Reference documentation for deal.II version 8.4.1
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:


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 ()
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 ()
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
 DeclException0 (ExcHistoryDataRequired)
- Public Member Functions inherited from Subscriptor
 Subscriptor ()
 Subscriptor (const Subscriptor &)
virtual ~Subscriptor ()
Subscriptoroperator= (const Subscriptor &)
void subscribe (const char *identifier=0) const
void unsubscribe (const char *identifier=0) const
unsigned int n_subscriptions () const
void list_subscribers () const
 DeclException3 (ExcInUse, int, char *, std::string &,<< "Object of class "<< arg2<< " is still used by "<< arg1<< " other objects."<< "\n\n"<< "(Additional information: "<< arg3<< ")\n\n"<< "See the entry in the Frequently Asked Questions of "<< "deal.II (linked to from for "<< "a lot more information on what this error means and "<< "how to fix programs in which it happens.")
 DeclException2 (ExcNoSubscriber, char *, char *,<< "No subscriber with identifier <"<< arg2<< "> subscribes to this object of class "<< arg1<< ". Consequently, it cannot be unsubscribed.")
template<class Archive >
void serialize (Archive &ar, const unsigned int version)

Static Public Member Functions

static void declare_parameters (ParameterHandler &param)

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< double > history_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.


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

Guido Kanschat

Definition at line 64 of file solver_control.h.

Constructor & Destructor Documentation

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 28 of file

SolverControl::~SolverControl ( )

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

Definition at line 48 of file

Member Function Documentation

void SolverControl::declare_parameters ( ParameterHandler param)

Interface to parameter file.

Definition at line 194 of file

void SolverControl::parse_parameters ( ParameterHandler param)

Read parameters from file.

Definition at line 204 of file

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). Note, however, that this check is only performed if the isnan function is provided by the operating system, which is not always true. CMake checks this with the 'check_01_cxx_features.cmake' test and sets the flag DEAL_II_HAVE_ISNAN in the include file deal.II/base/config.h if this function was found.

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 IterationNumberControl, and ReductionControl.

Definition at line 54 of file

SolverControl::State SolverControl::last_check ( ) const

Return the result of the last check operation.

Definition at line 113 of file

double SolverControl::initial_value ( ) const

Return the initial convergence criterion.

Definition at line 120 of file

double SolverControl::last_value ( ) const

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

Definition at line 127 of file

unsigned int SolverControl::last_step ( ) const

Number of last iteration step.

Definition at line 134 of file

unsigned int SolverControl::max_steps ( ) const

Maximum number of steps.

unsigned int SolverControl::set_max_steps ( const unsigned  int)

Change maximum number of steps.

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.

void SolverControl::clear_failure_criterion ( )

Disables failure check and resets relative_failure_residual and failure_residual to zero.

double SolverControl::tolerance ( ) const


double SolverControl::set_tolerance ( const double  )

Change tolerance.

void SolverControl::enable_history_data ( )

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

Definition at line 152 of file

double SolverControl::average_reduction ( ) const

Average error reduction over all steps.

Requires enable_history_data()

Definition at line 159 of file

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 187 of file

double SolverControl::step_reduction ( unsigned int  step) const

Error reduction of any iteration step.

Requires enable_history_data()

Definition at line 175 of file

void SolverControl::log_history ( const bool  )

Log each iteration step. Use log_frequency for skipping steps.

bool SolverControl::log_history ( ) const

Returns the log_history flag.

unsigned int SolverControl::log_frequency ( unsigned int  f)

Set logging frequency.

Definition at line 141 of file

void SolverControl::log_result ( const bool  )

Log start and end step.

bool SolverControl::log_result ( ) const

Returns the log_result flag.

SolverControl::DeclException0 ( ExcHistoryDataRequired  )

This exception is thrown if a function operating on the vector of history data of a SolverControl object id called, but storage of history data was not enabled by enable_history_data().

Member Data Documentation

unsigned int SolverControl::maxsteps

Maximum number of steps.

Definition at line 310 of file solver_control.h.

double SolverControl::tol

Prescribed tolerance to be achieved.

Definition at line 315 of file solver_control.h.

State SolverControl::lcheck

Result of last check operation.

Definition at line 320 of file solver_control.h.

double SolverControl::initial_val

Initial value.

Definition at line 325 of file solver_control.h.

double SolverControl::lvalue

Last value of the convergence criterion.

Definition at line 330 of file solver_control.h.

unsigned int SolverControl::lstep

Last step.

Definition at line 335 of file solver_control.h.

bool SolverControl::check_failure

Is set to true by set_failure_criterion and enables failure checking.

Definition at line 341 of file solver_control.h.

double SolverControl::relative_failure_residual

Stores the rel_failure_residual set by set_failure_criterion

Definition at line 346 of file solver_control.h.

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 354 of file solver_control.h.

bool SolverControl::m_log_history

Log convergence history to deallog.

Definition at line 359 of file solver_control.h.

unsigned int SolverControl::m_log_frequency

Log only every nth step.

Definition at line 364 of file solver_control.h.

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 371 of file solver_control.h.

bool SolverControl::history_data_enabled

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

Definition at line 376 of file solver_control.h.

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 384 of file solver_control.h.

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