jvx.numeric
Class PnEnergyMinimizer

java.lang.Object
  jv.object.PsObject
      jvx.numeric.PnEnergyMinimizer

All Implemented Interfaces:

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

public class PnEnergyMinimizer

extends PsObject

implements java.lang.Runnable

Main class to vary a surface to minimize a given energy functional. Minimization runs in a separate thread. For Dirichlet and Area minimization support for hessian and eigenvalues included.

See Also:

Serialized Form

Field Summary

static int	ALIGNMENT
static int	AREA
static int	CONFORMAL
static int	DIRICHLET
static int	GAUSS
static int	SPRING
static int	VOLUME

Fields inherited from class jv.object.PsObject

HAS_CONFIG_PANEL, HAS_INFO_PANEL, HAS_LABEL_PANEL, HAS_MATERIAL_PANEL, HAS_TEXTURE_PANEL, HAS_VECTOR_PANEL, INSPECTOR_INFO, INSPECTOR_INFO_EXT, IS_DELETED, IS_FIXED, IS_FOCUSSED, IS_PICKED, IS_SELECTED, IS_USED, NUM_TAGS

Constructor Summary

PnEnergyMinimizer()

Method Summary

boolean	computeEigenvectors() Compute eigenvectors either of Hessian or of an L2-corrected Hessian.
void	enableUpdateDomain(boolean flag) Flag whether domain is updated after each CG-minization loop.
PgElementSet	getDomain() Get currently registered domain geometry.
PnEnergy	getEnergy() Get current energy.
double	getInitialStepsize()
PgElementSet	getSurface() Get currently registered surface.
void	init() If instance has missing name then assign default name 'Object_NUMBER' where number is the total number of already created instances.
boolean	isEnabledConstrainMatrix() Determine if usage of a constrain matrix is enabled.
boolean	isEnabledFixVertices() Determine if marked vertices remain fixed during minimization.
boolean	isRunning() Check whether energy minimizer will be stopped.
boolean	isStopped() Check whether energy minimizer is currently NOT running a minimizing thread.
double	minimize() Minimize energy by invoking conjugate gradient method in a loop.
void	printEigenvalues() Print eigenvalues of hessian to JavaView console.
void	printEigenvectors() Print eigenvectors of hessian to JavaView console.
void	printGradient() Evaluate and print the energy gradient to the JavaView console.
void	printHessian() Evaluate the Hessian matrix of the energy and print its content to the JavaView console.
void	run() Do energy minimization until m_numLoops are done or until a call of stop().
void	saveEigenvectors() Save eigenvectors of hessian as vector fields of the surface.
void	setEnabledConstrainMatrix(boolean flag) Enable usage of a constrain matrix for index computation of Neumann boundary geometries.
void	setEnabledFixVertices(boolean flag) Enable if marked vertices remain fixed during minimization.
void	setEnergy(PnEnergy energy) Set new energy and clear all vector fields.
void	setInitialStepsize(double h)
void	setNumLoops(int numLoops) Set number of calls of conjugate gradient method to be performed during each call to PnEnergyMinimizer#minimize().
boolean	setSurface(PgElementSet domain, PgElementSet surface) Set references to domain and image surface.
void	setUpdateDomain(boolean flag) Set flag which enables the updating of the domain with the current surface after every minimization step.
void	showEigenvector(int ind) Show eigenvectors of hessian as vector field on the surface.
void	showGradient() Evaluate and show the gradient as vectors at each vertex.
void	showNone() Clear all internal vector fields of this class and of the registered surface.
void	start() Start energy minimization in separate thread.
void	step() Move vertices in negative gradient direction a certain amount.
void	step(int numSteps) Move vertices in negative gradient direction a certain amount.
void	stop() Stop energy minimization in separate thread.
boolean	update(java.lang.Object event) Update the class whenever a child has changed.

Methods inherited from class jv.object.PsObject

addInspector, addUpdateListener, assureInspector, clearTag, clone, clone, clone, copy, getFather, getInfoPanel, getInspector, getName, getNumObjects, getSymbol, hasInspector, hasTag, hasUpdateListener, instanceOf, instanceOf, newInspector, newInspector, removeInspector, removeInspector, removeUpdateListener, setName, setParent, setSymbol, setTag, toString, updatePanels

Methods inherited from class java.lang.Object

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

Field Detail

DIRICHLET

public static final int DIRICHLET

See Also:

Constant Field Values

AREA

public static final int AREA

See Also:

Constant Field Values

CONFORMAL

public static final int CONFORMAL

See Also:

Constant Field Values

SPRING

public static final int SPRING

See Also:

Constant Field Values

ALIGNMENT

public static final int ALIGNMENT

See Also:

Constant Field Values

VOLUME

public static final int VOLUME

See Also:

Constant Field Values

GAUSS

public static final int GAUSS

See Also:

Constant Field Values

Constructor Detail

PnEnergyMinimizer

public PnEnergyMinimizer()

Method Detail

init

public void init()

Description copied from class: PsObject

If instance has missing name then assign default name 'Object_NUMBER' where number is the total number of already created instances.

