Scatter and Gather

Collaboration diagram for Scatter and Gather:

Typedefs
template<class MPIContainer >
using	dg::get_mpi_view_type

Functions
template<class real_type , class MPITopology >
MPI_Vector< thrust::host_vector< real_type > >	dg::global2local (const thrust::host_vector< real_type > &global, const MPITopology &g)
	Take the relevant local part of a global vector.
template<class real_type , size_t Nd>
dg::IHMatrix_t< real_type >	dg::create::backproject (const aRealTopology< real_type, Nd > &g)
	Create a matrix \( PI\) that projects values to an equidistant grid.
template<class real_type , size_t Nd>
dg::IHMatrix_t< real_type >	dg::create::inv_backproject (const aRealTopology< real_type, Nd > &g)
	Create a matrix \( (PI)^{-1}\) that transforms values from an equidistant grid back to a dg grid.
template<class SharedContainer , class real_type >
void	dg::split (SharedContainer &in, std::vector< View< SharedContainer > > &out, const aRealTopology3d< real_type > &grid)
	Split a vector into planes along the last dimension (fast version)
template<class SharedContainer , class real_type >
std::vector< View< SharedContainer > >	dg::split (SharedContainer &in, const aRealTopology3d< real_type > &grid)
	Split a vector into planes along the last dimension (construct version)
template<class Container , class host_vector , class Topology >
void	dg::assign3dfrom2d (const host_vector &in2d, Container &out, const Topology &grid)
	Construct a 3d vector given a 2d host vector.
template<class MPIContainer , class real_type >
void	dg::split (MPIContainer &in, std::vector< get_mpi_view_type< MPIContainer > > &out, const aRealMPITopology3d< real_type > &grid)
	MPI Version of split (fast version)
template<class MPIContainer , class real_type >
std::vector< get_mpi_view_type< MPIContainer > >	dg::split (MPIContainer &in, const aRealMPITopology3d< real_type > &grid)
	MPI Version of split (construct version)
template<class real_type >
dg::IHMatrix_t< real_type >	dg::create::backscatter (const RealGrid1d< real_type > &g)
	Create a matrix \( B_{eq} F\) that interpolates values to an equidistant grid ready for visualisation.
template<class real_type >
dg::IHMatrix_t< real_type >	dg::create::backscatter (const aRealTopology2d< real_type > &g)
	Create a matrix \( B_{eq} F\) that interpolates values to an equidistant grid ready for visualisation.
template<class real_type >
dg::IHMatrix_t< real_type >	dg::create::backscatter (const aRealTopology3d< real_type > &g)
	Create a matrix \( B_{eq} F\) that interpolates values to an equidistant grid ready for visualisation.
template<class real_type >
dg::IHMatrix_t< real_type >	dg::create::inv_backscatter (const RealGrid1d< real_type > &g)
	Create a matrix \( (B_{eq} F)^{-1}\) that transforms values from an equidistant grid back to a dg grid.
template<class real_type >
dg::IHMatrix_t< real_type >	dg::create::inv_backscatter (const aRealTopology2d< real_type > &g)
	Create a matrix \( (B_{eq} F)^{-1}\) that transforms values from an equidistant grid back to a dg grid.
template<class real_type >
dg::IHMatrix_t< real_type >	dg::create::inv_backscatter (const aRealTopology3d< real_type > &g)
	Create a matrix \( (B_{eq} F)^{-1}\) that transforms values from an equidistant grid back to a dg grid.

Detailed Description

Typedef Documentation

get_mpi_view_type

template<class MPIContainer >

using dg::get_mpi_view_type

Initial value:

 
    std::conditional_t< std::is_const<MPIContainer>::value,
    MPI_Vector<View<const typename MPIContainer::container_type>>,
    MPI_Vector<View<typename MPIContainer::container_type>> >

Function Documentation

assign3dfrom2d()

template<class Container , class host_vector , class Topology >

void dg::assign3dfrom2d	(	const host_vector &	in2d,
		Container &	out,
		const Topology &	grid )

Construct a 3d vector given a 2d host vector.

A shortcut for

out = dg::construct<Container>(dg::kronecker ( dg::cooX2d, in2d, grid.abscissas(2)));

Parameters

in2d	the 2d input
out	output (memory will be allocated)
grid	provide dimensions in 3rd and first two dimensions

backproject()

template<class real_type , size_t Nd>

dg::IHMatrix_t< real_type > dg::create::backproject

(

const aRealTopology< real_type, Nd > &

g

)

Create a matrix \( PI\) that projects values to an equidistant grid.

Same as dg::create::transformation( g_equidist, g)

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::backscatter, dg::create::transformation

backscatter() [1/3]

template<class real_type >

dg::IHMatrix_t< real_type > dg::create::backscatter

(

const aRealTopology2d< real_type > &

g

)

Create a matrix \( B_{eq} F\) that interpolates values to an equidistant grid ready for visualisation.

Useful if you want to visualize a dg-formatted vector.

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::backproject

backscatter() [2/3]

template<class real_type >

dg::IHMatrix_t< real_type > dg::create::backscatter

(

const aRealTopology3d< real_type > &

g

)

Create a matrix \( B_{eq} F\) that interpolates values to an equidistant grid ready for visualisation.

Useful if you want to visualize a dg-formatted vector.

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::backproject

backscatter() [3/3]

template<class real_type >

dg::IHMatrix_t< real_type > dg::create::backscatter

(

const RealGrid1d< real_type > &

g

)

Create a matrix \( B_{eq} F\) that interpolates values to an equidistant grid ready for visualisation.

