  A free data-analysis framework for muSR has been developed. musrfit is fully
written in C++, is running under GNU/Linux, Mac OS X, as well as Microsoft
Windows, and is distributed under the terms of the GNU GPL. It is based on the
CERN ROOT framework and is utilizing the Minuit optimization routines for
fitting. It consists of a set of programs allowing the user to analyze and
visualize the data. The fitting process is controlled by an ascii-input file
with an extended syntax. A dedicated text editor is helping the user to create
and handle these files in an efficient way, execute the fitting, show the data,
get online help, and so on. A versatile tool for the generation of new input
files and the extraction of fit parameters is provided as well. musrfit
facilitates a plugin mechanism allowing to invoke user-defined functions.
Hence, the functionality of the framework can be extended with a minimal amount
of overhead for the user. Currently, musrfit can read the following facility
raw-data files: PSI-BIN, MDU (PSI), ROOT (LEM/PSI), WKM (outdated ascii
format), MUD (TRIUMF), NeXus (ISIS).
