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MPI_Type_contiguous - Creates a contiguous datatype.
#include <mpi.h>
int MPI_Type_contiguous(int count, MPI_Datatype oldtype,
MPI_Datatype *newtype)
INCLUDE ’mpif.h’
MPI_TYPE_CONTIGUOUS(COUNT, OLDTYPE, NEWTYPE, IERROR)
INTEGER COUNT, OLDTYPE, NEWTYPE, IERROR
#include <mpi.h>
Datatype Datatype::Create_contiguous(int count) const
- count
- Replication count (nonnegative integer).
- oldtype
- Old datatype (handle).
- newtype
- New datatype
(handle).
- IERROR
- Fortran only: Error status (integer).
The simplest
datatype constructor is MPI_Type_contiguous, which allows replication of
a datatype into contiguous locations.
newtype is the datatype obtained
by concatenating count copies of oldtype. Concatenation is defined using
the extent of oldtype as the size of the concatenated copies.
Example:
Let oldtype have type map {(double, 0), (char, 8)}, with extent 16, and
let count = 3. The type map of the datatype returned by newtype is
{(double, 0), (char, 8), (double, 16), (char, 24),
(double, 32), (char, 40)];
i.e., alternating double and char elements, with displacements 0, 8, 16,
24, 32, 40.
In general, assume that the type map of oldtype is
{(type(0), disp(0)),...,(type(n-1), disp(n-1))},
with extent ex. Then newtype has a type map with count times n entries defined
by:
{(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) + ex * (count - 1)),
...,(type(n-1), disp(n-1) + ex * (count - 1))}.
For more information about derived datatypes, see Section 3.12 of the MPI-1
Standard.
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.
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