How to fit parameters in an m.file to a curve?
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To understand my problem it would be best if you run this m file:
In the following I refer to the variable names in the file:
It will plot a measured_signal in blue to which I want to fit a function (modeled_signal, shown in red). This function is generated in the same file. However, it is not a simple one line equation (with which all curve fitting tutorials that I found are dealing). It is rather a convolution of two functions one of which is constant and the other contains some variables which I want to optimize.
How can I tell matlab to fit the "modeled_signal" to the "measured_signal" by changing the three variables in lines 9-11 (tmax, alpha, mag)?
Thank you very much for your help!
Seth DeLand on 7 Aug 2012
Take a look at lsqcurvefit from the Optimization Toolbox. http://www.mathworks.com/help/toolbox/optim/ug/lsqcurvefit.html
You can write a function that takes in a vector with the parameter values and a vector with the xdata (t in your case), and then returns the values for the calculated modeled_signal. Then use lsqcurvefit to find the optimal parameters that fit your function to your ydata (measured_signal).
There's an example along these lines here: http://www.mathworks.com/products/optimization/examples.html?file=/products/demos/shipping/optim/datdemo.html