artisynth.core.mechmodels

Class DynamicAttachment

java.lang.Object

artisynth.core.modelbase.ModelComponentBase

artisynth.core.mechmodels.DynamicAttachment

All Implemented Interfaces:

ModelComponent, java.lang.Cloneable, HasProperties, HierarchyNode, Scannable

Direct Known Subclasses:

FrameAttachment, PointAttachment

public abstract class DynamicAttachment
extends ModelComponentBase

Component that implements attachment between dynamic components. A component 'a' can be attached to one or more "master" components 'b' if it's position q_a can be made an explicit differentiable function of the positions q_m of the masters:

 q_a = f (q_m)
 

Differentiating means that the attached component velocity u_a is a linear function of the master velocities u_m:

 u_a = -G (u_m)
 

where G = -(d f)/(d q_m) is the "constraint matrix".

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
DynamicAttachment()

Method Summary

Modifier and Type	Method and Description
void	addAttachmentJacobian(SparseBlockMatrix S, VectorNd f, boolean[] reduced) Reduces the system matrix to account for this attachment.
void	addBackRefs() Every master component should contain a back reference to each attachment that references it.
abstract void	addMassToMasters()
void	addSolveBlocks(SparseNumberedBlockMatrix S, boolean[] reduced)
abstract void	applyForces()
java.lang.Object	clone()
void	connectToHierarchy() Update the attachment position state whenever we connect to the parent (i.e., plug in to the hierarchy).
static boolean	containsLoop(DynamicAttachment a, DynamicComponent slave, java.util.HashMap<DynamicComponent,DynamicAttachment> map)
static boolean	containsLoops(java.util.List<DynamicAttachment> list)
boolean	containsMaster(DynamicComponent comp)
DynamicAttachment	copy(int flags, java.util.Map<ModelComponent,ModelComponent> copyMap)
static java.util.ArrayList<DynamicAttachment>	createOrderedList(java.util.List<DynamicAttachment> list) Orders a list of (possibly interdependent) attachments so that the masters of any given attachment do not depend on any attachments further along the list.
void	disconnectFromHierarchy() Update the attachment position state whenever we connect to the parent (i.e., plug in to the hierarchy).
abstract boolean	getDerivative(double[] buf, int idx)
void	getHardReferences(java.util.List<ModelComponent> refs) Appends all hard references for this component to a list.
abstract DynamicComponent[]	getMasters()
abstract DynamicComponent	getSlave() Returns the slave DynamicMechComponent associated with this attachment.
abstract int	getSlaveSolveIndex() Returns the block index within the system solve matrix of the slave DynamicMechComponent associated with this attachment.
abstract void	invalidateMasters()
int	numMasters()
boolean	oneMasterActive()
void	reduceConstraints(SparseBlockMatrix GT, VectorNd dg) Reduces a sparse column matrix (such as the transpose of a constraint matrix) to account for this attachment.
void	reduceMass(SparseBlockMatrix M, VectorNd f)
void	reduceRowMatrix(SparseBlockMatrix G) Reduces a sparse row matrix (such as a constraint matrix) to account for this attachment.
void	removeBackRefs() Removes the back reference to this attachment's slave component from each of the master component.
abstract void	updateAttachment() Update attachment to reflect changes in the slave state.
abstract void	updatePosStates()
abstract void	updateVelStates()

Methods inherited from class artisynth.core.modelbase.ModelComponentBase

checkFlag, checkName, checkNameUniqueness, clearFlag, createTempFlag, getAllPropertyInfo, getChildren, getGrandParent, getName, getNameRange, getNavpanelVisibility, getNavpanelVisibility, getNumber, getParent, getProperty, getSoftReferences, hasChildren, hasState, isConnectedToHierarchy, isFixed, isMarked, isSelected, isWritable, makeValidName, makeValidName, notifyParentOfChange, postscan, printReferences, recursivelyContained, recursivelyContains, removeTempFlag, scan, setFixed, setFlag, setMarked, setName, setNavpanelVisibility, setNavpanelVisibility, setNumber, setParent, setSelected, updateReferences, write

Methods inherited from class java.lang.Object

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

Constructor Detail

DynamicAttachment

public DynamicAttachment()

Method Detail

getMasters

public abstract DynamicComponent[] getMasters()

numMasters

public int numMasters()

invalidateMasters

public abstract void invalidateMasters()

containsMaster

public boolean containsMaster(DynamicComponent comp)

oneMasterActive

public boolean oneMasterActive()

addBackRefs

public void addBackRefs()

Every master component should contain a back reference to each attachment that references it. This method adds the back reference for this attachment to each of the masters.

removeBackRefs

public void removeBackRefs()

Removes the back reference to this attachment's slave component from each of the master component.

getSlave

public abstract DynamicComponent getSlave()

Returns the slave DynamicMechComponent associated with this attachment. In some cases, the attachment may connect some other entity (such as a mesh vertex) to the master components, in which case this method should return null.

