lsqcurvefit help: Function value and YDATA sizes are not equal.

Hi all,

Just learning ODE fitting with Matlab and thought I followed the directions in Monod Kinetics but I'm running into an error that I cannot pinpoint. Would love any insight as to where my error is.

Just trying to fit a simple PK equation and I keep getting:

Error using lsqcurvefit (line 262)

Function value and YDATA sizes are not equal.

Matlab code below:

-----------

tdata=[0.25 0.5 1 2 4 6 8 24]; ydata=[0.1 0.5 1.19 2.2 2.8 2.2 2.17 .4];
par0=[1 0.5 1 1 1 1]';
[fitpars, resnorm] = lsqcurvefit(@PO_PK2comp,par0,tdata,ydata);


function yout=PO_PK2comp(params,tdata)
Dose=10;
x0=[Dose 0 0]';
[tvec,yvec]=ode45(@(t,y) PO_PK2compODE(t,y,params),tdata,x0);
yout=yvec(:,2);

function dy = PO_PK2compODE(t,y,params)

ka=params(1);
F=params(2);
CL1=params(3);
CL2=params(4);
V1=params(5);
V2=params(6);

dy(1)=-ka*y(1);
dy(2)=F*ka*y(1)-CL1*y(2)/V1-CL2*(y(2)/V1-y(3)/V2);
dy(3)=CL2*(y(2)/V1-y(3)/V2);
dy=dy';

end
end

Answer 1

[Matt J]

[fitpars, resnorm] = lsqcurvefit(@PO_PK2comp,par0,tdata,ydata.');

[Fiona Chandra]

Thank you, tht works! Tried ' before on both tdata and ydata, didn't realize it should just be on ydata