TimeStepper Class Reference

#include <TimeStepper.hpp>

Collaboration diagram for TimeStepper:

List of all members.

Public Member Functions

 TimeStepper (double startTime, double endTime, double dt, bool enforceConstantTimeStep=false, std::vector< double > additionalTimes=std::vector< double >())
void AdvanceOneTimeStep ()
double GetTime () const
double GetNextTime () const
double GetNextTimeStep ()
double GetIdealTimeStep ()
bool IsTimeAtEnd () const
unsigned EstimateTimeSteps () const
unsigned GetTotalTimeStepsTaken () const
void ResetTimeStep (double dt)

Private Member Functions

double CalculateNextTime ()
template<class Archive >
void serialize (Archive &archive, const unsigned int version)

Private Attributes

double mStart
double mEnd
double mDt
unsigned mTotalTimeStepsTaken
unsigned mAdditionalTimesReachedDeprecated
double mTime
double mNextTime
double mEpsilon
std::vector< doublemAdditionalTimesDeprecated

Friends

class TestTimeStepper
class boost::serialization::access

Detailed Description

A helper class that provides a robust way to deal with time loops.

An incremented integer counter is used to calculate the current time and ensure that the correct end time.

Definition at line 52 of file TimeStepper.hpp.


Constructor & Destructor Documentation

TimeStepper::TimeStepper ( double  startTime,
double  endTime,
double  dt,
bool  enforceConstantTimeStep = false,
std::vector< double additionalTimes = std::vector<double> () 
)

Create a new time stepper over some simulation interval. Time units are not specified, but all parameters should have consistent units.

Parameters:
startTime the start of the interval
endTime the end of the interval
dt the time step to use.
enforceConstantTimeStep If this is true the stepper estimates whether non-constant timesteps will be used and quits if so.
additionalTimes If the timestepper needs to stop at certain additional times, they can be passed in in this std::vector. Defaults to empty. These times must be in ascending order. DEPRECATION: Note that these additional times are checked in order to ensure that the stepper will stop at these times anyway. (For example we want to check that new events such as electrodes switching on will be detected in a regular time loop.) New additional times are not added but instead throw an exception.

Definition at line 43 of file TimeStepper.cpp.

References CalculateNextTime(), EstimateTimeSteps(), EXCEPTION, mDt, mEnd, mEpsilon, mNextTime, and mStart.


Member Function Documentation

void TimeStepper::AdvanceOneTimeStep (  ) 
double TimeStepper::CalculateNextTime (  )  [private]
Returns:
Compute what the time will be at the next time step.

Definition at line 106 of file TimeStepper.cpp.

References mAdditionalTimesDeprecated, mDt, mEnd, mEpsilon, mStart, and mTotalTimeStepsTaken.

Referenced by AdvanceOneTimeStep(), ResetTimeStep(), and TimeStepper().

unsigned TimeStepper::EstimateTimeSteps (  )  const
Returns:
Estimate number of time steps remaining, which may be an overestimate. Used to reserve memory for writing intermediate solutions.

Definition at line 170 of file TimeStepper.cpp.

References mDt, mEnd, and mStart.

Referenced by ExtendedBidomainProblem< DIM >::DefineWriterColumns(), AbstractCardiacProblem< ELEMENT_DIM, SPACE_DIM, PROBLEM_DIM >::DefineWriterColumns(), CvodeAdaptor::Solve(), AbstractOneStepIvpOdeSolver::Solve(), AbstractCvodeSystem::Solve(), and TimeStepper().

double TimeStepper::GetIdealTimeStep (  ) 
Returns:
Get the size of the ideal time step (as set in the constructor. Note when a fixed time step is used GetNextTimeStep() == GetIdealTimeStep() until the end of the simulation when GetNextTimeStep() == 0.0

Definition at line 160 of file TimeStepper.cpp.

References mDt.

double TimeStepper::GetNextTime (  )  const
double TimeStepper::GetNextTimeStep (  ) 
Returns:
Get the size of the next time step which will be taken.

Note that this is often reported as the ideal timestep.

