On Tuesday 19 June 2007, Jörg Haug wrote:
Dear all,
I have a question regarding the weighting for a multiple data set fitting. I found that there is the parameter Epsilon to do this in Artemis. But in the help file there is no description how to use this parameter. Which value did I have to use to set the weighting to (for example) double or half? Best regards
Jörg, This is an aspect of Artemis that is neither well designed nor well explained. Fortunately, it's possible to figure it out, if you know where to look. There are two ways of finding the value of epsilon(k). It is written to the log file and it gets written to the echo area when you select "What is epsilon_k?" from the Data menu. If you set epsilon to the reported value of epsilon(k) for each data group and rerun the fit, everything should be the same. That is, setting epsilon to 0 in Artemis means "use the value of epsilon(k) measured from the data." From there, you can change the weightings of the groups by changing the values of epsilon. B -- Bruce Ravel ---------------------------------------------- bravel@anl.gov Molecular Environmental Science Group, Building 203, Room E-165 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007 Argonne National Laboratory phone and voice mail: (1) 630 252 5033 Argonne IL 60439, USA fax: (1) 630 252 9793 My homepage: http://cars9.uchicago.edu/~ravel EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/