How about writing the relative intensities in % as well if not using "force to sum to 1"?
Doing so would presume a particular interpretation of the situation where the weights don't sum to one. You would expect the weights to sum to one if: 1. The standards and data are all calibrated and aligned consistently and that any e0 parameters used in the fit are well understood 2. The standards and data are all normalized consistently 3. The set of standards is representative of the contents of the unknown data If the best fit is one where the "sum to 1" constraint is lifted and the sum deviates considerably from 1, how do I know the reason a priori? So I (wearing my software developer hat) am hesitant to do what you suggest for fear of biasing the interpretation of someone else's data. BTW, thanks for yesterday's posting, Gerrit. It helped me find a pretty large number of bugs in the LCF dialog. B -- Bruce Ravel ----------------------------------- bravel@anl.gov -or- ravel@phys.washington.edu Environmental Research Division, Building 203, Room E-165 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://feff.phys.washington.edu/~ravel EXAFS software: http://feff.phys.washington.edu/~ravel/software/exafs/