mpifx_comm_module Module Reference

Contains the extended MPI communicator. More...

Data Types
type	mpifx_comm
	MPI communicator with some additional information. More...

Functions/Subroutines
subroutine	mpifx_comm_init (self, commid, error)
	Initializes a communicator to contain all processes.
subroutine	mpifx_comm_split (self, splitkey, rankkey, newcomm, error)
	Creates a new communicators by splitting the old one.
subroutine	mpifx_comm_split_type (self, splittype, rankkey, newcomm, error)
	Creates a new communicator by splitting the old one applying a given split type.
subroutine	mpifx_comm_free (self)
	Frees the MPI communicator.

Detailed Description

Contains the extended MPI communicator.

Function/Subroutine Documentation

mpifx_comm_free()

subroutine mpifx_comm_module::mpifx_comm_free ( class(mpifx_comm), intent(inout) self )

private

Frees the MPI communicator.

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

Parameters

self	Communicator instance.

mpifx_comm_init()

subroutine mpifx_comm_module::mpifx_comm_init	(	class(mpifx_comm), intent(out)	self,
		integer, intent(in), optional	commid,
		integer, intent(out), optional	error )

Initializes a communicator to contain all processes.

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.

mpifx_comm_split()

subroutine 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 )

private

Creates a new communicators 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)

mpifx_comm_split_type()

subroutine 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 )

private

Creates a new communicator by splitting the old one applying a given 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)