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From: "Thomas " <dorn.thomas@gmail.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Double exponential decay fit
Date: Wed, 18 Feb 2009 04:21:01 +0000 (UTC)
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Hi,

I was wondering if you have figured out a way of doing a double exponential equation fit in matlab

Thanks 

"Jean-Sebastien" <newsreader@mathworks.com> wrote in message <gkl7vl$nb0$1@fred.mathworks.com>...
> Hi folks,
> OK :
> You have a set of data points (time,response) which correspond to a simple two exponential decay function (peak to baseline). 
> You feed sigmaplot10 with it and using the simple equation y=a*exp(-bx)+c*exp(-dx) it gives you a nice fit. 
> Now you do it in Matlab using the same data, same equation and on 2 out of 3 fit you've got a funny fit which obviously is wrong... 
> Question:
> Does anyone can explain the decrepancy between the two softwares? why sigmaplot10 can fit a simple two exponential decay function while Matlab doesn't?
> Is there any issue with the method used? If so is there an alternative to make Matlab fit this simple two eponential decay function correctly?
> Thanks for your help,
> JS
>