ubermag/mumax3c

mumax3 calculator.

ubermag

Marijan Beg^1,2, Martin Lang², Samuel Holt^2,3, Swapneel Amit Pathak^2,4, Ryan A. Pepper⁵, Thomas Kluyver⁶, Jeroen Mulkers⁷, Jonathan Leliaert⁷, and Hans Fangohr^2,4,8

¹ Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK
² Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO17 1BJ, UK
³ Department of Physics, University of Warwick, Coventry CV4 7AL, UK
⁴ Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany
⁵ Research Software Group, University of Birmingham, Birmingham B15 2TT, UK
⁶ European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
⁷ Faculty of Sciences, Ghent University, Krijgslaan 281, S12, 9000 Ghent, Belgium
⁸ Center for Free-Electron Laser Science, Luruper Chaussee 149, 22761 Hamburg, Germany

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About

ubermag is a Python package, integrated with Jupyter, providing:

• Meta package for Ubermag project,

• Logging control in Ubermag packages.

It is available on Windows, MacOS, and Linux. It requires Python 3.8+.

Documentation

APIs and tutorials are available in the documentation. To access the documentation, use the badge in the table above.

Installation, testing, and upgrade

We recommend installation using conda package manager. Instructions can be found in the documentation.

Binder

This package can be used in the cloud via Binder. To access Binder, use the badge in the table above.

YouTube

YouTube video tutorials are available on the Ubermag channel.

Support

If you require support, have questions, want to report a bug, or want to suggest an improvement, please raise an issue in ubermag/help repository.

Contributions

All contributions are welcome, however small they are. If you would like to contribute, please fork the repository and create a pull request. If you are not sure how to contribute, please contact us by raising an issue in ubermag/help repository, and we are going to help you get started and assist you on the way.

Contributors:

License

Licensed under the BSD 3-Clause "New" or "Revised" License. For details, please refer to the LICENSE file.

How to cite

1. M. Beg, M. Lang, and H. Fangohr. Ubermag: Towards more effective micromagnetic workflows. IEEE Transactions on Magnetics 58, 7300205 (2022).

2. M. Beg, R. A. Pepper, and H. Fangohr. User interfaces for computational science: A domain specific language for OOMMF embedded in Python. AIP Advances 7, 56025 (2017).

3. Marijan Beg, Martin Lang, Samuel Holt, Swapneel Amit Pathak, Ryan A. Pepper, Thomas Kluyver, Jeroen Mulkers, Jonathan Leliaert, and Hans Fangohr. ubermag: Meta package for Ubermag project. DOI: 10.5281/zenodo.3539495 (2022).

Acknowledgements

• OpenDreamKit – Horizon 2020 European Research Infrastructure project (676541)

• EPSRC Programme Grant on Skyrmionics (EP/N032128/1)

mumax3c's Issues

Check ubermagtable

Subregion zero Ms leads to nan in output .mx3 file

Hi,
thanks for creating this great tool.

I think found an issue when there's a nan Ms set in the output .mx3 file:

Msat.setregion(2, nan) 

This line:

mumax3c/mumax3c/scripts/util.py

Line 93 in b5b9f08

array_max = np.max(array)

returns 0 for a region with a zero Ms set, which then in division leads to a nan. This nan propagates to the output .mx3 file. The function should probably return 0 if the array_max value is zero, assuming that the user did not set the Ms to a negative number.

Thanks!

Update Notebooks

Review notebooks

Refactor driver scripts to take into account all the energy terms

For example, at present, DMI energy is not added to the table. Refactor the driver_script to take such issues into account.

Number of repetition of the geometry for PBC

At present we use just one repetition for the PBC. Is this enough for all the cases? When should one use more and should we let the user decide this?

Add text to mx3

Incorporate the ability to add text directly to the mx3 file as a catch all for methods that are not currently implemented and advanced users.

`NotImplementedError` for missing features

Users currently don't notice that certain features (e.g. spin currents) are not supported and not added to the mx3 files. It would be good if we could raise NotImplementedErrors for the features that are currently missing.

Unique/close Ms values

Spin currents

Add more than one Zeeman fields.

