Fitting an XY data with lorenzian peak to know the FWHM of the peak

[Asarkar]

I am a new user to Labview having Labview 2013 version. I need to fit the attached X-Y data to a lorenzian peak profile to determine the FWHM value. Many of the previous liks have some examples but all those examples are giving me error saying singular matrix. Please help.

ASarkar

[altenbach]

What examples did you try? Show us your code that gives you a singular matrix. Did you provide initial guesses for the correct number of parameters?

[Asarkar]

I tried the solution given by this link

http://forums.ni.com/t5/LabVIEW/Lorentz-fit-of-a-curve-with-Lev-Mar/td-p/2111318

[altenbach]

You probably just need to give it reasonable initial guesses, e.g. as follows:

 

I am sure you could come up with an automatic algorithm to make good guesses based on the position of ymax, etc.

[Asarkar]

Than you very much. It is working. You are awesome.