artisynth.core.mechmodels

Class ConstrainerBase

java.lang.Object

artisynth.core.modelbase.ModelComponentBase

artisynth.core.mechmodels.ConstrainerBase

All Implemented Interfaces:

Constrainer, HasNumericState, ModelComponent, PostScannable, java.lang.Cloneable, HasProperties, HierarchyNode, Scannable

Direct Known Subclasses:

FrameFem3dConstraint, JointCoordinateCoupling, LinearPointConstraint, RenderableConstrainerBase, SimpleCoordinateCoupler

public abstract class ConstrainerBase
extends ModelComponentBase
implements Constrainer, HasNumericState

Nested Class Summary

Nested classes/interfaces inherited from interface artisynth.core.modelbase.ModelComponent

ModelComponent.NavpanelVisibility

Field Summary

Fields inherited from class artisynth.core.modelbase.ModelComponentBase

enforceUniqueCompositeNames, enforceUniqueNames, myNumber, myProps, NULL_OBJ, useCompactPathNames

Constructor Summary

Constructors

Constructor and Description
ConstrainerBase()

Method Summary

Modifier and Type	Method and Description
abstract int	addBilateralConstraints(SparseBlockMatrix GT, VectorNd dg, int numb) Appends the current bilateral force constraint matrix Gc^T to the matrix GT, by appending block columns to it.
int	addFrictionConstraints(SparseBlockMatrix DT, java.util.ArrayList<FrictionInfo> finfo, boolean prune, int idx) Appends the friction force constraint matrix Dc^T to the matrix DT, by appending block columns to it.
int	addUnilateralConstraints(SparseBlockMatrix NT, VectorNd dn, int numu) Appends the current unilateral force constraint matrix Nc^T to the matrix NT, by appending block columns to it.
abstract int	getBilateralForces(VectorNd lam, int idx) Returns the bilateral forces that were most recently set for this constrainer using Constrainer.setBilateralForces(maspack.matrix.VectorNd, double, int).
abstract int	getBilateralInfo(MechSystem.ConstraintInfo[] ginfo, int idx) Returns constraint information for each row of the bilateral constraint system
abstract void	getBilateralSizes(VectorNi sizes) Returns the sizes of each block column in the bilateral force constraint matrix.
abstract void	getConstrainedComponents(java.util.List<DynamicComponent> list) Collected all the dynamic components constrained by this constrainer.
int	getFrictionForces(VectorNd phi, int idx) Returns the friction forces that were most recently set for this constrainer using Constrainer.setFrictionForces(maspack.matrix.VectorNd, double, int).
int	getFrictionState(VectorNi state, int idx)
void	getState(DataBuffer data) Saves state information for this component by adding data to the supplied DataBuffer.
int	getUnilateralForces(VectorNd the, int idx) Returns the unilateral forces that were most recently set for this constrainer using Constrainer.setUnilateralForces(maspack.matrix.VectorNd, double, int).
int	getUnilateralInfo(MechSystem.ConstraintInfo[] ninfo, int idx) Returns constraint information for each row of the unilateral constraint system
void	getUnilateralSizes(VectorNi sizes) Returns the sizes of each block column in the unilateral force constraint matrix.
int	getUnilateralState(VectorNi state, int idx)
boolean	hasState() Queries if this component has state.
int	maxFrictionConstraintSets() Returns the maximum number of friction constraint sets that can be expected for this constraint.
abstract int	setBilateralForces(VectorNd lam, double s, int idx) Sets the bilateral forces that were computed to enforce this constraint.
int	setFrictionForces(VectorNd phi, double s, int idx) Sets the friction forces that were computed to enforce this constraint.
int	setFrictionState(VectorNi state, int idx)
void	setState(DataBuffer data) Restores the state for this component by reading from the supplied data buffer, starting at the current buffer offsets.
int	setUnilateralForces(VectorNd the, double s, int idx) Sets the unilateral forces that were computed to enforce this constraint.
int	setUnilateralState(VectorNi state, int idx)
abstract double	updateConstraints(double t, int flags) Updates the current set of constraints, and returns the maximum penetration > 0 associated with all of them.
abstract void	zeroForces() Zeros all bilateral and unilateral constraint forces in this constraint.

Methods inherited from class artisynth.core.modelbase.ModelComponentBase

checkFlag, checkName, checkNameUniqueness, clearFlag, clone, connectToHierarchy, copy, createTempFlag, disconnectFromHierarchy, getAllPropertyInfo, getChildren, getGrandParent, getHardReferences, getName, getNameRange, getNavpanelVisibility, getNavpanelVisibility, getNumber, getParent, getProperty, getSoftReferences, hasChildren, isFixed, isMarked, isScanning, isSelected, isWritable, makeValidName, makeValidName, notifyParentOfChange, postscan, printReferences, recursivelyContained, recursivelyContains, removeTempFlag, scan, setFixed, setFlag, setMarked, setName, setNavpanelVisibility, setNavpanelVisibility, setNumber, setParent, setScanning, setSelected, setWritable, updateReferences, write

Methods inherited from class java.lang.Object

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

Methods inherited from interface artisynth.core.modelbase.HasNumericState

advanceState, getAuxVarDerivative, getAuxVarState, getStateVersion, numAuxVars, requiresAdvance, setAuxVarState

Constructor Detail

ConstrainerBase

public ConstrainerBase()

Method Detail

getBilateralSizes

public abstract void getBilateralSizes(VectorNi sizes)

Description copied from interface: Constrainer

Returns the sizes of each block column in the bilateral force constraint matrix. The size for each block should be appended to the vector sizes.

Specified by:

getBilateralSizes in interface Constrainer

Parameters:

sizes - vector to which the block column sizes are appended

addBilateralConstraints

public abstract int addBilateralConstraints(SparseBlockMatrix GT,
                                            VectorNd dg,
                                            int numb)

Description copied from interface: Constrainer

Appends the current bilateral force constraint matrix Gc^T to the matrix GT, by appending block columns to it. If the argument dg is non-null, it should be used to return the velocity constraint time derivative, defined by

 \dot Gc vel
 

starting at the location numb. In all cases, the method must return an updated value of numb, incremented by the total row size of Gc.

Specified by:

addBilateralConstraints in interface Constrainer

Parameters:

GT - matrix to which the bilateral force contraint matrix is appended.

dg - if non-null, returns the velocity constraint time derivative

numb - starting index for time derivative in dg

Returns:

updated value of numb

getBilateralInfo

public abstract int getBilateralInfo(MechSystem.ConstraintInfo[] ginfo,
                                     int idx)

Description copied from interface: Constrainer

Returns constraint information for each row of the bilateral constraint system

 Gc vel = 0.
 

This information is placed in pre-allocated MechSystem.ConstraintInfo structures in ginfo, starting at idx. The method must return an updated value of idx, incremented by the number of rows of Gc.

The constraint information to be set in ConstraintInfo includes:

   dist        // distance to the constraint surface.
   compliance  // if > 0, gives constraint compliance value
   damping     // damping; only used if compliance > 0
   force       // used for computing non-linear compliance
 

Specified by:

getBilateralInfo in interface Constrainer

Parameters:

ginfo - returns the constraint information

idx - starting location in ginfo for returning constraint info

Returns:

updated value of idx

setBilateralForces

public abstract int setBilateralForces(VectorNd lam,
                                       double s,
                                       int idx)

Description copied from interface: Constrainer

Sets the bilateral forces that were computed to enforce this constraint. These are the Lagrange multipliers for the columns of the transposed bilateral constraint matrix. The forces are supplied in lam, starting at the index idx, and should be scaled by s. (In practice, s is used to convert from impulses to forces.) The method must return an updated value of idx, incremented by the number of forces associated with this constraint.

Specified by:

setBilateralForces in interface Constrainer

Parameters:

lam - supplies the force impulses, which should be scaled by s

s - scaling factor for the force values

idx - starting index of forces in lam

Returns:

updated value of idx

getBilateralForces

public abstract int getBilateralForces(VectorNd lam,
                                       int idx)

Description copied from interface: Constrainer

Returns the bilateral forces that were most recently set for this constrainer using Constrainer.setBilateralForces(maspack.matrix.VectorNd, double, int). The forces are returned in lam, starting at the index idx. The method must return an updated value of idx, incremented by the number of forces associated with this constraint.

