Fityk is nonlinear curve-fitting and data analysis software. It allows data visualization, separation of overlapping peaks, and least squares fitting using standard Levenberg-Marquardt algorithm, a genetic algorithm, or Nelder-Mead simplex method. It knows about many functions (mostly bell-shaped, like Gaussian, Loretzian, Pearson 7, Voigt, Pseudo-Voigt, and Doniach-Sunjic) and user-defined functions can be easily added. It also enables background subtracting, data calibration, and task automation with a simple script language. It is mainly used to analyze powder diffraction patterns, chromatography, photoluminescence, infrared, and Raman spectroscopy, but it can be used to fit analytical functions to any kind of data.
| Tags | Scientific/Engineering Chemistry Visualization curve-fitting |
|---|---|
| Licenses | GPLv2 |
| Operating Systems | Windows Windows POSIX Linux Mac OS X |
| Implementation | C++ |
Recent releases


Release Notes: Lua scripting has been improved. Problems with printing on Linux have been fixed. A new dialog has been added to the GUI (Configure > Default Directories).


Release Notes: This release adds C, Ruby, and Java binding to the libfityk library and enhances the Lua and Python API. A new fitting method has been added, an implementation of the Levenberg-Marquard algorithm which uses the MPFIT library.


Release Notes: A few minor bugs have been fixed. One new dialog (Model-Export Formula) has been added to the GUI.


Release Notes: A Lua interpreter has been embedded in the program. It is possible to subtract a background stored in another file now. Support for mouse wheel and extra buttons has been added. All reported bugs have been fixed.


Release Notes: A few minor bugs have been fixed.