MPI_Comm_split

Partitions the group that is associated with the specified communicator into a specified number of disjoint subgroups.

Syntax

• newcomm = MPI_Comm_split(comm, color, key)

Input argument

• comm - a MPI_Comm object.
• color - an integer value: The new communicator that the calling process is to be assigned to. The value of color must be non-negative.
• key - an integer value: The relative rank of the calling process in the group of the new communicator.

Output argument

• newcomm - MPI_Comm object: handle to a new communicator.

Description

Partitions the group that is associated with the specified communicator into a specified number of disjoint subgroups.

See also

MPI_Comm_rank.

Example

mpiexec([modulepath('mpi'), '/examples/help_examples/MPI_Comm_split.m'], 10)

if ~MPI_Initialized()
  MPI_Init();
end
comm = MPI_Comm_object();
world_rank = MPI_Comm_rank();
world_size = MPI_Comm_size();

color = world_rank * inv(4);

% Split the communicator based on the color and use the
% original rank for ordering
row_comm = MPI_Comm_split(comm, color, world_rank);

row_rank = MPI_Comm_rank();
row_size = MPI_Comm_size();

disp(['WORLD RANK/SIZE: ',int2str(world_rank), '/', int2str(world_size), ' ROW RANK/SIZE: ', int2str(row_rank), '/', int2str(row_size)]);
if MPI_Initialized()
  MPI_Finalize();
end

History

Author

Allan CORNET