Dear Elien and others, The constraints should apply to all fits, even in combination fitting. I have seen this effect before (negative fit component despite checked box) and found that if I check, uncheck, and recheck each constraint/option box it then works. You might also need to restart Athena, and make sure you have the newest version. I have been too busy to submit a bug report about this. I also see the popup warning message Elien mentioned but it does not seem to affect the fits. I have also been too busy to submit a bug report about that as well. Jeff On 10/18/2018 10:12 AM, Christopher Patridge wrote: Hi Elien, I might not be correct but are the results you are showing in the 2nd screen shot coming from the combinatorics? That might be different than “fitting the data” since the combinatorics get those results by using each combination of standard and finding the best fits using those are particular standards. So across all the combinations, the D standard fits best by using a negative value which I think might be different. I am not sure but the tick box might not apply to the combinatorics. Maybe someone else can clarify or correct my interpretation, Chris ********************************************** Dr Christopher Patridge Assistant Professor Department of Chemistry SASE 315 D’Youville College 320 Porter Ave. Buffalo, NY 14201 716-829-8096 / 315-529-0501 patridgc@dyc.edumailto:patridgc@dyc.edu On Oct 18, 2018, at 10:55 AM, Elien Lemmens mailto: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. Thanks in advance Elien _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.govmailto:Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.govmailto:Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

Hello Elien, You have the "Force Weights Sum to 1" box checked. Uncheck that and it should work. I think the negative value in the last standard is balancing out the sum of the other three standards so that the total sum is 1. Matt On Thu, Oct 18, 2018 at 11:19 AM Catalano, Jeff wrote:

Dear Elien and others,

The constraints should apply to all fits, even in combination fitting. I have seen this effect before (negative fit component despite checked box) and found that if I check, uncheck, and recheck each constraint/option box it then works. You might also need to restart Athena, and make sure you have the newest version. I have been too busy to submit a bug report about this.

I also see the popup warning message Elien mentioned but it does not seem to affect the fits. I have also been too busy to submit a bug report about that as well.

Jeff

On 10/18/2018 10:12 AM, Christopher Patridge wrote:

Hi Elien,

I might not be correct but are the results you are showing in the 2nd screen shot coming from the combinatorics? That might be different than “fitting the data” since the combinatorics get those results by using each combination of standard and finding the best fits using those are particular standards. So across all the combinations, the D standard fits best by using a negative value which I think might be different. I am not sure but the tick box might not apply to the combinatorics.

Maybe someone else can clarify or correct my interpretation,

Chris

********************************************** Dr Christopher Patridge Assistant Professor Department of Chemistry SASE 315 D’Youville College 320 Porter Ave. Buffalo, NY 14201 716-829-8096 / 315-529-0501 patridgc@dyc.edu

On Oct 18, 2018, at 10:55 AM, Elien Lemmens 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.

Thanks in advance Elien

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