Load Project and Fit: LBCO, HRPT¶

This is the most minimal example of using EasyDiffraction. It shows how to load a previously saved project from a directory and run refinement — all in just a few lines of code.

For this example, constant-wavelength neutron powder diffraction data for La0.5Ba0.5CoO3 from HRPT at PSI is used.

It does not contain any advanced features or options, and includes no comments or explanations — these can be found in the other tutorials.

Import Modules¶

In [2]:

from easydiffraction import Project
from easydiffraction import download_data
from easydiffraction import extract_project_from_zip

from easydiffraction import Project from easydiffraction import download_data from easydiffraction import extract_project_from_zip

Download Project Archive¶

In [3]:

zip_path = download_data(id=30, destination='data')

zip_path = download_data(id=30, destination='data')

Getting data...

Data #30: La0.5Ba0.5CoO3, HRPT (PSI), 300 K - Updated #28

✅ Data #30 downloaded to 'data/ed-30.zip'

Extract Project¶

In [4]:

project_dir = extract_project_from_zip(zip_path, destination='data')

project_dir = extract_project_from_zip(zip_path, destination='data')

Load Project¶

In [5]:

project = Project.load(project_dir)

project = Project.load(project_dir)

Perform Analysis¶

In [6]:

project.analysis.fit()

project.analysis.fit()

Standard fitting

📋 Using experiment 🔬 'hrpt' for 'single' fitting

🚀 Starting fit process with 'lmfit (leastsq)'...

📈 Goodness-of-fit (reduced χ²) change:

	iteration	χ²	improvement [%]
1	1	254.47
2	21	43.04	83.1% ↓
3	39	36.17	16.0% ↓
4	57	34.88	3.6% ↓
5	76	22.76	34.8% ↓
6	94	17.59	22.7% ↓
7	112	8.38	52.4% ↓
8	130	4.57	45.5% ↓
9	148	2.18	52.2% ↓
10	166	1.88	14.1% ↓
11	184	1.53	18.5% ↓
12	202	1.42	7.3% ↓
13	220	1.25	11.5% ↓
14	329	1.25

🏆 Best goodness-of-fit (reduced χ²) is 1.25 at iteration 328

✅ Fitting complete.

Saving project 📦 'lbco_hrpt' to

/home/runner/work/diffraction-lib/diffraction-lib/docs/docs/tutorials/data/lbco_project

├── 📄 project.cif

├── 📁 structures/

│   └── 📄 lbco.cif

├── 📁 experiments/

│   └── 📄 hrpt.cif

├── 📁 analysis/

│   └── 📄 analysis.cif

└── 📄 summary.cif

Show Results¶

In [7]:

project.analysis.display.fit_results()

project.analysis.display.fit_results()

Fit results

✅ Success: True

⏱️ Fitting time: 18.24 seconds

📏 Goodness-of-fit (reduced χ²): 1.25

📏 R-factor (Rf): 5.48%

📏 R-factor squared (Rf²): 4.94%

📏 Weighted R-factor (wR): 3.97%

📈 Fitted parameters:

	datablock	category	entry	parameter	start	fitted	uncertainty	units	change
1	lbco	cell		length_a	3.8800	3.8914	0.0001	Å	0.29 % ↑
2	lbco	atom_site	La	adp_iso	0.5000	0.5052	0.0273	Ų	1.05 % ↑
3	lbco	atom_site	Co	adp_iso	0.5000	0.2469	0.0558	Ų	50.62 % ↓
4	lbco	atom_site	O	adp_iso	1.0000	1.3921	0.0158	Ų	39.21 % ↑
5	hrpt	linked_phases	lbco	scale	7.0000	9.1234	0.0530		30.33 % ↑
6	hrpt	peak		asym_empir_2	0.0000	-0.0177	0.0019		N/A
7	hrpt	peak		asym_empir_4	0.0000	0.0318	0.0041		N/A
8	hrpt	peak		broad_gauss_u	0.1000	0.0859	0.0032	deg²	14.11 % ↓
9	hrpt	peak		broad_gauss_v	-0.1000	-0.1206	0.0067	deg²	20.57 % ↑
10	hrpt	peak		broad_gauss_w	0.1000	0.1225	0.0032	deg²	22.49 % ↑
11	hrpt	peak		broad_lorentz_y	0.0000	0.0830	0.0021	deg	N/A
12	hrpt	instrument		twotheta_offset	0.0000	0.6264	0.0026	deg	N/A
13	hrpt	background	1	y	168.4237	168.4068	1.3761		0.01 % ↓
14	hrpt	background	2	y	164.3727	164.4507	0.9871		0.05 % ↑
15	hrpt	background	3	y	166.8885	167.0188	0.7279		0.08 % ↑
16	hrpt	background	4	y	175.3971	175.4557	0.6394		0.03 % ↑
17	hrpt	background	5	y	174.3046	174.4162	0.8815		0.06 % ↑

Show parameter correlations¶

In [8]:

project.plotter.plot_param_correlations()

project.plotter.plot_param_correlations()

Plot Meas vs Calc¶

In [9]:

project.plotter.plot_meas_vs_calc(expt_name='hrpt', show_residual=True)

project.plotter.plot_meas_vs_calc(expt_name='hrpt', show_residual=True)