       Fitting Experimental Data

• To: mathgroup at smc.vnet.net
• Subject: [mg116433] Fitting Experimental Data
• From: mathilde Favier <fmath at hotmail.fr>
• Date: Tue, 15 Feb 2011 06:33:45 -0500 (EST)

```I am in trouble in trying to do a Fit using Mathematica7.

Here my problem:

My instrument on which I am working is giving me data looking like a plot with two round (more Gaussian) shape but with some picks on the top of each, the figures would have shown it, but you told me that I cannot enclose any file.

I am only interested in the 2 round shapes, .

My goal is to do a fit of those them.

First I am isolating those 2 parts (ie: Plotting them whithout the data between them.)

But the problem is that the picks on the top of each round shape will disturber my
fit so I have to remove them.So now I have removed the picks, I have just 2 kind of asymetrics Gaussians with a hall on the top of each. To describe it more properly, I would say I have the rising and falling edge of two differente asymetric Gaussian.

Now I start to look for a first Fit corresponding to the first asymetric Gaussian.

Here is my code:

model=
b+ a*(1/(s*\[Sqrt](2*Pi)))*
Exp[-(x-m)^2/(2*s^2)];

fit=FindFit[dataleftlowband,model,{b,a,s,m}, x, MaxIterations->100]

modelfit = Table[Evaluate[model/.fit],{x,1,Length[dataleftlowband]}];

tmodelfit = Transpose[{xdataleftlowband,modelfit}];

My big problem is that I removed some data
in the middle of my curve and I want that according to the values kept, the
fitting find out which should be the missing values, because I need to
approximately trace the top of my Gaussian shape.

I've tried a lot of stuff to find out how
to solve that as, random points in the Gap...

Is there a method like considering the
first part as the rising edge and the second as the falling edge of a Gaussian?

Is Mathematica able to solve that?

I hope that my problem is clearly explained. It's not that easy without any pictures to show how my data look like.

Tell me if you have any idea to find a solution.