Class DampingLaw

Applies damping forces to a set of MassObject's. Damping is a friction force like air resistance, or the surface friction of objects sliding on a table.

The set of objects can be specified with the addBody method, or the DampingLaw can observe a SimList and automatically add all bodies that have mass to the set of objects.

The damping force slows both the translational velocity and rotational velocity of a MassObject. The translational force is (-k*vx, -k*vy) where

k is the damping constant
(vx, vy) is the translational velocity of the body

The torque is -k*rotateRatio*vw where

k is the damping constant
rotateRatio is a constant used to calculate rotational damping
vw is the angular velocity of the body

The reason to have rotateRatio is so that it is easy to modify both translational and rotational damping by adjusting only the damping constant.

Parameters Created

ParameterNumber named DAMPING, see setDamping
ParameterNumber named ROTATE_RATIO, see setRotateRatio

Hierarchy (view full)

AbstractSubject
- DampingLaw

Implements

Constructors

constructor

new DampingLaw(damping, rotateRatio?, opt_simList?): DampingLaw
Parameters
- damping: number
  translational damping factor
- Optional rotateRatio: number
  the ratio used to calculate rotational damping, as a fraction of translational damping
- Optional opt_simList: SimList
  optional SimList to observe for when objects are added; also adds all existing bodies on that SimList.
Returns DampingLaw
Overrides AbstractSubject.constructor
- Defined in lab/model/DampingLaw.ts:71

Properties

`Private` rotateRatio_

rotateRatio_: number

rotational damping is this fraction of damping

Methods

addBodies

addBodies(bodies): void
Adds the SimObjects to list of objects that DampingLaw applies forces to, but only those with mass.
Parameters
- bodies: SimObject[]
  set of SimObjects to possibly add
Returns void
- Defined in lab/model/DampingLaw.ts:114

addBody

addBody(obj): void
Adds the SimObject to list of objects that DampingLaw applies forces to, but only if it has positive finite mass.
Parameters
- obj: SimObject
  the SimObject to possibly add
Returns void
- Defined in lab/model/DampingLaw.ts:122

addObserver

addObserver(observer): void
Adds the given Observer to this Subject's list of Observers, so that the Observer will be notified of changes in this Subject. An Observer may call Subject.addObserver during its observe method.
Parameters
- observer: Observer
  the Observer to add
Returns void
Implementation of Subject.addObserver
Inherited from AbstractSubject.addObserver
- Defined in lab/util/AbstractSubject.ts:67

addParameter

addParameter(parameter): void
Adds the Parameter to the list of this Subject's available Parameters.
Parameters
- parameter: Parameter
  the Parameter to add
Returns void
Throws
if a Parameter with the same name already exists.
Inherited from AbstractSubject.addParameter
- Defined in lab/util/AbstractSubject.ts:100

broadcast

broadcast(evt): void
Notifies all Observers that this Subject has changed by calling observe on each Observer.

An Observer may call addObserver or removeObserver during its observe method.
Parameters
- evt: SubjectEvent
  a SubjectEvent with information relating to the change
Returns void
Implementation of Subject.broadcast
Inherited from AbstractSubject.broadcast
- Defined in lab/util/AbstractSubject.ts:110

broadcastParameter

broadcastParameter(name): void
Notifies all Observers that the Parameter with the given name has changed by calling observe on each Observer.
Parameters
- name: string
  the language-independent or English name of the Parameter that has changed
Returns void
Throws
if there is no Parameter with the given name
Implementation of Subject.broadcastParameter
Inherited from AbstractSubject.broadcastParameter
- Defined in lab/util/AbstractSubject.ts:132

calculateForces

calculateForces(): Force[]
Returns a list of Forces generated by this ForceLaw.

Returns Force[]
list of forces generated by this ForceLaw.
Implementation of ForceLaw.calculateForces
- Defined in lab/model/DampingLaw.ts:137

connect

connect(simList): void
Connect to the given SimList, so that the force applies to all objects in the SimList. Also adds all existing bodies on that SimList.
Parameters
- simList: SimList
  the SimList to connect with
Returns void
- Defined in lab/model/DampingLaw.ts:161

disconnect

disconnect(): void
Ensures this ForceLaw is not connected to anything and so can be garbage collected. For example, if this ForceLaw is an Observer, this will stop observing its Subject.

Returns void
Implementation of ForceLaw.disconnect
- Defined in lab/model/DampingLaw.ts:168

getBodies

getBodies(): MassObject[]
Returns list of MassObjects being affected by this ForceLaw.

