molpro::linalg::array::util::BufferManager< T > Class Template Reference

BufferManager provides single-buffered or asynchronous double-buffered read access to the data in a collection of DistrArray objects. At construction, an amount of memory is allocated as a buffer, and the buffer is divided into one or more chunks that are independent windows on the data. Sequential access to the data is provided through iterators. More...

#include <BufferManager.h>

Detailed Description

template<class T>
class molpro::linalg::array::util::BufferManager< T >

BufferManager provides single-buffered or asynchronous double-buffered read access to the data in a collection of DistrArray objects. At construction, an amount of memory is allocated as a buffer, and the buffer is divided into one or more chunks that are independent windows on the data. Sequential access to the data is provided through iterators.

Template Parameters

T	a class that inherits from DistrArray

Classes
struct	Iterator
	Custom iterator for the BufferManager. This iterator is responsible for loading data into the buffers and providing access to that data. More...

Public Member Functions
	BufferManager (const CVecRef &arrays, size_t buffer_size=8192, int number_of_buffers=2)
	Construct a new Buffer Manager object and allocate memory for the chunks. More...
	BufferManager (const std::vector< T > &arrays, size_t buffer_size=8192, int number_of_buffers=2)
	BufferManager (const T &array, size_t buffer_size=8192, int number_of_buffers=2)
size_t	buffer_size () const
size_t	buffer_stride () const
size_t	buffer_offset () const
Iterator	begin ()
Iterator	end ()

Protected Types
using	value_type = typename T::value_type

Protected Member Functions
Span< value_type >	next (bool initial=false)
	Move to the next segment of the arrays and complete loading of the buffer. More...

Protected Attributes
const CVecRef &	m_arrays
const size_t	m_buffer_size = 8192
const int	m_number_of_buffers = 2
size_t	m_current_buffer_size
size_t	m_current_segment = 0
const std::pair< size_t, size_t >	m_range
std::vector< typename T::value_type >	m_buffer
std::future< void >	m_read_future

Member Typedef Documentation

value_type

template<class T >

using molpro::linalg::array::util::BufferManager< T >::value_type = typename T::value_type

protected

Constructor & Destructor Documentation

BufferManager() [1/3]

template<class T >

molpro::linalg::array::util::BufferManager< T >::BufferManager ( const CVecRef &  arrays, size_t  buffer_size = 8192, int  number_of_buffers = 2  )

inline

Construct a new Buffer Manager object and allocate memory for the chunks.

Parameters

arrays	the DistrArray objects that this BufferManager will access data from. They must have the same distribution.
buffer_size	number of array elements in each chunk.
number_of_buffers	how many buffers.

BufferManager() [2/3]

template<class T >

molpro::linalg::array::util::BufferManager< T >::BufferManager ( const std::vector< T > &  arrays, size_t  buffer_size = 8192, int  number_of_buffers = 2  )

inline

BufferManager() [3/3]

template<class T >

molpro::linalg::array::util::BufferManager< T >::BufferManager ( const T &  array, size_t  buffer_size = 8192, int  number_of_buffers = 2  )

inline

Member Function Documentation

begin()

template<class T >

Iterator molpro::linalg::array::util::BufferManager< T >::begin ( )

inline

buffer_offset()

template<class T >

size_t molpro::linalg::array::util::BufferManager< T >::buffer_offset ( ) const

inline

Offset of the current buffer

Returns

buffer_size()

template<class T >

size_t molpro::linalg::array::util::BufferManager< T >::buffer_size ( ) const

inline

The current buffer size

Returns

buffer_stride()

template<class T >

size_t molpro::linalg::array::util::BufferManager< T >::buffer_stride ( ) const

inline

The distance between buffers

Returns

end()

template<class T >

Iterator molpro::linalg::array::util::BufferManager< T >::end ( )

inline

next()

template<class T >

Span< value_type > molpro::linalg::array::util::BufferManager< T >::next ( bool  initial = false )

inlineprotected

Move to the next segment of the arrays and complete loading of the buffer.

Parameters

initial

whether this is the first iteration

Returns

the buffer contents for the new segment

Member Data Documentation

m_arrays

template<class T >

const CVecRef& molpro::linalg::array::util::BufferManager< T >::m_arrays

protected

m_buffer

template<class T >

std::vector<typename T::value_type> molpro::linalg::array::util::BufferManager< T >::m_buffer

protected

m_buffer_size

template<class T >

const size_t molpro::linalg::array::util::BufferManager< T >::m_buffer_size = 8192

protected

m_current_buffer_size

template<class T >

size_t molpro::linalg::array::util::BufferManager< T >::m_current_buffer_size

protected

m_current_segment

template<class T >

size_t molpro::linalg::array::util::BufferManager< T >::m_current_segment = 0

protected

m_number_of_buffers

template<class T >

const int molpro::linalg::array::util::BufferManager< T >::m_number_of_buffers = 2

protected

m_range

template<class T >

const std::pair<size_t, size_t> molpro::linalg::array::util::BufferManager< T >::m_range

protected

m_read_future

template<class T >

std::future<void> molpro::linalg::array::util::BufferManager< T >::m_read_future

protected