Re: [Help-gsl] Is there a way to change the step size used by the (multi)root finder?

[Andrew W. Steiner]

You can modify the GSL iterate functions to shorten the step size
by factors of two in the case until a legitimate step is found.

See for example lines 833-871 of
http://o2scl.svn.sourceforge.net/viewvc/o2scl/trunk/src/root/gsl_mroot_hybrids.h?revision=46&view=markup
where I've made a similar modification in the C++ context.

Take care,
Andrew

On Mon, Nov 2, 2009 at 6:22 PM, Huaiyu Duan <address@hidden> wrote:
> If the step size of the (multi)root finder is too big, it can enter
> the region where the function is undefined (e.g., sqrt(-1)). I tried
> having the function return the out of range error (GSL_EDOM), and the
> iteration failed with the bad function error (GSL_EBADFUNC). I then
> tried changing the solver's step size by manipulating solver->dx which
> actually did not affect the step size. Is there a way to change the
> step size used by the root finder? Thanks!
>
>
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