Swiss options may also be explored if committee members with relevant expertise are able to contribute.

7. CECAM Workshop 2026

EG reported on planning for the CECAM workshop “The Atomic Simulation Environment: Integration into Wider Community Projects” (15–19 June 2026, Mainz).

Key points:

  • Planning is progressing well. The format will follow the successful 2025 workshop, with talks followed by breakout discussions.
  • The initial speaker list will be confirmed soon.
  • Discussion topics will be finalised closer to the event, with flexibility to incorporate attendee suggestions.
  • It is hoped that ASE 4 prototypes will be sufficiently advanced for participants to experiment with during the workshop.
  • HT noted that not all committee members were yet invited; many are expected to attend.

Consensus: A hybrid Steering Committee meeting will be held on Thursday 18 June, 14:00–16:00 CEST, during breakout sessions.

8. Documentation Sprints

HT reported on documentation sprint progress.

Key points:

  • Two substantial sprints have been held, focusing on porting tutorials to sphinx-gallery.
  • 10–15 people have participated at various times, with a core team of approximately 5 people consistently active.
  • Progress is tracked via a GitLab milestone: 35 issues completed, 11 ongoing, 11 not yet started.
  • The sprints have been effective at welcoming new contributors and lowering the barrier to first contributions.
  • EG noted that organising in-person sprint sessions at institutions has been particularly effective.

Website improvements:

  • PE suggested the landing page should advertise upcoming sprints, but this is technically challenging as it should not be part of the main codebase.
  • AHL has started a repository for the top-level website.
  • Consensus that existing documentation URLs breaking is acceptable, as this has already occurred during recent restructuring.

New action: PE and AHL to meet and advance the website work by June.

The next documentation sprint is scheduled for 18 February. Committee members were encouraged to participate.

9. ASE 4.0 Development

JK and AHL reported on ASE 4 development progress.

Key points:

  • The ASE 4 working group has met and EG and YI have been developing proposals as working code.
  • The approach of introducing new concepts progressively in small increments was endorsed.
  • The separation of Atoms and Calculator concepts has received strong community support, including at a recent ML workshop.
  • AHL has been developing new APIs based on this work, including a new Optimizer interface building on the Optimizable interface. This addresses long-standing issues with save/restart functionality and convergence criteria.
  • Work on symmetry-reduced optimisation demonstrates the benefits of this cleaner approach.
  • The plugins architecture is progressing; AJJ hopes it will be ready for participants to explore at the CECAM workshop.

Communication:

  • XW asked where proposals and progress can be viewed. AHL noted the work is happening in merge requests which can be shared.
  • The committee acknowledged it is burdensome to maintain detailed explanations as work evolves, but agreed better communication of ASE 4 activity would be valuable.

New actions:

  • JK and the ASE 4 group to organise another sprint, with the goal of developing a calculator with the new interface.
  • ASE 4 team to create and use a GitLab milestone, linked from developer documentation.

10. Technical Sub-Committee Update

AHL provided the TSC update.

Release status:

  • Version 3.27 was released over Christmas.
  • Version 3.28 will follow soon, including changes to NEB that users have requested.

Development documentation:

  • The developer documentation is outdated. Actions to write guidance on good merge requests should be addressed as part of broader documentation improvements.

Optimizer improvements:

  • The new Optimizer approach separates the algorithm from the “target” (which manages optimisation properties, degrees of freedom, and convergence criteria).
  • This work is already showing practical benefits, including for symmetry-reduced optimisation.
  • Tests for all optimizers except GPMin now work on flat vectors.
  • PE asked whether this will help with non-spherical particles; AHL confirmed it likely will.

Other topics:

  • AJJ proposed discussing logging at the CECAM workshop.
  • The TSC does not currently require specific Steering Committee support, though noted that calculator additions/rejections can be controversial.

11. Any Other Business

PySimHub listing:

The committee received a request to list ASE on PySimHub. There were no objections.

New action: TSC to respond and arrange the listing.

AI contributions:

The committee discussed the question of AI-assisted contributions. Key points:

  • There is risk that AI could generate large volumes of low-quality contributions, though this concern is not unique to AI.
  • The general principle was affirmed that contributions should be of a size and quality consistent with thoughtful human work.

New action: TSC and documentation group to consider this topic as part of developer documentation revisions.

CECAM slides on ASE governance:

JK presented slides from the CECAM workshop “A Roadmap for an Atomistic ML Software Ecosystem” (January 2026, Lausanne), discussing ASE’s role as infrastructure for machine learning potentials.

Discussion points:

  • The idea of the Calculator as a concept beyond ASE — potentially formalised as a general specification rather than just a Python interface — was raised.
  • MH noted interest from the Julia community in such specifications.
  • EG emphasised that ASE 4 Calculator design should align with this broader vision.
  • PE questioned whether effort should be invested in this versus other priorities.
  • AHL noted the priority is ASE’s own API; patterns may emerge through that work.

12. Date of Next Meeting

The next meeting will be held on Thursday 18 June 2026, 14:00–16:00 CEST, during the CECAM workshop in Mainz. The meeting will be hybrid, with in-person attendance in Mainz and online participation available.

Summary of New Actions

ID Owner Description
A20 All Provide web/email link to AHL for website listing
A21 James Kermode (JK) Update Terms of Reference to clarify TSC members are full SC members
A22 James Kermode (JK) Investigate UK CIC option in more detail
A23 Lars Pastewka (LP) Investigate German legal structures (Verein or alternatives) and report back
A24 Committee members (optional) Investigate Swiss foundation options if able
A25 Paul Erhart (PE) / Ask Hjorth Larsen (AHL) Meet to advance website work by June
A26 JK / ASE4 Group Organise ASE 4 sprint with goal to develop a calculator with new interface
A27 ASE4 Team Create and use GitLab milestone for ASE 4 work; link from dev docs
A28 ASE-TSC Respond to PySimHub listing request
A29 ASE-TSC / Docs Group Consider AI contributions guidance as part of developer docs revisions

Updated: