How can I do the best fit of a power function with my original data

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Ahmed Abdalazeez
Ahmed Abdalazeez 2018-6-20
评论： Ahmed Abdalazeez 2018-6-21
I have two variables (x,y). we found by eye that y = x^1/2.33, but it is not perfect for what I want and also when I test the correlation it gives me ONE but I think it should not be one because there is a variance value 0.0113. I can use the 'basic fitting' but there is no option of the power function. Thanks in advance

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采纳的回答

Ameer Hamza
Ameer Hamza 2018-6-20
You can use lsqcurvefit() for least square curve fitting. For example
% sample data
x = 0:10;
y = x.^0.33 + 0.2*rand(size(x));
f = @(x, xdata) xdata.^x(1); % function to fit, 'x' will be estimated
solution = lsqcurvefit(f, 0, x, y)
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Ameer Hamza
Ameer Hamza 2018-6-20
solution is the estimated value of the exponent. you need to use (x,y) values from your own dataset.

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更多回答（1 个）

Torsten
Torsten 2018-6-20
xdata = ...;
ydata = ...;
a0 = 1/2.33;
fun = @(a)sum((ydata-xdata.^a).*xdata.^a.*log(xdata));
a = fzero(fun,a0)
Best wishes
Torsten.

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