Reference documentation for deal.II version 9.6.0
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Public Types | Public Member Functions | Static Public Member Functions | Protected Attributes | Private Types | Private Member Functions | Private Attributes | Static Private Attributes | List of all members
ReductionControl Class Reference
Linear algebra classes » Linear solver classes

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

Inheritance diagram for ReductionControl:
Inheritance graph
[legend]

Public Types

enum  State { iterate = 0 , success , failure }
 

Public Member Functions

 ReductionControl (const unsigned int maxiter=100, const double tolerance=1.e-10, const double reduce=1.e-2, const bool log_history=false, const bool log_result=true)
 
 ReductionControl (const SolverControl &c)
 
ReductionControl & operator= (const SolverControl &c)
 
virtual ~ReductionControl () override=default
 
void parse_parameters (ParameterHandler &param)
 
virtual State check (const unsigned int step, const double check_value) override
 
double reduction () const
 
double set_reduction (const double)
 
State last_check () const
 
double initial_value () const
 
double last_value () const
 
unsigned int last_step () const
 
unsigned int max_steps () const
 
unsigned int set_max_steps (const unsigned int)
 
void set_failure_criterion (const double rel_failure_residual)
 
void clear_failure_criterion ()
 
double tolerance () const
 
double set_tolerance (const double)
 
void enable_history_data ()
 
const std::vector< double > & get_history_data () const
 
double average_reduction () const
 
double final_reduction () const
 
double step_reduction (unsigned int step) const
 
void log_history (const bool)
 
bool log_history () const
 
unsigned int log_frequency (unsigned int)
 
void log_result (const bool)
 
bool log_result () 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 declare_parameters (ParameterHandler &param)
 
static ::ExceptionBase & ExcHistoryDataRequired ()
 
static ::ExceptionBase & ExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBase & ExcNoSubscriber (std::string arg1, std::string arg2)
 

Protected Attributes

double reduce
 
double reduced_tol
 
unsigned int maxsteps
 
double tol
 
State lcheck
 
double initial_val
 
double lvalue
 
unsigned int lstep
 
bool check_failure
 
double relative_failure_residual
 
double failure_residual
 
bool m_log_history
 
unsigned int m_log_frequency
 
bool m_log_result
 
bool history_data_enabled
 
std::vector< double > history_data
 

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

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

Specialization of SolverControl which returns success if either the specified tolerance is achieved or if the initial residual (or whatever criterion was chosen by the solver class) is reduced by a given factor. This is useful in cases where you don't want to solve exactly, but rather want to gain two digits or if the maximal number of iterations is achieved. For example: The maximal number of iterations is 20, the reduction factor is 1% and the tolerance is 0.1%. The initial residual is 2.5. The process will break if 20 iteration are completed or the new residual is less then 2.5*1% or if it is less then 0.1%.

Definition at line 423 of file solver_control.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.

Member Enumeration Documentation

◆ State

enum SolverControl::State
inherited

Enum denoting the different states a solver can be in. See the general documentation of this class for more information.

Enumerator
iterate 

Continue iteration.

success 

Stop iteration, goal reached.

failure 

Stop iteration, goal not reached.

Definition at line 73 of file solver_control.h.

Constructor & Destructor Documentation

◆ ReductionControl() [1/2]

ReductionControl::ReductionControl ( const unsigned int maxiter = 100,
const double tolerance = 1.e-10,
const double reduce = 1.e-2,
const bool log_history = false,
const bool log_result = true )
explicit

Constructor. Provide the reduction factor in addition to arguments that have the same meaning as those of the constructor of the SolverControl constructor.

Definition at line 229 of file solver_control.cc.

◆ ReductionControl() [2/2]

ReductionControl::ReductionControl ( const SolverControl & c)
explicit

Initialize with a SolverControl object. The result will emulate SolverControl by setting reduce to zero.

Definition at line 240 of file solver_control.cc.

◆ ~ReductionControl()

virtual ReductionControl::~ReductionControl ( )
overridevirtualdefault

Virtual destructor is needed as there are virtual functions in this class.

Member Function Documentation

◆ operator=()

ReductionControl & ReductionControl::operator= ( const SolverControl & c)

Assign a SolverControl object to ReductionControl. The result of the assignment will emulate SolverControl by setting reduce to zero.

Definition at line 250 of file solver_control.cc.

◆ declare_parameters()

void ReductionControl::declare_parameters ( ParameterHandler & param)
static

Interface to parameter file.

Definition at line 299 of file solver_control.cc.

◆ parse_parameters()

void ReductionControl::parse_parameters ( ParameterHandler & param)

Read parameters from file.

Definition at line 307 of file solver_control.cc.

◆ check()

SolverControl::State ReductionControl::check ( const unsigned int step,
const double check_value )
overridevirtual

Decide about success or failure of an iteration. This function calls the one in the base class, but sets the tolerance to reduction * initial value upon the first iteration.

Reimplemented from SolverControl.

Definition at line 260 of file solver_control.cc.

◆ reduction()

double ReductionControl::reduction ( ) const

Reduction factor.

◆ set_reduction()

double ReductionControl::set_reduction ( const double )

Change reduction factor.

◆ last_check()

SolverControl::State SolverControl::last_check ( ) const
inherited

Return the result of the last check operation.

Definition at line 108 of file solver_control.cc.

◆ initial_value()

double SolverControl::initial_value ( ) const
inherited

Return the initial convergence criterion.

Definition at line 115 of file solver_control.cc.

