Documentation of 'jvx.numeric.PnEnergyMinimizer' Java class
PnEnergyMinimizer ("JavaView Reference Manual")
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"JavaView? v5.03.003"
jvx.numeric

Class PnEnergyMinimizer

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, java.lang.Runnable, PsUpdateIf

    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
    Author:
    Konrad Polthier
    Version:
    06.02.04, 1.80 revised (kp) Fixing of marked vertices corrected since checkbox showed no effect.
    19.12.01, 1.70 revised (ep) Internationalization.
    17.01.01, 1.60 revised (ep) Thread handling slightly corrected. More coming later.
    04.01.01, 1.50 revised (kp) Domain geometry may be missing.
    08.11.00, 2.10 revised (kp) Replace formatting with PuString rather than Fmt.
    21.07.99, 2.00 revised (kp)
    00.00.98, 1.00 created (kp)

    • 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

      • 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.
        Version:
        04.01.01, 1.10 revised (kp) Domain geometry may be missing.

      • 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-minimization 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 accuracy 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()
        Get stepsize used in cg iteration.

      • setInitialStepsize

        public void setInitialStepsize(double h)
        Set stepsize used in cg iteration.

      • 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)
        Version:
        26.06.01, 1.60 revised (kp) Allow a small tolerance when searching for step size.
        14.03.01, 1.50 revised (kp) No longer multiply h with numLoops.

      • 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()
        Version:
        14.03.01, 1.00 created (kp)

      • 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 int computeEigenvectors()
        Compute eigenvectors either of Hessian or of an L2-corrected Hessian.
        Version:
        12.02.03, 1.10 revised (kp) Implement Neumann conditions for pure 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.

      • getEigenSolver

        public java.lang.String[] getEigenSolver()
        Returns:
        Names of available eigensolver.

      • getEigenSolverPanel

        public PsPanel getEigenSolverPanel(int id)
        Parameters:
        id - of eigensolver corresponding to order in of Names in Array returned by getEigenSolver().
        Returns:
        InfoPanel of eigensolver.

      • setEigenSolver

        public void setEigenSolver(int id)
        Parameters:
        id - of eigensolver corresponding to order in of Names in Array returned by getEigenSolver().

      • isRunning

        public boolean isRunning()
        Check whether energy minimizer will be stopped.
        Returns:
        false, if the energy minimizer will stop (just shutting down regularly).

      • 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.
        Version:
        02.08.00, 1.10 revised (kp) Disabled setting of m_energy.enableEvaluation(false).

      • 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
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