Motofit Error when using Genetic fitting for neutron reflectivity data

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Thu, 12/15/2011 - 02:18 pm

I'm using MotoFit to analyse some neutron reflectivity data. When using the Genetic optimisation I am occasionally getting an error message saying the FitFunction returned one or more NaN/INF values. It seems to happen quite randomly i.e. it will fit one reflectivity profile but not one which is almost identical.
This is the error message:
GENcurvefit/MAT=2/x=w8341_q/D=fit_w8341_R /k={100,10,0.7,0.5}/TOL = 0.001 motofit,w8341_R,coef_Cref,"1111000000",root:packages:motofit:old_genoptimise:GENcurvefitlimits

I've attached an experiment file with 2 runs as an example- w8339 is ok but not the w8441.

Any help is much appreciated.
Thanks,
Ed

 motofit_error.pxp
Dear Ed,
I'll look into this and get back to you. In future please email me directly.

cheers,
Andrew.

December 15, 2011 at 10:35 pm - Permalink

BTW,
it would be good if you could update to the latest cutting edge version. You can obtain this from:

https://motofit.svn.sourceforge.net/svnroot/motofit/branches/dev/instal…
OR
https://motofit.svn.sourceforge.net/svnroot/motofit/branches/dev/instal…

This updated version does not work with older experiment files unless you convert them. Select the menu option "Motofit->Transfer..."
Fitting those two datasets did not give me any NaN problems.

A.

December 15, 2011 at 10:49 pm - Permalink

Glad it's working for you now. If you ever need any extra features please let me know. Did you know you can do analytic SLD functions in Motofit?

December 16, 2011 at 03:33 am - Permalink