Re: non-linear regression

[Dmitri A. Sergatskov]

Al Niessner wrote:
> I am trying to fit a sine wave (A*sin(b*x+C) +D) to a set of data --
> least square. Is there an existing function in octave to help with this.
> I checked the documentation (online) and browsed the 'octave> help' but
> nothing jumped out at me.

I had to do it some time ago. The signal consisted of few sharp lines
So I did fft first to find the frequencies f(n) and then did OLS fit
to A(n)*sin(2*pi*f(n)*t(i)) + B(n)*cos(2*pi*f(n)*t(i)) + D
Sum by n; t(i) is time vector. That worked very well, but max n was
something like 4.

Sincerely,

Dmitri.



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