| T O P I C R E V I E W |
| Valerietti |
Posted - 06/06/2019 : 06:49:27 AM
Origin Ver. and Service Release (Select Help-->About Origin): OriginPro2017
Operating System: Windows
I have a set of 10 curves that I'd like to fit with two partially overlapping gaussians.
With the "global fit" option of the non-linear curve fitting, I reproduced fairly well the curves.
However, I'd like to add the constraint that keeps constant the sum of the two gaussian curves, i.e. the global integral of the fitted curves.
May anyone help me with that?
Thank you in advance.  |
| 2 L A T E S T R E P L I E S (Newest First) |
| Valerietti |
Posted - 06/06/2019 : 11:54:52 AM
Hi Malgoska,
Thank you for your help!
I'm gonna try this straight away!
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| malgoska |
Posted - 06/06/2019 : 07:42:55 AM
Hi,
you can try creating your own function defined like that:
y = y0 + A1/(w1*sqrt(pi/(4*ln(2)))) * exp(-4*ln(2)*(x-xc1)^2/w1^2) + (S-A1)/(w2*sqrt(pi/(4*ln(2)))) * exp(-4*ln(2)*(x-xc2)^2/w2^2)
with parameters: A1, w1, xc1, S, w2, xc2, y0.
with S being be the sum of the two areas, (S-A1) would be the area of the second Gaussian.
With such a function you can perform a global fit on 10 curves and share S (and anything else) among the fits. Of course, you can set it as constant value, as well.
Hope it helps, best regards,
malgoska
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