Re: [Ifeffit] third cumulant in Larch

2022-08-19 Thread Andy Zhang
Hi Matt,

Thank you very much for your email! I did not add it to the Path in my
previous fit. I modified the file based on your email and now it works.

Many thanks for your help and have a nice day!

Best,
Harry

On Fri, Aug 19, 2022 at 7:35 PM Matt Newville 
wrote:

> Hi Harry,
>
>
>
>
> On Fri, Aug 19, 2022 at 9:10 AM Andy Zhang  wrote:
>
>> Dear all,
>>
>> I have a quick question related to EXAFS fitting using Larch. I wonder
>> how to include the third cumulant in the fitting. I tried to add "third" in
>> the "pars" section, but it seems it did not work.
>>
>> [image: image.png]
>>
>> Thanks a lot for your help!
>>
>>
> By itself, that just sets up the parameters to be varied during the fit.
> It does not specify how those will be used.
>
> So: did you use the parameter named "third" in any of the Path Parameter
> definitions?  Something like this
>
>  path1 = feffpath('feff0001.dat',   s02 = 'amp', e0 = 'del_e0',
>  sigma2='sigma2_eins(300, theta)',
>deltar='alpha*reff',
>third='third')
>
> should work.
>
> If not, please post a complete, minimal example showing what you are doing.
>
> --Matt
>
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Re: [Ifeffit] third cumulant in Larch

2022-08-19 Thread Matt Newville
Hi Harry,




On Fri, Aug 19, 2022 at 9:10 AM Andy Zhang  wrote:

> Dear all,
>
> I have a quick question related to EXAFS fitting using Larch. I wonder how
> to include the third cumulant in the fitting. I tried to add "third" in the
> "pars" section, but it seems it did not work.
>
> [image: image.png]
>
> Thanks a lot for your help!
>
>
By itself, that just sets up the parameters to be varied during the fit.
It does not specify how those will be used.

So: did you use the parameter named "third" in any of the Path Parameter
definitions?  Something like this

 path1 = feffpath('feff0001.dat',   s02 = 'amp', e0 = 'del_e0',
 sigma2='sigma2_eins(300, theta)',
   deltar='alpha*reff',
   third='third')

should work.

If not, please post a complete, minimal example showing what you are doing.

--Matt
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[Ifeffit] third cumulant in Larch

2022-08-19 Thread Andy Zhang
Dear all,

I have a quick question related to EXAFS fitting using Larch. I wonder how
to include the third cumulant in the fitting. I tried to add "third" in the
"pars" section, but it seems it did not work.

[image: image.png]

Thanks a lot for your help!

Have a nice day!

Best,
Harry
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