Draft Feature List

[AndrewSazonov]

User interface components:

• LIB – Python library API
• CLI – Command-line interface (with text-based input and output)
• APP – Graphical application

Implementation status:

• ✅ Done
• ☑️ Partially done
• 🚧 Work in progress
• 📅 Planned
  • 📅 5/5 – highest Urgent. Needs attention ASAP
  • 📅 4/5 – high Should be prioritized soon
  • 📅 3/5 – medium Normal/default priority
  • 📅 2/5 – low Low importance
  • 📅 1/5 – lowest Very low urgency
• — Not applicable

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1. Structure Model

1.1 Crystal Structure

Space Group

Feature	LIB	CLI	APP
Hermann-Mauguin space-group symbol	✅	✅	✅
Space group IT number	📅	📅	📅
IT coordinate system code	✅	✅	✅

Cell

Feature	LIB	CLI	APP
Lengths a, b, c	✅	✅	✅
Angles α, β, γ	✅	✅	✅

Atom Sites

Feature	LIB	CLI	APP
X-ray scattering factors (tabulated, CrysPy)	✅	✅	✅
Neutron scattering lengths (tabulated, CrysPy)	✅	✅	✅
Custom neutron scattering length	📅	📅	📅
Fractional coordinates x, y, z	✅	✅	✅
Occupancy	✅	✅	✅
Symmetry wyckoff_letter	✅	✅	✅

Atomic Displacement (ADP)

Feature	LIB	CLI	APP
Isotropic Biso	✅	✅	📅
Isotropic Uiso	🚧	🚧	✅
Anisotropic Bani (B11, B22, B33, B12, B13, B23)	🚧	🚧	📅
Anisotropic Uani (U11, U22, U33, U12, U13, U23)	🚧	🚧	📅

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1.2 Magnetic Structure - EPIC

Feature	LIB	CLI	APP
Irreducible representations	📅	📅	📅
Magnetic Space Groups	📅	📅	📅
Symmetry-adapted modes	📅	📅	📅
Magnetic propagation vector (kx, ky, kz)	📅	📅	📅
Magnetic moments (mx, my, mz)	📅	📅	📅
Local Susceptibility (𝜒11, 𝜒22, 𝜒33, 𝜒12, 𝜒13, 𝜒23)	📅	📅	📅

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2. Experiment Model

Feature	LIB	CLI	APP
2.1. Powder Diffraction	☑️	☑️	☑️
2.1.1. Common features	☑️	☑️	☑️
2.1.2. Standard Bragg diffraction (CWL)	☑️	☑️	☑️
2.1.2. Standard Bragg diffraction (TOF)	☑️	☑️	☑️
2.1.3. Total Scattering (Pair Distribution Function)	☑️	☑️	📅
2.2. Single-Crystal Diffraction	☑️	☑️	☑️
2.2.1. Single-Crystal Diffraction (CWL)	☑️	☑️	☑️
2.2.2. Single-Crystal Diffraction (TOF)	☑️	☑️	☑️
2.3. Polarized Powder Diffraction	📅	📅	📅
2.3.1. Flipping-ratio method (TOF)	📅	📅	📅
2.3.2. Flipping-ratio method (CWL)	📅	📅	📅
2.4. Polarized Single-Crystal Diffraction	📅	📅	📅
2.4.1. Flipping-ratio method (CWL)	📅	📅	📅
2.4.2. Flipping-ratio method (TOF)	📅	📅	📅
2.4.3. Spherical neutron polarimetry	📅	📅	📅

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2.1. Powder Diffraction

2.1.1. Common features

Linked Phases

Feature	LIB	CLI	APP
Scale factor	✅	✅	✅

Excluded Regions

Feature	LIB	CLI	APP
Multiple regions start/end positions	✅	✅	📅

2.1.2. Standard Bragg diffraction

Fitting Methods

Feature	LIB	CLI	APP
Rietveld refinement (full pattern)	✅	✅	✅
Le Bail refinement (profile matching)	📅	📅	📅

Background

Feature	LIB	CLI	APP
Chebyshev polynomial type order, coefficient	✅	✅	📅
Line segments type x, y	✅	✅	✅
Line segments type x, y (auto-detection)	📅	📅	📅

Preferred Orientation

Feature	LIB	CLI	APP
Exponential function (G1, G2 — FullProf "Nor=0")	📅	📅	📅
Modified March's function (G1, G2 — FullProf "Nor=1", CrysPy)	📅 4/5	📅 4/5	📅

