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MPI_Type_create_indexed_block(3)      MPI     MPI_Type_create_indexed_block(3)


NAME

       MPI_Type_create_indexed_block -  Create an indexed datatype with
       constant-sized blocks


SYNOPSIS

       int MPI_Type_create_indexed_block(int count,
                                      int blocklength,
                                      MPICH2_CONST int array_of_displacements[],
                                      MPI_Datatype oldtype,
                                      MPI_Datatype *newtype)


INPUT PARAMETERS

       count  - length of array of displacements (integer)
       blocklength
              - size of block (integer)
       array_of_displacements
              - array of displacements (array of integer)
       oldtype
              - old datatype (handle)


OUTPUT PARAMETER

       newtype
              - new datatype (handle)


NOTES

       The indices are displacements, and are based on a zero origin.  A
       common error is to do something like the following
       integer a(100)
       integer blens(10), indices(10)
       do i=1,10
       10       indices(i) = 1 + (i-1)*10
       call MPI_TYPE_CREATE_INDEXED_BLOCK(10,1,indices,MPI_INTEGER,newtype,ierr)
       call MPI_TYPE_COMMIT(newtype,ierr)
       call MPI_SEND(a,1,newtype,...)

       expecting this to send a(1),a(11),...  because the indices have values
       1,11,...  .  Because these are displacements from the beginning of a ,
       it actually sends a(1+1),a(1+11),...  .

       If you wish to consider the displacements as indices into a Fortran
       array, consider declaring the Fortran array with a zero origin
       integer a(0:99)


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_TYPE
              - Invalid datatype argument.  May be an uncommitted MPI_Datatype
              (see MPI_Type_commit ).
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not
              identified by a specific error class (e.g., MPI_ERR_RANK ).


LOCATION

       src/mpi/datatype/type_create_indexed_block.c

                                   9/20/2012  MPI_Type_create_indexed_block(3)

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