[Bug-gsl] GSL nonlinear least-squares fitting: error calculation

[Andreas Wolf]

Dear GSL team! 

I am using the GSL nonlinear least-squares fitting algorithm and I have
some questions concerning the example program provided on your page
(Reference Manual), 
especially the calculation of the errors using the covariance matrix:

The calculated error is not changing when the data is multiplied by a
factor. I have made the following changes (main program, line 50(?)):

y[i] = 10*(1.0 + 5 * exp (-0.1 * t) + gsl_ran_gaussian(r, 0.1));
//factor = 10

the output errors of A and b do not change, only the lambda error is
reduced by the factor. 
If the calculated errors are absolute errors, shouldn't the A and b
errors increase by
the same factor the data is multiplied with? 
I hope that you can help me with this problem.

best regards,

Andreas Wolf