MPI_Group_incl function

Creates a new group that contains a subset of the processes in an existing group.

Syntax

int MPIAPI MPI_Group_incl(
        MPI_Group         group,
        int               n,
        _In_count_(n) int *ranks,
  _Out_ MPI_Group         *newgroup
);

Parameters

• group
  The existing group.

• n
  The number of elements in the ranks parameter and the size of the new group.

• ranks
  The processes to be included in the new group.

• newgroup [out]
  A pointer to a handle that represents the new group, which contains the included processes in the order that they are specified in the ranks parameter.

Return value

Returns MPI_SUCCESS on success. Otherwise, the return value is an error code.

In Fortran, the return value is stored in the IERROR parameter.

Fortran

    MPI_GROUP_INCL(GROUP, N, RANKS, NEWGROUP, IERROR)
        INTEGER GROUP, N, RANKS(*), NEWGROUP, IERROR

Remarks

This function can be used to reorder the elements of a group.

This is a local operation. Different processes can define distinct groups. A process can define a group that does not include itself.

The MPI implementation does not provide a mechanism to build a group from scratch, but only from existing groups. The base group, upon which all other groups are defined, can be retrieved by using the MPI_Comm_group function. It is the group that is associated with the initial communicator MPI_COMM_WORLD.

Requirements

See also

MPI Group Functions

MPI_Comm_group