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Math Forum » Discussions » Software » comp.soft-sys.matlab

Topic: fitting ( cftool )
Replies: 4   Last Post: Dec 10, 2012 7:55 AM

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Steven Lord

Posts: 17,944
Registered: 12/7/04
Re: fitting ( cftool )
Posted: Dec 9, 2012 10:53 PM
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"ariel " <arn335@msn.com> wrote in message
news:k9veu1$7s$1@newscl01ah.mathworks.com...
> im trying to do a fitting between a vector and a function .
> my vector is a intensity summed by 20 degree angle (160-180) as a function
> of the beam radius, as the following pics describe : this is the picture :
> http://postimage.org/image/baff0lf63/
> the imagesc pic after cutting by angle plus intensity graph by radius (
> the angle is summed ) : http://postimage.org/image/s9l2d8j5b/
>
> my try to to do fitting with cftool :
> http://postimage.org/image/6so1ugaeh/
>
> the function i try to do fitting with : sin(b*sin(atan(x./0.05)).^2).^2+c
> which i took from theory .
> as you can see the fitting is total joke, and ideas ?


1) My guess is that the Curve Fitting window told you that there was some
difficulty with the fit. If so, what did it say?

2) How certain are you of your function? From the image of your data it
looks more like a sinusoidal times a quadratic or something similar. Taking
sine of sine of arctangent seems odd to me.

--
Steve Lord
slord@mathworks.com
To contact Technical Support use the Contact Us link on
http://www.mathworks.com




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