Roadmap

User interface components:

• LIB – Python library API
• APP – Graphical application
• CLI – Command-line interface

Implementation status:

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

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1. Structure Model

1.1 Crystal Structure

Space Group

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

Cell

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

Atom Sites

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

Atomic Displacement (ADP)

Feature	LIB	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	APP
Magnetic Space Groups	📅	📅
Irreducible representations	📅	📅
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	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 (CWL)	☑️	☑️
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	APP
Scale factor	✅	✅

Excluded Regions

Feature	LIB	APP
Multiple regions start/end positions	✅	📅

2.1.2. Standard Bragg diffraction

Fitting Methods

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

Background

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

Preferred Orientation

Feature	LIB	APP
Basic preferred orientation model (CrysPy)	📅high	📅

Instrument — Constant Wavelength

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

Instrument — Time-of-Flight

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

Peak Profile — Constant Wavelength

Feature	LIB	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 (CrysFML)	☑️	📅

Peak Profile — Time-of-Flight

Feature	LIB	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 (CrysFML)	📅	📅

2.1.3. Total Scattering (Pair Distribution Function)

Peak Profile

Feature	LIB	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

CrysPy's extinction is an analytical Becker-Coppens spherical model with Gaussian or Lorentzian mosaicity distributions.

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

Domains / Twinning

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

Instrument — Constant Wavelength

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

Instrument — Time-of-Flight

Feature	LIB	APP
Individual wavelength per reflection	✅	📅

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2.3. Polarized Neutron Diffraction - EPIC

2.3.1. Polarized Neutron Powder Diffraction

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

2.3.2. Polarized Neutron Single Crystal Diffraction

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

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3. Multi-Dataset Support

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

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4. Analysis (Fitting)

Refinement Algorithms (numerical derivatives)

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

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5. Refinement Execution

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

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6. Constraints

Feature	LIB	APP
Automatic symmetry constraints	✅	☑️
User-defined constraints	✅	📅

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7. Data Management

Data Loading

Feature	LIB	APP	CLI
Load structure from CIF	✅	✅	—
Load experiment data from ASCII	✅	✅	—
Load experiment data from CIF	✅	✅	—

Project Files

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

SciCat Integration

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

External Resources

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

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8. Visualization

8.1. Structure

Crystal Structure

Feature	LIB	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	📅	✅
Orthogonal unit cell	📅	✅
Non-orthogonal unit cell	📅	📅

Magnetic Structure

Feature	LIB	APP
Visualize magnetic moments as arrows	📅	📅

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8.2. Experiment

Powder Diffraction

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

Single Crystal Diffraction

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

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8.3. Analysis

Feature	LIB	APP	CLI
Live update of plots on parameter change with slider	—	✅	—
Live update of plots during refinement	—	✅	—
Parameter evolution (sequential refinement)	☑️	📅	—

Fitting

Feature	LIB	APP	CLI
Live update of plots	—	✅	—
Live update of fit quality (change in χ²)	✅	✅	✅
Plot correlation between parameters	✅	📅	✅

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9. User documentation

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

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10. Unsorted features

• Restraints (soft constraints, e.g. bond lengths, angles)
• Refinement using analytical derivatives
• Global optimization algorithms (e.g. simulated annealing)
• Incommensurate structures
• 2D Rietveld refinement