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MPI_Type_create_hindexed.3.rst

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MPI_Type_create_hindexed

:ref:`MPI_Type_create_hindexed` |mdash| Creates an indexed datatype with offsets in bytes.

SYNTAX

C Syntax

#include <mpi.h>

int MPI_Type_create_hindexed(int count, int *array_of_blocklengths,
     MPI_Aint *array_of_displacements, MPI_Datatype oldtype,
     MPI_Datatype *newtype)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'

MPI_TYPE_CREATE_HINDEXED(COUNT, ARRAY_OF_BLOCKLENGTHS,
          ARRAY_OF_DISPLACEMENTS, OLDTYPE, NEWTYPE, IERROR)
    INTEGER COUNT, ARRAY_OF_BLOCKLENGTHS(*)
    INTEGER ARRAY_OF_DISPLACEMENTS(*), OLDTYPE, NEWTYPE
    INTEGER IERROR

INPUT PARAMETERS

  • count: Number of blocks |mdash| also number of entries in array_of_displacements and array_of_blocklengths (integer).
  • array_of_blocklengths: Number of elements in each block (array of nonnegative integers).
  • array_of_displacements: Byte displacement of each block (C: array of MPI_Aint, Fortran: array of integer).
  • oldtype: Old datatype (handle).

OUTPUT PARAMETERS

  • newtype: New datatype (handle).
  • ierror: Fortran only: Error status (integer).

DESCRIPTION

The function is identical to :ref:`MPI_Type_indexed`, except that block displacements in array_of_displacements are specified in bytes, rather than in multiples of the oldtype extent.

Assume that oldtype has type map

{(type(0), disp(0)), ..., (type(n-1), disp(n-1))},

with extent ex. Let B be the array_of_blocklength argument and D be the array_of_displacements argument. The newly created datatype has

n x S^count-1
    (i=0)        B[i]  entries:

  {(type(0), disp(0) + D[0]),...,(type(n-1), disp(n-1) + D[0]),...,
  (type(0), disp(0) + (D[0] + B[0]-1)* ex),...,
  type(n-1), disp(n-1) + (D[0]+ B[0]-1)* ex),...,
  (type(0), disp(0) + D[count-1]),...,(type(n-1), disp(n-1) + D[count-1]),...,
  (type(0), disp(0) +  D[count-1] + (B[count-1] -1)* ex),...,
  (type(n-1), disp(n-1) + D[count-1] + (B[count-1] -1)* ex)}

ERRORS

.. seealso::
   * :ref:`MPI_Type_create_struct`
   * :ref:`MPI_Type_create_hvector`
   * :ref:`MPI_Type_indexed`