Specified by:

getBilateralForces in interface Constrainer

Parameters:

lam - returns the forces

idx - starting index for forces in lam

Returns:

updated value of idx

zeroForces

public abstract void zeroForces()

Description copied from interface: Constrainer

Zeros all bilateral and unilateral constraint forces in this constraint.

Specified by:

zeroForces in interface Constrainer

getUnilateralSizes

public void getUnilateralSizes(VectorNi sizes)

Description copied from interface: Constrainer

Returns the sizes of each block column in the unilateral force constraint matrix. The size for each block should be appended to the vector sizes.

Specified by:

getUnilateralSizes in interface Constrainer

Parameters:

sizes - vector to which the block column sizes are appended

addUnilateralConstraints

public int addUnilateralConstraints(SparseBlockMatrix NT,
                                    VectorNd dn,
                                    int numu)

Description copied from interface: Constrainer

Appends the current unilateral force constraint matrix Nc^T to the matrix NT, by appending block columns to it. If the argument dn is non-null, it should be used to return the velocity constraint time derivative, defined by

 \dot Nc vel
 

starting at the location numu. In all cases, the method must return an updated value of numu, incremented by the total row size of Nc.

Specified by:

addUnilateralConstraints in interface Constrainer

Parameters:

NT - matrix to which the unilateral force contraint matrix is appended.

dn - if non-null, returns the velocity constraint time derivative

numu - starting index for time derivative in dn

Returns:

updated value of numu

getUnilateralInfo

public int getUnilateralInfo(MechSystem.ConstraintInfo[] ninfo,
                             int idx)

Description copied from interface: Constrainer

Returns constraint information for each row of the unilateral constraint system

 Nc vel > 0.
 

This information is placed in pre-allocated MechSystem.ConstraintInfo structures in ninfo, starting at idx. The method must return an updated value of idx, incremented by the number of rows of Nc.

The constraint information to be set in ConstraintInfo includes:

   dist        // distance to the constraint surface.
   compliance  // if > 0, gives constraint compliance value
   damping     // damping; only used if compliance > 0
   force       // used for computing non-linear compliance
 

Specified by:

getUnilateralInfo in interface Constrainer

Parameters:

ninfo - returns the constraint information

idx - starting location in ninfo for returning constraint info

Returns:

updated value of idx

setUnilateralForces

public int setUnilateralForces(VectorNd the,
                               double s,
                               int idx)

Description copied from interface: Constrainer

Sets the unilateral forces that were computed to enforce this constraint. These are the Lagrange multipliers for the columns of the transposed unilateral constraint matrix. The forces are supplied in the, starting at the index idx, and should be scaled by s. (In practice, s is used to convert from impulses to forces.) The method must return an updated value of idx, incremented by the number of forces associated with this constraint.

Specified by:

setUnilateralForces in interface Constrainer

Parameters:

the - supplies the force impulses, which should be scaled by s

s - scaling factor for the force values

idx - starting index of forces in the

Returns:

updated value of idx

getUnilateralForces

public int getUnilateralForces(VectorNd the,
                               int idx)

Description copied from interface: Constrainer

Returns the unilateral forces that were most recently set for this constrainer using Constrainer.setUnilateralForces(maspack.matrix.VectorNd, double, int). The forces are returned in the, starting at the index idx. The method must return an updated value of idx, incremented by the number of forces associated with this constraint.

Specified by:

getUnilateralForces in interface Constrainer

Parameters:

the - returns the forces

idx - starting index for forces in the

Returns:

updated value of idx

setUnilateralState

public int setUnilateralState(VectorNi state,
                              int idx)

Specified by:

setUnilateralState in interface Constrainer

getUnilateralState

public int getUnilateralState(VectorNi state,
                              int idx)

Specified by:

getUnilateralState in interface Constrainer

maxFrictionConstraintSets

public int maxFrictionConstraintSets()

Description copied from interface: Constrainer

Returns the maximum number of friction constraint sets that can be expected for this constraint. There should be one constraint set for each bilateral or unilateral constraint that may be associated with friction. This method is used for presizing the finfo argument that is passed to Constrainer.addFrictionConstraints(maspack.matrix.SparseBlockMatrix, java.util.ArrayList<maspack.spatialmotion.FrictionInfo>, boolean, int).

