Reference documentation for deal.II version GIT dad323def1 2022-06-25 19:00:02+00:00
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Classes | Public Types | Public Member Functions | Static Public Member Functions | Private Types | Static Private Member Functions | Private Attributes | Static Private Attributes | List of all members
GrowingVectorMemory< VectorType > Class Template Referenceabstract

#include <deal.II/lac/vector_memory.h>

Inheritance diagram for GrowingVectorMemory< VectorType >:
[legend]

Classes

struct  Pool
 

Public Types

using size_type = types::global_dof_index
 

Public Member Functions

 GrowingVectorMemory (const size_type initial_size=0, const bool log_statistics=false)
 
virtual ~GrowingVectorMemory () override
 
virtual VectorType * alloc () override
 
virtual void free (const VectorType *const) override
 
virtual std::size_t memory_consumption () const
 
virtual void free (const ::Vector< double > *const)=0
 

Static Public Member Functions

static void release_unused_memory ()
 
static ::ExceptionBaseExcNotAllocatedHere ()
 

Private Types

using entry_type = std::pair< bool, std::unique_ptr< VectorType > >
 

Static Private Member Functions

static Poolget_pool ()
 

Private Attributes

size_type total_alloc
 
size_type current_alloc
 
bool log_statistics
 

Static Private Attributes

static Threads::Mutex mutex
 

Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

using map_value_type = decltype(counter_map)::value_type
 
using map_iterator = decltype(counter_map)::iterator
 
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
 
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
 
template<class Archive >
void serialize (Archive &ar, const unsigned int version)
 
static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 
void check_no_subscribers () const noexcept
 

Detailed Description

template<typename VectorType = ::Vector<double>>
class GrowingVectorMemory< VectorType >

A pool based memory management class. See the documentation of the base class for a description of its purpose.

Each time a vector is requested from this class, it checks if it has one available and returns its address, or allocates a new one on the heap. If a vector is returned from its user, through the GrowingVectorMemory::free() member function, it doesn't return the allocated memory to the operating system memory subsystem, but keeps it around unused for later use if GrowingVectorMemory::alloc() is called again. The class therefore avoid the overhead of repeatedly allocating memory on the heap if temporary vectors are required and released frequently; on the other hand, it doesn't release once-allocated memory at the earliest possible time and may therefore lead to an increased overall memory consumption.

All GrowingVectorMemory objects of the same vector type use the same memory pool. (In other words: The pool of vectors from which this class draws is global, rather than a regular member variable of the current class that is destroyed at the time that the surrounding GrowingVectorMemory object is destroyed.) Therefore, functions can create such a GrowingVectorMemory object whenever needed without the performance penalty of creating a new memory pool every time. A drawback of this policy is that vectors once allocated are only released at the end of the program run.

Definition at line 313 of file vector_memory.h.

Member Function Documentation

◆ free()

virtual void VectorMemory< ::Vector< double > >::free ( const ::Vector< double > * const  )
pure virtualinherited

Return a vector and indicate that it is not going to be used any further by the place that called alloc() to get a pointer to it.

Warning
Just like using new and delete explicitly in code invites bugs where memory is leaked (either because the corresponding delete is forgotten altogether, or because of exception safety issues), using the alloc() and free() functions explicitly invites writing code that accidentally leaks memory. You should consider using the VectorMemory::Pointer class instead, which provides the same kind of service that std::unique provides for arbitrary memory allocated on the heap.

◆ ExcNotAllocatedHere()

static ::ExceptionBase& VectorMemory< ::Vector< double > >::ExcNotAllocatedHere ( )
staticinherited

Vector was not allocated from this memory pool.

Note
The message that will be printed by this exception reads:
"You are trying to deallocate a vector from a memory pool, but this " "vector has not actually been allocated by the same pool before."

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