Fitspy

What Fitspy is

Fitspy is a spectral-fitting tool for working with spectra without tying analysis to a particular physical quantity or database. It can read single one-dimensional spectra and spectra arranged in two-dimensional maps, with imports that include .txt, .dm3, .dm4, .emd, .hspy, .nxs, .h5, .h4, .hdf, and NXCanSAS-related files. Peak options include Gaussian, Lorentzian, asymmetric Gaussian, asymmetric Lorentzian, and Pseudovoigt models; users can also define models with expressions or Python scripts. Baselines may be drawn manually or handled with the semi-automatic ARPLS algorithm.

Fitspy uses the lmfit package and supports multiprocessing, parameter bounds, and constraints. It can turn off peak models in noisy regions and detect outliers, a feature particularly suited to 2D-map spectra. The GUI is available in Tkinter and PySide versions, with future fixes and updates focused mainly on PySide. GUI workflows can also be scripted; saved models can be replayed or applied to other datasets. The CEA-MetroCarac organization, which describes its work as metrology and characterization activities at the French Alternative Energies and Atomic Energy Commission, distributes Fitspy under GPLv3. It is free desktop software for Linux, macOS, and Windows, requires Python 3.9 or later, and is recommended for installation through PyPI with `pip install fitspy`.

Who it suits

Fitspy suits researchers and other users fitting spectra, including those handling either a few spectra through the GUI or batches of thousands or more through Python. It is relevant when work calls for configurable peak models, baseline handling, or automation across datasets.

Limits

User-defined models initialize all parameters to 1, which can lead to poor convergence. Fitspy requires Python 3.9 or later.

Getting started

1. Install Python 3.9 or later.
2. Install Fitspy from PyPI with `pip install fitspy`, or use the documented GitHub installation route.
3. Choose the Tkinter or PySide GUI, or use Python scripts for batch workflows.
4. Import supported spectra files and configure peak models and baselines.

Verdict

Choose Fitspy if you need a free spectral-fitting tool that supports both GUI work and Python batch workflows. Its broad import support, customizable models, and 2D-map outlier detection are useful for varied fitting tasks. Allow for Python 3.9 or later, and take care with user-defined models because their parameters initialize at 1 and may converge poorly.