Re: [Bug-gsl] Multidimensional Root-Finding (gnewton)

[Brian Gough]

At Fri, 24 Jun 2011 14:05:13 +0100,
Allan Leal wrote:
> I have detected that the solver *gnewton* does not call the *fdf*
> function. It only calls *f* and *df*.  This does not happen in the
> *newton* solver, which only uses the *fdf* function.

Thanks for the email.  In gnewton the steps are subject to an
acceptance condition and the derivatives are only calculated after
that has been tested.  Evaluating the function and derivatives
simultaneously would cause extra derivative evaluations on the failed
steps.