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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, 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_vec-tor(count, MPI_Type_vector(count,
       tor(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




Open MPI 1.2                                   September 2006                      MPI_Type_vector(3OpenMPI)

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