Instrument — Constant Wavelength

Feature	LIB	CLI	APP
Wavelength	✅	✅	✅
Second wavelength	📅	📅	📅
2θ offset	✅	✅	✅
Sample displacement correction (FullProf SyCos, SySin)	📅	📅	📅

Instrument — Time-of-Flight

Feature	LIB	CLI	APP
2θ bank	✅	✅	✅
d → TOF conversion reciprocal, offset, linear, quadratic	✅	✅	✅

Peak Profile — Constant Wavelength

Feature	LIB	CLI	APP
Pseudo-Voigt + Empirical asymmetry Gaussian broadening U, V, W. Lorentzian broadening X, Y Empirical asymmetry p1, p2, p3, p4 (CrysPy)	✅	✅	✅
Thompson-Cox-Hastings Pseudo-Voigt + Finger-Cox-Jephcoat asymmetry Gaussian broadening U, V, W. Lorentzian broadening X, Y Finger-Cox-Jephcoat asymmetry 1, 2 (FullProf "Npr 7")	☑️	☑️	📅

Peak Profile — Time-of-Flight

Feature	LIB	CLI	APP
Jorgensen (back-to-back exponentials ⊗ Gaussian) Gaussian broadening σ₀, σ₁, σ₂ Back-to-back exponential rise α₀, α₁ and decay β₀, β₁ (CrysPy "Gauss")	✅	✅	✅
Jorgensen-Von Dreele (back-to-back exponentials ⊗ pseudo-Voigt) Gaussian broadening σ₀, σ₁, σ₂. Lorentzian broadening γ₀, γ₁, γ₂ Back-to-back exponential rise α₀, α₁ and decay β₀, β₁ (CrysPy "pseudo-Voigt")	✅	✅	✅
Double back-to-back exponentials ⊗ pseudo-Voigt Gaussian broadening σ₀, σ₁, σ₂. Lorentzian broadening γ₀, γ₁, γ₂ Rise α₁, α₂. Fast decay β₀₀, β₀₁. Slow decay β₁₀. Switching r₀₁, r₀₂, r₀₃ (CrysPy "type0m", Z-Rietveld "type0m")	☑️	☑️	📅
Ikeda-Carpenter ⊗ pseudo-Voigt Moderator pulse α₀, α₁, β₀, κ Gaussian broadening σ². Lorentzian broadening γ (FullProf "Npr 13")	📅	📅	📅

2.1.3. Total Scattering (Pair Distribution Function)

Peak Profile

Feature	LIB	CLI	APP
Gaussian-damped sinc termination function cutoff q. broadening q. sharpening δ₁, δ₂ damping q, particle diameter (Pdffit2)	✅	✅	📅

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2.2. Single Crystal Diffraction

Extinction

Feature	LIB	CLI	APP
Isotropic Becker-Coppens, Gaussian model: radius, mosaicity (CrysPy)	✅	✅	✅
Isotropic Becker-Coppens, Lorentzian model: radius, mosaicity (CrysPy)	✅	✅	✅
Anisotropic extinction correction	📅	📅	📅

Twinning / domains

Feature	LIB	CLI	APP
Twinning / domains for single-crystal diffraction	📅	📅	📅

Instrument — Constant Wavelength

Feature	LIB	CLI	APP
Wavelength	✅	✅	✅
Half wavelength (λ/2)	📅	📅	📅

Instrument — Time-of-Flight

Feature	LIB	CLI	APP
Individual wavelength per reflection	✅	✅	📅

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2.3. Polarized Neutron Powder Diffraction - EPIC

Feature	LIB	CLI	APP
Flipping-ratio method (TOF)	📅	📅	📅
Flipping-ratio method (CWL)	📅	📅	📅

2.4. Polarized Neutron Single-Crystal Diffraction - EPIC

Feature	LIB	CLI	APP
Flipping-ratio method (TOF)	📅	📅	📅
Flipping-ratio method (CWL)	📅	📅	📅
Spherical neutron polarimetry	📅	📅	📅

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3. Multi-Dataset Support

Feature	LIB	CLI	APP
Multiple structural data blocks	✅	✅	✅
Multiple experimental data blocks	✅	✅	📅

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4. Analysis (Fitting)

Refinement Algorithms (numerical derivatives)

Feature	LIB	CLI	APP
Levenberg–Marquardt LMFIT minimizer	✅	✅	✅
Levenberg–Marquardt LMFIT minimizer (scipy-based)	✅	✅	✅
Levenberg–Marquardt BUMPS minimizer	🚧	🚧	📅
Derivative-free minimization DFO-LS minimizer	✅	✅	✅
Bayesian analysis BUMPS minimizer	📅	📅	📅

