dg::MPI_Vector< container > Struct Template Reference

mpi Vector class More...

Public Types
typedef container	container_type

Public Member Functions
	MPI_Vector ()
	no data is allocated, communicators are MPI_COMM_NULL More...
	MPI_Vector (const container &data, MPI_Comm comm)
	construct a vector More...
template<class OtherContainer >
	MPI_Vector (const MPI_Vector< OtherContainer > &src)
	Conversion operator. More...
const container &	data () const
	Get underlying data. More...
container &	data ()
	Set underlying data. More...
MPI_Comm	communicator () const
	Get the communicator to which this vector belongs. More...
MPI_Comm	communicator_mod () const
	Returns a communicator of fixed size 128. More...
MPI_Comm	communicator_mod_reduce () const
	Returns a communicator consisting of all processes with rank 0 in communicator_mod() More...
void	set_communicator (MPI_Comm comm, MPI_Comm comm_mod, MPI_Comm comm_mod_reduce)
	Set the communicators with dg::exblas::mpi_reduce_communicator. More...
unsigned	size () const
	Return the size of the data object. More...
void	swap (MPI_Vector &src)
	Swap data and communicator. More...

Detailed Description

template<class container>
struct dg::MPI_Vector< container >

mpi Vector class

This class is a simple wrapper around a container object and an MPI_Comm. The blas1 and blas2 functionality is available iff it is available for the container type. We use mpi to communicate (e.g. boundary points in matrix-vector multiplications) and use the existing blas functions for the local computations. (At the blas level 1 communication is needed only for scalar products)

Template Parameters

container

local container type. Must have a size() and a swap() member function and a specialization of the TensorTraits class.

Member Typedef Documentation

container_type

template<class container >

typedef container dg::MPI_Vector< container >::container_type

typedef to acces underlying container

Constructor & Destructor Documentation

MPI_Vector() [1/3]

template<class container >

dg::MPI_Vector< container >::MPI_Vector ( )

inline

no data is allocated, communicators are MPI_COMM_NULL

MPI_Vector() [2/3]

template<class container >

dg::MPI_Vector< container >::MPI_Vector ( const container &  data, MPI_Comm  comm  )

inline

construct a vector

calls dg::exblas::mpi_reduce_communicator() (collective call)

Parameters

data	internal data copy
comm	MPI communicator (may not be MPI_COMM_NULL)

MPI_Vector() [3/3]

template<class container >

template<class OtherContainer >

dg::MPI_Vector< container >::MPI_Vector ( const MPI_Vector< OtherContainer > &  src )

inline

Conversion operator.

uses conversion between compatible containers

Template Parameters

OtherContainer

another container class (container must be copy constructible from OtherContainer)

Parameters

src	the source

Member Function Documentation

communicator()

template<class container >

MPI_Comm dg::MPI_Vector< container >::communicator ( ) const

inline

Get the communicator to which this vector belongs.

Returns

read access to MPI communicator

communicator_mod()

template<class container >

MPI_Comm dg::MPI_Vector< container >::communicator_mod ( ) const

inline

Returns a communicator of fixed size 128.

communicator_mod_reduce()

template<class container >

MPI_Comm dg::MPI_Vector< container >::communicator_mod_reduce ( ) const

inline

Returns a communicator consisting of all processes with rank 0 in communicator_mod()

Returns

returns MPI_COMM_NULL to processes not part of that group

data() [1/2]

template<class container >

container & dg::MPI_Vector< container >::data ( )

inline

Set underlying data.

Returns

write access to data

data() [2/2]

template<class container >

const container & dg::MPI_Vector< container >::data ( ) const

inline

Get underlying data.

Returns

read access to data

set_communicator()

template<class container >

void dg::MPI_Vector< container >::set_communicator ( MPI_Comm  comm, MPI_Comm  comm_mod, MPI_Comm  comm_mod_reduce  )

inline

Set the communicators with dg::exblas::mpi_reduce_communicator.

The reason why you can't just set the comm and need three parameters is that generating communicators involves communication, which you might want to avoid when you do it many times. So you have to call the function as

MPI_Comm comm = MPI_COMM_WORLD, comm_mod, comm_mod_reduce;
dg::exblas::mpi_reduce_communicator( comm, &comm_mod, &comm_mod_reduce);
mpi_vector.set_communicator( comm, comm_mod, comm_mod_reduce);

size()

template<class container >

unsigned dg::MPI_Vector< container >::size ( ) const

inline

Return the size of the data object.

Returns

data.size()

swap()

template<class container >

void dg::MPI_Vector< container >::swap ( MPI_Vector< container > &  src )

inline

Swap data and communicator.

Parameters

src	communicator and data is swapped

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

• backend/mpi_vector.h