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)

       int MPI_Type_indexed_c(MPI_Count count, const MPI_Count array_of_blocklengths[],
       const MPI_Count 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
              (non-negative integer)
       array_of_blocklengths
              - number of elements per block (non-negative integer)
       array_of_displacements
              - displacement for each block, in multiples of oldtype (integer)
       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 guarantee 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_ARG
              -  Invalid  argument.   Some  argument  is invalid and is not identified by a specific error class
              (e.g., MPI_ERR_RANK ).
       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_OTHER
              - Other error; use MPI_Error_string to get more information about this error code.

                                                    2/9/2024                                 MPI_Type_indexed(3)