Fit Strategies

Feature	LIB	CLI	APP
Single fit of one experimental data block to one or more structural data blocks	✅	✅	✅
Sequential fit of experimental data blocks	✅	✅	📅
Joint fit of experimental data blocks within the same calculation engine	✅	✅	📅
Joint fit of experimental data blocks using different calculation engines (e.g. CrysPy + Pdffit2)	✅	✅	📅
Custom weighting for joint fit: weight per dataset	✅	✅	📅

Live Fitting

Feature	LIB	CLI	APP
Live fitting during real-time data acquisition	📅	📅	📅

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5. Refinement Execution

Feature	LIB	CLI	APP
Scripted refinement workflow	✅	—	—
Command-line refinement execution	—	✅	—
GUI-driven refinement workflow	—	—	✅
Parameter modification	✅	☑️	✅
Load individual structure or experiment files	✅	☑️	✅
Project-based refinement	✅	✅	✅
Sequential refinement	✅	📅	📅
Save refinement results to project	✅	✅	✅

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6. Constraints

Feature	LIB	CLI	APP
Automatic symmetry constraints	✅	✅	☑️
User-defined constraints Basic types, e.g.: "biso_Ba = biso_La" "occ_Ba = 1 - occ_La"	✅	☑️	📅

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7. Data Management

Project Files

Project files are a way to save and load the full state of a refinement, including the structure model, experimental data, fit settings, and results.

Feature	LIB	CLI	APP
Load project from disk	✅	✅	✅
Save project to disk	✅	✅	✅

Data Loading

Feature	LIB	CLI	APP
Add structure (to project) from CIF	✅	☑️	✅
Add experiment data (to project) from CIF	✅	☑️	✅
Add experiment data (to project) from ASCII	✅	☑️	✅
Add experiment data (to project) from NeXus	📅	📅	📅

SciCat Integration

Feature	LIB	CLI	APP
Load full project from SciCat	📅	📅	📅
Save full project to SciCat	📅	📅	📅

External Resources

Feature	LIB	CLI	APP
List available tutorial notebooks	✅	✅	—
Download tutorial notebooks	✅	✅	—

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8. Visualization

8.1. Structure

Crystal Structure

Feature	LIB	CLI	APP
Visualize unit cell	📅	📅	☑️
Visualize multiple unit cells	📅	📅	📅
Visualize atom sites as spheres	📅	📅	✅
Visualize atoms occupied same position	📅	📅	📅
Visualize bonds	📅	📅	📅
Visualize polyhedra	📅	📅	📅
Interactive mode 3D rotation, zooming	📅	📅	✅

Magnetic Structure

Feature	LIB	CLI	APP
Visualize magnetic moments	📅	📅	📅
Visualize magnetization densities	📅	📅	📅

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8.2. Experiment

Powder Diffraction

Feature	LIB	CLI	APP
Plot experimental curve	✅	✅	✅
Plot calculated curve	✅	✅	✅
Plot residual curve	✅	✅	✅
Plot Bragg peaks	📅 5/5	—	✅
Interactive mode zooming, panning	✅	—	✅

Single Crystal Diffraction

Feature	LIB	CLI	APP
Plot obs vs calc for reflections	✅	✅	✅
Interactive mode zooming, panning	✅	—	✅

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8.3. Analysis

Feature	LIB	CLI	APP
Live update of plots on parameter change with slider	—	—	✅
Live update of plots during refinement	—	—	✅
Live update of fit quality (change in χ²) table	✅	✅	—
Live update of fit quality (change in χ²) chart	📅	—	📅
Parameter evolution (sequential refinement)	☑️	—	📅
Correlation between parameters	✅	✅	📅

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9. User documentation

Feature	LIB	CLI	APP
New unified documentation structure	✅	✅	📅
Introduction	✅	✅	☑️
Installation and setup guide	✅	✅	☑️
User guide	✅	✅	☑️
Tutorials	✅	📅	📅
API reference	✅	—	—

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10. Unsorted features

Feature	LIB	CLI	APP
Set free parameters by category (e.g. all atomic positions, all ADPs)
Add category with fit quality metrics (e.g. chi2, R-factors)
Restraints (soft constraints, e.g. bond lengths, angles)
Refinement using analytical derivatives
Global optimization algorithms (e.g. simulated annealing)
Incommensurate structures
2D Rietveld refinement