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Andreas_L
Germany
2 Posts |
 Posted - 04/10/2002 : 12:26:58 PM
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Dear all,
I have several set of data, all a function of
x, which were obtained at three different temperatures: f1(x,T1), f2(x,T2), f3(x,T3).
Now, I am able to construct a fitting function
f0(x,T), where f0(x,T1)=f1(x,T1) and the same for T2 and T3, so it is a common function for all three set of data, with one set of parameters to be refined. How can I fit simultaneously the paramteters of f0(x,T) to all three data-sets?
It should actually work, if one could fit a two-dimensional function
f(x,y), where y = T1, T2, T3.
But I think that is not possible in Origin.
Any help?
Best regards
Andreas Leineweber |
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easwar
USA
1965 Posts |
Posted - 04/10/2002 : 2:49:24 PM
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Hi Andreas,
1> Plot all three datasets
2> Define your function f0(x,Temp) in NLSF (or select one of the built-in functions if appropriate)
Note: You cannot use 'T' for your indep variable - this is reserved/system variable in Origin.
3> Go to the Action | Datasets dialog of the NLSF
4> Check the "Fit Multiple Datasets" checkbox
5> Click on the "Add Data" button twice
6> Now go to the list box at the top, select each y variable (y(1), y(2), and y(3)) and assign datasets to them
7> x datasets will get assigned automatically in step 6>
8> Go to the Action | Fit dialog. You should now see three parameters for your indep variable.
If your indep variable was Temp, then you will see Temp, Temp_2, Temp_3
9> Assign initial parameter (guess) values
10> You can now proceed to fit your three datasets simultaneously
Easwar
OriginLab
Edited by - easwar on 04/10/2002 14:50:35 |
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simultaneous fitting of several functions