mpifx_comm_module::mpifx_comm Type Reference

MPI communicator with some additional information. More...

Public Member Functions
procedure	init (self, commid, error)
	Initializes the MPI environment.
procedure	split (self, splitkey, rankkey, newcomm, error)
	Creates a new communicator by splitting the old one.
procedure	split_type (self, splittype, rankkey, newcomm, error)
	Creates a new communicator by splitting the old one given a split type.
procedure	free (self)
	Frees the communicator. The communicator should not be used after this.

Public Attributes
integer	id
	Communicator id.
integer	size
	Nr. of processes (size).
integer	rank
	Rank of the current process.
integer	leadrank
	Index of the lead node.
logical	lead
	True if current process is the lead (rank == 0).

Detailed Description

MPI communicator with some additional information.

Member Function/Subroutine Documentation

free()

procedure mpifx_comm_module::mpifx_comm::free

(

class(mpifx_comm), intent(inout)

self

)

Frees the communicator. The communicator should not be used after this.

After this call, the passed communicator should not be used any more.

Parameters

self	Communicator instance.

init()

procedure mpifx_comm_module::mpifx_comm::init	(	class(mpifx_comm), intent(out)	self,
		integer, intent(in), optional	commid,
		integer, intent(out), optional	error )

Initializes the MPI environment.

Parameters

self	Initialized instance on exit.
commid	MPI Communicator ID (default: MPI_COMM_WORLD)
error	Error flag on return containing the first error occuring during the calls mpi_comm_size and mpi_comm_rank.

split()

procedure mpifx_comm_module::mpifx_comm::split	(	class(mpifx_comm), intent(inout)	self,
		integer, intent(in)	splitkey,
		integer, intent(in)	rankkey,
		class(mpifx_comm), intent(out)	newcomm,
		integer, intent(out), optional	error )

Creates a new communicator by splitting the old one.

Parameters

self	Communicator instance.
splitkey	Key for the splitting. Processes invoking the routine with the same value for splitkey will be belong to the same communicator.
rankkey	Is used to determine the rank of the process in its new communicator. Processes calling the routine with a higher value will have a higher rank in the new communicator.
newcomm	New communicator for the given process.
error	Optional error code on return.

Example:

program test_split
  use libmpifx_module
  implicit none

  type(mpifx_comm) :: allproc, groupproc
  integer :: groupsize, mygroup

  call mpifx_init()
  call allproc%init()
  groupsize = allproc%size / 2
  mygroup = allproc%rank / groupsize
  call allproc%split(mygroup, allproc%rank, groupproc)
  write(*, "(3(A,1X,I0,1X))") "ID:", allproc%rank, "SUBGROUP", &
      & mygroup, "SUBGROUP ID", groupproc%rank
  call mpifx_finalize()

end program test_split

See also

MPI documentation (MPI_COMM_SPLIT)

split_type()

procedure mpifx_comm_module::mpifx_comm::split_type	(	class(mpifx_comm), intent(inout)	self,
		integer, intent(in)	splittype,
		integer, intent(in)	rankkey,
		class(mpifx_comm), intent(out)	newcomm,
		integer, intent(out), optional	error )

Creates a new communicator by splitting the old one given a split type.

Parameters

self	Communicator instance.
splittype	Determines which ranks to be grouped together. In MPI 3.0, this can only be MPI_COMM_TYPE_SHARED grouping all MPI ranks together that can share memory (usually on a node).
rankkey	Is used to determine the rank of the process in its new communicator. Processes calling the routine with a higher value will have a higher rank in the new communicator.
newcomm	New communicator for the given process.
error	Optional error code on return.

Example:

program test_split_type
  use libmpifx_module
  implicit none

  type(mpifx_comm) :: allproc, splitproc

  call mpifx_init()
  call allproc%init()
  call allproc%split_type(MPI_COMM_TYPE_SHARED, allproc%rank, splitproc)
  write(*, "(2(A,1X,I0,1X))") "ID:", allproc%rank, "SPLIT ID", splitproc%rank
  call mpifx_finalize()

end program test_split_type

See also

MPI documentation (MPI_COMM_SPLIT_TYPE)

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The documentation for this type was generated from the following file:

• mpifx_comm.fpp