NAME

       MPI_Type_indexed -  Creates an indexed datatype

SYNOPSIS

       int MPI_Type_indexed(int count,
       const int *array_of_blocklengths,
       const int *array_of_displacements,
       MPI_Datatype oldtype, MPI_Datatype * newtype)

INPUT PARAMETERS

       count  - number of blocks -- also number of entries in array_of_displacements and array_of_blocklengths
       array_of_blocklengths
              - number of elements in each block (array of nonnegative integers)
       array_of_displacements
              - displacement of each block in multiples of oldtype (array of integers)
       oldtype
              - old datatype (handle)

OUTPUT PARAMETERS

       newtype
              - new datatype (handle)

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.

       The  array_of_displacements  are  displacements, and are based on a zero origin.  A common error is to do
       something like to following
       integer a(100)
       integer array_of_blocklengths(10), array_of_displacements(10)
       do i=1,10
       array_of_blocklengths(i)   = 1
       10       array_of_displacements(i) = 1 + (i-1)*10
       call MPI_TYPE_INDEXED(10,array_of_blocklengths,array_of_displacements,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  array_of_displacements  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 array_of_displacements into a Fortran array, consider
       declaring the Fortran array with a zero origin
       integer a(0:99)

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_ERR_COUNT
              - Invalid count argument.  Count arguments must be non-negative; a count of zero is often valid.
       MPI_ERR_TYPE
              -  Invalid  datatype  argument.  Additionally, this error can occur if an uncommitted MPI_Datatype
              (see MPI_Type_commit ) is used in a communication call.
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not identified  by  a  specific  error  class
              (e.g., MPI_ERR_RANK ).
       MPI_ERR_INTERN
              - This error is returned when some part of the MPICH implementation is unable to acquire memory.

                                                   11/12/2019                                MPI_Type_indexed(3)