|
Packit Service |
c5cf8c |
.TH MPI_Comm_compare 3 "11/12/2019" " " "MPI"
|
|
Packit Service |
c5cf8c |
.SH NAME
|
|
Packit Service |
c5cf8c |
MPI_Comm_compare \- Compares two communicators
|
|
Packit Service |
c5cf8c |
.SH SYNOPSIS
|
|
Packit Service |
c5cf8c |
.nf
|
|
Packit Service |
c5cf8c |
int MPI_Comm_compare(MPI_Comm comm1, MPI_Comm comm2, int *result)
|
|
Packit Service |
c5cf8c |
.fi
|
|
Packit Service |
c5cf8c |
.SH INPUT PARAMETERS
|
|
Packit Service |
c5cf8c |
.PD 0
|
|
Packit Service |
c5cf8c |
.TP
|
|
Packit Service |
c5cf8c |
.B comm1
|
|
Packit Service |
c5cf8c |
- comm1 (handle)
|
|
Packit Service |
c5cf8c |
.PD 1
|
|
Packit Service |
c5cf8c |
.PD 0
|
|
Packit Service |
c5cf8c |
.TP
|
|
Packit Service |
c5cf8c |
.B comm2
|
|
Packit Service |
c5cf8c |
- comm2 (handle)
|
|
Packit Service |
c5cf8c |
.PD 1
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
.SH OUTPUT PARAMETERS
|
|
Packit Service |
c5cf8c |
.PD 0
|
|
Packit Service |
c5cf8c |
.TP
|
|
Packit Service |
c5cf8c |
.B result
|
|
Packit Service |
c5cf8c |
- integer which is
|
|
Packit Service |
c5cf8c |
.I MPI_IDENT
|
|
Packit Service |
c5cf8c |
if the contexts and groups are the
|
|
Packit Service |
c5cf8c |
same,
|
|
Packit Service |
c5cf8c |
.I MPI_CONGRUENT
|
|
Packit Service |
c5cf8c |
if different contexts but identical groups,
|
|
Packit Service |
c5cf8c |
.I MPI_SIMILAR
|
|
Packit Service |
c5cf8c |
if different contexts but similar groups, and
|
|
Packit Service |
c5cf8c |
.I MPI_UNEQUAL
|
|
Packit Service |
c5cf8c |
otherwise
|
|
Packit Service |
c5cf8c |
.PD 1
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
.SH USING 'MPI_COMM_NULL' WITH 'MPI_COMM_COMPARE'
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
It is an error to use
|
|
Packit Service |
c5cf8c |
.I MPI_COMM_NULL
|
|
Packit Service |
c5cf8c |
as one of the arguments to
|
|
Packit Service |
c5cf8c |
.I MPI_Comm_compare
|
|
Packit Service |
c5cf8c |
\&.
|
|
Packit Service |
c5cf8c |
The relevant sections of the MPI standard are
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
\&.
|
|
Packit Service |
c5cf8c |
(2.4.1 Opaque Objects)
|
|
Packit Service |
c5cf8c |
A null handle argument is an erroneous
|
|
Packit Service |
c5cf8c |
.I IN
|
|
Packit Service |
c5cf8c |
argument in MPI calls, unless an
|
|
Packit Service |
c5cf8c |
exception is explicitly stated in the text that defines the function.
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
\&.
|
|
Packit Service |
c5cf8c |
(5.4.1. Communicator Accessors)
|
|
Packit Service |
c5cf8c |
where there is no text in
|
|
Packit Service |
c5cf8c |
.I MPI_COMM_COMPARE
|
|
Packit Service |
c5cf8c |
allowing a null handle.
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
.SH THREAD AND INTERRUPT SAFETY
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
This routine is thread-safe. This means that this routine may be
|
|
Packit Service |
c5cf8c |
safely used by multiple threads without the need for any user-provided
|
|
Packit Service |
c5cf8c |
thread locks. However, the routine is not interrupt safe. Typically,
|
|
Packit Service |
c5cf8c |
this is due to the use of memory allocation routines such as
|
|
Packit Service |
c5cf8c |
.I malloc
|
|
Packit Service |
c5cf8c |
or other non-MPICH runtime routines that are themselves not interrupt-safe.
|
|
Packit Service |
c5cf8c |
(To perform the communicator comparisions, this routine may need to
|
|
Packit Service |
c5cf8c |
allocate some memory. Memory allocation is not interrupt-safe, and hence
|
|
Packit Service |
c5cf8c |
this routine is only thread-safe.)
