#include <mpi.h> int MPI_Type_create_subarray(int ndims, int array_of_sizes[], int array_of_subsizes[], int array_of_starts[], int order, MPI_Datatype oldtype, MPI_Datatype *newtype)
INCLUDE 'mpif.h' MPI_TYPE_CREATE_SUBARRAY(NDIMS, ARRAY_OF_SIZES, ARRAY_OF_SUBSIZES, ARRAY_OF_STARTS, ORDER, OLDTYPE, NEWTYPE, IERROR) INTEGER NDIMS, ARRAY_OF_SIZES(*), ARRAY_OF_SUBSIZES(*), ARRAY_OF_STARTS(*), ORDER, OLDTYPE, NEWTYPE, IERROR
#include <mpi.h> MPI::Datatype MPI::Datatype::Create_subarray(int ndims, const int array_of_sizes[], const int array_of_subsizes[], const int array_of_starts[], int order) const
This type constructor can handle arrays with an arbitrary number of dimensions and works for both C- and Fortran-ordered matrices (that is, row-major or column-major). Note that a C program may use Fortran order and a Fortran program may use C order.
The ndims parameter specifies the number of dimensions in the full data array and gives the number of elements in array_of_sizes, array_of_subsizes, and array_of_starts.
The number of elements of type oldtype in each dimension of the n-dimensional array and the requested subarray are specified by array_of_sizes and array_of_subsizes, respectively. For any dimension i, it is erroneous to specify array_of_subsizes[i] < 1 or array_of_subsizes[i] > array of sizes[i].
The array_of_starts contains the starting coordinates of each dimension of the subarray. Arrays are assumed to be indexed starting from zero. For any dimension i, it is erroneous to specify
array_of_starts[i] < 0
or
array_of_starts[i] > (array_of_sizes[i] - array_of_subsizes[i]).
The order argument specifies the storage order for the subarray as well as the full array. It must be set to one of the following:
- MPI_ORDER_C: The ordering used by C arrays, (that is, row-major order)
- MPI_ORDER_FORTRAN: The ordering used by Fortran arrays, (that is, column-major order)
A ndims-dimensional subarray (newtype) with no extra padding can be defined by the function Subarray() as follows:
newtype = Subarray(ndims, {size , size ,..., size }, 0 1 ndims-1 {subsize , subsize , ..., subsize }, 0 1 ndims-1 {start , start , ..., start }, oldtype) 0 1 bduns-1
Let the typemap of oldtype have the form:
{(type , disp ), (type , disp ), ..., (type , disp )} 0 0 1 1 n-1 n-1
where typei is a predefined MPI data type, and let ex be the extent of oldtype.
The Subarray() function is defined recursively in three equations on page 72 of the MPI-2 standard.
For an example use of MPI_Type_create_subarray in the context of I/O, see Section 9.9.2 of the MPI-2 standard.
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.