2013/6/6 Ralph Castain <r...@open-mpi.org>
> Afraid not. You could start a single process, and then have that process
> call MPI_Comm_spawn to launch the rest of them
>
Mmmm... sounds good
I'm writing an example program using ScaLAPACK. I have written the
ScaLAPACK code in an independent function that must be called after some
work in an individual node (the root one). So I need the first part of the
program be executed by one process. My example looks like:
int main()
{
//some work that must be done by only one node
.....
//function that runs internally some scalapack computations
funcCompScalapack();
//other work must be done by the original node
....
return 0;
}
void funcCompScalapack()
{
//Initialize MPI
MPI_Init(NULL,NULL);
//here I think I should write some code in order to inform that the
work must be done by a number X or processors
//maybe using MPI_Comm_spawn?
....
//some BLACS and ScaLAPACK computations
....
//finalize MPI
MPI_Finalize();
return;
}
When I execute this program as mpirun -np X myprogram, the pieces of code
before and after the call to function funcCompScalapack() are executed by X
nodes, but these orders must be executed only by one. So my idea is to
execute the binary as ./myprogram (the same I think as mpirun -np 1
myprogram) and internally set the number of processes in
funcCompScalapack() after the MPI_Init() call.
Is my idea possible?
Thanks
>
> On Jun 6, 2013, at 7:54 AM, José Luis García Pallero <jgpall...@gmail.com>
> wrote:
>
> Hello:
>
> I'm newbie in the use of MPI, so probably I ask some stupid question (or
> previously asked, but in this case I have searched in the archive and I
> haven't found anything):
>
> Exists any other way than -np X in order to pass the number of processes
> to start for an MPI program? I mean a function of the style
> MPI_Set_Number_Processes() or similar
>
> Thanks
>
> --
> *****************************************
> José Luis García Pallero
> jgpall...@gmail.com
> (o<
> / / \
> V_/_
> Use Debian GNU/Linux and enjoy!
> *****************************************
> _______________________________________________
> users mailing list
> us...@open-mpi.org
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>
>
>
> _______________________________________________
> users mailing list
> us...@open-mpi.org
> http://www.open-mpi.org/mailman/listinfo.cgi/users
>
--
*****************************************
José Luis García Pallero
jgpall...@gmail.com
(o<
/ / \
V_/_
Use Debian GNU/Linux and enjoy!
*****************************************
