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! *****************************************