Re: [Bug-gsl] Re: [bug #30947] Please, include fixed step size control object for ode suite

[Tuomo Keskitalo]

Hi,

On 09/03/2010 11:36 AM, Sergey B Kirpichev wrote:

> >   Also, I'm afraid that using your cfxd may not guarantee the use of a fixed
> >   step size; also evolve_apply can change the step length, so you might have to
> >   have a function something like "evolve_apply_fixed_step_size" to do the job.
>
> Why?  fc_control_hadjust() always returns GSL_ODEIV_HADJ_NIL - there
> is no reason to change step size.

Please see function gsl_odeiv2_evolve_apply in evolve.c. If step_apply 
returns with a failure, then a smaller step size is attempted. 
evolve_apply tries hard to make a step forward, even if it has to use a 
smaller step size than the user or previous step suggested.

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