dg::View< ThrustVector > Struct Template Reference

A vector view class, usable in dg functions. More...

Public Types
using	pointer
using	const_pointer = typename ThrustVector::const_pointer
using	iterator = pointer
using	const_iterator = const_pointer

Public Member Functions
	View (void)
	Initialize empty view.
template<class OtherView >
	View (OtherView &src)
	Construct from another View or Vector.
template<class InputIterator >
	View (InputIterator data, unsigned size)
	Construct view from pointer and size.
template<class InputIterator >
void	construct (InputIterator data, unsigned size)
	Construct view from pointer and size.
pointer	data () const
	Constant Reference of the pointer.
iterator	begin () const
	Iterator to the beginning.
const_iterator	cbegin () const
	const Iterator to the beginning
iterator	end () const
	Iterator to the end.
const_iterator	cend () const
	const Iterator to the end
unsigned	size () const
	Get the size.
void	swap (View &src)
	Swap pointer and size with another View.

Detailed Description

template<class ThrustVector>
struct dg::View< ThrustVector >

A vector view class, usable in dg functions.

The view class holds a pointer and a size. It does not own the pointer. The user is responsible for allocating and deallocating memory. The intention is to use Views in dg::blas1 functions.

The class can be used as a traditional "view" in the sense that it can view part of a larger contiguous chunk of data and thus apply operations to only part of that data. The second use would be to imitate for example a full dg::DVec without allocating or copying memory for it. This might be useful if you want to use the dg::blas1 functions without specializing TensorTraits for your own vector class or deep copying data, like the following example demonstrates:

SomeDeviceVectorClass vector( 1e6, 20.); //vector of size 1e6, all elements equal 20
 
//create a view of a device vector to enable parallel execution
dg::View<dg::DVec> view( vector.data(), vector.size());
 
dg::blas1::copy( 7., view); //elements of vector now equal 7 instead of 20

Attention

when constructing a View from a pointer the user also promises that the pointer can be dereferenced on the device the View acts on.

Note

Cannot be used as a target to in dg::construct or dg::assign but can be used as the source from

You cannot have a View of an MPI_Vector but you can have an MPI_Vector of View

Template Parameters

ThrustVector

TensorTraits exists for this class and the tensor_category derives from ThrustVectorTag

See also

dg::split

Member Typedef Documentation

const_iterator

template<class ThrustVector >

using dg::View< ThrustVector >::const_iterator = const_pointer

const_pointer

template<class ThrustVector >

using dg::View< ThrustVector >::const_pointer = typename ThrustVector::const_pointer

iterator

template<class ThrustVector >

using dg::View< ThrustVector >::iterator = pointer

pointer

template<class ThrustVector >

using dg::View< ThrustVector >::pointer

Initial value:

 std::conditional_t<std::is_const<ThrustVector>::value,
          typename ThrustVector::const_pointer,
          typename ThrustVector::pointer>

Constructor & Destructor Documentation

View() [1/3]

template<class ThrustVector >

dg::View< ThrustVector >::View ( void )

inline

Initialize empty view.

View() [2/3]

template<class ThrustVector >

template<class OtherView >

dg::View< ThrustVector >::View ( OtherView< ThrustVector > & src )

inline

Construct from another View or Vector.

The pointer types must be compatible

Template Parameters

OtherView

Must provide members: data() and size()

Parameters

src	Initialize from src.data() and src.size()

View() [3/3]

template<class ThrustVector >

template<class InputIterator >

dg::View< ThrustVector >::View ( InputIterator data, unsigned size )

inline

Construct view from pointer and size.

Parameters

data	the beginning of the contiguous chunk of data
size	the number of elements in the contiguous chunk of data

Template Parameters

InputIterator

pointer must be constructible from this type

Attention

when constructing a View from a pointer the user also promises that the pointer can be dereferenced on the device the View acts on.

Member Function Documentation

begin()

template<class ThrustVector >

iterator dg::View< ThrustVector >::begin ( ) const

inline

Iterator to the beginning.

Returns

iterator to the first element

cbegin()

template<class ThrustVector >

const_iterator dg::View< ThrustVector >::cbegin ( ) const

inline

const Iterator to the beginning

Returns

iterator to the first element

cend()

template<class ThrustVector >

const_iterator dg::View< ThrustVector >::cend ( ) const

inline

const Iterator to the end

Returns

iterator to the end

construct()

template<class ThrustVector >

template<class InputIterator >

void dg::View< ThrustVector >::construct ( InputIterator data, unsigned size )

inline

Construct view from pointer and size.

Parameters

data	the beginning of the contiguous chunk of data
size	the number of elements in the contiguous chunk of data

Template Parameters

InputIterator

pointer must be constructible from this type

Attention

when constructing a View from a pointer the user also promises that the pointer can be dereferenced on the device the View acts on.

data()

template<class ThrustVector >

pointer dg::View< ThrustVector >::data ( ) const

inline

Constant Reference of the pointer.

Returns

pointer to first element

end()

template<class ThrustVector >

iterator dg::View< ThrustVector >::end ( ) const

inline

Iterator to the end.

Returns

iterator to the end

size()

template<class ThrustVector >

unsigned dg::View< ThrustVector >::size ( ) const

inline

Get the size.

Returns

number elements in the data view

swap()

template<class ThrustVector >

void dg::View< ThrustVector >::swap ( View< ThrustVector > & src )

inline

Swap pointer and size with another View.

Parameters

src	the source view

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

• backend/view.h