QssIntegrator Class Reference

A Quasi-Steady-State ODE Integrator based on CHEMEQ2. More...

#include <qssintegrator.h>

Public Member Functions
	QssIntegrator ()
virtual	~QssIntegrator ()
void	setOde (QssOde *ode)
	Set the ODE object to be integrated.
virtual void	initialize (size_t N)
	Initialize integrator arrays (problem size of N)
void	setState (const dvec &yIn, double tStart)
	Set state at the start of a global timestep.
int	integrateToTime (double tf)
	Take as many steps as needed to reach tf.
int	integrateOneStep (double tf)
	Take one step toward tf without stepping past it.

Public Attributes
double	tn
	Internal integrator time (relative to tstart)
dvec	y
	current state vector
bool	stabilityCheck
	Flag to enable convergence-based stability check on timestep.
int	itermax
	Number of corrector iterations to perform.
double	epsmin
	Accuracy parameter for determining the next timestep.
double	epsmax
	Repeat timestep if correction is greater than #epsmax * #epsmin * #y[i] for any i.
double	dtmin
	Minimum timestep allowed.
double	dtmax
	Maximum timestep allowed.
dvec	ymin
	Minimum value allowed for each component.
dvec	enforce_ymin
	Enforce the minimum value specified in ymin for each component.
double	abstol
	Minimum component value to consider when determining stability / step size.
int	rcount
	Total number of timestep repeats (after failed timesteps)
int	gcount
	Total number of ODE function calls.

Private Member Functions
void	getInitialStepSize (double tf)
	Estimate the initial step size.

Private Attributes
QssOde *	ode_
size_t	N
	Number of state variables.
double	ts
	Time at the start of the current internal timestep.
double	tfd
	Round-off parameter used to determine when integration is complete.
double	dt
	Integrator internal timestep.
double	tstart
	Independent variable at the start of the global timestep.
dvec	ym1
	Previous corrector iterate.
dvec	ym2
	Second previous corrector iterate.
dvec	scratch
	temporary array.
dvec	q
	production rate
dvec	d
	loss rate
dvec	rtau
	ratio of timestep to timescale.
dvec	rtaus
	ratio of timestep to initial timescale for current timestep
dvec	y1
	predicted value
dvec	ys
	initial conditions for the chemical timestep
dvec	qs
	initial production rate
bool	firstStep
	Flag to trigger integrator restart on the next call to integrateToTime or integrateOneStep.

Detailed Description

A Quasi-Steady-State ODE Integrator based on CHEMEQ2.

Constructor & Destructor Documentation

QssIntegrator()

QssIntegrator::QssIntegrator

(

)

~QssIntegrator()

virtual QssIntegrator::~QssIntegrator ( )

inlinevirtual

Member Function Documentation

setOde()

void QssIntegrator::setOde

(

QssOde *

ode

)

Set the ODE object to be integrated.

initialize()

void QssIntegrator::initialize ( size_t  N )

virtual

Initialize integrator arrays (problem size of N)

setState()

void QssIntegrator::setState	(	const dvec &	yIn,
		double	tStart
	)

Set state at the start of a global timestep.

integrateToTime()

int QssIntegrator::integrateToTime

(

double

tf

)

Take as many steps as needed to reach tf.

Note that tf is relative to tstart, not absolute.

integrateOneStep()

int QssIntegrator::integrateOneStep

(

double

tf

)

Take one step toward tf without stepping past it.

getInitialStepSize()

void QssIntegrator::getInitialStepSize ( double  tf )

private

Estimate the initial step size.

Strongly increasing functions(q >> d assumed here) use a step- size estimate proportional to the step needed for the function to reach equilibrium where as functions decreasing or in equilibrium use a stepsize estimate directly proportional to the characteristic stepsize of the function. convergence of the integration scheme is likely since the smallest estimate is chosen for the initial stepsize.

Member Data Documentation

tn

double QssIntegrator::tn

Internal integrator time (relative to tstart)

y

dvec QssIntegrator::y

current state vector

stabilityCheck

bool QssIntegrator::stabilityCheck

Flag to enable convergence-based stability check on timestep.

itermax

int QssIntegrator::itermax

Number of corrector iterations to perform.

epsmin

double QssIntegrator::epsmin

Accuracy parameter for determining the next timestep.

epsmax

double QssIntegrator::epsmax

Repeat timestep if correction is greater than #epsmax * #epsmin * #y[i] for any i.

dtmin

double QssIntegrator::dtmin

Minimum timestep allowed.

dtmax

double QssIntegrator::dtmax

Maximum timestep allowed.

ymin

dvec QssIntegrator::ymin

Minimum value allowed for each component.

enforce_ymin

dvec QssIntegrator::enforce_ymin

Enforce the minimum value specified in ymin for each component.

abstol

double QssIntegrator::abstol

Minimum component value to consider when determining stability / step size.

rcount

int QssIntegrator::rcount

Total number of timestep repeats (after failed timesteps)

gcount

int QssIntegrator::gcount

Total number of ODE function calls.

ode_

QssOde* QssIntegrator::ode_

private

N

size_t QssIntegrator::N

private

Number of state variables.

ts

double QssIntegrator::ts

private

Time at the start of the current internal timestep.

tfd

double QssIntegrator::tfd

private

Round-off parameter used to determine when integration is complete.

dt

double QssIntegrator::dt

private

Integrator internal timestep.

tstart

double QssIntegrator::tstart

private

Independent variable at the start of the global timestep.

ym1

dvec QssIntegrator::ym1

private

Previous corrector iterate.

ym2

dvec QssIntegrator::ym2

private

Second previous corrector iterate.

scratch

dvec QssIntegrator::scratch

private

temporary array.

q

dvec QssIntegrator::q

private

production rate

d

dvec QssIntegrator::d

private

loss rate

rtau

dvec QssIntegrator::rtau

private

ratio of timestep to timescale.

rtaus

dvec QssIntegrator::rtaus

private

ratio of timestep to initial timescale for current timestep

y1

dvec QssIntegrator::y1

private

predicted value

ys

dvec QssIntegrator::ys

private

initial conditions for the chemical timestep

qs

dvec QssIntegrator::qs

private

initial production rate

firstStep

bool QssIntegrator::firstStep

private

Flag to trigger integrator restart on the next call to integrateToTime or integrateOneStep.

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

• src/qssintegrator.h
• src/qssintegrator.cpp