PFIT correlation function fitting software.

The PFIT software can either be run in the GSQ suite (in OPENGENIE), or it can be run in standalone mode.

GSQ

In OpenGenie, type a command like pnfit tor or pxfit dx (where tor is a workspace containing a neutron correlation function, or dx is a workspace containing an X-ray correlation function).

After a fit has been performed, the fitted function can be regenerated from the fit parameters by the commands pfc or xpfc (for neutron or X-ray diffraction, respectively).

Standalone mode

To run the software separate from OpenGenie, it must first be installed, either by installing the GSQ suite, or by installing pfit.zip

The data for the correlation function to be fitted must be in an ascii file or a Genie binary file. An example of each type of file is provided in pfit.zip:
tor_geo2.txt Gem12430.tor

Two Fortran programs are provided for fitting either neutron or X-ray diffraction data: pnfitf or pxfitf

Running the fit

Commands for use in the fitting programs include: D P, S P, F, G, B, C (type help for more information)

Fit parameters are stored in files named .pxparm or .pxparm

After a fit has been done, the DOS program pn2px can be used to convert a .pnparm file to a .pxparm file, and calculate coordination numbers, including errors.