Why Matrix dimensions do not agree?

This is my script:

function Langner_Ue1

    load data1 P v; 
    Vmax3 = 4; 
    S2 = 40-P; 
    Km3 = 3; 
    k1 = 30; 
    P0 = [Vmax3, Km3, k1]; 
    lsqcurvefit(@Michaelis_Menten_Substratinhibierung_2, P0, S2, v) 
    figure(2) 
    plot(S2,v,'r*') 
    hold on 
    plot(S2,vMMI2,'r') 
    hold on 
    legend('v über S', 'MMI2 über S') 
    end 

    function MMI2 = Michaelis_Menten_Substratinhibierung_2(Vmax3, S2, Km3, k1) 
    MMI2 = (Vmax3.*S2)./(Km3+S2+(S2.^2./k1)); 
    end

Matrix dimensions must agree.

Error in Langner_Ue1>Michaelis_Menten_Substratinhibierung_2 (line 40) MMI2 = (Vmax3.*S2)./(Km3+S2+(S2.^2./k1));

Error in lsqcurvefit (line 213) initVals.F = feval(funfcn_x_xdata{3},xCurrent,XDATA,varargin{:});

Error in Langner_Ue1 (line 30) lsqcurvefit(@Michaelis_Menten_Substratinhibierung_2, P0, S2, v)

Caused by: Failure in initial objective function evaluation. LSQCURVEFIT cannot continue.

If I perform the function 'Michaelis_Menten_Substratinhibierung_2' directly in the command window there is no failure and verything works fine. Why do I get a failure when I try to run the script?

[madhan ravi]

 data1 P v???

[Marcel Langner]

Im new to Matlab. I dont understand your question?

I tried to load the variables P and v from the dataset data1.mat

[madhan ravi]

upload your file by clicking the paper clip button

[Marcel Langner]

Uploaded file

Answer 1

[Bruno Luong]

Try this:

    load data1 P v; 
    Vmax3 = 4; 
    S2 = 40-P; 
    Km3 = 3; 
    k1 = 30; 
    P0 = [Vmax3, Km3, k1]; 
    P = lsqcurvefit(@Michaelis_Menten_Substratinhibierung_2, P0, S2, v);
    MMI2 = Michaelis_Menten_Substratinhibierung_2(P, S2);

    figure(2) 
    plot(S2,v,'r*') 
    hold on 
    plot(S2,vMMI2,'r') 
    hold on 
    legend('v über S', 'MMI2 über S') 
    end 

    function MMI2 = Michaelis_Menten_Substratinhibierung_2(P, S2) 
    Vmax3 = P(1);
    Km3 = P(2);
    k1 = P(3);
    MMI2 = (Vmax3.*S2)./(Km3+S2+(S2.^2./k1)); 
    end

[Marcel Langner]

Thanks a lot. It worked. But i dont understand it totally. Why did you define P? Its a given Variable I got from the data set. Isnt it overwritten, when i define it again?

[Bruno Luong]

In any optimization function you have to provide the parameters as a vector, up to you to split the vector in a meaningful way.

I just guess because you supply

P0 = [Vmax3, Km3, k1];

So the order of parameters must be as written in Michaelis_Menten_Substratinhibierung_2.

[Marcel Langner]

Nice thanks a lot!