NAME

       MPI_Type_vector - Creates a vector (strided) datatype.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Type_vector(int count, int blocklength, int stride,
            MPI_Datatype oldtype, MPI_Datatype *newtype)

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_TYPE_VECTOR(COUNT, BLOCKLENGTH, STRIDE, OLDTYPE, NEWTYPE,
                 IERROR)
            INTEGER   COUNT, BLOCKLENGTH, STRIDE, OLDTYPE
            INTEGER   NEWTYPE, IERROR

C++ Syntax

       #include <mpi.h>
       Datatype Datatype::Create_vector(int count, int blocklength,
            int stride) const

INPUT PARAMETERS

       count     Number of blocks (nonnegative integer).

       blocklength
                 Number of elements in each block (nonnegative integer).

       stride    Number of elements between start of each block (integer).

       oldtype   Old datatype (handle).

OUTPUT PARAMETERS

       newtype   New datatype (handle).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       The  function  MPI_Type_vector  is  a  general  constructor  that  allows  replication of a datatype into
       locations that consist of equally spaced blocks. Each block is obtained by concatenating the same  number
       of  copies  of  the  old  datatype.  The  spacing  between  blocks is a multiple of the extent of the old
       datatype.

       Example 1: Assume, again, that oldtype has type map {(double, 0), (char, 8)}, with extent 16. A  call  to
       MPI_Type_vector(2, 3, 4, oldtype, newtype) will create the datatype with type map
           {(double, 0), (char, 8), (double, 16), (char, 24),
           (double, 32), (char, 40),
           (double, 64), (char, 72),
           (double, 80), (char, 88), (double, 96), (char, 104)}

       That  is,  two  blocks  with three copies each of the old type, with a stride of 4 elements (4 x 6 bytes)
       between the blocks.

       Example 2:  A call to  MPI_Type_vector(3, 1, -2, oldtype, newtype) will create the datatype

           {(double, 0), (char, 8), (double, -32), (char, -24),
           (double, -64), (char, -56)}

       In general, assume that oldtype has type map

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

       with extent ex. Let bl be the blocklength. The newly created datatype has a type map with count x bl x  n
       entries:

           {(type(0), disp(0)), ..., (type(n-1), disp(n-1)),
           (type(0), disp(0) + ex), ..., (type(n-1), disp(n-1) + ex), ...,
           (type(0), disp(0) + (bl -1) * ex),...,
           (type(n-1), disp(n-1) + (bl -1)* ex),
           (type(0), disp(0) + stride * ex),..., (type(n-1),
           disp(n-1) + stride * ex), ...,
           (type(0), disp(0) + (stride + bl - 1) * ex), ...,
           (type(n-1), disp(n-1) + (stride + bl -1) * ex), ...,
           (type(0), disp(0) + stride * (count -1) * ex), ...,
           (type(n-1), disp(n-1) + stride * (count -1) * ex), ...,
           (type(0), disp(0) + (stride * (count -1) + bl -1) * ex), ...,
           (type(n-1), disp(n-1) + (stride * (count -1) + bl -1) * ex)}

       A  call to MPI_Type_contiguous(count, oldtype, newtype) is equivalent to a call to MPI_Type_vector(count,
       1, 1, oldtype, newtype), or to a call to MPI_Type_vector(1, count, n, oldtype, newtype), n arbitrary.

ERRORS

       Almost all MPI routines return an error value; C routines as  the  value  of  the  function  and  Fortran
       routines in the last argument. C++ functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the  C++  exception  mechanism  will  be  used  to  throw  an
       MPI::Exception object.

       Before  the  error  value  is  returned,  the current MPI error handler is called. By default, this error
       handler aborts the MPI job, except for I/O function  errors.  The  error  handler  may  be  changed  with
       MPI_Comm_set_errhandler; 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.

SEE ALSO

       MPI_Type_create_hvector
       MPI_Type_hvector