Reference documentation for deal.II version Git 803d21ff95 2020-10-01 11:19:45 -0600
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Public Types | Public Member Functions | Static Public Member Functions | Protected Attributes | List of all members
ReductionControl Class Reference

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

Inheritance diagram for ReductionControl:

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)
ReductionControloperator= (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 ::ExceptionBaseExcHistoryDataRequired ()
static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
static ::ExceptionBaseExcNoSubscriber (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< doublehistory_data

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 Enumeration Documentation

◆ State

enum SolverControl::State

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


Continue iteration.


Stop iteration, goal reached.


Stop iteration, goal not reached.

Definition at line 72 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 

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 227 of file

◆ ReductionControl() [2/2]

ReductionControl::ReductionControl ( const SolverControl c)

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

Definition at line 238 of file

◆ ~ReductionControl()

virtual ReductionControl::~ReductionControl ( )

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 248 of file

◆ declare_parameters()

void ReductionControl::declare_parameters ( ParameterHandler param)

Interface to parameter file.

Definition at line 294 of file

◆ parse_parameters()

void ReductionControl::parse_parameters ( ParameterHandler param)

Read parameters from file.

Definition at line 302 of file

◆ check()

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

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 258 of file

◆ 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

Return the result of the last check operation.

Definition at line 106 of file

◆ initial_value()

double SolverControl::initial_value ( ) const

Return the initial convergence criterion.

Definition at line 113 of file

◆ last_value()

double SolverControl::last_value ( ) const

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

Definition at line 120 of file

◆ last_step()

unsigned int SolverControl::last_step ( ) const

Number of last iteration step.

Definition at line 127 of file

◆ max_steps()

unsigned int SolverControl::max_steps ( ) const

Maximum number of steps.

◆ set_max_steps()

unsigned int SolverControl::set_max_steps ( const unsigned  int)

Change maximum number of steps.

◆ set_failure_criterion()

void SolverControl::set_failure_criterion ( const double  rel_failure_residual)

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 ( )

Disables failure check and resets relative_failure_residual and failure_residual to zero.

◆ tolerance()

double SolverControl::tolerance ( ) const


◆ set_tolerance()

double SolverControl::set_tolerance ( const double  )

Change tolerance.

◆ enable_history_data()

void SolverControl::enable_history_data ( )

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

Definition at line 145 of file

◆ get_history_data()

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

Provide read access to the collected residual data.

Definition at line 153 of file

◆ average_reduction()

double SolverControl::average_reduction ( ) const

Average error reduction over all steps.

Requires enable_history_data()

Definition at line 169 of file

◆ final_reduction()

double SolverControl::final_reduction ( ) const

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

Requires enable_history_data()

Definition at line 197 of file

◆ step_reduction()

double SolverControl::step_reduction ( unsigned int  step) const

Error reduction of any iteration step.

Requires enable_history_data()

Definition at line 185 of file

◆ log_history() [1/2]

void SolverControl::log_history ( const bool  )

Log each iteration step. Use log_frequency for skipping steps.

◆ log_history() [2/2]

bool SolverControl::log_history ( ) const

Return the log_history flag.

◆ log_frequency()

unsigned int SolverControl::log_frequency ( unsigned int  f)

Set logging frequency.

Definition at line 134 of file

◆ log_result() [1/2]

void SolverControl::log_result ( const bool  )

Log start and end step.

◆ log_result() [2/2]

bool SolverControl::log_result ( ) const

Return the log_result flag.

◆ subscribe()

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

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

◆ unsubscribe()

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

Unsubscribes a user from the object.

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

Definition at line 156 of file

◆ n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const

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

List the subscribers to the input stream.

Definition at line 317 of file subscriptor.h.

◆ list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const

List the subscribers to deallog.

Definition at line 204 of file

◆ serialize()

template<class Archive >
void Subscriptor::serialize ( Archive &  ar,
const unsigned int  version 

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

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.

Member Data Documentation

◆ reduce

double ReductionControl::reduce

Desired reduction factor.

Definition at line 492 of file solver_control.h.

◆ reduced_tol

double ReductionControl::reduced_tol

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

Maximum number of steps.

Definition at line 334 of file solver_control.h.

◆ tol

double SolverControl::tol

Prescribed tolerance to be achieved.

Definition at line 339 of file solver_control.h.

◆ lcheck

State SolverControl::lcheck

Result of last check operation.

Definition at line 344 of file solver_control.h.

◆ initial_val

double SolverControl::initial_val

Initial value.

Definition at line 349 of file solver_control.h.

◆ lvalue

double SolverControl::lvalue

Last value of the convergence criterion.

Definition at line 354 of file solver_control.h.

◆ lstep

unsigned int SolverControl::lstep

Last step.

Definition at line 359 of file solver_control.h.

◆ check_failure

bool SolverControl::check_failure

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

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

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

Log convergence history to deallog.

Definition at line 383 of file solver_control.h.

◆ m_log_frequency

unsigned int SolverControl::m_log_frequency

Log only every nth step.

Definition at line 388 of file solver_control.h.

◆ m_log_result

bool SolverControl::m_log_result

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

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

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.

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