Originally Posted by

**Bwts** Hi

i am trying to obtain to constants using 'lsqcurvefit' here's the code,

xdata=stretch_r(:,2).';

ydata=stress_r.';

x0=[100; 1];

[x,resnorm]=lsqcurvefit(@MooneyRivlin,x0,xdata,ydata)

function F=MooneyRivlin(x,xdata)

F=(2*x(1)+2*x(2)/xdata)*(xdata-1/xdata^2);

Both 'stretch' and 'stress' are of length 14 but I keep getting the error,

??? Error using ==> optim\private\lsqncommon at 98

LSQCURVEFIT cannot continue because user supplied objective function failed with the following error:

Error using ==> mrdivide

Matrix dimensions must agree.

Error in ==> lsqcurvefit at 182

[x,Resnorm,FVAL,EXITFLAG,OUTPUT,LAMBDA,JACOB] = ...

Error in ==> MonneyLSQ at 4

[x,resnorm]=lsqcurvefit(@MooneyRivlin,x0,xdata,ydata)

Any suggestions for this rather annoying error would be much appriciated thankyou.

Nic