Reference documentation for deal.II version GIT eef19498cf 2022-10-05 14:45:02+00:00
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Classes | 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
SolverControl Class Reference

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

Inheritance diagram for SolverControl:


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

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

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.


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 67 of file solver_control.h.

Member Typedef Documentation

◆ map_value_type

using Subscriptor::map_value_type = decltype(counter_map)::value_type

The data type used in counter_map.

Definition at line 230 of file subscriptor.h.

◆ map_iterator

using Subscriptor::map_iterator = decltype(counter_map)::iterator

The iterator type used in counter_map.

Definition at line 235 of file subscriptor.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.


Continue iteration.


Stop iteration, goal reached.


Stop iteration, goal not reached.

Definition at line 74 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

◆ ~SolverControl()

virtual SolverControl::~SolverControl ( )

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

Member Function Documentation

◆ declare_parameters()

void SolverControl::declare_parameters ( ParameterHandler param)

Interface to parameter file.

Definition at line 204 of file

◆ parse_parameters()

void SolverControl::parse_parameters ( ParameterHandler param)

Read parameters from file.

Definition at line 215 of file

◆ check()

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

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

◆ 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 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

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.

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 53 of file

Member Data Documentation

◆ maxsteps

unsigned int SolverControl::maxsteps

Maximum number of steps.

Definition at line 335 of file solver_control.h.

◆ tol

double SolverControl::tol

Prescribed tolerance to be achieved.

Definition at line 340 of file solver_control.h.

◆ lcheck

State SolverControl::lcheck

Result of last check operation.

Definition at line 345 of file solver_control.h.

◆ initial_val

double SolverControl::initial_val

Initial value.

Definition at line 350 of file solver_control.h.

◆ lvalue

double SolverControl::lvalue

Last value of the convergence criterion.

Definition at line 355 of file solver_control.h.

◆ lstep

unsigned int SolverControl::lstep

Last step.

Definition at line 360 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 366 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 371 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 379 of file solver_control.h.

◆ m_log_history

bool SolverControl::m_log_history

Log convergence history to deallog.

Definition at line 384 of file solver_control.h.

◆ m_log_frequency

unsigned int SolverControl::m_log_frequency

Log only every nth step.

Definition at line 389 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 396 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 401 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 409 of file solver_control.h.

◆ counter

std::atomic<unsigned int> Subscriptor::counter

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.

◆ counter_map

std::map<std::string, unsigned int> Subscriptor::counter_map

In this map, we count subscriptions for each different identification string supplied to subscribe().

Definition at line 225 of file subscriptor.h.

◆ validity_pointers

std::vector<std::atomic<bool> *> Subscriptor::validity_pointers

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.

◆ object_info

const std::type_info* Subscriptor::object_info

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.

◆ mutex

std::mutex Subscriptor::mutex

A mutex used to ensure data consistency when printing out the list of subscribers.

Definition at line 271 of file subscriptor.h.

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