[OMPI users] Any reason why I can't start an mpirun job from within an mpi process?
>From the rank #0 process, I wish to start another mpi job (to create some data to be used by the parent job). I'm trying to do this with the command istat= system( "/...path.../mpirun -np 2 /...path.../prog2 args >file.log 2>&1" ) within the code executed by the rank #0 process, where ...path... is the path to the executables, prog2 is the daughter program, and args its arguments. On return, the status istat = 256, and, although the log file file.log has been created, it is empty. DOes anybody have an idea why this doesn't work?
Re: [OMPI users] Any reason why I can't start an mpirun job from within an mpi process?
You cannot cascade mpirun cmds like that - the child mpirun picks up envars that causes it to break. You'd have to either use comm_spawn to start the child job, or do a fork/exec where you can set the environment to be some pristine set of values. > On Jul 11, 2020, at 1:12 PM, John Retterer via users > wrote: > > From the rank #0 process, I wish to start another mpi job (to create some > data to be used by the parent job). > I'm trying to do this with the command > >istat= system( "/...path.../mpirun -np 2 /...path.../prog2 args >file.log > 2>&1" ) > > within the code executed by the rank #0 process, where ...path... is the > path to the executables, prog2 is the daughter program, and args its > arguments. > > On return, the status istat = 256, and, although the log file file.log has > been created, it is empty. > > DOes anybody have an idea why this doesn't work?
Re: [OMPI users] Any reason why I can't start an mpirun job from within an mpi process?
Thank you, Ralph. I was afraid that was the reason it didn’t work but I wanted to be sure. John On Sat, Jul 11, 2020 at 5:37 PM Ralph Castain via users < users@lists.open-mpi.org> wrote: > You cannot cascade mpirun cmds like that - the child mpirun picks up > envars that causes it to break. You'd have to either use comm_spawn to > start the child job, or do a fork/exec where you can set the environment to > be some pristine set of values. > > > > On Jul 11, 2020, at 1:12 PM, John Retterer via users < > users@lists.open-mpi.org> wrote: > > > > From the rank #0 process, I wish to start another mpi job (to create > some data to be used by the parent job). > > I'm trying to do this with the command > > > >istat= system( "/...path.../mpirun -np 2 /...path.../prog2 args > >file.log 2>&1" ) > > > > within the code executed by the rank #0 process, where ...path... is > the path to the executables, prog2 is the daughter program, and args its > arguments. > > > > On return, the status istat = 256, and, although the log file file.log > has been created, it is empty. > > > > DOes anybody have an idea why this doesn't work? > > >
