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Project

The Project serves as a container for all data and metadata associated with a particular data analysis task. It acts as the top-level entity in EasyDiffraction, ensuring structured organization and easy access to relevant information. Each project can contain multiple experimental datasets, with each dataset containing contribution from multiple structures.

EasyDiffraction allows you to:

  • Manually create a new project by specifying its metadata.
  • Load an existing saved project from its project directory.

Below are instructions on how to set up a project in EasyDiffraction. It is assumed that you have already imported the easydiffraction package, as described in the First Steps section.

Creating a Project Manually

You can manually create a new project and specify its short name, title and description. All these parameters are optional.

# Create a new project
project = edi.Project(name='lbco_hrpt')

# Define project metadata
project.metadata.title = 'La0.5Ba0.5CoO3 from neutron diffraction at HRPT@PSI'
project.metadata.description = """This project demonstrates a standard refinement
of La0.5Ba0.5CoO3, which crystallizes in a perovskite-type structure, using
neutron powder diffraction data collected in constant wavelength mode at the
HRPT diffractometer (PSI)."""

Saving a Project

Saving the initial project requires specifying the directory path:

project.save_as(dir_path='lbco_hrpt')

If working in the interactive mode in a Jupyter notebook or similar environment, you can also save the project after every significant change. This is useful for keeping track of changes and ensuring that your work is not lost. If you already saved the project with save_as, you can just call the save:

project.save()

Loading a Saved Project

If you have an existing saved project, load it from the project directory created by project.save_as() or project.save(). This is useful for continuing a previous session or reusing a downloaded saved project.

project = edi.Project.load('lbco_hrpt')

Project Structure

The example below illustrates a typical project structure for a constant-wavelength powder neutron diffraction experiment:

📁 La0.5Ba0.5CoO3     - project root
├── 📄 project.edi - project configuration
├── 📁 structures  - structures
│   ├── 📄 lbco.edi - LBCO
│   └── ...
├── 📁 experiments - experiments
│   ├── 📄 hrpt.edi - HRPT pattern
│   └── ...
├── 📁 analysis    - analysis
│   ├── 📄 analysis.edi - fit state
│   └── 📄 mcmc.h5   - Bayesian arrays
└── 📁 reports     - reports
    ├── 📄 La0.5Ba0.5CoO3.cif  - IUCr
    └── 📄 La0.5Ba0.5CoO3.html - HTML

Project Files

Below is a representative project example stored in the La0.5Ba0.5CoO3 directory, showing the main files created by a typical workflow.

Important

If you save the project right after creating it, the project directory will only contain the project.edi file. The other folders and files will be created as you add structures, experiments, and set up the analysis. The reports folder is created only when at least one of project.report.cif, project.report.html, project.report.tex, or project.report.pdf is set to True before project.save().

1. project.edi

This file stores project-level metadata and display configuration.

_edi.schema_version 1

_metadata.name          lbco_hrpt
_metadata.title         "La0.5Ba0.5CoO3 from neutron diffraction at HRPT@PSI"
_metadata.description   "neutrons, powder, constant wavelength, HRPT@PSI"
_metadata.created       "18 May 2026 10:15:00"
_metadata.last_modified "18 May 2026 10:20:00"

_rendering_plot.type      auto
_report.cif               false
_report.html              true
_report.tex               false
_report.pdf               false
_report.html_offline      false
_rendering_table.type     auto
_rendering_structure.type auto
_structure_view.show_labels false
_structure_style.atom_view covalent
_structure_style.color_scheme jmol
_verbosity.fit         full

2. structures / lbco.edi

This file contains crystallographic information associated with the structure model, including space group, unit cell parameters, and atomic positions.

data_lbco

_space_group.name_H-M_alt              "P m -3 m"
_space_group.IT_coordinate_system_code 1

_cell.length_a      3.8909(1)
_cell.length_b      3.8909
_cell.length_c      3.8909
_cell.angle_alpha  90
_cell.angle_beta   90
_cell.angle_gamma  90

loop_
_atom_site.id
_atom_site.type_symbol
_atom_site.fract_x
_atom_site.fract_y
_atom_site.fract_z
_atom_site.Wyckoff_symbol
_atom_site.occupancy
_atom_site.ADP_type
_atom_site.B_iso_or_equiv
La La   0   0   0     a   0.5  Biso 0.4958
Ba Ba   0   0   0     a   0.5  Biso 0.4943
Co Co   0.5 0.5 0.5   b   1    Biso 0.2567
O  O    0   0.5 0.5   c   1    Biso 1.4041

3. experiments / hrpt.edi

This file contains the experiment type, calculation engine, instrumental parameters, peak parameters, associated phases, background parameters and measured diffraction data.

data_hrpt

_experiment_type.beam_mode        "constant wavelength"
_experiment_type.radiation_probe  neutron
_experiment_type.sample_form      powder
_experiment_type.scattering_type  bragg

_calculator.type cryspy

_instrument.setup_wavelength        1.494
_instrument.calib_twotheta_offset 0.6225(4)

_peak.broad_gauss_u    0.0834
_peak.broad_gauss_v   -0.1168
_peak.broad_gauss_w    0.123
_peak.broad_lorentz_x  0
_peak.broad_lorentz_y  0.0797

loop_
_linked_structure.structure_id
_linked_structure.scale
lbco 9.0976(3)

loop_
_background.id
_background.position
_background.intensity
1  10  174.3
2  20  159.8
3  30  167.9
4  50  166.1
5  70  172.3
6  90  171.1

loop_
_data.id
_data.two_theta
_data.intensity_meas
_data.intensity_meas_su
1  10.00  167  12.6
2  10.05  157  12.5
3  10.10  187  13.3
4  10.15  197  14.0
5  10.20  164  12.5
6  10.25  171  13.0
...
164.60  153  20.7
164.65  173  30.1
164.70  187  27.9
164.75  175  38.2
164.80  168  30.9
164.85  109  41.2

4. analysis / analysis.edi

This file contains settings used for data analysis, including the choice of calculation and fitting engines, as well as user defined constraints.

_fitting_mode.type              single
_minimizer.type                 lmfit

loop_
_alias.id
_alias.parameter_unique_name
biso_La  lbco.atom_site.La.B_iso_or_equiv
biso_Ba  lbco.atom_site.Ba.B_iso_or_equiv
occ_La   lbco.atom_site.La.occupancy
occ_Ba   lbco.atom_site.Ba.occupancy

loop_
_constraint.id
_constraint.expression
biso_Ba  "biso_Ba = biso_La"
occ_Ba   "occ_Ba = 1 - occ_La"

When a Bayesian fit stores persisted posterior or predictive arrays, the same analysis/ directory also contains mcmc.h5.


Now that the Project has been defined, you can proceed to the next step: Structure.