◆ last_value()

double SolverControl::last_value ( ) const
inherited

Return the convergence value of last iteration step for which check was called by the solver.

Definition at line 122 of file solver_control.cc.

◆ last_step()

unsigned int SolverControl::last_step ( ) const
inherited

Number of last iteration step.

Definition at line 129 of file solver_control.cc.

◆ max_steps()

unsigned int SolverControl::max_steps ( ) const
inherited

Maximum number of steps.

◆ set_max_steps()

unsigned int SolverControl::set_max_steps ( const unsigned int )
inherited

Change maximum number of steps.

◆ set_failure_criterion()

void SolverControl::set_failure_criterion ( const double rel_failure_residual)
inherited

Enables the failure check. Solving is stopped with ReturnState failure if residual>failure_residual with failure_residual := rel_failure_residual*first_residual.

◆ clear_failure_criterion()

void SolverControl::clear_failure_criterion ( )
inherited

Disables failure check and resets relative_failure_residual and failure_residual to zero.

◆ tolerance()

double SolverControl::tolerance ( ) const
inherited

Tolerance.

◆ set_tolerance()

double SolverControl::set_tolerance ( const double )
inherited

Change tolerance.

◆ enable_history_data()

void SolverControl::enable_history_data ( )
inherited

Enables writing residuals of each step into a vector for later analysis.

Definition at line 147 of file solver_control.cc.

◆ get_history_data()

const std::vector< double > & SolverControl::get_history_data ( ) const
inherited

Provide read access to the collected residual data.

Definition at line 155 of file solver_control.cc.

◆ average_reduction()

double SolverControl::average_reduction ( ) const
inherited

Average error reduction over all steps.

Requires enable_history_data()

Definition at line 171 of file solver_control.cc.

◆ final_reduction()

double SolverControl::final_reduction ( ) const
inherited

Error reduction of the last step; for stationary iterations, this approximates the norm of the iteration matrix.

Requires enable_history_data()

Definition at line 199 of file solver_control.cc.

◆ step_reduction()

double SolverControl::step_reduction ( unsigned int step) const
inherited

Error reduction of any iteration step.

Requires enable_history_data()

Definition at line 187 of file solver_control.cc.

◆ log_history() [1/2]

void SolverControl::log_history ( const bool )
inherited

Log each iteration step. Use log_frequency for skipping steps.

◆ log_history() [2/2]

bool SolverControl::log_history ( ) const
inherited

Return the log_history flag.

◆ log_frequency()

unsigned int SolverControl::log_frequency ( unsigned int f)
inherited

Set logging frequency.

Definition at line 136 of file solver_control.cc.

◆ log_result() [1/2]

void SolverControl::log_result ( const bool )
inherited

Log start and end step.

◆ log_result() [2/2]

bool SolverControl::log_result ( ) const
inherited

Return the log_result flag.

◆ 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

◆ reduce

double ReductionControl::reduce
protected

Desired reduction factor.

Definition at line 492 of file solver_control.h.

◆ reduced_tol

double ReductionControl::reduced_tol
protected

Reduced tolerance. Stop iterations if either this value is achieved or if the base class indicates success.

Definition at line 498 of file solver_control.h.

◆ maxsteps

unsigned int SolverControl::maxsteps
protectedinherited

Maximum number of steps.

Definition at line 334 of file solver_control.h.

◆ tol

double SolverControl::tol
protectedinherited

Prescribed tolerance to be achieved.

Definition at line 339 of file solver_control.h.

◆ lcheck

State SolverControl::lcheck
protectedinherited

Result of last check operation.

Definition at line 344 of file solver_control.h.

◆ initial_val

double SolverControl::initial_val
protectedinherited

Initial value.

Definition at line 349 of file solver_control.h.

◆ lvalue

double SolverControl::lvalue
protectedinherited

Last value of the convergence criterion.

Definition at line 354 of file solver_control.h.

◆ lstep

unsigned int SolverControl::lstep
protectedinherited

Last step.

Definition at line 359 of file solver_control.h.

◆ check_failure

bool SolverControl::check_failure
protectedinherited

Is set to true by set_failure_criterion and enables failure checking.

Definition at line 365 of file solver_control.h.

◆ relative_failure_residual

double SolverControl::relative_failure_residual
protectedinherited

Stores the rel_failure_residual set by set_failure_criterion

Definition at line 370 of file solver_control.h.

◆ failure_residual

double SolverControl::failure_residual
protectedinherited

failure_residual equals the first residual multiplied by relative_crit set by set_failure_criterion (see there).

Until the first residual is known it is 0.

Definition at line 378 of file solver_control.h.

◆ m_log_history

bool SolverControl::m_log_history
protectedinherited

Log convergence history to deallog.

Definition at line 383 of file solver_control.h.

◆ m_log_frequency

unsigned int SolverControl::m_log_frequency
protectedinherited

Log only every nth step.

Definition at line 388 of file solver_control.h.

◆ m_log_result

bool SolverControl::m_log_result
protectedinherited

Log iteration result to deallog. If true, after finishing the iteration, a statement about failure or success together with lstep and lvalue are logged.

Definition at line 395 of file solver_control.h.

◆ history_data_enabled

bool SolverControl::history_data_enabled
protectedinherited

Control over the storage of history data. Set by enable_history_data().

Definition at line 400 of file solver_control.h.

◆ history_data

std::vector<double> SolverControl::history_data
protectedinherited

Vector storing the result after each iteration step for later statistical analysis.

Use of this vector is enabled by enable_history_data().

Definition at line 408 of file solver_control.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.

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