jvx.numeric
Class PnGeodesicRK

java.lang.Object
  |
  +--jv.object.PsObject
        |
        +--jvx.numeric.PnGeodesicRK

All Implemented Interfaces:

java.lang.Cloneable, PsUpdateIf, java.io.Serializable

Direct Known Subclasses:

PnElementRK, PnTranslationRK, PnVertexRK

public class PnGeodesicRK

extends PsObject

Discret Runge-Kutta method on ElementSets. ElementSet must be triangulated.

Version:

20.02.00, 1.04 revised (ep) removed "small velocity bug", added StepLength 28.12.99, 1.03 revised (ep) added fast-mode (euler-mode)
27.12.99, 1.02 revised (ep) corrected handling of |vector| == 0
21.11.99, 1.01 revised (ep) split into PnGeodesicRK, PnVertexRK, PnElementRK

See Also:

PgElementSet.triangulate(jv.geom.PgElementSet), Serialized Form

Field Summary

protected boolean	m_fast If m_fast == true then a first order (i.e. euler) method is used.
protected PgElementSet	m_geom Discrete surface.
protected double	m_lastLength Euklidian length of the last rk-step.
protected PgPolygonOnElementSet	m_outpoly Contains the polygon of the whole RK integration.

Fields inherited from class jv.object.PsObject

HAS_CONFIG_PANEL, HAS_INFO_PANEL, HAS_MATERIAL_PANEL, INSPECTOR_INFO, INSPECTOR_INFO_EXT, IS_DELETED, IS_FIXED, IS_SELECTED, IS_USED, m_infoPanel, m_name, m_panelList, m_parent, m_tag, m_updateList, NUM_TAGS

Constructor Summary

PnGeodesicRK(PgElementSet geom)

Method Summary

void	eval(int elemInd, PdBary bary, PdBaryDir out) Evaluate vector field on given element at given barycentric coordinate.
double	getStepLength()
PgPolygonOnElementSet	getStepPolygon()
boolean	nextStep() Calculates the next step of actual integration.
boolean	prepareSolve(PgPolygonOnElementSet outpoly, int iniElem, PdBary iniPoint, double h) If not method solve is used, this method has to be called before integration.
protected int	rungeKutta(int elemInd, PdBary pos, PdBaryDir dir, double stepsize) Calculates next direction of runge-kutta step.
void	setFirstOrder(boolean flag) Sets integration method to euler if flag is true, else to 4th-order Runge-Kutta.
void	setFourthOrder(boolean flag) Sets integration method to 4th-order Runge-Kutta if flag is true, else to euler.
void	setGeometry(PgElementSet geom) Sets underlying geometry.
void	solve(PgPolygonOnElementSet outpoly, int iniElem, PdBary iniPoint, double h, int numIterations) Returns a whole integral line.

Methods inherited from class jv.object.PsObject

addInspector, addUpdateListener, clearTag, clone, clone, clone, copy, getFather, getInfoPanel, getInspector, getName, getNumObjects, hasInspector, hasTag, hasUpdateListener, init, instanceOf, instanceOf, removeInspector, removeUpdateListener, setName, setParent, setTag, toString, update, updatePanels

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

m_geom

protected PgElementSet m_geom

Discrete surface. On that surface integration is done.

m_fast

protected boolean m_fast

If m_fast == true then a first order (i.e. euler) method is used.

m_outpoly

protected PgPolygonOnElementSet m_outpoly

Contains the polygon of the whole RK integration.

m_lastLength

protected double m_lastLength

Euklidian length of the last rk-step.

Constructor Detail

PnGeodesicRK

public PnGeodesicRK(PgElementSet geom)

Method Detail

setGeometry

public void setGeometry(PgElementSet geom)

Sets underlying geometry.

Parameters:

geom - new underlying geometry

setFirstOrder

public void setFirstOrder(boolean flag)

Sets integration method to euler if flag is true, else to 4th-order Runge-Kutta.

Parameters:

flag - true: euler; false: 4th-order RK

setFourthOrder

public void setFourthOrder(boolean flag)

Sets integration method to 4th-order Runge-Kutta if flag is true, else to euler.

Parameters:

flag - true: 4th-order RK; false: euler

solve

public void solve(PgPolygonOnElementSet outpoly,
                  int iniElem,
                  PdBary iniPoint,
                  double h,
                  int numIterations)

Returns a whole integral line. To get an integral line of unfixed length step by step, use prepareSolve, nextStep and getStepPolygon.

Parameters:

outpoly - output: here the polygon is saved

iniElem - initial element index

iniPoint - initial barycentric coordinates

h - stepsize

numIterations - length of polygon is h*numIterations

See Also:

prepareSolve(jvx.geom.PgPolygonOnElementSet, int, jv.vecmath.PdBary, double), nextStep(), getStepPolygon()

prepareSolve

public boolean prepareSolve(PgPolygonOnElementSet outpoly,
                            int iniElem,
                            PdBary iniPoint,
                            double h)

If not method solve is used, this method has to be called before integration. It initializes all internal variables.

Parameters:

outpoly - output: here the polygon is saved

iniElem - initial element index

iniPoint - initial barycentric coordinates

h - stepsize

See Also:

solve(jvx.geom.PgPolygonOnElementSet, int, jv.vecmath.PdBary, double, int)

nextStep

public boolean nextStep()

Calculates the next step of actual integration.

Returns:

false if integration stopped by error or because edge was reached or next direction would be of zero length

See Also:

solve(jvx.geom.PgPolygonOnElementSet, int, jv.vecmath.PdBary, double, int), prepareSolve(jvx.geom.PgPolygonOnElementSet, int, jv.vecmath.PdBary, double), getStepPolygon()

getStepPolygon

public PgPolygonOnElementSet getStepPolygon()

Returns:

polygon that had been added to the integral line at last integration step

getStepLength

public double getStepLength()

Returns:

euklidian length of last runge-kutta step

rungeKutta

protected int rungeKutta(int elemInd,
                         PdBary pos,
                         PdBaryDir dir,
                         double stepsize)

Calculates next direction of runge-kutta step.

Parameters:

elemInd - global element index of starting point

pos - barycentric coordinates of starting point

dir - output: barycentric direction

stepsize - stepsize

Returns:

index of the element on which calculated direction lies;
-1 at error or if direction would be of zero length

eval

public void eval(int elemInd,
                 PdBary bary,
                 PdBaryDir out)

Evaluate vector field on given element at given barycentric coordinate. Implementation in PnGeodesicRK does nothing. Has to be overwritten in subclasses.

Parameters:

elemInd - the element in which the vector field will be evaluated

bary - barycentric coordinates of the point in which the vector field will be evaluated

out - output: in this PdBaryDir the evaluated direction will be stored

See Also:

PnElementRK.eval(int, jv.vecmath.PdBary, jv.vecmath.PdBaryDir), PnVertexRK.eval(int, jv.vecmath.PdBary, jv.vecmath.PdBaryDir), PnTranslationRK.eval(int, jv.vecmath.PdBary, jv.vecmath.PdBaryDir)