MPI_Comm_group function

Retrieves the group that is associated with a communicator.

Syntax

int MPIAPI MPI_Comm_group(
        MPI_Comm  comm,
  _Out_ MPI_Group *group
);

Parameters

• comm
  The communicator on which to base the group.

• group [out]
  On return, contains the handle to the group that is associated with the specified communicator.

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_COMM_GROUP(COMM, GROUP, IERROR)
        INTEGER COMM, GROUP, IERROR

Remarks

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, on which all other groups are defined, is the group that is associated with the initial communicator MPI_COMM_WORLD.

Requirements

See also

MPI Group Functions