Specified by:

maxFrictionConstraintSets in interface Constrainer

Returns:

maximum number of friction constraint sets

addFrictionConstraints

public int addFrictionConstraints(SparseBlockMatrix DT,
                                  java.util.ArrayList<FrictionInfo> finfo,
                                  boolean prune,
                                  int idx)

Description copied from interface: Constrainer

Appends the friction force constraint matrix Dc^T to the matrix DT, by appending block columns to it. Each block column in Dc^T corresponds to a friction constraint set, for which information should be supplied in the pre-allocated FrictionInfo structures in finfo, starting at idx. The method must return an updated value of idx, incremented by the number of friction constraint sets.

Specified by:

addFrictionConstraints in interface Constrainer

Parameters:

DT - matrix to which the friction force contraint matrix is appended.

finfo - returns friction constraint information for each block column in Dc^T

prune - restrict entries of DT to friction constraints for which the contact force is > 0.

idx - starting index for friction information in finfo

Returns:

updated value of idx

setFrictionForces

public int setFrictionForces(VectorNd phi,
                             double s,
                             int idx)

Sets the friction forces that were computed to enforce this constraint. These are the Lagrange multipliers for the columns of the transposed friction constraint matrix. The forces are supplied in phi, starting at the index idx, and should be scaled by s. (In practice, s is used to convert from impulses to forces.) The method must return an updated value of idx, incremented by the number of forces associated with this constraint.

Specified by:

setFrictionForces in interface Constrainer

Parameters:

phi - supplies the force impulses, which should be scaled by s

s - scaling factor for the force values

idx - starting index of forces in phi

Returns:

updated value of idx

getFrictionForces

public int getFrictionForces(VectorNd phi,
                             int idx)

Returns the friction forces that were most recently set for this constrainer using Constrainer.setFrictionForces(maspack.matrix.VectorNd, double, int). The forces are returned in phi, starting at the index idx. The method must return an updated value of idx, incremented by the number of forces associated with this constraint.

Specified by:

getFrictionForces in interface Constrainer

Parameters:

phi - returns the forces

idx - starting index for forces in phi

Returns:

updated value of idx

setFrictionState

public int setFrictionState(VectorNi state,
                            int idx)

Specified by:

setFrictionState in interface Constrainer

getFrictionState

public int getFrictionState(VectorNi state,
                            int idx)

Specified by:

getFrictionState in interface Constrainer

updateConstraints

public abstract double updateConstraints(double t,
                                         int flags)

Description copied from interface: Constrainer

Updates the current set of constraints, and returns the maximum penetration > 0 associated with all of them. If no constraints are presently active, returns -1.

Specified by:

updateConstraints in interface Constrainer

getConstrainedComponents

public abstract void getConstrainedComponents(java.util.List<DynamicComponent> list)

Description copied from interface: Constrainer

Collected all the dynamic components constrained by this constrainer. Not currently used.

Specified by:

getConstrainedComponents in interface Constrainer

Parameters:

list - list to which constrained components should be appended

getState

public void getState(DataBuffer data)

Description copied from interface: HasNumericState

Saves state information for this component by adding data to the supplied DataBuffer. Existing data in the buffer should not be disturbed.

Specified by:

getState in interface HasNumericState

Parameters:

data - buffer for storing the state values.

setState

public void setState(DataBuffer data)

Description copied from interface: HasNumericState

Restores the state for this component by reading from the supplied data buffer, starting at the current buffer offsets.

Specified by:

setState in interface HasNumericState

Parameters:

data - buffer containing the state information

hasState

public boolean hasState()

Queries if this component has state. Structure change events involving components that have state will cause the current state history of of the system to be cleared.

Specified by:

hasState in interface HasNumericState

Specified by:

hasState in interface ModelComponent

Overrides:

hasState in class ModelComponentBase

Returns:

true if this component has state