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Reference documentation for deal.II version 9.5.0
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Reference documentation for deal.II version 9.5.0
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#include <deal.II/lac/vector_memory.h>
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 |
| 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 void | release_unused_memory () |
| static ::ExceptionBase & | ExcNotAllocatedHere () |
| static ::ExceptionBase & | ExcInUse (int arg1, std::string arg2, std::string arg3) |
| static ::ExceptionBase & | ExcNoSubscriber (std::string arg1, std::string arg2) |
Private Types | |
| using | entry_type = std::pair< bool, std::unique_ptr< VectorType > > |
| 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 |
Static Private Member Functions | |
| static Pool & | get_pool () |
Private Attributes | |
| size_type | total_alloc |
| size_type | current_alloc |
| bool | log_statistics |
| 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 Threads::Mutex | mutex |
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 315 of file vector_memory.h.
| using GrowingVectorMemory< VectorType >::size_type = types::global_dof_index |
Declare type for container size.
Definition at line 321 of file vector_memory.h.
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private |
A type that describes this entries of an array that represents the vectors stored by this object. The first component of the pair is be a flag telling whether the vector is used, the second a pointer to the vector itself.
Definition at line 398 of file vector_memory.h.
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privateinherited |
The data type used in counter_map.
Definition at line 230 of file subscriptor.h.
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privateinherited |
The iterator type used in counter_map.
Definition at line 235 of file subscriptor.h.
| GrowingVectorMemory< VectorType >::GrowingVectorMemory | ( | const size_type | initial_size = 0, |
| const bool | log_statistics = false |
||
| ) |
Constructor. The argument allows to preallocate a certain number of vectors. The default is not to do this.
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overridevirtual |
Destructor. The destructor also checks that all vectors that have been allocated through the current object have all been released again. However, as discussed in the class documentation, this does not imply that their memory is returned to the operating system.
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overridevirtual |
Return a pointer to a new vector. The number of elements or their subdivision into blocks (if applicable) is unspecified and users of this function should reset vectors to their proper size. The same holds for the contents of vectors: they are unspecified. In other words, the place that calls this function will need to resize or reinitialize it appropriately.
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. Implements VectorMemory< VectorType >.
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overridevirtual |
Return a vector and indicate that it is not going to be used any further by the instance that called alloc() to get a pointer to it.
For the present class, this means retaining the vector for later reuse by the alloc() method.
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. Implements VectorMemory< VectorType >.
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static |
Release all vectors that are not currently in use.
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virtual |
Memory consumed by this class and all currently allocated vectors.
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staticprivate |
Return an array of allocated vectors.
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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 136 of file subscriptor.cc.
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inherited |
Unsubscribes a user from the object.
identifier and the validity pointer must be the same as the one supplied to subscribe(). Definition at line 156 of file subscriptor.cc.
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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.
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inlineinherited |
List the subscribers to the input stream.
Definition at line 317 of file subscriptor.h.
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inherited |
List the subscribers to deallog.
Definition at line 204 of file subscriptor.cc.
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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.
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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.
Definition at line 53 of file subscriptor.cc.
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private |
Overall number of allocations. Only used for bookkeeping and to generate output at the end of an object's lifetime.
Definition at line 441 of file vector_memory.h.
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private |
Number of vectors currently allocated in this object; used for detecting memory leaks.
Definition at line 447 of file vector_memory.h.
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private |
A flag controlling the logging of statistics by the destructor.
Definition at line 452 of file vector_memory.h.
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staticprivate |
Mutex to synchronize access to internal data of this object from multiple threads.
Definition at line 458 of file vector_memory.h.
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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 219 of file subscriptor.h.
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mutableprivateinherited |
In this map, we count subscriptions for each different identification string supplied to subscribe().
Definition at line 225 of file subscriptor.h.
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mutableprivateinherited |
In this vector, we store pointers to the validity bool in the SmartPointer objects that subscribe to this class.
Definition at line 241 of file subscriptor.h.
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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 249 of file subscriptor.h.
1.9.7