lsqcurvefit error when using example

When I copy/paste

myfun = @(x,xdata) x(1)*exp(x(2)*xdata);

% Assume you determined xdata and ydata experimentally

xdata = [0.9 1.5 13.8 19.8 24.1 28.2 35.2 60.3 74.6 81.3];

ydata = [455.2 428.6 124.1 67.3 43.2 28.1 13.1 -0.4 -1.3 -1.5];

x0 = [100; -1];

[x] = lsqcurvefit(myfun,x0,xdata,ydata);

into the command window I get the following error.

??? Attempt to reference field of non-structure array.

Error in ==> optimget>optimgetfast at 95
     value = defaultopt.(name);

Error in ==> optimget at 25
    o = optimgetfast(options,name,default);

Error in ==> lsqncommon at 24
switch optimget(options,'Display',defaultopt,'fast')

Error in ==> lsqcurvefit at 182
[x,Resnorm,FVAL,EXITFLAG,OUTPUT,LAMBDA,JACOB] = ...

Answer 1

[Sean de Wolski]

myfun = @(x,xdata) x(1)*exp(x(2)*xdata);
% Assume you determined xdata and ydata experimentally
xdata = [0.9 1.5 13.8 19.8 24.1 28.2 35.2 60.3 74.6 81.3];
ydata = [455.2 428.6 124.1 67.3 43.2 28.1 13.1 -0.4 -1.3 -1.5];
x0 = [100; -1];
[x] = lsqcurvefit(myfun,x0,xdata,ydata);

Local minimum possible.

lsqcurvefit stopped because the final change in the sum of squares relative to its initial value is less than the default value of the function tolerance.

stopping criteria details

x

x =

       498.83
     -0.10126

   myfun(x,xdata)

ans =

Columns 1 through 7

       455.38       428.54       123.34        67.18       43.466       28.698       14.126

Columns 8 through 10

       1.1124      0.26145      0.13267

Works for me. Do you have another function 'myfun' somewhere?

[Nathan]

No other 'myfun'. I am running a trial of R2011a, and R2007b is still on my machine, but no paths cross.

[Nathan]

I take that back, no myfun.m lying around, but I had a rouge lsqcurvefit.m for some reason. Removed the old lsqcurvefit.m, kept the new, things work now.

Thanks for the inspiration to clean up my own mess.