Command for basic fitting

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Yün Han 2011-9-26

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Hi,

I know we can use Tools -> Basic Fitting from the menu bar in the plot to generate linear or higher order equations for relationships between x and y. But it is a graphic way, if I want to draw the fitting curve by using m-script, which command should I use?

Thanks.

Y-L

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Answer 1

Grzegorz Knor 2011-9-26

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To find the coefficients of a polynomial of degree n use polyfit function.

Alternatively use the option: File -> Generate M-file, to preview the source code.

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Yün Han 2011-9-26

Thanks. I know that polyfit could be used to calculate the coefficients of polynomials but what I want is after those coefficients are found out by polyfit, I want to use scripts to plot the fitting curve on the plot, just like using basic fitting. Any further ideas?

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Answer 2

UJJWAL 2011-9-26

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在 MATLAB Online 中打开

Gregorz is right. Here is a bit of an example :

a= 1:0.1:10;
p = polyfit(a,exp(a),5); % Fits a fifth degree polynomial to exp(a) in the Least squares sense
v = polyval(p,a);
plot(a,v,a,exp(a)) % You will see the difference.

Happy To help