Overrides:

init in class PsObject

update

public boolean update(java.lang.Object event)

Update the class whenever a child has changed. Method is usually invoked from the children.

Specified by:

update in interface PsUpdateIf

Overrides:

update in class PsObject

See Also:

PsObject.setParent(PsUpdateIf), PsObject.getFather(), PsObject.addUpdateListener(PsUpdateIf)

getEnergy

public PnEnergy getEnergy()

Get current energy.

setEnergy

public void setEnergy(PnEnergy energy)

Set new energy and clear all vector fields. Domain argument maybe null.

isEnabledFixVertices

public boolean isEnabledFixVertices()

Determine if marked vertices remain fixed during minimization.

setEnabledFixVertices

public void setEnabledFixVertices(boolean flag)

Enable if marked vertices remain fixed during minimization.

isEnabledConstrainMatrix

public boolean isEnabledConstrainMatrix()

Determine if usage of a constrain matrix is enabled.

setEnabledConstrainMatrix

public void setEnabledConstrainMatrix(boolean flag)

Enable usage of a constrain matrix for index computation of Neumann boundary geometries.

enableUpdateDomain

public void enableUpdateDomain(boolean flag)

Flag whether domain is updated after each CG-minization loop. When iteratively computing harmonic maps copy image surface into domain after minimization to update domain metric. Main use is inside Pinkall/Polthier algorithm on computing minimal surfaces by iterating harmonic maps.

getDomain

public PgElementSet getDomain()

Get currently registered domain geometry.

getSurface

public PgElementSet getSurface()

Get currently registered surface.

setSurface

public boolean setSurface(PgElementSet domain,
                          PgElementSet surface)

Set references to domain and image surface. Image surface is usually being minimized while domain surface is often used when minimizing energy of maps between surfaces. Dimension of vertices of domain and surface may be different, e.g., domain may have 2-dimensional and surface may have 1-dimensional vertices.

Remark: If the geometries are changed outside this energy minimizer, the user must call setSurface() again to update the energy minimizer. Otherwise, further minimization calls will use the old geometry information.

setNumLoops

public void setNumLoops(int numLoops)

Set number of calls of conjugate gradient method to be performed during each call to PnEnergyMinimizer#minimize().

This number of loops is independent of the number of iterations used in each single invocation of the CG-method, which depends on the requested accurracy PnEnergyMinimizer#m_cgEps.

See Also:

minimize()

minimize

public double minimize()

Minimize energy by invoking conjugate gradient method in a loop. A separate thread is started which calls in each step a conjugate gradient method. The number of loops may be set using #setNumLoops(int).

See Also:

setNumLoops(int)

setUpdateDomain

public void setUpdateDomain(boolean flag)

Set flag which enables the updating of the domain with the current surface after every minimization step. This is an essential part of the computation of minimal surface through an iteration of minimizing the Dirichlet energy, but in some other cases the domain is preferably not updated.

getInitialStepsize

public double getInitialStepsize()

setInitialStepsize

public void setInitialStepsize(double h)

step

public void step()

Move vertices in negative gradient direction a certain amount. Amount is gradient*h with user defined stepsize. This method is applied numLoops times.

See Also:

step(int)

step

public void step(int numSteps)

Move vertices in negative gradient direction a certain amount. Amount is gradient*h with h=0.01. This method is applied numSteps times.

Method starts a new thread if numSteps>1 which calls step().

See Also:

step()

printGradient

public void printGradient()

Evaluate and print the energy gradient to the JavaView console.

showNone

public void showNone()

Clear all internal vector fields of this class and of the registered surface.

showGradient

public void showGradient()

Evaluate and show the gradient as vectors at each vertex. This method assigns a new vector field to the surface, or reuses a vector field with name "Vector Field".

printHessian

public void printHessian()

Evaluate the Hessian matrix of the energy and print its content to the JavaView console. This method should only be applied to surfaces with few coordinates.

computeEigenvectors

public boolean computeEigenvectors()

Compute eigenvectors either of Hessian or of an L2-corrected Hessian.

printEigenvalues

public void printEigenvalues()

Print eigenvalues of hessian to JavaView console. If the eigenvectors are null, then compute eigenvectors.

printEigenvectors

public void printEigenvectors()

Print eigenvectors of hessian to JavaView console. If the eigenvectors are null, then compute eigenvectors.

saveEigenvectors

public void saveEigenvectors()

Save eigenvectors of hessian as vector fields of the surface. If the eigenvectors are null, then compute eigenvectors.

showEigenvector

public void showEigenvector(int ind)

Show eigenvectors of hessian as vector field on the surface. If the eigenvectors are null, then compute eigenvectors.

isRunning

public boolean isRunning()

Check whether energy minimizer will be stopped.

Returns:

false, if the energy minimizer will stop (just shutting down regularely).

isStopped

public boolean isStopped()

Check whether energy minimizer is currently NOT running a minimizing thread.

start

public void start()

Start energy minimization in separate thread.

stop

public void stop()

Stop energy minimization in separate thread.

run

public void run()

Do energy minimization until m_numLoops are done or until a call of stop().

Specified by:

run in interface java.lang.Runnable