Hi Elien,

On Thu, Oct 18, 2018 at 9:59 AM Elien Lemmens <elien.lemmens1@kuleuven.be> wrote:

Dear,

I was trying to do some linear combination fitting using Athena software. Although the box “All weight between 0 and 1” is ticked I get negative weight results.

I have read the online Athena’s User's Guide, but I did not find what the issue can be. Do you have any ideas?

Below you can find some print screens of my actions. I also get an “error” (print screen 2), which I don’t understand.

This is not really an answer for how to do this with Athena, but the Larch XAS Viewer program can also do such linear combination analysis, and allows setting an upper and lower limit on each weight and constraining the sum of weights to be 1.

The GUI interface is slightly different, but the interface should be pretty familiar to Athena users, and it can read in modern Athena Project files.

That is, it might be worth trying.

--Matt

To download and install, see https://millenia.cars.aps.anl.gov/xraylarch/installation.html