MPI_GROUP_RANGE_INCL(3)				     Open MPI				   MPI_GROUP_RANGE_INCL(3)

MPI_Group_range_incl — Creates a new group from ranges of ranks in an existing group.

SYNTAX
   C Syntax
	  #include <mpi.h>

	  int MPI_Group_range_incl(MPI_Group group, int n, int ranges[][3],
	       MPI_Group *newgroup)

   Fortran Syntax
	  USE MPI
	  ! or the older form: INCLUDE 'mpif.h'
	  MPI_GROUP_RANGE_INCL(GROUP, N, RANGES, NEWGROUP, IERROR)
	       INTEGER GROUP, N, RANGES(3,*), NEWGROUP, IERROR

   Fortran 2008 Syntax
	  USE mpi_f08
	  MPI_Group_range_incl(group, n, ranges, newgroup, ierror)
	       TYPE(MPI_Group), INTENT(IN) :: group
	       INTEGER, INTENT(IN) :: n, ranges(3,n)
	       TYPE(MPI_Group), INTENT(OUT) :: newgroup
	       INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS
       • group: Group (handle).

       • n: Number of triplets in array ranges (integer).

       • ranges:  A  one-dimensional  array  of	 integer  triplets,  of	 the  form (first rank, last rank, stride)
	 indicating ranks in group or processes to be included in newgroup.

OUTPUT PARAMETERS
       • newgroup: New group derived from above, in the order defined by ranges (handle).

       • ierror: Fortran only: Error status (integer).

DESCRIPTION
       If ranges consist of the triplets

	  (first1, last1, stride1), ..., (firstn, lastn, striden)

       then newgroup consists of the sequence of processes in group with ranks

							 last(1)-first(1)
	  first(1), first(1) + stride(1),..., first(1) + ---------------- stride(1),...
							     stride(1)

							 last(n)-first(n)
	  first(n), first(n) + stride(n),..., first(n) + ---------------- stride(n).
							     stride(n)

       Each computed rank must be a valid rank in group and all computed ranks	must  be  distinct,  or	 else  the
       program	is  erroneous. Note that we may have first(i) > last(i), and stride(i) may be negative, but cannot
       be zero.

       The functionality of this routine is specified to be equivalent to expanding the	 array	of  ranges  to	an
       array  of the included ranks and passing the resulting array of ranks and other arguments to MPI_Group_incl
       <#mpi-group-incl>.  A  call  to	 MPI_Group_incl	  <#mpi-group-incl>   is   equivalent	to   a	 call	to
       MPI_Group_range_incl with each rank i in ranks replaced by the triplet (i,i,1) in the argument ranges.

NOTE
       This  implementation  does not currently check to see that the list of ranges to include are valid ranks in
       the group.

ERRORS
       Almost all MPI routines return an error value; C routines as the return result of the function and  Fortran
       routines in the last argument.

       Before  the error value is returned, the current MPI error handler associated with the communication object
       (e.g., communicator, window, file) is called.  If no communication object is associated with the MPI  call,
       then  the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When
       MPI_COMM_SELF is not initialized (i.e.,	before	MPI_Init  <#mpi-init>/MPI_Init_thread  <#mpi-init-thread>,
       after  MPI_Finalize  <#mpi-finalize>,  or  when	using the Sessions Model exclusively) the error raises the
       initial error handler. The initial error handler can  be	 changed  by  calling  MPI_Comm_set_errhandler	<#
       mpi-comm-set-errhandler>	 on  MPI_COMM_SELF  when  using the World model, or the mpi_initial_errhandler CLI
       argument	 to  mpiexec  or  info	key   to   MPI_Comm_spawn   <#mpi-comm-spawn>/MPI_Comm_spawn_multiple	<#
       mpi-comm-spawn-multiple>.   If  no other appropriate error handler has been set, then the MPI_ERRORS_RETURN
       error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error  handler  is  called  for  all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT  An  error handler that can be invoked on a communicator, window, file, or session. When
	 called on a communicator, it acts as if MPI_Abort <#mpi-abort> was called on that communicator. If called
	 on a window or file, acts as if MPI_Abort <#mpi-abort> was called on a communicator containing the  group
	 of processes in the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler	 <#mpi-comm-create-errhandler>	   then	    MPI_Comm_set_errhandler	<#
	 mpi-comm-set-errhandler>

       • MPI_File_create_errhandler	<#mpi-file-create-errhandler>	  then	   MPI_File_set_errhandler	<#
	 mpi-file-set-errhandler>

       • MPI_Session_create_errhandler	 <#mpi-session-create-errhandler>   then   MPI_Session_set_errhandler	<#
	 mpi-session-set-errhandler> or at MPI_Session_init <#mpi-session-init>

       • MPI_Win_create_errhandler	<#mpi-win-create-errhandler>	  then	    MPI_Win_set_errhandler	<#
	 mpi-win-set-errhandler>

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page <#open-mpi> for a full list of MPI error codes <#open-mpi-errors>.

       See the Error Handling section of the MPI-3.1 standard for more information.

       See also:

	  • MPI_Group_incl <#mpi-group-incl>

	  • MPI_Group_free <#mpi-group-free>

Copyright
       2003-2026, The Open MPI Community

						   Mar 05, 2026				   MPI_GROUP_RANGE_INCL(3)
