Fitting an Amplitude-Response Curve
3 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
Chinwe Orie
il 23 Feb 2019
Commentato: Chinwe Orie
il 6 Mar 2019
Hi,
I'm trying to fit an amplitude-frequency response curve to a particular equation (in picture below).
![example.jpg](https://www.mathworks.com/matlabcentral/answers/uploaded_files/205466/image.jpeg)
![equation pic.png](https://www.mathworks.com/matlabcentral/answers/uploaded_files/205467/image.png)
I've tried using code to do it but I keep getting the following:
f1 = fittype( @(F, w0, g, m, w) F.*(cos(m.*(w0.^2-w.^2)./sqrt(m.^2*(w.^2-w0.^2).^2 + g.^2*w.^2)))....
./sqrt(m.^2*(w.^2-w0.^2).^2 + g.^2*w.^2), 'independent', {'w'},...
'dependent', {'y'} );
![failedattempt.jpg](https://www.mathworks.com/matlabcentral/answers/uploaded_files/205468/image.jpeg)
Also, I get a warning which says, "Warning: Start point not provided, choosing random start point." What does this mean?
Thanks!
0 Commenti
Risposta accettata
Rishabh Gupta
il 4 Mar 2019
Hi Chinwe,
Generally Curve Fitting and Optimizations algorithms require you to give a starting point satisfying all your contraints(if any) from where the algorithms starts its logic and tries to find the best fit/best solution. In this case, you did not specify the starting point, hence the warning. But the algorithm needs a starting point, therefore it chooses a random starting point. Howecver this is not an error and may not affect your algorithm/results much. Please note in some case choice of starting point affects the solution.
I hope it was helpful.
Thanks
Più risposte (0)
Vedere anche
Categorie
Scopri di più su Linear and Nonlinear Regression in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!