dftd3_mpi_utils Module

Thin wrappers around the MPI calls used by s-dftd3.

This is the only place besides dftd3_feature that is preprocessed. Without MPI support every wrapper reports the missing feature in the error handler.

Interfaces

public interface mpi_allreduce_sum

Sum a real quantity over all ranks of a communicator, in place

• private subroutine allreduce_sum_rank1(comm, val, error)

  Sum an array over all ranks of a communicator

  Arguments

  Type	Intent	Optional	Attributes		Name
  integer,	intent(in)			::	comm	MPI communicator handle
  real(kind=wp),	intent(inout),		contiguous	::	val(:)	Values to reduce
  type(error_type),	intent(out),		allocatable	::	error	Error handling

• private subroutine allreduce_sum_rank2(comm, val, error)

  Sum a matrix over all ranks of a communicator

  Arguments

  Type	Intent	Optional	Attributes		Name
  integer,	intent(in)			::	comm	MPI communicator handle
  real(kind=wp),	intent(inout),		contiguous, target	::	val(:,:)	Values to reduce
  type(error_type),	intent(out),		allocatable	::	error	Error handling

Subroutines

public subroutine get_mpi_comm_info(comm, rank, nranks, error)

Determine rank and size of a communicator

Arguments

Type	Intent	Optional	Attributes		Name
integer,	intent(in)			::	comm	MPI communicator handle, users of mpi_f08 pass comm%mpi_val
integer,	intent(out)			::	rank	Zero-based rank of the calling process
integer,	intent(out)			::	nranks	Number of processes in the communicator
type(error_type),	intent(out),		allocatable	::	error	Error handling