# MPI_Group_range_excl

Produces a group by excluding ranges of processes from an existing group

## Synopsis

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

## Input Parameters

group
  group (handle)
n
  number of elements in array `ranks` (integer)
ranges
  a one-dimensional array of integer triplets of the form (first rank, last rank, stride), indicating the ranks in `group` of processes to be excluded from the output group `newgroup` .

## Output Parameters

newgroup
  new group derived from above, preserving the order in `group` (handle)

## Note

The MPI standard requires that each of the ranks to be excluded must be a valid rank in the group and all elements must be distinct or the function is erroneous.

## 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` or other non-MPICH runtime routines that are themselves not interrupt-safe.

## Notes for Fortran

All MPI routines in Fortran (except for `MPI_WTIME` and `MPI_WTICK`) have an additional argument `ierr` at the end of the argument list. `ierr` 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` statement.

All MPI objects (e.g., `MPI_Datatype`, `MPI_Comm`) are of type `INTEGER` in Fortran.

## Errors

All MPI routines (except `MPI_Wtime` and `MPI_Wtick`) 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` (for communicators), `MPI_File_set_errhandler` (for files), and `MPI_Win_set_errhandler` (for RMA windows). The MPI-1 routine `MPI_Errhandler_set` may be used but its use is deprecated. The predefined error handler `MPI_ERRORS_RETURN` may be used to cause error values to be returned. Note that MPI does not guarentee that an MPI program can continue past an error; however, MPI implementations will attempt to continue whenever possible.

MPI_SUCCESS
  No error; MPI routine completed successfully.

MPI_ERR_GROUP
  Null or invalid group passed to function.

MPI_ERR_INTERN
  This error is returned when some part of the MPICH implementation is unable to acquire memory.

MPI_ERR_RANK
  Invalid source or destination rank. Ranks must be between zero and the size of the communicator minus one; ranks in a receive (`MPI_Recv`, `MPI_Irecv`, `MPI_Sendrecv`, etc.) may also be `MPI_ANY_SOURCE`.

MPI_ERR_ARG
  Invalid argument. Some argument is invalid and is not identified by a specific error class (e.g., `MPI_ERR_RANK`).

## See Also

MPI_Group_free