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chmonster

Russia
4 Posts

Posted - 05/03/2013 : 09:08:13 AM

Origin Ver.: 8 SR4
Operating System: Windows 7

Hi all.
I'm newbie to the Origin and have a problem with writing User-Defined Fit Function. So I will by very happy, if somebody can help me with that.

I have an experimental data - fluorescence spectrum, which I want to fit with polynomial function like that:

y = a*(poly 1) + b*(poly2) + c*(poly3);
This function contains 3 polynomial of 5th power and 3 parameters. It's suppose, that after fitting I must obtain values of these parameters, so I can know what contribution have each of three polynomial to my spectrum.

And there is a condition, that a+b+c=1

I can fit my data with such a function, but parameters values don't converge with conditions (i.e a+b+c>1)

How can I include these equation (a+b+c=1) to my function??

Please help..

(P.S. i'm sorry, if such subject has already been discussed, but I can't find answer using forum search yet)

chmonster

Russia
4 Posts

Posted - 05/03/2013 : 5:25:04 PM

And one more question:

When I fit data on my graph, I obtain a fitting results table right on my graph, containing some parameters. (I think that is what called "Output report")
If I have several datasheets on my graph, so after fitting there are NOT several tables with results, but just one, with parameters changing after each fit operation.

What I want - that I have as much result tables on my graph, as many times I've done fitting operation (i.e. 3 datasheets on graph - 3 times make fitting - 3 fitting result tables on graph)

Does somebody know, how to solve that problem?
Thanks
And sorry for my bad english