Re: [Help-gsl] Checking error in ODE system

[Pau Cervera Badia]

Hi,

I think the error is located at the yerr field of the gsl_odeiv_evolve 
pointer type that has the name evolve in your piece of code. I think you 
can access the value via,

double error_at_i = evolve->yerr[i];

You can see the definition of the evolution object at gsl_odeiv.h. You 
can see other uses of yerr in the source for the stepper methods where 
the errors ara estimated; see rk2.c in rk2_apply, for instance.

If someone knows a better way, I would like to know it. Thanks!

I hope that will help you Sebastien,

Sebastien Maret wrote:
> Hello,
>
> I am trying to solve a system of stiff ODEs using the GSL. The part of
> my code that solve the equations looks like:
>
>      for (i = 0; i < time_steps; i++)
>        {
>          while (t < tim[i])
>              gsl_odeiv_evolve_apply (evolve, control, step, &syst,
>                                      &t, tim[i], &h, y);
>        }
>
> I would like to check what is the error for y[] reached at the end of each
> gsl_odeiv_evolve_apply() call.
>
> How can I do that? An example would be appreciated.
>
> Sébastien
>  
>
>
>
> _______________________________________________
> Help-gsl mailing list
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>
>
>   

--
Pau Cervera i Badia (e-mail address@hidden)
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