Returns:

slave DynamicMechComponent, if any

getSlaveSolveIndex

public abstract int getSlaveSolveIndex()

Returns the block index within the system solve matrix of the slave DynamicMechComponent associated with this attachment. If there is no such component (see getSlave()), this method returns -1.

Returns:

solve index of slave DynamicMechComponent, or -1.

updatePosStates

public abstract void updatePosStates()

updateVelStates

public abstract void updateVelStates()

updateAttachment

public abstract void updateAttachment()

Update attachment to reflect changes in the slave state.

applyForces

public abstract void applyForces()

reduceConstraints

public void reduceConstraints(SparseBlockMatrix GT,
                              VectorNd dg)

Reduces a sparse column matrix (such as the transpose of a constraint matrix) to account for this attachment. This is done by applying the transform

 GT = P GT
 

where

             T
     [ I -Gka  ]
 P = [         ]
     [ 0   0   ]
 

and Gka is the constraint matrix for this attachment.

reduceRowMatrix

public void reduceRowMatrix(SparseBlockMatrix G)

Reduces a sparse row matrix (such as a constraint matrix) to account for this attachment. This is done by applying the transform

        T
 G = G P
 

where

             T
     [ I -Gka  ]
 P = [         ]
     [ 0   0   ]
 

and Gka is the constraint matrix for this attachment.

At present, this method requires the matrix G to be vertically linked.

addMassToMasters

public abstract void addMassToMasters()

reduceMass

public void reduceMass(SparseBlockMatrix M,
                       VectorNd f)

addSolveBlocks

public void addSolveBlocks(SparseNumberedBlockMatrix S,
                           boolean[] reduced)

addAttachmentJacobian

public void addAttachmentJacobian(SparseBlockMatrix S,
                                  VectorNd f,
                                  boolean[] reduced)

Reduces the system matrix to account for this attachment. This is done by applying the transform

          T
 M = P M P
 

where

             T
     [ I -Gka  ]
 P = [         ]
     [ 0   0   ]
 

and Gka is the constraint matrix for this attachment.

getDerivative

public abstract boolean getDerivative(double[] buf,
                                      int idx)

containsLoops

public static boolean containsLoops(java.util.List<DynamicAttachment> list)

containsLoop

public static boolean containsLoop(DynamicAttachment a,
                                   DynamicComponent slave,
                                   java.util.HashMap<DynamicComponent,DynamicAttachment> map)

createOrderedList

public static java.util.ArrayList<DynamicAttachment> createOrderedList(java.util.List<DynamicAttachment> list)

Orders a list of (possibly interdependent) attachments so that the masters of any given attachment do not depend on any attachments further along the list. This means that state can be updated correctly by starting at the beginning of the list and running through to the end. It also implicitly requires that the attachment configuration does not contain loops.

getHardReferences

public void getHardReferences(java.util.List<ModelComponent> refs)

Description copied from class: ModelComponentBase

Appends all hard references for this component to a list. References are other components, outside of this component's immediate ancestry, on which this component depends. For example, an AxialSpring refers to two Point components as for it's end points. A hard reference is one which the referring component must have, and which if deleted, implies that the referring component should be deleted too.

Specified by:

getHardReferences in interface ModelComponent

Overrides:

getHardReferences in class ModelComponentBase

Parameters:

refs - list to which hard references are appended

connectToHierarchy

public void connectToHierarchy()

Update the attachment position state whenever we connect to the parent (i.e., plug in to the hierarchy).

Specified by:

connectToHierarchy in interface ModelComponent

Overrides:

connectToHierarchy in class ModelComponentBase

disconnectFromHierarchy

public void disconnectFromHierarchy()

Update the attachment position state whenever we connect to the parent (i.e., plug in to the hierarchy).

Specified by:

disconnectFromHierarchy in interface ModelComponent

Overrides:

disconnectFromHierarchy in class ModelComponentBase

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Overrides:

clone in class ModelComponentBase

Throws:

java.lang.CloneNotSupportedException

copy

public DynamicAttachment copy(int flags,
                              java.util.Map<ModelComponent,ModelComponent> copyMap)

Overrides:

copy in class ModelComponentBase