[Ifeffit] More for dealing the LCF

[Hana]

I would be happy to get advices for LCF of EXAFS spectra, at the following 
context:
1. Constraining the sum of components fractions to one – 
 - when to apply? 
 - Which factors should be considered at this context while working with soil 
samples? 
 - How would you suggest dealing the penalty when sum of components is different 
than one in these heterogeneous soil samples (with unknown composition and 
probably high effect of disorder)?

2. Any reason not to constrain all fractions to be positive?

Thanks,
Hana