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Subject: Re: [OMPI users] Object Send Doubt
From: Gabriele Fatigati (g.fatigati_at_[hidden])
Date: 2008-07-13 14:31:24


Hi Carlos,
but why you need to pass an object? I don't understand this. Usuall, in MPI,
we don't need to do this.

2008/7/13 Andreas Schäfer <gentryx_at_[hidden]>:

> On 08:10 Sun 13 Jul , Carlos Henrique da Silva Santos wrote:
> > Ok. Gabriele,
> > But I would like to know, how can I define DATATYPE on send and
> > recv? Could you give me an example?
> > For example, my class has the following design and I want to
> > send/recv Test object.
> >
> > class Test {
> > private:
> > int coordinate;
> > vector<double> s;
> > public:
> > void setD(int, vector<double>);
> > double getParameter(int);
> > vector<double> getAll(void);
> > }
>
> Hi Carlos,
>
> the problem with this object is that it contains a pointer to malloc'd
> memory (the vector). Since datatypes can only be used for objects with
> fixed size (and layout), you can't define an MPI_Datatype for
> this. I'd suggest you to use Boost.MPI in this case
> (http://www.boost.org/doc/libs/1_35_0/doc/html/mpi.html)
>
> Cheers
> -Andreas
>
>
> --
> ============================================
> Andreas Schäfer
> Cluster and Metacomputing Working Group
> Friedrich-Schiller-Universität Jena, Germany
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-- 
Gabriele Fatigati
CINECA Systems & Tecnologies Department
Supercomputing Group
Via Magnanelli 6/3, Casalecchio di Reno (BO) Italy
www.cineca.it Tel: +39 051 6171722
g.fatigati_at_[hidden]