Asymmetry in the μSR software landscape

This page positions Asymmetry alongside the established μSR analysis programs — WiMDA, musrfit, and Mantid — and publishes the team’s near-term roadmap. It is the public summary of a more detailed internal comparison maintained under docs/porting/ in the Asymmetry repository.

The intended reader is a μSR practitioner who already uses one of WiMDA, musrfit, or Mantid and wants to know where Asymmetry fits.

For end-to-end analyses analogous to the typical workflows in those tools, see Analysis workflows.

The reference programs

Tool	Authors / facility	Language / stack	Strength
WiMDA	Francis Pratt (ISIS)	Object Pascal (Delphi)	Legacy ISIS standard; rich frequency-domain tools (MaxEnt, moments, eigenvalue spectral estimator)
musrfit	Suter, B. Wojek (PSI)	C++ / ROOT / Minuit2	Hand-editable .msr workflow files; largest built-in theory library (~34 functions); robust Minuit2 fitting
Mantid	ISIS + ORNL community	C++ core / Python GUI / matplotlib	Workspace-based pipeline; unique ALC interface; broadest set of specialist muonium fit functions
Asymmetry	Asymmetry contributors	Python / PySide6 / matplotlib	Modern Python stack; Fit Wizard (AICc-ranked); composite-model expression syntax; interactive parameter trending

At a glance: feature coverage

Symbols: ✅ present ◐ partial / stub ❌ absent ★ distinctive strength.

Category	WiMDA	musrfit	Mantid	Asymmetry
Multi-format data ingestion (NeXus, PSI BIN, MUD, ROOT)	✅	✅	✅	✅
Deadtime correction	◐	◐	✅	✅
Asymmetry calculation (F/B grouping, α)	✅	✅	✅	✅
Automatic phase calibration	❌	❌	★	◐
Rotating Reference Frame	❌	◐	★	✅
Theory function library	◐ ~12	★ ~34	★ ~15 specialist	◐ growing
Static Kubo–Toyabe (ZF / LF)	✅	✅	✅	✅
Dynamic Kubo–Toyabe	✅	✅	★	✅
Composite-model expression syntax	❌	◐	◐	★
MIGRAD / MINOS / HESSE	◐ Hessian only	★ full set	✅ via Mantid Fit	✅ full set
Multi-spectrum / global fit	◐ sequential	✅ shared params	✅	✅
Multi-group time-domain fit	◐	✅	✅	✅
Fourier (FFT + apodisation)	✅	✅	✅	✅
MaxEnt frequency reconstruction	★ Burg pole-scan	◐	★ iterative	✅
Spectral moments analysis	★	❌	❌	✅
Interactive parameter trending	◐ table	◐ msr2data CLI	◐ table	★ panel
Avoided Level Crossing (ALC) workflow	❌	❌	★	✅
Period arithmetic (pulsed data)	◐	❌	★	✅
Logbook / multi-run manager	✅	◐	✅	★
Synthetic data simulation	★	❌	❌	✅
User-defined functions	◐ DLL	◐ C++ plugin	◐ Mantid plugin	✅ Python plugins
Project files (hand-editable)	❌	★ .msr	◐ .mantid	✅ .asymp (JSON)
Model-recommendation wizard	❌	❌	❌	★ Fit Wizard

Where Asymmetry leads

These are the parts of the workflow where Asymmetry’s implementation is materially richer or more ergonomic than the alternatives.

Fit Wizard (AICc-ranked model recommendation).

No equivalent in WiMDA, musrfit, or Mantid. The wizard runs a curated portfolio of candidate models on the active dataset and ranks them by an information-theoretic metric (AICc by default). Especially valuable for new users encountering an unfamiliar spectrum. See Fit wizard.

Composite-model expression syntax.

Free-form arithmetic over registered components — Exponential * Oscillatory + Constant, with fraction-group syntax (...){frac} for shared-amplitude bundles. musrfit’s FUNCTIONS block is the closest analogue but is more limited; WiMDA and Mantid require building composite functions procedurally. See Composite models.

