Working with lsqcurvefit: edit optimization options structure

Hi,

i tried to fix some Data to the folling function:

function Z = FitFunc(p, f ) % Vector p must be [R1, C1, R2, C2]'

Z = abs( 1 ./ (1/p(1) + i*2*pi*f*p(2)) + 1 ./ (1/p(3) + i*2*pi*f*p(4)));

end

The function represents a electric circuit.

%for f i used:

f = logspace(1,6)

%for p:

p = [1000, 1e-9, 10, 1e-7]

%after saving for y:

y = FitFunc(p,f);

%i tried to fix the problem with the following startvalues

p2 = [1100, 5e-9, 22, 5.5e-7]

[x, resnorm] = lsqcurvefit(@FitFunc, p2, f, y);

%But Matlab the says: %Local minimum possible.

%lsqcurvefit stopped because the size of the current step is less %than the default value of the step size tolerance.

%<stopping criteria details>

%i already worked with optimset:

options = optimset('TolX', 1e-12, 'TolFun', 1e-12, 'MaxFunEvals', 4000, 'MaxIter', 4000);

%and used than:

[x, resnorm] = lsqcurvefit(@FitFunc, p2, f, y, [], [], options);

but it says again the same thing.

Thanks for your help!

Jan

Answer 1

[Jan]

nobody has a idea?