Hello @samjrholt and @lang-m, I read the other day on the Mumax3 docs that one can add multiple Zeeman fields. I wanted to use this in one of the simulations, and hence, I have opened a PR for the same.

Time dependent fields not supported

`RunWhile` Support

@SeregaKR suggested adding support for RunWhile in mumax3c in #81. We have a few questions on this topic.

1. What conditions (and how many) does mumax3 support in RunWhile?
2. Are any of these conditions already present in any way in micrimagneticmodel?
3. Is it worth making this part of the TimeDriver rather than a separate driver?
4. Can mumax3 combine multiple conditions with logic operators?

We do in general like the following suggestion:

td = mc.<...Driver>()
td.drive(system, condition="MaxTorque > 0.005")

Micromagnetic data

Add functionality to allow micromagneticdata to work with mumax3c
ubermag/micromagneticdata#28

Refactor `Driver.drive`

Fix tests

Unique material parameters

Scripts do not finish running if there are too many unique Ms values.

First release

• Update repository metadata
• Update devtools
• Update Ubermag

Skip tests if mumax3 is not available

In the ubermag meta-package we execute all unit tests from all subpackages. We generally cannot assume that mumax3 is installed on a system. We could have a second fixture to skip all tests if mumax3 is not available.

Advanced Functionality To do

• Time-dependent energy terms
• Check compute for mumax3
• Can Ms=0 all be the same region?
• Check available energies in mumax3
• PBC more than 1 repeat
• Spatially dependent Zeeman Field
• Magnetoelastic coupling
• Advanced running e.g. RunWhile, steps, and SetSolver
• Fixed Magnetisation Subregions
• Output step mumax3 equivilent?
• Add evolvers, i.e. spin currents
• Global DMI and subregions of A

Add required input scripts to run the macrospin example similar to `oommfc`

Use `mumax3c-changes` branch in `micromagnetictests`

Allowed attributes for drivers

Calculate mumax3 subregions

• Add code to mumax3c
• Add Ms to mx3 files
• Add region_relator to system
• Informative error message
• Use mesh to create slices

Update energy terms

• Change to using mumax3 regions
• Relate ubermag regions to mumax3 regions
• Deal with energies between mumax3 regions
  - [ ] Check available energies in mumax3
• Compatible with micromagneticmodel

Runners for mumax3

Review runner in mumax3c and oommfc to remove potential code duplication.

Activate all tests

We currently only use a small subset of the tests in micromagnetictests because we only import a few test.

mumax3c/mumax3c/tests/test_micromagnetictests.py

Lines 1 to 6 in 57ce3d0

	from micromagnetictests.calculatortests import ( # noqa: F401
	TestDemag,
	TestDMI,
	TestExchange,
	TestZeeman,
	)

In oommfc we import all tests (from micromagnetictests.calculatortests import *). It would be good if we could use the same here.

To do

• #7
• #43
• #15
• #14
• #16
• #9
• #18
• Document and comment code
• Complete all TODO in driver.py
• #28
• #27
• #26
• #22
• Output table mumax3
• Output file types
• #35
• #40
• #41

Cleanup in the end

• Use master branch from micromagnetictests

Move `.rst` content to website

ZhangLi `u` from `df.Field`

Mumax3 expects a vector field for J, OOMMF a scalar field for u (hard-coded in x direction). mumax3c should check whether the field u is a scalar or vector field. For best compatibility I would convert a scalar field to a vector field and add 0 for the additional two directions.

mumax3c/mumax3c/scripts/driver.py

Lines 54 to 58 in 3e8d96a

	if system.dynamics.get(type=mm.ZhangLi):
	(zh_li_term,) = system.dynamics.get(type=mm.ZhangLi)
	u = (
	zh_li_term.u
	if isinstance(zh_li_term.u, df.Field)

Use new discretisedfield syntax

Mumax questions

• Which equation is used for DMI type Dind (interfacial Cnv type)? [My guess would be it is equivalent to Cnv_z in OOMMF].
• Can we fix the spins in one of the regions?
• Can we save multiple steps for mindriver, relaxdriver?
• What type of data can we use in compute?
• Can there be a need to have multiple subregions in the Ms = 0 part (outside the sample)?
• Proper definition of boundary conditions.