MPICommspawnmultiple(3OpenMPI) MPICommspawnmultiple(3OpenMPI)

NAME
       MMPPIICCoommmmssppaawwnnmmuullttiippllee  - Spawns multiple binaries, or the same binary
       with multiple sets of arguments.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPICommspawnmultiple(int count, char *arrayofcommands[],
            char **arrayofargv[], int arrayofmaxprocs[], MPIInfo
            arrayofinfo[], int root, MPIComm comm, MPIComm *intercomm,
            int arrayoferrcodes[])


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPICOMMSPAWNMULTIPLE(COUNT, ARRAYOFCOMMANDS, ARRAYOFARGV,
            ARRAYOFMAXPROCS, ARRAYOFINFO, ROOT, COMM, INTERCOMM,
            ARRAYOFERRCODES, IERROR)
            INTEGER   COUNT, ARRAYOFINFO(*), ARRAYOFMAXPROCS(*), ROOT,
                 COMM, INTERCOMM, ARRAYOFERRCODES(*), IERROR
            CHARACTER*(*) ARRAYOFCOMMANDS(*), ARRAYOFARGV(COUNT, *)


CC++++ SSyynnttaaxx
       #include 
       MPI::Intercomm MPI::Intracomm::Spawnmultiple(int count,
            const char* arrayofcommands[], const char** arrayofargv[],
            const int arrayofmaxprocs[], const MPI::Info arrayofinfo[],
            int root, int arrayoferrcodes[])

       MPI::Intercomm MPI::Intracomm::Spawnmultiple(int count,
            const char* arrayofcommands[], const char** arrayofargv[],
            const int arrayofmaxprocs[], const MPI::Info arrayofinfo[],
            int root)


IINNPPUUTT PPAARRAAMMEETTEERRSS
       count     Number of commands (positive integer, significant to MPI only
                 at root - see NOTES).

       arrayofcommands
                 Programs  to  be executed (array of strings, significant only
                 at root).

       arrayofargv
                 Arguments for commands (array of array of strings,   signifi-
                 cant only at root).

       arrayofmaxprocs
                 Maximum  number of processes to start for each command (array
                 of integers, significant only at root).

       arrayofinfo
                 Info objects telling the runtime  system  where  and  how  to
                 start processes (array of handles, significant only at root).

       root      Rank of process in  which  previous  arguments  are  examined
                 (integer).

       comm      Intracommunicator  containing  group  of  spawning  processes
                 (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       intercomm Intercommunicator  between  original  group  and  the   newly
                 spawned group (handle).

       arrayoferrcodes
                 One code per process (array of integers).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPICommspawnmultiple  is  identical to MPICommspawn except that it
       can specify multiple executables. The first argument, count,  indicates
       the  number  of executables. The next three arguments are arrays of the
       corresponding  arguments  in   MPICommspawn.   The   next   argument,
       arrayofinfo,  is  an array of info arguments; however, only the first
       argument in that array is used.  Any subsequent arguments in the  array
       are  ignored because an info argument applies to the entire job that is
       spawned, and cannot be different for each executable in the  job.   See
       the INFO ARGUMENTS section for more information.

       For    the    Fortran    version    of   arrayofargv,   the   element
       arrayofargv(i,j) is the jth argument to command number i.

       In any language, an application may  use  the  constant  MPIARGVSNULL
       (which  is  likely to be (char ***)0 in C) to specify that no arguments
       should be passed to any commands. The effect of setting individual ele-
       ments  of  arrayofargv  to  MPIARGVNULL  is not defined. To specify
       arguments for some commands but not others, the commands without  argu-
       ments  should  have  a  corresponding  argv whose first element is null
       ((char *)0 in C and empty string in Fortran).

       All of the spawned processes have the same MPICOMMWORLD. Their  ranks
       in  MPICOMMWORLD  correspond  directly to the order in which the com-
       mands are specified in MPICommspawnmultiple.  Assume  that  m1  pro-
       cesses  are  generated by the first command, m2 by the second, etc. The
       processes corresponding to the first command have ranks 0, 1,..., m1-1.
       The  processes in the second command have ranks m1, m1+1, ..., m1+m2-1.
       The processes in the third have ranks m1+m2, m1+m2+1, ...,  m1+m2+m3-1,
       etc.

       The arrayoferrcodes argument is 1-dimensional array of size

              count
            \       n ,
            / i=1   i

       where  i is the ith element of arrayofmaxprocs. Command number i cor-
       responds to the i contiguous slots in this array from element

                                           
              i-1          |    i          |
            \       n ,  to |  \      n      | -1
            / j=1   i      |  / j=1  j     |
                            |              |

       Error codes are treated as for MPICommspawn.



IINNFFOO AARRGGUUMMEENNTTSS
       The following values for info are recognized  in  Open  MPI  1.2.  (The
       reserved  values  mentioned  in Section 5.3.4 of the MPI-2 standard are
       not implemented.)


       Key value             Type      Description
       -----            --      ------

       host                  char *    Host on which the process should be spawned.
       wdir                  char *    Directory where the executable is located.


       Note that in Open MPI 1.2, the first array location in arrayofinfo is
       applied to all the commands in arrayofcommands.


NNOOTTEESS
       The  argument  count  is  interpreted  by  MPI  only at the root, as is
       arrayofargv. Since the leading dimension of arrayofargv is count, a
       nonpositive  value of count at a nonroot node could theoretically cause
       a runtime bounds check  error,  even  though  arrayofargv  should  be
       ignored  by the subroutine. If this happens, you should explicitly sup-
       ply a reasonable value of count on the nonroot nodes.

       Calling MPICommspawn many times would create many  sets  of  children
       with different MPICOMMWORLDs, whereas MPICommspawnmultiple creates
       children with a single MPICOMMWORLD, so the two methods are not  com-
       pletely  equivalent.  Also   if you need to spawn multiple executables,
       you may get better performance by using MPICommspawnmultiple instead
       of calling MPICommspawn several times.


EERRRROORRSS
       Almost  all MPI routines return an error value; C routines as the value
       of the function and Fortran routines in the last  argument.  C++  func-
       tions  do  not  return  errors.  If the default error handler is set to
       MPI::ERRORSTHROWEXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       Before  the  error  value is returned, the current MPI error handler is
       called. By default, this error handler aborts the MPI job,  except  for
       I/O   function   errors.   The   error  handler  may  be  changed  with
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       may  be  used  to cause error values to be returned. Note that MPI does
       not guarantee that an MPI program can continue past an error.


SEE ALSO
       MPICommspawn(3)
       MPICommgetparent(3)
       mpirun(1)




Open MPI 1.2                    September 2006MPICommspawnmultiple(3OpenMPI)