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Reference documentation for deal.II version 8.1.0
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#include <solver_control.h>
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 () |
void | parse_parameters (ParameterHandler ¶m) |
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) | |
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Subscriptor () | |
Subscriptor (const Subscriptor &) | |
virtual | ~Subscriptor () |
Subscriptor & | operator= (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"<< "(Additional information: "<< arg3<< ")\n"<< "Note the entry in the Frequently Asked Questions of "<< "deal.II (linked to from http://www.dealii.org/) for "<< "more information on what this error means.") | |
DeclException2 (ExcNoSubscriber, char *, char *,<< "No subscriber with identifier \""<< arg2<< "\" did subscribe to this object of class "<< arg1) | |
template<class Archive > | |
void | serialize (Archive &ar, const unsigned int version) |
Static Public Member Functions | |
static void | declare_parameters (ParameterHandler ¶m) |
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 |
Control class for iterative solvers.
Used by iterative methods to determine whether the iteration should be continued. To this respect, 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
iterate = 0
: continue the iteration. success:
the goal is reached, the iterative method can terminate successfully. failure:
the iterative method should stop because convergence could not be achieved or at least was not achieved within the given maximal number of iterations. Definition at line 66 of file solver_control.h.
enum SolverControl::State |
Enum denoting the different states a solver can be in. See the general documentation of this class for more information.
Enumerator | |
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iterate |
Continue iteration. |
success |
Stop iteration, goal reached. |
failure |
Stop iteration, goal not reached. |
Definition at line 74 of file solver_control.h.
SolverControl::SolverControl | ( | const unsigned int | n = 100 , |
const double | tol = 1.e-10 , |
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const bool | log_history = false , |
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const bool | log_result = true |
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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.
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virtual |
Virtual destructor is needed as there are virtual functions in this class.
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static |
Interface to parameter file.
void SolverControl::parse_parameters | ( | ParameterHandler & | param | ) |
Read parameters from file.
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. The configure
scripts checks for this and sets the flag HAVE_ISNAN
in the file Make.global_options
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.
State SolverControl::last_check | ( | ) | const |
Return the result of the last check operation.
double SolverControl::initial_value | ( | ) | const |
Return the initial convergence criterion.
double SolverControl::last_value | ( | ) | const |
Return the convergence value of last iteration step for which check
was called by the solver.
unsigned int SolverControl::last_step | ( | ) | const |
Number of last iteration step.
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 |
Tolerance.
void SolverControl::enable_history_data | ( | ) |
Enables writing residuals of each step into a vector for later analysis.
double SolverControl::average_reduction | ( | ) | const |
Average error reduction over all steps.
Requires enable_history_data()
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()
Error reduction of any iteration step.
Requires enable_history_data()
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 | ) |
Set logging frequency.
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().
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Maximum number of steps.
Definition at line 299 of file solver_control.h.
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Prescribed tolerance to be achieved.
Definition at line 304 of file solver_control.h.
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Result of last check operation.
Definition at line 309 of file solver_control.h.
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Initial value.
Definition at line 314 of file solver_control.h.
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Last value of the convergence criterion.
Definition at line 319 of file solver_control.h.
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Last step.
Definition at line 324 of file solver_control.h.
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Is set to true
by set_failure_criterion
and enables failure checking.
Definition at line 330 of file solver_control.h.
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Stores the rel_failure_residual
set by set_failure_criterion
Definition at line 335 of file solver_control.h.
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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 343 of file solver_control.h.
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Log convergence history to deallog
.
Definition at line 348 of file solver_control.h.
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Log only every nth step.
Definition at line 353 of file solver_control.h.
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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 360 of file solver_control.h.
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protected |
Control over the storage of history data. Set by enable_history_data().
Definition at line 366 of file solver_control.h.
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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 374 of file solver_control.h.