Interactive parameter trending.

Per-run fit parameters appear as a sortable trend table that drives an integrated parametric-model fit panel (e.g. SC_TwoGap_SS for σ(T) → λ(T) in superconductors). musrfit’s msr2data is a CLI-only batch tool; Mantid’s results table does not perform secondary parametric fits in the same window. See Parameter trending.

Modern PySide6 + matplotlib single-process GUI.

musrfit fragments across separate musrview, musredit, musrWiz, mupp processes. Mantid is a heavy install (~1 GB). Asymmetry runs in one process with a single pip install.

Schema-versioned JSON project files (``.asymp``).

Forward-compatible state serialisation with documented schema migrations. .mantid files are HDF5 binary; .msr files lack a versioned schema. See Project files.

Where the other tools lead

Areas where Asymmetry currently lags. Each item is tracked as a candidate in the roadmap (see below).

Theory function breadth (musrfit / Mantid).

musrfit ships ~34 built-in theory functions; Mantid adds ~15 specialist muon-only functions (Keren, Meier, MuonFInteraction, four *Muonium* variants, MuoniumDecouplingCurve). Asymmetry’s component library is smaller and still filling in specialist forms (Keren, Abragam, Bessel, SpinGlass, Meier). Tracked as theory-library-expansion.

Automatic phase calibration (Mantid).

Mantid’s CalMuonDetectorPhases fits every detector phase automatically from early-time data in one step. Asymmetry estimates per-group FFT phases and can fit per-group phases inside the MaxEnt reconstruction, but has no equivalent one-click full-detector auto-calibration. Tracked as phase-auto-calibration.

musrfit ``.msr`` project import.

Asymmetry reads its own .asymp projects but cannot yet import a musrfit .msr file. Cross-tool interoperability is tracked as msr-import.

Shipped since the first landscape survey

Much of the original gap list has since landed and is documented in the reference manual: MINOS asymmetric errors (Asymmetric (MINOS) errors), dynamic Kubo–Toyabe (Kubo–Toyabe), the MaxEnt reconstruction and Burg pole-scan (Fourier analysis, Frequency-domain conditioning), the rotating-reference-frame transform (Rotating-reference-frame display), spectral moments (Spectral moments), synthetic-data simulation (Synthetic runs and degraded statistics), period arithmetic and RF-μSR resonance (Integral scan mode (avoided-level-crossing field scans)), Python user-function plugins (User functions), and negative-muon analysis (Negative-muon capture-lifetime analysis (experimental)).

Roadmap — the remaining gaps

The team works through a prioritised list of the gaps that remain. Priority is set by an explicit impact × ease score (see docs/porting/ROADMAP.md in the repository for the full methodology). The near-term candidates are:

• Theory library expansion — continue porting specialist forms (Keren, Abragam, Bessel, SpinGlass, Meier, MuoniumDecouplingCurve, and the time-domain superconductor vortex-lattice function) from musrfit / Mantid.

• Automatic phase calibration — a one-step full-detector auto-phase for TF datasets, analogous to Mantid’s CalMuonDetectorPhases.

• musrfit ``.msr`` import — read a musrfit project file for cross-tool interoperability.

The roadmap is refreshed quarterly. The latest ranked candidate list lives in docs/porting/ROADMAP.md in the repository.

References

Software references:

• WiMDA: F. L. Pratt, Physica B 289–290, 710 (2000).

• musrfit: A. Suter and B. M. Wojek, Phys. Procedia 30, 69 (2012). Source: https://bitbucket.org/muonspin/musrfit

• Mantid: O. Arnold et al., Nucl. Instrum. Methods A 764, 156 (2014). Source: https://github.com/mantidproject/mantid

For the underlying physics see S. J. Blundell, R. De Renzi, T. Lancaster, and F. L. Pratt, Muon Spectroscopy: An Introduction (Oxford University Press, Oxford, 2022).