Originally, FTK was supposed to fit for the event's position, direction and energy. But I would eventually like to finish grad school, so FTK became just an energy fitter. Users should be running FTK on versions 5.0087 or later.
FTK can be run using the position reconstruction information from any of the SNO position fitters. See the sample command file run_ftk_energy_fitter.cmd for an example. The output of FTK is stored in FTXK which is linked off the FTXA link for each fitter. The user can also have FTK use the MC position and direction for the event information. Call FTK with -1 to do this. If FTK is called with MC position and direction, the output is stored off the FTK link.