Wyn Williams
Project lead & co-developer
University of Edinburgh
Why MERRILL 3?
MERRILL has been the community standard for grain-scale micromagnetic simulation in rock magnetism for over a decade. The forthcoming MERRILL 3 is a ground-up redevelopment that replaces the current Fortran scripting layer with a clean Python API, moves the build and test infrastructure to continuous integration on Bitbucket, standardises mesh and output formats around HDF5, and extends the benchmark suite to cover the full range of material parameters and grain geometries used in palaeomagnetic and planetary scienc
The project is international and openly collaborative. Development milestones, advisory-board reviews, and a user training workshop are planned at regular intervals through 2027, culminating in a stable public release and an updated community roadmap.
Phased development plan — 2027
Project start: January 2027 · Target release: Q4 2027
Q1
January – March 2027
Architecture & Setup
Milestones
- Developer retreat to agree architecture, benchmarks, and overall workplan (Williams, Fabian, Paterson, Klebes).
- Initial Python API skeleton and internal prototype established (Klebes, Williams).
- First core benchmarks and continuous integration set up in Bitbucket (Klebes, Nagy, Fabian).
Key meetings & events
- 5-day in-person developer retreat
- Online project kick-off
- Initial advisory-board call
- Regular co-lead coordination calls
Q2
April – June 2027
API & Documentation
Milestones
- Extended Python API covering core laboratory workflows (Klebes, Williams, Paterson).
- Draft online manual structure and first tutorials prepared (Paterson, Nagy, Klebes, Williams).
- Mesh/HDF5 design agreed and initial implementation completed (Nagy, Klebes, Fabian).
- Updated performance and accuracy benchmarks on representative models (Fabian, Klebes).
Key meetings & events
- Internal mid-strand check-ins
- Formal mid-project internal review (end of June)
Q3
July – September 2027
Community workshop & stabilisation
Milestones
- Stable minimal Python API with comprehensive tests (Klebes).
- Mesh and compact output support nearing completion (Klebes, Fabian).
- Regression suite integrated across key workflows (Klebes, Nagy, Fabian).
- Workshop-ready API, worked examples, and training materials exercised with users (Paterson, Nagy, Klebes).
Key meetings & events
- In-person User Training Workshop — Edinburgh (September)
- In-person advisory-board meeting immediately after the workshop
- Ongoing co-lead coordination calls
Q4
October – December 2027
Release & documentation freeze
Milestones
- Large-model interoperability tests completed (Fabian, Klebes).
- Final refactoring and performance tuning (Fabian, Klebes, Williams).
- Public release candidate followed by final tagged release (Klebes, Williams).
- Documentation freeze, benchmark summary, and sustainability/governance notes published (Williams, Paterson, Nagy).
Key meetings & events
- Short in-person developer retreat
- Online advisory-board check-in
- Final review and roadmap update communicated to the community
Activities are phased so that API development, documentation, interoperability, and
numerical-maintenance milestones feed into a Month 9 user workshop and advisory-board
review, culminating in a stable release and updated roadmap by project end.
Development team
MERRILL 3 is a collaborative effort spanning several institutions. The team brings together expertise in micromagnetics, rock magnetism, numerical methods, and software engineering.
Karl Fabian
Numerical methods & benchmarks
Norwegian University of Science and Technology (NTNU)
Greig Paterson
Documentation & tutorials
University of Liverpool
Jason Klebes
Python API & CI/CD
University of Edinburgh
Lesleis Nagy
Mesh & HDF5 implementation
University of Liverpool
Get involved
Join the MERRILL 3 project
MERRILL 3 is open to collaborators with expertise in micromagnetics, rock magnetism, numerical methods, or scientific software engineering. The project includes funded developer positions, advisory-board participation, and community workshop involvement. All source code will be openly available on Bitbucket under the project's existing open-source licence.