Reference documentation for deal.II version Git d51799cb54 2020-09-28 09:22:08 +0200
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Classes | Public Types | Public Member Functions | Static Public Member Functions | Protected Attributes | List of all members
SolverControl Class Reference

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

Inheritance diagram for SolverControl:
[legend]

Classes

class  NoConvergence
 

Public Types

enum  State { iterate = 0, success, failure }
 

Public Member Functions

 SolverControl (const unsigned int n=100, const double tol=1.e-10, const bool log_history=false, const bool log_result=true)
 
virtual ~SolverControl () override=default
 
void parse_parameters (ParameterHandler &param)
 
virtual State check (const unsigned int step, const double check_value)
 
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

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

Control class to determine convergence of iterative solvers.

Used by iterative methods to determine whether the iteration should be continued. To this end, the virtual function check() is called in each iteration with the current iteration step and the value indicating convergence (usually the residual).

After the iteration has terminated, the functions last_value() and last_step() can be used to obtain information about the final state of the iteration.

check() can be replaced in derived classes to allow for more sophisticated tests.

State

The return states of the check function are of type State, which is an enum local to this class. It indicates the state the solver is in.

The possible values of State are

Definition at line 65 of file solver_control.h.

Member Enumeration Documentation

◆ State

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 72 of file solver_control.h.

Constructor & Destructor Documentation

◆ SolverControl()

SolverControl::SolverControl ( const unsigned int  n = 100,
const double  tol = 1.e-10,
const bool  log_history = false,
const bool  log_result = true 
)

Constructor. The parameters n and tol are the maximum number of iteration steps before failure and the tolerance to determine success of the iteration.

log_history specifies whether the history (i.e. the value to be checked and the number of the iteration step) shall be printed to deallog stream. Default is: do not print. Similarly, log_result specifies the whether the final result is logged to deallog. Default is yes.

Definition at line 30 of file solver_control.cc.

◆ ~SolverControl()

virtual SolverControl::~SolverControl ( )
overridevirtualdefault

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

Member Function Documentation

◆ declare_parameters()

void SolverControl::declare_parameters ( ParameterHandler param)
static

Interface to parameter file.

Definition at line 204 of file solver_control.cc.

◆ parse_parameters()

void SolverControl::parse_parameters ( ParameterHandler param)

Read parameters from file.

Definition at line 215 of file solver_control.cc.

◆ check()

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

Decide about success or failure of an iteration. This function gets the current iteration step to determine, whether the allowed number of steps has been exceeded and returns failure in this case. If check_value is below the prescribed tolerance, it returns success. In all other cases iterate is returned to suggest continuation of the iterative procedure.

The iteration is also aborted if the residual becomes a denormalized value (NaN).

check() additionally preserves step and check_value. These values are accessible by last_value() and last_step().

Derived classes may overload this function, e.g. to log the convergence indicators (check_value) or to do other computations.

Reimplemented in ConsecutiveControl, IterationNumberControl, and ReductionControl.

Definition at line 52 of file solver_control.cc.

◆ last_check()

SolverControl::State SolverControl::last_check ( ) const

Return the result of the last check operation.

Definition at line 106 of file solver_control.cc.

◆ initial_value()

double SolverControl::initial_value ( ) const

Return the initial convergence criterion.

Definition at line 113 of file solver_control.cc.

◆ 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 solver_control.cc.

◆ last_step()

unsigned int SolverControl::last_step ( ) const

Number of last iteration step.

Definition at line 127 of file solver_control.cc.

◆ 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

Tolerance.

◆ 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 solver_control.cc.

◆ 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 solver_control.cc.

◆ average_reduction()

double SolverControl::average_reduction ( ) const

Average error reduction over all steps.

Requires enable_history_data()

Definition at line 169 of file solver_control.cc.

◆ 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 solver_control.cc.

◆ 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 solver_control.cc.

◆ 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 solver_control.cc.

◆ 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
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.

◆ 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 156 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 204 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.

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

◆ maxsteps

unsigned int SolverControl::maxsteps
protected

Maximum number of steps.

Definition at line 334 of file solver_control.h.

◆ tol

double SolverControl::tol
protected

Prescribed tolerance to be achieved.

Definition at line 339 of file solver_control.h.

◆ lcheck

State SolverControl::lcheck
protected

Result of last check operation.

Definition at line 344 of file solver_control.h.

◆ initial_val

double SolverControl::initial_val
protected

Initial value.

Definition at line 349 of file solver_control.h.

◆ lvalue

double SolverControl::lvalue
protected

Last value of the convergence criterion.

Definition at line 354 of file solver_control.h.

◆ lstep

unsigned int SolverControl::lstep
protected

Last step.

Definition at line 359 of file solver_control.h.

◆ check_failure

bool SolverControl::check_failure
protected

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
protected

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
protected

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
protected

Log convergence history to deallog.

Definition at line 383 of file solver_control.h.

◆ m_log_frequency

unsigned int SolverControl::m_log_frequency
protected

Log only every nth step.

Definition at line 388 of file solver_control.h.

◆ m_log_result

bool SolverControl::m_log_result
protected

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
protected

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
protected

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: