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Reference documentation for deal.II version 9.6.0
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#include <deal.II/multigrid/mg_smoother.h>
Public Member Functions | |
MGSmootherRelaxation (const unsigned int steps=1, const bool variable=false, const bool symmetric=false, const bool transpose=false) | |
template<typename MatrixType2 > | |
void | initialize (const MGLevelObject< MatrixType2 > &matrices, const typename RelaxationType::AdditionalData &additional_data=typename RelaxationType::AdditionalData()) |
template<typename MatrixType2 , typename DataType > | |
void | initialize (const MGLevelObject< MatrixType2 > &matrices, const MGLevelObject< DataType > &additional_data) |
template<typename MatrixType2 , typename DataType > | |
void | initialize (const MGLevelObject< MatrixType2 > &matrices, const DataType &additional_data, const unsigned int block_row, const unsigned int block_col) |
template<typename MatrixType2 , typename DataType > | |
void | initialize (const MGLevelObject< MatrixType2 > &matrices, const MGLevelObject< DataType > &additional_data, const unsigned int block_row, const unsigned int block_col) |
void | clear () |
virtual void | smooth (const unsigned int level, VectorType &u, const VectorType &rhs) const |
virtual void | apply (const unsigned int level, VectorType &u, const VectorType &rhs) const |
std::size_t | memory_consumption () const |
void | set_steps (const unsigned int) |
void | set_variable (const bool) |
void | set_symmetric (const bool) |
void | set_transpose (const bool) |
void | set_debug (const unsigned int level) |
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) |
Public Attributes | |
MGLevelObject< RelaxationType > | smoothers |
Protected Attributes | |
GrowingVectorMemory< VectorType > | vector_memory |
unsigned int | steps |
bool | variable |
bool | symmetric |
bool | transpose |
unsigned int | debug |
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 | |
MGLevelObject< LinearOperator< VectorType > > | matrices |
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 |
Smoother using a solver that satisfies the relaxation concept.
This class performs smoothing on each level. The operation can be controlled by several parameters. First, the relaxation parameter omega
is used in the underlying relaxation method. steps
is the number of relaxation steps on the finest level (on all levels if variable
is off). If variable
is true
, the number of smoothing steps is doubled on each coarser level. This results in a method having the complexity of the W-cycle, but saving grid transfers. This is the method proposed by Bramble at al.
The option symmetric
switches on alternating between the smoother and its transpose in each step as proposed by Bramble.
transpose
uses the transposed smoothing operation using Tstep
instead of the regular step
of the relaxation scheme.
If you are using block matrices, the second initialize
function offers the possibility to extract a single block for smoothing. In this case, the multigrid method must be used only with the vector associated to that single block.
The library contains instantiation for SparseMatrix<.>
and Vector<.>
, where the template arguments are all combinations of float
and double
. Additional instantiations may be created by including the file mg_smoother.templates.h.
Definition at line 295 of file mg_smoother.h.
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privateinherited |
The data type used in counter_map.
Definition at line 229 of file subscriptor.h.
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privateinherited |
The iterator type used in counter_map.
Definition at line 234 of file subscriptor.h.
MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >::MGSmootherRelaxation | ( | const unsigned int | steps = 1, |
const bool | variable = false, | ||
const bool | symmetric = false, | ||
const bool | transpose = false ) |
Constructor. Sets smoothing parameters.
void MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >::initialize | ( | const MGLevelObject< MatrixType2 > & | matrices, |
const typename RelaxationType::AdditionalData & | additional_data = typename RelaxationType::AdditionalData() ) |
Initialize for matrices. This function stores pointers to the level matrices and initializes the smoothing operator with the same smoother for each level.
additional_data
is an object of type RelaxationType::AdditionalData
and is handed to the initialization function of the relaxation method.
void MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >::initialize | ( | const MGLevelObject< MatrixType2 > & | matrices, |
const MGLevelObject< DataType > & | additional_data ) |
Initialize for matrices. This function stores pointers to the level matrices and initializes the smoothing operator with the according smoother for each level.
additional_data
is an object of type RelaxationType::AdditionalData
and is handed to the initialization function of the relaxation method.
void MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >::initialize | ( | const MGLevelObject< MatrixType2 > & | matrices, |
const DataType & | additional_data, | ||
const unsigned int | block_row, | ||
const unsigned int | block_col ) |
Initialize for single blocks of matrices. Of this block matrix, the block indicated by block_row
and block_col
is selected on each level. This function stores pointers to the level matrices and initializes the smoothing operator with the same smoother for each level.
additional_data
is an object of type RelaxationType::AdditionalData
and is handed to the initialization function of the relaxation method.
void MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >::initialize | ( | const MGLevelObject< MatrixType2 > & | matrices, |
const MGLevelObject< DataType > & | additional_data, | ||
const unsigned int | block_row, | ||
const unsigned int | block_col ) |
Initialize for single blocks of matrices. Of this block matrix, the block indicated by block_row
and block_col
is selected on each level. This function stores pointers to the level matrices and initializes the smoothing operator with the according smoother for each level.
additional_data
is an object of type RelaxationType::AdditionalData
and is handed to the initialization function of the relaxation method.
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virtual |
Empty all vectors.
Implements MGSmootherBase< VectorType >.
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virtual |
The actual smoothing method.
Implements MGSmootherBase< VectorType >.
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virtual |
The apply variant of smoothing, setting the vector u to zero before calling the smooth function. This function is equivalent to the following code
In the multigrid preconditioner interfaces, the apply() method is used for the pre-smoothing operation because the previous content in the solution vector needs to be overwritten for a new incoming residual. On the other hand, all subsequent operations need to smooth the content already present in the vector u
given the right hand side, which is done by smooth().
Reimplemented from MGSmootherBase< VectorType >.
std::size_t MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >::memory_consumption | ( | ) | const |
Memory used by this object.
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inherited |
Modify the number of smoothing steps on finest level.
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inherited |
Switch on/off variable smoothing.
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inherited |
Switch on/off symmetric smoothing.
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inherited |
Switch on/off transposed smoothing. The effect is overridden by set_symmetric().
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inherited |
Set debug
to a nonzero value to get debug information logged to deallog
. Increase to get more information
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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 135 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 155 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 203 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 52 of file subscriptor.cc.
MGLevelObject<RelaxationType> MGSmootherRelaxation< MatrixType, RelaxationType, VectorType >::smoothers |
Object containing relaxation methods.
Definition at line 398 of file mg_smoother.h.
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private |
Pointer to the matrices.
Definition at line 411 of file mg_smoother.h.
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mutableprotectedinherited |
A memory object to be used for temporary vectors.
The object is marked as mutable since we will need to use it to allocate temporary vectors also in functions that are const.
Definition at line 99 of file mg_smoother.h.
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protectedinherited |
Number of smoothing steps on the finest level. If no variable smoothing is chosen, this is the number of steps on all levels.
Definition at line 105 of file mg_smoother.h.
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protectedinherited |
Variable smoothing: double the number of smoothing steps whenever going to the next coarser level
Definition at line 111 of file mg_smoother.h.
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protectedinherited |
Symmetric smoothing: in the smoothing iteration, alternate between the relaxation method and its transpose.
Definition at line 117 of file mg_smoother.h.
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protectedinherited |
Use the transpose of the relaxation method instead of the method itself. This has no effect if symmetric smoothing is chosen.
Definition at line 123 of file mg_smoother.h.
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protectedinherited |
Output debugging information to deallog
if this is nonzero.
Definition at line 128 of file mg_smoother.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 218 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 224 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 240 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 248 of file subscriptor.h.
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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.