The actual time step is mNextTime - mTime which could be evaluated as GetNextTime() - GetTime() = mNextTime - mTime ~= mStart + (mTotalTimeStepsTaken + 1)*mDt - mTime ~= mStart + (mTotalTimeStepsTaken + 1)*mDt - (mStart + mTotalTimeStepsTaken*mDt) ~= mDt This wouldn't evaluate to mDt in general but to within 2*mEpsilon <= 2*DBL_EPSILON*mEnd*mDt When mEnd and/or mStart are a long way from zero then the value reported mNextTime - mTime will differ from mDt, even when the actual step is mDt

Definition at line 149 of file TimeStepper.cpp.

References mAdditionalTimesDeprecated, mDt, mEnd, mNextTime, and mTime.

Referenced by AbstractOneStepIvpOdeSolver::InternalSolve(), and AbstractDynamicLinearPdeSolver< ELEMENT_DIM, SPACE_DIM, PROBLEM_DIM >::Solve().

double TimeStepper::GetTime (  )  const
unsigned TimeStepper::GetTotalTimeStepsTaken (  )  const
bool TimeStepper::IsTimeAtEnd (  )  const
void TimeStepper::ResetTimeStep ( double  dt  ) 

Set the time step to use for adaptive time integration. Note that this also resets mStart to be the current time and zeroes mTotalTimeStepsTaken.

Parameters:
dt is the new time-step

Definition at line 180 of file TimeStepper.cpp.

References CalculateNextTime(), mDt, mNextTime, mStart, mTime, and mTotalTimeStepsTaken.

Referenced by AbstractDynamicLinearPdeSolver< ELEMENT_DIM, SPACE_DIM, PROBLEM_DIM >::Solve().

template<class Archive >
void TimeStepper::serialize ( Archive &  archive,
const unsigned int  version 
) [inline, private]
Parameters:
archive the archive
version the current version of this class

Definition at line 193 of file TimeStepper.hpp.

References mAdditionalTimesDeprecated, mAdditionalTimesReachedDeprecated, mDt, mEnd, mEpsilon, mNextTime, mStart, mTime, and mTotalTimeStepsTaken.


Friends And Related Function Documentation

friend class boost::serialization::access [friend]

Needed for serialization.

Definition at line 185 of file TimeStepper.hpp.


Member Data Documentation

DEPRECATED Vector to store the additional times the stepper must stop at.

Definition at line 182 of file TimeStepper.hpp.

Referenced by CalculateNextTime(), GetNextTimeStep(), and serialize().

DEPRECATED: The number of times one of the 'additional times' has been passed.

Definition at line 163 of file TimeStepper.hpp.

Referenced by serialize().

The end time.

Definition at line 154 of file TimeStepper.hpp.

Referenced by CalculateNextTime(), EstimateTimeSteps(), GetNextTimeStep(), IsTimeAtEnd(), serialize(), and TimeStepper().

An architecture-dependent scaling factor. This is so that we can compare relative to the end time when mEnd is large. mEpsilon = DBL_EPSILON when mEnd is small = mEnd*DBL_EPSILON when mEnd is large

Definition at line 176 of file TimeStepper.hpp.

Referenced by CalculateNextTime(), serialize(), and TimeStepper().

What the time will be after the next time step.

Definition at line 169 of file TimeStepper.hpp.

Referenced by AdvanceOneTimeStep(), GetNextTime(), GetNextTimeStep(), ResetTimeStep(), serialize(), and TimeStepper().

The start time.

Definition at line 151 of file TimeStepper.hpp.

Referenced by CalculateNextTime(), EstimateTimeSteps(), ResetTimeStep(), serialize(), and TimeStepper().

The current time.

Definition at line 166 of file TimeStepper.hpp.

Referenced by AdvanceOneTimeStep(), GetNextTimeStep(), GetTime(), IsTimeAtEnd(), ResetTimeStep(), and serialize().

The total number of time steps taken.

Definition at line 160 of file TimeStepper.hpp.

Referenced by AdvanceOneTimeStep(), CalculateNextTime(), GetTotalTimeStepsTaken(), ResetTimeStep(), and serialize().


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

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