Useful if you want to visualize a dg-formatted vector.

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::backproject

global2local()

template<class real_type , class MPITopology >

MPI_Vector< thrust::host_vector< real_type > > dg::global2local	(	const thrust::host_vector< real_type > &	global,
		const MPITopology &	g )

Take the relevant local part of a global vector.

Parameters

global	a vector the size of the global grid
g	the assumed topology

Returns

an MPI_Vector that is the distributed version of the global vector

inv_backproject()

template<class real_type , size_t Nd>

dg::IHMatrix_t< real_type > dg::create::inv_backproject

(

const aRealTopology< real_type, Nd > &

g

)

Create a matrix \( (PI)^{-1}\) that transforms values from an equidistant grid back to a dg grid.

Same as dg::create::transformation( g, g_equidist)

Note

The inverse of the backproject matrix is not its adjoint!

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::inv_backscatter dg::create::backproject

inv_backscatter() [1/3]

template<class real_type >

dg::IHMatrix_t< real_type > dg::create::inv_backscatter

(

const aRealTopology2d< real_type > &

g

)

Create a matrix \( (B_{eq} F)^{-1}\) that transforms values from an equidistant grid back to a dg grid.

The inverse of dg::create::backscatter

Note

The inverse of the backscatter matrix is not its adjoint! The adjoint \( (B_{eq}F)^\dagger\) is the matrix that computes the (inexact) projection integral on an equidistant grid.

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::inv_backproject dg::create::backscatter

inv_backscatter() [2/3]

template<class real_type >

dg::IHMatrix_t< real_type > dg::create::inv_backscatter

(

const aRealTopology3d< real_type > &

g

)

Create a matrix \( (B_{eq} F)^{-1}\) that transforms values from an equidistant grid back to a dg grid.

The inverse of dg::create::backscatter

Note

The inverse of the backscatter matrix is not its adjoint! The adjoint \( (B_{eq}F)^\dagger\) is the matrix that computes the (inexact) projection integral on an equidistant grid.

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::inv_backproject dg::create::backscatter

inv_backscatter() [3/3]

template<class real_type >

dg::IHMatrix_t< real_type > dg::create::inv_backscatter

(

const RealGrid1d< real_type > &

g

)

Create a matrix \( (B_{eq} F)^{-1}\) that transforms values from an equidistant grid back to a dg grid.

The inverse of dg::create::backscatter

Note

The inverse of the backscatter matrix is not its adjoint! The adjoint \( (B_{eq}F)^\dagger\) is the matrix that computes the (inexact) projection integral on an equidistant grid.

Parameters

g	The grid on which to operate

Returns

transformation matrix (block diagonal)

See also

dg::create::inv_backproject dg::create::backscatter

split() [1/4]

template<class MPIContainer , class real_type >

std::vector< get_mpi_view_type< MPIContainer > > dg::split	(	MPIContainer &	in,
		const aRealMPITopology3d< real_type > &	grid )

MPI Version of split (construct version)

may take longer due to the many calls to MPI group creation functions

Parameters

in	contiguous 3d vector (must be of size grid.size())
grid	provide dimensions in 3rd and first two dimensions

Returns

out contains grid.nz()*grid.Nz() 2d vector views of 2d size on output

Note

two seperately split vectors have congruent (not identical) MPI_Communicators Note here the MPI concept of congruent (same process group, different contexts) vs. identical (same process group, same context) communicators.

Template Parameters

MPIContainer

An MPI_Vector of a SharedContainer

split() [2/4]

template<class MPIContainer , class real_type >

void dg::split	(	MPIContainer &	in,
		std::vector< get_mpi_view_type< MPIContainer > > &	out,
		const aRealMPITopology3d< real_type > &	grid )

MPI Version of split (fast version)

Note

every plane in out must hold a 2d Cartesian MPI_Communicator congruent (same process group) or ident (same process group, same context) with the communicator in grid

Attention

This version will NOT adapt the communicators in out

out will NOT be resized

Parameters

in	contiguous 3d vector (must be of size grid.size())
out	contains grid.nz()*grid.Nz() 2d vector views of 2d size on output
grid	provide dimensions in 3rd and first two dimensions

Template Parameters

MPIContainer

An MPI_Vector of a SharedContainer

split() [3/4]

template<class SharedContainer , class real_type >

std::vector< View< SharedContainer > > dg::split	(	SharedContainer &	in,
		const aRealTopology3d< real_type > &	grid )

Split a vector into planes along the last dimension (construct version)

Parameters

in	contiguous 3d vector (must be of size grid.size())
grid	provide dimensions in 3rd and first two dimensions

Returns

out contains grid.nz()*grid.Nz() 2d vector views of 2d size on output

Template Parameters

SharedContainer

TensorTraits exists for this class and the tensor_category derives from SharedVectorTag

split() [4/4]

template<class SharedContainer , class real_type >

void dg::split	(	SharedContainer &	in,
		std::vector< View< SharedContainer > > &	out,
		const aRealTopology3d< real_type > &	grid )

Split a vector into planes along the last dimension (fast version)

Parameters

in	contiguous 3d vector (must be of size grid.size())
out	contains grid.nz()*grid.Nz() 2d vector views of 2d size on output
grid	provide dimensions in 3rd and first two dimensions

Attention

out will NOT be resized

Template Parameters

SharedContainer

TensorTraits exists for this class and the tensor_category derives from SharedVectorTag