MPI-/ tries to spawn maxprocs processes. If it is unable to spawn maxprocs processes, it raises an error of class MPI_ERR_SPAWN.
An implementation may allow the info argument to change
the default behavior, such that if the implementation is
unable to spawn all maxprocs processes, it may
spawn a smaller number of processes instead of raising
an error. In principle, the info
argument may specify an arbitrary set
of allowed values for the number of
processes spawned. The set
does not necessarily
include the value maxprocs. If an implementation
is able to spawn one of these allowed numbers of processes,
MPI_COMM_SPAWN returns successfully
and the number of spawned processes,
,
is given by the size of the remote group of intercomm.
If
is less than
maxproc, reasons why the other processes
were not spawned are given in array_of_errcodes
as described below. If it is
not possible to spawn one of the allowed numbers of processes,
MPI_COMM_SPAWN raises an
error of class MPI_ERR_SPAWN.
A spawn call with the default behavior is called hard.
A spawn call for which fewer than maxprocs processes may be
returned is called soft. See Section 5.3.4
on page for
more information on the soft key for info.
MPI-Standard for MARMOT