Fityk [fi:tik] is a program for data processing
and nonlinear curve fitting.
Although it is primarily used...
- by scientists who analyse data from powder diffraction, chromatography,
photoluminescence and photoelectron spectroscopy,
infrared and Raman spectroscopy, and other experimental techniques,
- to fit peaks – bell-shaped functions (Gaussian, Lorentzian, Voigt,
Pearson VII, bifurcated Gaussian, EMG, Doniach-Sunjic, etc.),
... the program can be used for any task that requires fitting a curve
to 2D (x,y) data.
- intuitive graphical interface (and also command line interface),
- support for many data file formats, thanks to
the xylib library,
- dozens of built-in functions and support for user-defined functions,
- equality constraints,
- fitting systematic errors of the x coordinate of points (for example
instrumental zero error or sample displacement correction
in powder diffraction),
- manual, graphical placement of peaks and auto-placement using peak detection
- various optimization methods (standard Marquardt least-squares algorithm,
Genetic Algorithms, Nelder-Mead simplex),
- handling series of datasets,
- automation with macros (scripts) and embedded Lua for more complex scripting
- the accuracy of nonlinear regression verified
with reference datasets from NIST,
- an add-on for powder diffraction data (Pawley refinement)
- modular architecture,
- open source licence (GPL).
In an attempt to make this software self-sustaining and actively
developed in the future,
new binaries are available to subscribers only:
MS Windows: fityk-1.2.9-setup.exe $
Mac OS X (10.6 or later): fityk-1.2.9-osx.zip $
Linux: binary RPM and deb packages
for about 10 distros (incl. Ubuntu, Fedora, Suse), 32- and 64-bit.
Subscribers have access to all versions of the program and to e-mail support.
The program can be installed on many computers and can be also used
after the end of subscription.
There is a discount for home users and students,
email firstname.lastname@example.org for details.
Versions 0.9.8 and older are free:
and Linux (Ubuntu PPA and RPMs from OBS).
Source code: GitHub
Version 1.2.9 was released on 2014-04-13
New version notifications
are delivered via email and feeds.
Feel free to send questions, comments, requests, bug reports,
and success stories.
Asking for a new feature usually results in adding the request to
the TODO list
or, if it already is in the list, in assigning higher priority to it.