Curve Fitting
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I've been trying to fit different series/methods to a certain set of data. I have a polynomial fitted to the data: P = polyfit(x,y,3)
but I cannot get the fourier or the gaussian commands to work: p = fit(x,y,'fourier3)
Can someone help me?
Thanks
回答（4 个）
Teja Muppirala
2012-6-6
As proecsm points out, your data needs to be made into columns. Like this:
x = 1:1000; %Row vector
y = sin(0.01*x) + cos(0.03*x) + 0.1*randn(size(x)); %Row vector
F = fit(x(:),y(:),'fourier3') %Use (:) to turn it into a column
plot(x,y)
hold on
plot(F)
Also, are you aware of the Curve Fitting Tool GUI?
cftool
This makes it easier to try out different fits interactively (for both curves and surfaces), and you can automatically generate MATLAB code from your results.
Brandon Armstrong
2012-6-5
0 个投票
Does not work mean you get an error, or just that the fit is very bad? If it is not fitting properly you can try giving some initial guesses and and upper and lower bounds for your coefficients using 'fitoptions'.
bym
2012-6-5
polyfit()
will work with both row-oriented or column-oriented data, whereas the documentation specifically mentions columns for
fit()
I don't have the curve fitting toolbox to test this.
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