MGLevelObject< Object > Class Template Reference

#include <deal.II/base/mg_level_object.h>

Inheritance diagram for MGLevelObject< Object >:

Public Member Functions
template<class... Args>
	MGLevelObject (const unsigned int minlevel, const unsigned int maxlevel, Args &&...args)
	MGLevelObject (const unsigned int minlevel=0, const unsigned int maxlevel=0)
Object &	operator[] (const unsigned int level)
const Object &	operator[] (const unsigned int level) const
const Object &	back () const
template<class... Args>
void	resize (const unsigned int new_minlevel, const unsigned int new_maxlevel, Args &&...args)
MGLevelObject< Object > &	operator= (const double d)
void	clear ()
void	clear_elements ()
unsigned int	min_level () const
unsigned int	max_level () const
unsigned int	n_levels () const
template<typename ActionFunctionObjectType >
void	apply (ActionFunctionObjectType action)
std::size_t	memory_consumption () const
template<class Archive >
void	serialize (Archive &ar, const unsigned int version)
Subscriptor functionality
Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.
void	subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
void	unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
unsigned int	n_subscriptions () const
template<typename StreamType >
void	list_subscribers (StreamType &stream) const
void	list_subscribers () const

Static Public Member Functions
static ::ExceptionBase &	ExcInUse (int arg1, std::string arg2, std::string arg3)
static ::ExceptionBase &	ExcNoSubscriber (std::string arg1, std::string arg2)

Private Types
using	map_value_type = decltype(counter_map)::value_type
using	map_iterator = decltype(counter_map)::iterator

Private Member Functions
void	check_no_subscribers () const noexcept

Private Attributes
unsigned int	minlevel
std::vector< std::shared_ptr< Object > >	objects
std::atomic< unsigned int >	counter
std::map< std::string, unsigned int >	counter_map
std::vector< std::atomic< bool > * >	validity_pointers
const std::type_info *	object_info

Static Private Attributes
static std::mutex	mutex

Detailed Description

template<class Object>
class MGLevelObject< Object >

This class represents an array with one object for each used level of a multilevel hierarchy, for example for use in the multigrid algorithms. In contrast to just a generic std::vector, this class allows to store objects only between some minimal and maximal index (=level), as one often wants to run a multilevel algorithm only on a subset of the levels of a mesh (e.g., because the second or third coarsest level is already small enough that it is cheaper to run a direct solver there, rather than recurse to even coarser levels). Despite storing objects only for these "interesting" levels, the class allows indexing simply by level. Internally, this is of course done by simply shifting the given index by the minimum level we have stored.

In a typical use case for this class, the objects stored on each level are either matrices or vectors.

Definition at line 48 of file mg_level_object.h.

Member Typedef Documentation

map_value_type

using Subscriptor::map_value_type = decltype(counter_map)::value_type

privateinherited

The data type used in counter_map.

Definition at line 229 of file subscriptor.h.

map_iterator

using Subscriptor::map_iterator = decltype(counter_map)::iterator

privateinherited

The iterator type used in counter_map.

Definition at line 234 of file subscriptor.h.

Constructor & Destructor Documentation

MGLevelObject() [1/2]

template<class Object >

template<class... Args>

MGLevelObject< Object >::MGLevelObject	(	const unsigned int	minlevel,
		const unsigned int	maxlevel,
		Args &&...	args )

Constructor. Create a multilevel object with given minimal and maximal level, and allocate storage for objects on maxlevel-minlevel+1 levels.

Note

Unlike in many other places of the library, the two arguments here do not denote the first level and last-plus-one level, but indeed an inclusive range of levels for which to allocate storage for level objects. Consequently, the defaults for the two arguments will create an array with one level object, rather than an empty array.

Parameters

[in]	minlevel	The lowest level for which to provision memory for level objects.
[in]	maxlevel	The highest level for which to provision memory for level objects.
[in]	args	Optional arguments passed to the constructor of the underlying object.

Precondition

minlevel <= maxlevel

Definition at line 207 of file mg_level_object.h.

MGLevelObject() [2/2]

template<class Object >

MGLevelObject< Object >::MGLevelObject	(	const unsigned int	minlevel = 0,
		const unsigned int	maxlevel = 0 )

Constructor. Same as above but without arguments to be forwarded to the constructor of the underlying object.

Definition at line 217 of file mg_level_object.h.

Member Function Documentation

operator[]() [1/2]

template<class Object >

Object & MGLevelObject< Object >::operator[]

(

const unsigned int

level

)

Access object on level level.

Definition at line 227 of file mg_level_object.h.

operator[]() [2/2]

template<class Object >

const Object & MGLevelObject< Object >::operator[]

(

const unsigned int

level

)

const

Access object on level level.

This function can be called on a const object, and consequently returns a const reference.

Definition at line 237 of file mg_level_object.h.

back()

template<class Object >

const Object & MGLevelObject< Object >::back

(

)

const

Return object on level max.

Definition at line 247 of file mg_level_object.h.

resize()

template<class Object >

template<class... Args>

void MGLevelObject< Object >::resize	(	const unsigned int	new_minlevel,
		const unsigned int	new_maxlevel,
		Args &&...	args )

Delete all previous contents of this object and reset its size according to the values of new_minlevel and new_maxlevel.

Parameters

[in]	new_minlevel	The lowest level for which to provision memory for level objects.
[in]	new_maxlevel	The highest level for which to provision memory for level objects.
[in]	args	Optional arguments passed to the constructor of the underlying object.

