127 lines
3.6 KiB
Groff
127 lines
3.6 KiB
Groff
.TH MPIX_Comm_agree 3 "2/3/2025" " " "MPI"
|
|
.SH NAME
|
|
MPIX_Comm_agree \- Performs agreement operation on comm
|
|
.SH SYNOPSIS
|
|
.nf
|
|
.fi
|
|
.nf
|
|
int MPIX_Comm_agree(MPI_Comm comm, int *flag)
|
|
.fi
|
|
|
|
|
|
.SH INPUT PARAMETERS
|
|
.PD 0
|
|
.TP
|
|
.B comm
|
|
- communicator (handle)
|
|
.PD 1
|
|
|
|
.SH OUTPUT PARAMETERS
|
|
.PD 0
|
|
.TP
|
|
.B flag
|
|
- new communicator (logical)
|
|
.PD 1
|
|
|
|
.SH NOTES
|
|
The purpose of this collective communication is to agree on the integer value flag and on the group of failed processes in comm.
|
|
|
|
On completion, all non-failed MPI processes have agreed to set the output integer value of flag to the result of a bitwise AND operation over the contributed input values of flag. If comm is an intercommunicator, the value of flagis a bitwise AND operation over the values contributed by the remote group.
|
|
|
|
When an MPI process fails before contributing to the operation, the flag is computed ignoring its contribution, and MPIX_Comm_agree raises an error of class MPI_ERR_PROC_FAILED. However, if all MPI processes have acknowledged this failure priorto the call to MPIX_Comm_agree, using MPIX_Comm_failure_ack, the error related to this failure is not raised. When an error of class MPI_ERR_PROC_FAILED is raised, it is consistently raised at allMPI processes, in both the local and remote groups (if applicable).
|
|
|
|
After MPIX_Comm_agree raised an error of class MPI_ERR_PROC_FAILED, a subse-quent call to MPIX_Comm_failure_ack on comm acknowledges the failure of every MPI process that didn
|
|
.I t contribute to the computation offlag.
|
|
|
|
.SH THREAD AND INTERRUPT SAFETY
|
|
|
|
This routine is thread-safe. This means that this routine may be
|
|
safely used by multiple threads without the need for any user-provided
|
|
thread locks. However, the routine is not interrupt safe. Typically,
|
|
this is due to the use of memory allocation routines such as
|
|
malloc
|
|
.I or other non-MPICH runtime routines that are themselves not interrupt-safe.
|
|
|
|
.SH NOTES FOR FORTRAN
|
|
All MPI routines in Fortran (except for
|
|
MPI_WTIME
|
|
.I and
|
|
MPI_WTICK
|
|
.I ) have
|
|
an additional argument
|
|
ierr
|
|
.I at the end of the argument list.
|
|
ierr
|
|
.I is an integer and has the same meaning as the return value of the routine
|
|
in C. In Fortran, MPI routines are subroutines, and are invoked with the
|
|
call
|
|
.I statement.
|
|
|
|
All MPI objects (e.g.,
|
|
MPI_Datatype
|
|
.I ,
|
|
MPI_Comm
|
|
.I ) are of type
|
|
INTEGER
|
|
.I in Fortran.
|
|
|
|
.SH ERRORS
|
|
|
|
All MPI routines (except
|
|
MPI_Wtime
|
|
.I and
|
|
MPI_Wtick
|
|
.I ) return an error value;
|
|
C routines as the value of the function and Fortran routines in the last
|
|
argument. Before the value is returned, the current MPI error handler is
|
|
called. By default, this error handler aborts the MPI job. The error handler
|
|
may be changed with
|
|
MPI_Comm_set_errhandler
|
|
.I (for communicators),
|
|
MPI_File_set_errhandler
|
|
.I (for files), and
|
|
MPI_Win_set_errhandler
|
|
.I (for
|
|
RMA windows). The MPI-1 routine
|
|
MPI_Errhandler_set
|
|
.I may be used but
|
|
its use is deprecated. The predefined error handler
|
|
MPI_ERRORS_RETURN
|
|
.I may be used to cause error values to be returned.
|
|
Note that MPI does
|
|
.B not
|
|
guarantee that an MPI program can continue past
|
|
an error; however, MPI implementations will attempt to continue whenever
|
|
possible.
|
|
|
|
.PD 0
|
|
.TP
|
|
.B MPI_SUCCESS
|
|
- No error; MPI routine completed successfully.
|
|
.PD 1
|
|
.PD 0
|
|
.TP
|
|
.B MPI_ERR_ARG
|
|
- Invalid argument. Some argument is invalid and is not
|
|
identified by a specific error class (e.g.,
|
|
MPI_ERR_RANK
|
|
.I ).
|
|
.PD 1
|
|
.PD 0
|
|
.TP
|
|
.B MPI_ERR_COMM
|
|
- Invalid communicator. A common error is to use a null
|
|
communicator in a call (not even allowed in
|
|
MPI_Comm_rank
|
|
.I ).
|
|
.PD 1
|
|
.PD 0
|
|
.TP
|
|
.B MPI_ERR_OTHER
|
|
- Other error; use
|
|
MPI_Error_string
|
|
.I to get more information
|
|
about this error code.
|
|
.PD 1
|
|
|