.\" -*- nroff -*-
.\" Copyright 2013 Los Alamos National Security, LLC. All rights reserved.
.\" Copyright 2010 Cisco Systems, Inc.  All rights reserved.
.\" Copyright 2006-2008 Sun Microsystems, Inc.
.\" Copyright (c) 1996 Thinking Machines Corporation
.\" $COPYRIGHT$
.TH MPI_Group_incl 3 "Sep 30, 2023" "4.1.6" "Open MPI"
.SH NAME
\fBMPI_Group_incl \fP \- Produces a group by reordering an existing group and taking only listed members.

.SH SYNTAX
.ft R
.SH C Syntax
.nf
#include <mpi.h>
int MPI_Group_incl(MPI_Group \fIgroup\fP, int\fI n\fP, const int\fI ranks\fP[],
	MPI_Group\fI *newgroup\fP)

.fi
.SH Fortran Syntax
.nf
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_GROUP_INCL(\fIGROUP, N, RANKS, NEWGROUP, IERROR\fP)
	INTEGER	\fIGROUP, N, RANKS(*), NEWGROUP, IERROR\fP

.fi
.SH Fortran 2008 Syntax
.nf
USE mpi_f08
MPI_Group_incl(\fIgroup\fP, \fIn\fP, \fIranks\fP, \fInewgroup\fP, \fIierror\fP)
	TYPE(MPI_Group), INTENT(IN) :: \fIgroup\fP
	INTEGER, INTENT(IN) :: \fIn\fP, \fIranks(n)\fP
	TYPE(MPI_Group), INTENT(OUT) :: \fInewgroup\fP
	INTEGER, OPTIONAL, INTENT(OUT) :: \fIierror\fP

.fi
.SH C++ Syntax
.nf
#include <mpi.h>
Group Group::Incl(int \fIn\fP, const int \fIranks\fP[]) const

.fi
.SH INPUT PARAMETERS
.ft R
.TP 1i
group
Group (handle).
.TP 1i
n
Number of elements in array ranks (and size of \fInewgroup\fP)(integer).
.TP 1i
ranks
Ranks of processes in group to appear in newgroup (array of integers).

.SH OUTPUT PARAMETERS
.ft R
.TP 1i
newgroup
New group derived from above, in the order defined by ranks (handle).
.ft R
.TP 1i
IERROR
Fortran only: Error status (integer).

.SH DESCRIPTION
.ft R
The function MPI_Group_incl creates a group group_out that consists of the n processes in group with ranks rank[0], \&..., rank[n-1]; the process with rank i in group_out is the process with rank ranks[i] in group. Each of the n elements of ranks must be a valid rank in group and all elements must be distinct, or else the program is erroneous. If n = 0, then group_out is MPI_GROUP_EMPTY. This function can, for instance, be used to reorder the elements of a group.

.SH NOTE
.ft R
This implementation does not currently check to ensure that there are no
duplicates in the list of ranks.

.SH ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw an MPI::Exception object.
.sp
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 MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN 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.

.SH SEE ALSO
.ft R
.sp
MPI_Group_compare
.br
MPI_Group_range_incl
.br
MPI_Group_free