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rdRKF Class Reference

A class which integrates the equations of motion forward one step in time. More...

#include <rdRKF.h>

Inheritance diagram for rdRKF:

List of all members.

Public Member Functions
	rdRKF (rdModel *aModel, double aTol=1.0e-4, double aTolFine=-1.0)
	Default constructor.
virtual	~rdRKF ()
	Destructor.
rdModel *	getModel ()
	Get the model.
int	getNY ()
	Get the number of states being integrated.
void	setTolerance (double aTol, double aTolFine=-1.0)
	Set the tolerances of the integrator.
double	getTolerance ()
	Get the tolerance of the integrator.
void	setFineTolerance (double aFineTol)
	Set the fine tolerance of the integrator.
double	getFineTolerance ()
	Get the fine tolerance of the integrator.
int	step (double dt, double t, rdControlSet &x, double *y)
	Step forward in time by dt.
int	step (double dt, double t, double *x, double *y)
	Step forward in time by dt.
int	stepFixed (double dt, double t, rdControlSet &x, double *y)
	Step forward in time by dt.
int	stepFixed (double dt, double t, double *x, double *y)
	Step forward in time by dt.
Protected Attributes
double	_tol
	Integration tolerance.
double	_tolFine
	Integration fine tolerance.
rdModel *	_model
	Dynamic model.
int	_nx
	Number of controls.
double *	_x
	Controls at time t.
int	_ny
	Number of states.
double *	_yv
	Work arrays for computing the new states.
double *	_ye
	Work arrays for computing the new states.
double *	_dy
	Work arrays for computing the new states.
double *	_k1
double *	_k2
double *	_k3
double *	_k4
double *	_k5
double *	_k6
Private Member Functions
int	allocateMemory ()
	Allocate the memory needed to perform the integration.
int	freeMemory ()
	Free the memory needed to perform the integration.

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Detailed Description

A class which integrates the equations of motion forward one step in time.

The integration method is based on a Runge-Kutta-Feldberg 5-6 Variable-Step Integrator adapted from one given by Atkinson, L.V., et al, "Numerical Methods with Fortran 77.", pp. 310-322, Addison-Wesley Publishing Company, 1989.

The user must supply a pointer to an rdModel on construction.

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Member Function Documentation

double rdRKF::getFineTolerance (   )

Get the fine tolerance of the integrator. The fine tollerance specifies the accuracy tolerance of an integration. If the accuracy is better than aTolFine, the integration step size is doubled.

double rdRKF::getTolerance (   )

Get the tolerance of the integrator. The tolerance specifies the allowd error of an integration. If the error exceeds the tolerance, the integration step size is halved.

void rdRKF::setFineTolerance (  double  aFineTol  )

Set the fine tolerance of the integrator. The fine tollerance, aTolFine, specifies the accuracy tolerance of an integration. If the accuracy is better than aTolFine, the integration step size should be doubled.

void rdRKF::setTolerance (  double  aTol, double  aTolFine = -1.0 )

Set the tolerances of the integrator. The tolerance, aTol, specifies the allowd error of an integration. If the error exceeds the tolerance, the integration step size should be halved. The fine tollerance, aTolFine, specifies the accuracy tolerance of an integration. If the accuracy is better than aTolFine, the integration step size should be doubled.

int rdRKF::step (  double  dt, double  t, double *  x, double *  y )

Step forward in time by dt. Parameters: dt  Requested integration time step. t  Current time. x  Controls. y  States. Returns: rdRKF_NORMAL on a successful step, rdRKF_NAN if not-a-number is encountered in any of the states, rdRKF_POOR if the integration error is worse than the specified tolerance, or rdRKF_FINE if the integration error is better than the specified fine tolerance.

int rdRKF::step (  double  dt, double  t, rdControlSet &  x, double *  y )

Step forward in time by dt. Parameters: dt  Requested integration time step. t  Current time. controlSet  Controls. y  States. Returns: rdRKF_NORMAL on a successful step, rdRKF_NAN if not-a-number is encountered in any of the states, rdRKF_POOR if the integration error is worse than the specified tolerance, or rdRKF_FINE if the integration error is better than the specified fine tolerance.

int rdRKF::stepFixed (  double  dt, double  t, double *  x, double *  y )

Step forward in time by dt. This method does not estimate the integration error and does not return any kind of integration status other than rdRKF_NORMAL or rdRKF_NAN. Parameters: dt  Requested integration step. t  Current time. x  Controls. y  States. Returns: rdRKF_NORMAL on a successful step, or rdRKF_NAN if not-a-number is encountered in any of the states.

int rdRKF::stepFixed (  double  dt, double  t, rdControlSet &  x, double *  y )

Step forward in time by dt. This method does not estimate the integration error and does not return any kind of integration status other than rdRKF_NORMAL or rdRKF_NAN. Parameters: dt  Requested integration step. t  Current time. controlSet  Controls. y  States. Returns: rdRKF_NORMAL on a successful step, or rdRKF_NAN if not-a-number is encountered in any of the states.

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

• rdRKF.h
• rdRKF.cpp

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