MATLAB: How to fit multiple data sets

dataset

Dear all, I have the following question: I need to determine some coefficients(A,B,C,D,E):
    ydata=[1:1:10];
    xdata=[0.1:0.1:1];
    zdata=[10:10:100];
    Y=[A+B*X+C*X^2+D*X^3]*Z^E;
    the code look as:
    xx=xdata'; % X
    yy=ydata'; % Y
    zz=zdata'; % Z
    vect_ones=(10,1);
    %declare function 
    functionfit=@(x,a)x(1)*vect_ones+x(2)*a(1,:)+x(3)*power(a(1,:),2)+x(4)*power(a(1,:),3))*power(b(1,:),x(5));
    initial values;
    x0=[1 1 1 1 1]; % how arbitrary should be this value? 
    [x] = lsqcurvefit(functionfit,x0,XX,ZZ,XX);
Questions:
Why "b" is not recognized as variable as "a" is? Can lsqcurvefit function really work with two (multiple) sets of data)?
Thank you

Best Answer

Why "b" is not recognized as variable as "a" is?
Because you didn't designate it as a variable. You only designated x and a
 functionfit=@(x,a)...
That's the way Anonymous Functions work.
Can lsqcurvefit function really work with two (multiple) sets of data)?
It's not clear what you mean by multiple sets of data. As long as ydata has the same dimensions as the output of functionfit, it should be fine.
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