"ariel " <email@example.com> wrote in message news:firstname.lastname@example.org... > 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.