Re: [Bug-gsl] [bug #30540] please, add convergence checks in rk4imp/rk2imp

[Tuomo Keskitalo]

Hi,

A quick comment: You need to specify the function for calculating the
Jacobian for sys-henon, the new implicit codes require it. Please look
at documentation in doc/ode-initval.texi. Use of fixed step size is
similar to old ode-initval.

BR,
Tuomo

On Thu, Aug 26, 2010 at 3:05 PM, Sergey B Kirpichev
<address@hidden> wrote:
>
> Follow-up Comment #2, bug #30540 (project gsl):
>
> I can't figure out how to use this code for fixed step size.  imprk2/imprk4
> seems to be not working at all for this case:
> $ ./bug
> Segmentation fault
>
> Other steppers works (e.g. rk2) just fine.  See bug-ode2.c.
>
> Second, Newton-type iterations could be inefficient in general.  See: Ernst
> Hairer, Christian Lubich, Gerhard Wanner, Geometric Numerical Integration.
> Structure-Preserving Algorithms for Ordinary Differential Equations. Springer
> Series in Comput. Mathematics, Vol. 31, Springer-Verlag 2002. pp. 330-332.
>
>
> (file #21314)
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