lcf_fit bug

[tschoonj]

Hi @bruceravel @newville

Some of our B18 staff have run into a bug when trying to perform linear combination fitting in Athena (Demeter 0.9.26) with Larch 0.9.40 backend.

Basically the fit fails with an error dialog with contents:

06:12:34 PM: Argument "RPC::XML::Client::send_request: parse-level error: Bad f..." isn't numeric in addition (+) at /usr/lib64/perl5/vendor_perl/Demeter/LCF.pm line 458, <F> line 27.
06:12:35 PM: Argument "RPC::XML::Client::send_request: parse-level error: Bad f..." isn't numeric in sprintf at /usr/lib64/perl5/vendor_perl/Demeter/UI/Athena/LCF.pm line 610, <F> line 27.

At the same time the terminal shows the error message:

NameError
   <_ast.Module object at 0x7feff89f6890>
       ^^^
name 'demlcf' is not defined

I did some digging in the code to try and understand where this is coming from and it would appear to be coming out of the Larch lcf_fit template:

demeter/lib/Demeter/templates/analysis/larch/lcf_fit.tmpl

Lines 13 to 15 in 8245df1

	##| set up the LCF objective function
	demlcf.ninfo = {$S->ninfo}

I failed to come up with a fix for it however 😢

Let me know if you need any further information!

[bruceravel]

It's 100% an @bruceravel problem. I am pretty swamped at the beamline this week, but I'll try to get to it ASAP.

[newville]

@tschoonj I would be interested to know if you or any of the B18 staff have tried the Linear Combo capabilities in Larch's XAS Viewer (included in 0.9.40) and whether you all might have any comments on it.

[tschoonj]

I'll ask around.

[tschoonj]

Hi Bruce,

Have you had some time to look into this issue?

Thanks,

Tom