APPSCHEMA(5)

NAME
appschema - LAM application schema format

SYNTAX
#
# comments
#
[<where>] [-np #] [-s <where>] [-wd <dir>] [-x <env>] <program> [<args>]
[<where>] [-np #] [-s <where>] [-wd <dir>] [-x <env>] <program> [<args>]
 ...

DESCRIPTION
The application schema is an ASCII file containing a description of the programs which constitute an application. It is used by mpirun(1), MPI_Comm_spawn, and MPI_Comm_spawn_multiple to start an MPI application (the MPI_Info key "file" can be used to specify an app schema to MPI_Comm_spawn and MPI_Comm_spawn_multiple). All tokens after the program name will be passed as command line arguments to the new processes. Ordering of the other elements on the command line is not important.

The meaning of the options is the same as in mpirun(1). See the mpirun(1) man page for a lengthy discussion of the nomenclature used for <where>. Note, however, that if -wd is used in the application schema file, it will override any -wd value specified on the command line.

For each program line, processes will be created on LAM nodes according to the presence of <where> and the process count option (-np).

only <where>
    One process is created on each node.

only -np
    The specified number of processes are scheduled across all LAM nodes/CPUs.

both
    The specified number of processes are scheduled across the specified nodes/CPUs.

neither
    One process is created on the local node.

  Program Transfer
By default, LAM searches for executable programs on the target node where a particular instantiation will run. If the file system is not shared, the target nodes are homogeneous, and the program is frequently recompiled, it can be convenient to have LAM transfer the program from a source node (usually the local node) to each target node. The -s option specifies this behaviour and identifies the single source node.

EXAMPLE
#
# Example application schema
# Note that it may be necessary to specify the entire pathname for
# "master" and "slave" if you get "File not found" errors from
# mpirun(1).
#
# This schema starts a "master" process on CPU 0 with the argument
# "42.0", and then 10 "slave" processes (that are all sent from the
# local node) scheduled across all available CPUs.
#
c0 master 42.0
C -np 10 -s h slave

SEE ALSO
mpirun(1), MPI_Comm_spawn(2), MPI_Comm_Spawn_multiple(2), MPIL_Spawn(2), introu(1)