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
.SH NOTES FOR FORTRAN
|
|
Packit Service |
c5cf8c |
All MPI routines in Fortran (except for
|
|
Packit Service |
c5cf8c |
.I MPI_WTIME
|
|
Packit Service |
c5cf8c |
and
|
|
Packit Service |
c5cf8c |
.I MPI_WTICK
|
|
Packit Service |
c5cf8c |
) have
|
|
Packit Service |
c5cf8c |
an additional argument
|
|
Packit Service |
c5cf8c |
.I ierr
|
|
Packit Service |
c5cf8c |
at the end of the argument list.
|
|
Packit Service |
c5cf8c |
.I ierr
|
|
Packit Service |
c5cf8c |
is an integer and has the same meaning as the return value of the routine
|
|
Packit Service |
c5cf8c |
in C. In Fortran, MPI routines are subroutines, and are invoked with the
|
|
Packit Service |
c5cf8c |
.I call
|
|
Packit Service |
c5cf8c |
statement.
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
All MPI objects (e.g.,
|
|
Packit Service |
c5cf8c |
.I MPI_Datatype
|
|
Packit Service |
c5cf8c |
,
|
|
Packit Service |
c5cf8c |
.I MPI_Comm
|
|
Packit Service |
c5cf8c |
) are of type
|
|
Packit Service |
c5cf8c |
.I INTEGER
|
|
Packit Service |
c5cf8c |
in Fortran.
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
.SH ERRORS
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
All MPI routines (except
|
|
Packit Service |
c5cf8c |
.I MPI_Wtime
|
|
Packit Service |
c5cf8c |
and
|
|
Packit Service |
c5cf8c |
.I MPI_Wtick
|
|
Packit Service |
c5cf8c |
) return an error value;
|
|
Packit Service |
c5cf8c |
C routines as the value of the function and Fortran routines in the last
|
|
Packit Service |
c5cf8c |
argument. Before the value is returned, the current MPI error handler is
|
|
Packit Service |
c5cf8c |
called. By default, this error handler aborts the MPI job. The error handler
|
|
Packit Service |
c5cf8c |
may be changed with
|
|
Packit Service |
c5cf8c |
.I MPI_Comm_set_errhandler
|
|
Packit Service |
c5cf8c |
(for communicators),
|
|
Packit Service |
c5cf8c |
.I MPI_File_set_errhandler
|
|
Packit Service |
c5cf8c |
(for files), and
|
|
Packit Service |
c5cf8c |
.I MPI_Win_set_errhandler
|
|
Packit Service |
c5cf8c |
(for
|
|
Packit Service |
c5cf8c |
RMA windows). The MPI-1 routine
|
|
Packit Service |
c5cf8c |
.I MPI_Errhandler_set
|
|
Packit Service |
c5cf8c |
may be used but
|
|
Packit Service |
c5cf8c |
its use is deprecated. The predefined error handler
|
|
Packit Service |
c5cf8c |
.I MPI_ERRORS_RETURN
|
|
Packit Service |
c5cf8c |
may be used to cause error values to be returned.
|
|
Packit Service |
c5cf8c |
Note that MPI does
|
|
Packit Service |
c5cf8c |
.B not
|
|
Packit Service |
c5cf8c |
guarentee that an MPI program can continue past
|
|
Packit Service |
c5cf8c |
an error; however, MPI implementations will attempt to continue whenever
|
|
Packit Service |
c5cf8c |
possible.
|
|
Packit Service |
c5cf8c |
|
|
Packit Service |
c5cf8c |
.PD 0
|
|
Packit Service |
c5cf8c |
.TP
|
|
Packit Service |
c5cf8c |
.B MPI_SUCCESS
|
|
Packit Service |
c5cf8c |
- No error; MPI routine completed successfully.
|
|
Packit Service |
c5cf8c |
.PD 1
|
|
Packit Service |
c5cf8c |
.PD 0
|
|
Packit Service |
c5cf8c |
.TP
|
|
Packit Service |
c5cf8c |
.B MPI_ERR_ARG
|
|
Packit Service |
c5cf8c |
- Invalid argument. Some argument is invalid and is not
|
|
Packit Service |
c5cf8c |
identified by a specific error class (e.g.,
|
|
Packit Service |
c5cf8c |
.I MPI_ERR_RANK
|
|
Packit Service |
c5cf8c |
).
|
|
Packit Service |
c5cf8c |
.PD 1
|