SYNTAX¶

#include <mpi.h>
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_create_hindexed(int count,


     const int array_of_blocklengths[],


     const MPI_Aint array_of_displacements[], MPI_Datatype oldtype,


     MPI_Datatype *newtype)

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_TYPE_INDEXED(COUNT, ARRAY_OF_BLOCKLENGTHS,


             ARRAY_OF_DISPLACEMENTS, OLDTYPE, NEWTYPE, IERROR)


     INTEGER COUNT, ARRAY_OF_BLOCKLENGTHS(*)


     INTEGER ARRAY_OF_DISPLACEMENTS(*), OLDTYPE, NEWTYPE


     INTEGER IERROR
MPI_TYPE_CREATE_HINDEXED(COUNT, ARRAY_OF_BLOCKLENGTHS,


             ARRAY_OF_DISPLACEMENTS, OLDTYPE, NEWTYPE, IERROR)


     INTEGER COUNT, ARRAY_OF_BLOCKLENGTHS(*)


     INTEGER OLDTYPE, NEWTYPE


     INTEGER(KIND=MPI_ADDRESS_KIND) ARRAY_OF_DISPLACEMENTS(*)


     INTEGER IERROR

USE mpi_f08
MPI_Type_indexed(count, array_of_blocklengths, array_of_displacements,


             oldtype, newtype, ierror)


     INTEGER, INTENT(IN) :: count, array_of_blocklengths(count),


     array_of_displacements(count)


     TYPE(MPI_Datatype), INTENT(IN) :: oldtype


     TYPE(MPI_Datatype), INTENT(OUT) :: newtype


     INTEGER, OPTIONAL, INTENT(OUT) :: ierror
MPI_Type_create_hindexed(count, array_of_blocklengths,


             array_of_displacements, oldtype, newtype, ierror)


     INTEGER, INTENT(IN) :: count, array_of_blocklengths(count)


     INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) ::


     array_of_displacements(count)


     TYPE(MPI_Datatype), INTENT(IN) :: oldtype


     TYPE(MPI_Datatype), INTENT(OUT) :: newtype


     INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS¶

OUTPUT PARAMETERS¶

DESCRIPTION¶

The function MPI_Type_indexed allows replication of an old datatype into a sequence of blocks (each block is a concatenation of the old datatype), where each block can contain a different number of copies and have a different displacement. All block displacements are multiples of the old data type’s extent.

Example: Let oldtype have type map {(double, 0), (char, 8)}, with extent 16. Let B = (3, 1) and let D = (4, 0). A call to MPI_Type_indexed(2, B, D, oldtype, newtype) returns a datatype with type map

{(double, 64), (char, 72), (double, 80), (char, 88),
(double, 96), (char, 104),
(double, 0), (char, 8)}

That is, three copies of the old type starting at displacement 4 x 16 = 64, and one copy starting at displacement 0.

In general, 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]* ex), ...,


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


    (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]* ex), ...,


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


    (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)}

A call to MPI_Type_vector(count, blocklength, stride, oldtype, newtype) is equivalent to a call to MPI_Type_indexed(count, B, D, oldtype, newtype) where

    D[j] = j * stride, j = 0,..., count-1
and


    B[j] = blocklength, j = 0, .., count-1

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

ERRORS¶

Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument.

Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions.

Open MPI includes three predefined error handlers that can be used:

MPI applications can also implement their own error handlers by calling:

Note that MPI does not guarantee that an MPI program can continue past an error.

See the MPI man page for a full list of MPI error codes.

See the Error Handling section of the MPI-3.1 standard for more information.

SEE ALSO:

COPYRIGHT¶

2003-2024, The Open MPI Community