[This is preliminary documentation and is subject to change.]

Merge all of the processes in both groups of an intercommunicator into a single intracommunicator. While the intercommunicator only allows communication among processes in different groups, the merged intracommunicator allows communication among all of the processes in either group, regardless of which group the source and target were in.

Namespace:  MPI
Assembly:  MPI (in MPI.dll)
Version: (


public Intracommunicator Merge(
	bool upper
Visual Basic (Declaration)
Public Function Merge ( _
	upper As Boolean _
) As Intracommunicator
Visual C++
Intracommunicator^ Merge(
	bool upper


Type: System..::.Boolean
All of the processes within each group should provide the same value. If one group's processes provide the value true while the other group's processes provide the value false, the group providing the value true will receive the higher-numbered ranks in the resulting intracommunicator. If all processes provide the same value, the order of the union is arbitrary.

Return Value

The new intracommunicator.

See Also