NAME

       MPI_Type_indexed -  Creates an indexed datatype

SYNOPSIS

       #include <mpi.h>
       int MPI_Type_indexed(int count, int *lengths, int *disps,
                           MPI_Datatype oldtype, MPI_Datatype *newtype)

INPUT PARAMETERS

       count  - number of blocks -- also number of entries in indices and blocklens
       lengths
              - number of elements in each block (array of nonnegative integers)
       disps  - displacement of each block in multiples of old_type (array of integers)
       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 to following

       integer a(100)
       integer blens(10), indices(10)
       do i=1,10
       blens(i)   = 1
       10       indices(i) = 1 + (i-1)*10
       call MPI_TYPE_INDEXED(10,blens,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,...   (and  so
       on).    Because   these   are   disps  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)

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

       If an error occurs in an MPI function, the current MPI error handler is called  to  handle
       it.   By default, this error handler aborts the MPI job.  The error handler may be changed
       with MPI_Errhandler_set ; the predefined error handler MPI_ERRORS_RETURN may  be  used  to
       cause  error values to be returned (in C and Fortran; this error handler is less useful in
       with the C++ MPI bindings.   The  predefined  error  handler  MPI::ERRORS_THROW_EXCEPTIONS
       should  be  used in C++ if the error value needs to be recovered).  Note that MPI does not
       guarantee that an MPI program can continue past an error.

       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.  The C++ bindings for
       MPI do not return error  values;  instead,  error  values  are  communicated  by  throwing
       exceptions of type MPI::Exception (but not by default).  Exceptions are only thrown if the
       error value is not MPI::SUCCESS .

       Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return
       upon an error, there will be no way to recover what the actual error value was.
       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.   May   be   an   uncommitted   MPI_Datatype   (see
              MPI_Type_commit ).
       MPI_ERR_COUNT
              - Invalid count argument.  Count arguments must be non-negative; a count of zero is
              often valid.
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not identified by  a  specific
              error class.  This is typically a NULL pointer or other such error.
       MPI_ERR_OTHER
              -  This error is returned when some part of the LAM/MPI implementation is unable to
              acquire memory.

MORE INFORMATION

       For more information, please see the official MPI Forum web site, which contains the  text
       of both the MPI-1 and MPI-2 standards.  These documents contain detailed information about
       each MPI function (most of which is not duplicated in these man pages).

       http://www.mpi-forum.org/

ACKNOWLEDGEMENTS

       The LAM Team would like the thank the MPICH Team for the handy  program  to  generate  man
       pages   ("doctext"  from  ftp://ftp.mcs.anl.gov/pub/sowing/sowing.tar.gz  ),  the  initial
       formatting, and some initial text for most of the MPI-1 man pages.

LOCATION

       tindex.c