17.2.381. MPI_Type_contiguous

MPI_Type_contiguous — Creates a contiguous datatype.

17.2.381.1. SYNTAX

17.2.381.1.1. C Syntax

#include <mpi.h>

int MPI_Type_contiguous(int count, MPI_Datatype oldtype,
     MPI_Datatype *newtype)

17.2.381.1.2. Fortran Syntax

! or the older form: INCLUDE 'mpif.h'

17.2.381.1.3. Fortran 2008 Syntax

USE mpi_f08
MPI_Type_contiguous(count, oldtype, newtype, ierror)
     INTEGER, INTENT(IN) :: count
     TYPE(MPI_Datatype), INTENT(IN) :: oldtype
     TYPE(MPI_Datatype), INTENT(OUT) :: newtype


  • count: Replication count (nonnegative integer).

  • oldtype: Old datatype (handle).


  • newtype: New datatype (handle).

  • ierror: Fortran only: Error status (integer).

17.2.381.4. DESCRIPTION

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 the Datatypes chapter in the MPI Standard.

17.2.381.5. ERRORS

Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument.

Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions.

Open MPI includes three predefined error handlers that can be used:

  • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

  • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if MPI_Abort was called on that communicator. If called on a window or file, acts as if MPI_Abort was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process.

  • MPI_ERRORS_RETURN Returns an error code to the application.

MPI applications can also implement their own error handlers by calling:

Note that MPI does not guarantee that an MPI program can continue past an error.

See the MPI man page for a full list of MPI error codes.

See the Error Handling section of the MPI-3.1 standard for more information.