LBCO Resume¶

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 Library¶

In [2]:

import easydiffraction as edi

import easydiffraction as edi

📂 Load Project¶

Locate Project¶

Download and extract the saved project from the EasyDiffraction data repository.

In [3]:

project_dir = edi.download_data('proj-lbco-hrpt', destination='projects')

project_dir = edi.download_data('proj-lbco-hrpt', destination='projects')

Getting data...

Data 'proj-lbco-hrpt': La0.5Ba0.5CoO3, HRPT (PSI), 300 K

✅ Data 'proj-lbco-hrpt' downloaded and extracted to '../../../projects/proj-lbco-hrpt-69567a192590'

Load Project¶

In [4]:

project = edi.Project.load(project_dir)

project = edi.Project.load(project_dir)

Re-save the project to a fresh working directory so fitting below writes there instead of the bundled read-only copy.

In [5]:

project.save_as(dir_path='projects/load-and-fit-lbco-hrpt')

project.save_as(dir_path='projects/load-and-fit-lbco-hrpt')

Saving project 📦 'lbco_hrpt' to '../../../projects/load-and-fit-lbco-hrpt'

├── 📄 project.edi
├── 📁 structures/
│   └── 📄 lbco.edi
├── 📁 experiments/
│   └── 📄 hrpt.edi
├── 📁 analysis/
│   └── 📄 analysis.edi
└── 📁 reports/
    └── 📄 lbco_hrpt.html

🚀 Perform Analysis¶

Display Structure¶

In [6]:

project.display.structure(struct_name='lbco')

project.display.structure(struct_name='lbco')

Structure 🧩 'lbco' (Atom view type: 'covalent')

Loading plot…

drag = rotate
wheel = zoom
right-drag = pan

Run Fitting¶

In [7]:

project.analysis.minimizer.chi_square_change_tolerance = 1e-2

project.analysis.minimizer.chi_square_change_tolerance = 1e-2

In [8]:

project.analysis.fit()

project.analysis.fit()

Standard fitting

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

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

📈 Goodness-of-fit progress:

	iteration	time (s)	χ²	change / status
1	1	0.05	1.27
2	20	0.89	1.26

🏆 Best goodness-of-fit (reduced χ²) is 1.26 at iteration 19

✅ Fitting complete.

Display Fit Results¶

In [9]:

project.display.fit.results()

project.display.fit.results()

⚙️ Settings used:

	Name	Value	Description
1	max_iterations	1000	Maximum solver iterations.
2	chi_square_change_tolerance	0.01	Relative change in the objective (chi-square) used to stop fitting.
3	parameter_change_tolerance	1e-08	Relative change in fitted parameters used to stop fitting.
4	gradient_tolerance	0.0	Gradient orthogonality used to stop fitting; zero disables it.

📋 Least-squares fit results:

	Metric	Value
1	🧪 Minimizer	lmfit
2	✅ Overall status	success
3	⏱️ Fitting time (seconds)	0.89
4	🔁 Iterations	17
5	📏 Goodness-of-fit (reduced χ²)	1.26
6	📏 R-factor (Rf, %)	5.57
7	📏 R-factor squared (Rf², %)	5.23
8	📏 Weighted R-factor (wR, %)	7.13

📈 Refined parameters:

	datablock	category	entry	parameter	units	start	value	s.u.	change
1	lbco	cell		length_a	Å	3.8908	3.8908	0.0000	0.00 % ↑
2	lbco	atom_site	La	adp_iso	Ų	0.4920	0.4651	0.0302	5.47 % ↓
3	lbco	atom_site	Co	adp_iso	Ų	0.2490	0.2891	0.0447	16.10 % ↑
4	lbco	atom_site	O	adp_iso	Ų	1.4040	1.4066	0.0146	0.19 % ↑
5	hrpt	linked_structure	lbco	scale		9.1280	9.1103	0.0588	0.19 % ↓
6	hrpt	peak		broad_gauss_u	deg²	0.0803	0.0813	0.0032	1.19 % ↑
7	hrpt	peak		broad_gauss_v	deg²	-0.1125	-0.1153	0.0068	2.44 % ↑
8	hrpt	peak		broad_gauss_w	deg²	0.1195	0.1203	0.0033	0.66 % ↑
9	hrpt	peak		broad_lorentz_y	deg	0.0836	0.0843	0.0021	0.79 % ↑
10	hrpt	instrument		twotheta_offset	deg	0.6205	0.6204	0.0008	0.00 % ↓
11	hrpt	background	1	intensity		166.9200	166.9117	0.8920	0.00 % ↓
12	hrpt	background	2	intensity		167.6100	167.6729	0.6889	0.04 % ↑
13	hrpt	background	3	intensity		172.8800	172.6700	0.7111	0.12 % ↓
14	hrpt	background	4	intensity		180.9200	181.0439	0.8757	0.07 % ↑
15	hrpt	background	5	intensity		168.7000	162.6407	1.2406	3.59 % ↓

• start = parameter value before refinement
• value = refined value from least-squares minimization
• s.u. = standard uncertainty (one sigma), from the covariance matrix
• change = relative change from start, in %; ↑ = increase, ↓ = decrease

In [10]:

project.display.fit.correlations()

project.display.fit.correlations()

Loading plot…

In [11]:

project.display.pattern(expt_name='hrpt')

project.display.pattern(expt_name='hrpt')

Loading plot…

💾 Save Project¶

In [12]:

project.save_as(dir_path='projects/load-and-fit-lbco-hrpt')

project.save_as(dir_path='projects/load-and-fit-lbco-hrpt')

Saving project 📦 'lbco_hrpt' to '../../../projects/load-and-fit-lbco-hrpt'

├── 📄 project.edi
├── 📁 structures/
│   └── 📄 lbco.edi
├── 📁 experiments/
│   └── 📄 hrpt.edi
├── 📁 analysis/
│   └── 📄 analysis.edi
└── 📁 reports/
    └── 📄 lbco_hrpt.html