RK2 Class Reference

#include <ConstantStepOdeSolver.h>

Inheritance diagram for RK2:

Public Member Functions
const char *	methodName () const
	RK2 ()
	RK2 (const AbsODERHS &rhs)
Public Member Functions inherited from ConstantStepOdeSolver
	ConstantStepOdeSolver ()
	ConstantStepOdeSolver (const AbsODERHS &rhs)
	ConstantStepOdeSolver (const ConstantStepOdeSolver &r)
double	getCoordinate (const unsigned which, const unsigned idx) const
double	getIntegrated (unsigned which, unsigned idx) const
double	getPeakTime (unsigned which) const
const AbsODERHS *	getRHS () const
AbsODERHS *	getRHS ()
double	getTime (const unsigned idx) const
double	interpolateCoordinate (unsigned which, double t, bool cubic=false) const
double	interpolateIntegrated (unsigned which, double t, bool cubic=false) const
double	lastDeltaT () const
unsigned	lastDim () const
double	lastMaxT () const
unsigned	lastRunLength () const
ConstantStepOdeSolver &	operator= (const ConstantStepOdeSolver &r)
void	run (const double *initialConditions, unsigned lenConditions, double dt, unsigned nSteps)
void	setHistory (double dt, const double *data, unsigned dim, unsigned runLen)
void	setRHS (const AbsODERHS &rhs)
void	truncateCoordinate (unsigned which, double minValue, double maxValue)
void	writeHistory (std::ostream &os, double dt, bool cubic=false) const
void	writeIntegrated (std::ostream &os, unsigned which, double dt, bool cubic=false) const
virtual	~ConstantStepOdeSolver ()

Private Member Functions
void	step (double t, double dt, const double *x, unsigned lenX, double *coordIncrement) const

Private Attributes
std::vector< double >	buf_

Additional Inherited Members
Protected Attributes inherited from ConstantStepOdeSolver
AbsODERHS *	rhs_

Detailed Description

Definition at line 149 of file ConstantStepOdeSolver.h.

Constructor & Destructor Documentation

RK2::RK2 ( )

inline

Definition at line 152 of file ConstantStepOdeSolver.h.

: ConstantStepOdeSolver() {}

RK2::RK2 ( const AbsODERHS &  rhs )

inlineexplicit

Definition at line 154 of file ConstantStepOdeSolver.h.

: ConstantStepOdeSolver(rhs) {}

Member Function Documentation

const char* RK2::methodName ( ) const

inlinevirtual

Implements ConstantStepOdeSolver.

Definition at line 156 of file ConstantStepOdeSolver.h.

{return "2nd order Runge-Kutta";}

void RK2::step ( double  t, double  dt, const double *  x, unsigned  lenX, double *  coordIncrement  ) const

privatevirtual

Implements ConstantStepOdeSolver.

Definition at line 354 of file ConstantStepOdeSolver.cc.

References buf_, AbsODERHS::calc(), i, and ConstantStepOdeSolver::rhs_.

{
    const double halfstep = dt/2.0;
    if (buf_.size() < lenX)
        buf_.resize(lenX);
    double* midpoint = &buf_[0];
    rhs_->calc(t, x, lenX, midpoint);
    for (unsigned i=0; i<lenX; ++i)
    {
        midpoint[i] *= halfstep;
        midpoint[i] += x[i];
    }
    rhs_->calc(t + halfstep, midpoint, lenX, coordIncrement);
    for (unsigned i=0; i<lenX; ++i)
        coordIncrement[i] *= dt;
}

Member Data Documentation

std::vector<double> RK2::buf_

mutableprivate

Definition at line 163 of file ConstantStepOdeSolver.h.

Referenced by step().