[Help-gsl] Nonlinear fitting with finite Difference Jacobian

[Kazimierz Skrobas]

In gsl help is written (section 38.4):

"
For the algorithms which require a Jacobian matrix of derivatives of the
fit functions, there
are times when an analytic Jacobian may be unavailable or too expensive to
compute.

Therefore GSL supports approximating the Jacobian numerically using finite
differences of
the fit functions.

"

Does somebody implemented above method of nonlinear fitting ?

Short information in gsl help says: "This is typically done by setting the
relevant function pointers of the gsl_multifit_function_fdf data type to
NULL"  but code based on these method doesn't work. Program finishes with
segmantation fault.

If somebody knows the answer and can put example code
I will be grateful


address@hidden

Kaz