Re: [Help-gsl] passing multiple parameters to func() & jac() while integrating ODE's in gsl

[Analabha Roy]

Thanks, I'll give it a whirl.

---------- Forwarded message ----------
From: Joakim Hove <address@hidden>
Date: Feb 19, 2006 3:46 PM
Subject: Re: [Help-gsl] passing multiple parameters to func() & jac() while
integrating ODE's in gsl
To: Analabha Roy <address@hidden>

"Analabha Roy" <address@hidden> writes:

> I assumed that, in order to do it for multiple parameters, I'd have
> to put the parameters in an array and pass the base address to the
> gsl_odeiv_system datatype, then use pointer arithmetic in the


1. I would strongly recommend defining a struct to contain your set of
   parameters; that is considerably less error prone than an array:

typedef struct {
   double mass;
   double w;
} harmonic_type;




int func(double t, const double y[], double dydt[], void *params) {
   harmonic_type *p = (harmonic_type *) params;
   double mass = p->mass;
   double w    = w->w;
   ...
   ....

         double mass,w;

        mass=*(double *)params;

2. I guess this pointer arithimitc comes out wrong, becuse params is
   *not* of type double.

        params++;

   Anyway, you do not have to worry about that when using a struct.

HTH - Joakim

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Joakim Hove
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