Some of the advanced EXAFS analysis features of FEFF and FEFFIT are describ
ed. The scattering path formalism from FEFF and cumulant expansion are used
as the basic building blocks of EXAFS analysis, giving a flexible and robu
st parameterization of most EXAFS problems. The ability to model EXAFS data
in terms of generalized physical variables is shown, including the simulta
neous refinement of two different polarizations for Co K EXAFS data of CoPt
3.