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MPI_Type_vector(3OpenMPI)                            MPI_Type_vector(3OpenMPI)




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,  old-
       type, 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++ func-
       tions 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(3), MPI_Type_hvector(3)




Open MPI 1.2                    September 2006       MPI_Type_vector(3OpenMPI)

Mac OS X 10.6 - Generated Thu Sep 17 20:13:21 CDT 2009
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