Precondition

minlevel <= maxlevel

Definition at line 256 of file mg_level_object.h.

operator=()

template<class Object >

MGLevelObject< Object > & MGLevelObject< Object >::operator=

(

const double

d

)

Call operator = (s) on all objects stored by this object. This clearly requires that the objects stored on each level allow for this operation. This is, in particular, true for vectors and matrices if d is zero, thereby zeroing out all vector or matrix entries.

Definition at line 275 of file mg_level_object.h.

clear()

template<class Object >

void MGLevelObject< Object >::clear

(

)

Clear all data fields and brings the class into a condition similar to after having called the default constructor.

Definition at line 286 of file mg_level_object.h.

clear_elements()

template<class Object >

void MGLevelObject< Object >::clear_elements

(

)

Call clear on all objects stored by this object. This function is only implemented for some Object classes, e.g., matrix types or the PreconditionBlockSOR and similar classes. Using this function will fail with a compiler error if the Object template type to this class does not provide a clear() member function.

Definition at line 295 of file mg_level_object.h.

min_level()

template<class Object >

unsigned int MGLevelObject< Object >::min_level

(

)

const

The coarsest level for which this class stores a level object.

Definition at line 305 of file mg_level_object.h.

max_level()

template<class Object >

unsigned int MGLevelObject< Object >::max_level

(

)

const

The highest level for which this class stores a level object.

Definition at line 313 of file mg_level_object.h.

n_levels()

template<class Object >

unsigned int MGLevelObject< Object >::n_levels

(

)

const

Number of levels, i.e., max_level()-min_level()+1.

Definition at line 321 of file mg_level_object.h.

apply()

template<class Object >

template<typename ActionFunctionObjectType >

void MGLevelObject< Object >::apply

(

ActionFunctionObjectType

action

)

Apply the action action to every object stored in here. The parameter action is expected to be a function object that accepts the syntax action(const unsigned int level, Object &object); This means this function can accept a lambda, a std::function, or a plain function pointer.

Definition at line 329 of file mg_level_object.h.

memory_consumption()

template<class Object >

std::size_t MGLevelObject< Object >::memory_consumption

(

)

const

Memory used by this object.

Definition at line 340 of file mg_level_object.h.

subscribe()

void Subscriptor::subscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const

inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 135 of file subscriptor.cc.

unsubscribe()

void Subscriptor::unsubscribe ( std::atomic< bool > *const validity, const std::string & identifier = "" ) const

inherited

Unsubscribes a user from the object.

Note

The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 155 of file subscriptor.cc.

n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const

inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 300 of file subscriptor.h.

list_subscribers() [1/2]

template<typename StreamType >

void Subscriptor::list_subscribers ( StreamType & stream ) const

inlineinherited

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const

inherited

List the subscribers to deallog.

Definition at line 203 of file subscriptor.cc.

serialize()

template<class Archive >

void Subscriptor::serialize ( Archive & ar, const unsigned int version )

inlineinherited

Read or write the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

This function does not actually serialize any of the member variables of this class. The reason is that what this class stores is only who subscribes to this object, but who does so at the time of storing the contents of this object does not necessarily have anything to do with who subscribes to the object when it is restored. Consequently, we do not want to overwrite the subscribers at the time of restoring, and then there is no reason to write the subscribers out in the first place.

Definition at line 309 of file subscriptor.h.

check_no_subscribers()

void Subscriptor::check_no_subscribers ( ) const

privatenoexceptinherited

Check that there are no objects subscribing to this object. If this check passes then it is safe to destroy the current object. It this check fails then this function will either abort or print an error message to deallog (by using the AssertNothrow mechanism), but will not throw an exception.

Note

Since this function is just a consistency check it does nothing in release mode.

If this function is called when there is an uncaught exception then, rather than aborting, this function prints an error message to the standard error stream and returns.

Definition at line 52 of file subscriptor.cc.

Member Data Documentation

minlevel

template<class Object >

unsigned int MGLevelObject< Object >::minlevel

private

Level of first component.

Definition at line 193 of file mg_level_object.h.

objects

template<class Object >

std::vector<std::shared_ptr<Object> > MGLevelObject< Object >::objects

private

Array of the objects to be held.

Definition at line 198 of file mg_level_object.h.

counter

std::atomic<unsigned int> Subscriptor::counter

mutableprivateinherited

Store the number of objects which subscribed to this object. Initially, this number is zero, and upon destruction it shall be zero again (i.e. all objects which subscribed should have unsubscribed again).

The creator (and owner) of an object is counted in the map below if HE manages to supply identification.

We use the mutable keyword in order to allow subscription to constant objects also.

This counter may be read from and written to concurrently in multithreaded code: hence we use the std::atomic class template.

Definition at line 218 of file subscriptor.h.

counter_map

std::map<std::string, unsigned int> Subscriptor::counter_map

mutableprivateinherited

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 224 of file subscriptor.h.

validity_pointers

std::vector<std::atomic<bool> *> Subscriptor::validity_pointers

mutableprivateinherited

In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.

Definition at line 240 of file subscriptor.h.

object_info

const std::type_info* Subscriptor::object_info

mutableprivateinherited

Pointer to the typeinfo object of this object, from which we can later deduce the class name. Since this information on the derived class is neither available in the destructor, nor in the constructor, we obtain it in between and store it here.

Definition at line 248 of file subscriptor.h.

mutex

std::mutex Subscriptor::mutex

staticprivateinherited

A mutex used to ensure data consistency when accessing the mutable members of this class. This lock is used in the subscribe() and unsubscribe() functions, as well as in list_subscribers().

Definition at line 271 of file subscriptor.h.

---

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

• include/deal.II/base/mg_level_object.h