How to get the fitted data by using Matlab's "Fit" Function?

37 vues (au cours des 30 derniers jours)
Zheng
Zheng le 21 Sep 2012
For example, by using below code
load franke;
fitresult = fit( [x, y], z, 'poly33' );
From fitresult, I can get the formula used to fit x,y and z data
But how can I get the fitted data matrix via this "fit" function?

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Wayne King
Wayne King le 22 Sep 2012
It gives you a 1-D vector, but that 1-D vector is a polynomial in two variables, hence it is a function of the form f(x,y)=z
Calling
formula(fitresult)
shows you exactly what the terms in x and y the coefficients multiply

Plus de réponses (1)

Wayne King
Wayne King le 22 Sep 2012
Hi, you can use the coeffvalues() method on the fitresult object.
coeffs = coeffvalues(fitresult);
That will give you the coefficients of your polynomial in x and y.
To see how those coefficients enter into the polynomial equation:
formula(fitresult)
  2 commentaires
Zheng
Zheng le 22 Sep 2012
Thanks, Wayne. But how can I use this formula to calculate the surface (shown as below)? This formula can only help me get a 1-D vector, not 2-D matrix.
grace
grace le 22 Fév 2013
May I know what is the code for goodness of fit? coeffs = coeffvalues(fitresult); Similarly, rsquare = code(fitresult); I wanted to get the rsquare values from cftool to display in command window.

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