FiniteSizeHistory< T > Class Template Reference

#include <deal.II/numerics/history.h>

Public Member Functions
	FiniteSizeHistory (const std::size_t max_elements=0)
void	add (const T &element)
void	remove (const std::size_t index)
T &	operator[] (const std::size_t index)
const T &	operator[] (const std::size_t index) const
std::size_t	size () const
std::size_t	max_size () const
void	clear ()

Private Attributes
std::size_t	max_n_elements
std::deque< std::unique_ptr< T > >	data
std::deque< std::unique_ptr< T > >	cache

Detailed Description

template<typename T>
class FiniteSizeHistory< T >

A helper class to store a finite-size collection of objects of type T. If the number of elements exceeds the specified maximum size of the container, the oldest element is removed. Additionally, random access and removal of elements is implemented. Indexing is done relative to the last added element.

In order to optimize the container for usage with memory-demanding objects (i.e. linear algebra vectors), the removal of an element does not free the memory. Instead the element is being kept in a separate cache so that subsequent addition does not require re-allocation of memory.

The primary usage of this class is in solvers to store a history of vectors. That is, if at the iteration \(k\) we store \(m\) vectors from previous iterations \(\{k-1,k-2,...,k-m\}\), then addition of the new element will make the object contain elements from iterations \(\{k,k-1,k-2,...,k-m+1\}\).

Author

Denis Davydov, 2018

Definition at line 51 of file history.h.

Constructor & Destructor Documentation

FiniteSizeHistory()

template<typename T >

FiniteSizeHistory< T >::FiniteSizeHistory

(

const std::size_t

max_elements = 0

)

Constructor.

Parameters

max_elements

maximum number of elements to be stored in the history.

Member Function Documentation

add()

template<typename T >

void FiniteSizeHistory< T >::add

(

const T &

element

)

Add new object by copying. If the maximum number of elements is reached, the oldest element is removed.

remove()

template<typename T >

void FiniteSizeHistory< T >::remove

(

const std::size_t

index

)

Remove an element with index index, counting from the last added element. index==0 therefore corresponds to removing the newset element.

operator[]() [1/2]

template<typename T >

T& FiniteSizeHistory< T >::operator[]

(

const std::size_t

index

)

Read/write access to an element with index index, counting from the last added element. index==0 therefore corresponds to the newset element.

operator[]() [2/2]

template<typename T >

const T& FiniteSizeHistory< T >::operator[]

(

const std::size_t

index

)

const

Read access to an element with index index, counting from the last added element. index==0 therefore corresponds to the newset element.

size()

template<typename T >

std::size_t FiniteSizeHistory< T >::size

(

)

const

Return the current size of the history.

max_size()

template<typename T >

std::size_t FiniteSizeHistory< T >::max_size

(

)

const

Return the maximum allowed size of the history.

clear()

template<typename T >

void FiniteSizeHistory< T >::clear

(

)

Clear the contents, including the cache.

Member Data Documentation

max_n_elements

template<typename T >

std::size_t FiniteSizeHistory< T >::max_n_elements

private

Maximum number of elements to be stored.

Definition at line 119 of file history.h.

data

template<typename T >

std::deque<std::unique_ptr<T> > FiniteSizeHistory< T >::data

private

A deque which stores the data.

Definition at line 124 of file history.h.

cache

template<typename T >

std::deque<std::unique_ptr<T> > FiniteSizeHistory< T >::cache

private

A deque to cache data, in particular for the case when removal is followed by addition.

Definition at line 130 of file history.h.

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

• include/deal.II/numerics/history.h