Returns MassObject[]
list of MassObjects being affected by this ForceLaw
Implementation of ForceLaw.getBodies
- Defined in lab/model/DampingLaw.ts:175

`Protected` getBroadcast

getBroadcast(): boolean
Returns whether broadcasting is enabled for this Subject. See setBroadcast.

Returns boolean
whether broadcasting is enabled for this Subject
Inherited from AbstractSubject.getBroadcast
- Defined in lab/util/AbstractSubject.ts:144

getClassName

getClassName(): string
Returns name of class of this object.

Returns string
name of class of this object.
Overrides AbstractSubject.getClassName
- Defined in lab/model/DampingLaw.ts:106

getDamping

getDamping(): number
Returns the strength of the damping force.

Returns number
the strength of the damping force.
- Defined in lab/model/DampingLaw.ts:182

getName

getName(): string
Return the language-independent name of this Subject for scripting purposes.

Returns string
name the language-independent name of this Subject
Implementation of Subject.getName
Inherited from AbstractSubject.getName
- Defined in lab/util/AbstractSubject.ts:154

getObservers

getObservers(): Observer[]
Returns a copy of the list of Observers of this Subject.

Returns Observer[]
a copy of the list of Observers of this Subject.
Implementation of Subject.getObservers
Inherited from AbstractSubject.getObservers
- Defined in lab/util/AbstractSubject.ts:159

getParameter

getParameter(name): Parameter
Returns the Parameter with the given name.
Parameters
- name: string
  the language-independent or English name of the Parameter
Returns Parameter
the Parameter with the given name

Throws
if there is no Parameter with the given name
Implementation of Subject.getParameter
Inherited from AbstractSubject.getParameter
- Defined in lab/util/AbstractSubject.ts:173

getParameterBoolean

getParameterBoolean(name): ParameterBoolean
Returns the ParameterBoolean with the given name.
Parameters
- name: string
  the language-independent or English name of the ParameterBoolean
Returns ParameterBoolean
the ParameterBoolean with the given name

Throws
if there is no ParameterBoolean with the given name
Implementation of Subject.getParameterBoolean
Inherited from AbstractSubject.getParameterBoolean
- Defined in lab/util/AbstractSubject.ts:182

getParameterNumber

getParameterNumber(name): ParameterNumber
Returns the ParameterNumber with the given name.
Parameters
- name: string
  the language-independent or English name of the ParameterNumber
Returns ParameterNumber
the ParameterNumber with the given name

Throws
if there is no ParameterNumber with the given name
Implementation of Subject.getParameterNumber
Inherited from AbstractSubject.getParameterNumber
- Defined in lab/util/AbstractSubject.ts:191

getParameterString

getParameterString(name): ParameterString
Returns the ParameterString with the given name.
Parameters
- name: string
  the language-independent or English name of the ParameterString
Returns ParameterString
the ParameterString with the given name

Throws
if there is no ParameterString with the given name
Implementation of Subject.getParameterString
Inherited from AbstractSubject.getParameterString
- Defined in lab/util/AbstractSubject.ts:200

getParameters

getParameters(): Parameter[]
Returns a copy of the list of this Subject's available Parameters.

Returns Parameter[]
a copy of the list of available Parameters for this Subject
Implementation of Subject.getParameters
Inherited from AbstractSubject.getParameters
- Defined in lab/util/AbstractSubject.ts:209

getPotentialEnergy

getPotentialEnergy(): number
Returns the potential energy due to this ForceLaw.

Returns number
the potential energy due to this ForceLaw
Implementation of ForceLaw.getPotentialEnergy
- Defined in lab/model/DampingLaw.ts:187

getRotateRatio

getRotateRatio(): number
Returns the ratio used to calculate rotational damping, as fraction of translational damping.

Returns number
ratio used to calculate rotational damping
- Defined in lab/model/DampingLaw.ts:195

observe

observe(event): void
Notifies this Observer that a change has occurred in the Subject.
Parameters
- event: SubjectEvent
  contains information about what has changed in the Subject: typically either a one-time GenericEvent, or a change to the value of a Parameter
Returns void
Implementation of Observer.observe
- Defined in lab/model/DampingLaw.ts:200

removeObserver

removeObserver(observer): void
Removes the Observer from this Subject's list of Observers. An Observer may call removeObserver during its observe method.
Parameters
- observer: Observer
  the Observer to detach from list of Observers
Returns void
Implementation of Subject.removeObserver
Inherited from AbstractSubject.removeObserver
- Defined in lab/util/AbstractSubject.ts:214

removeParameter

removeParameter(parameter): void
Removes the Parameter from the list of this Subject's available Parameters.
Parameters
- parameter: Parameter
  the Parameter to remove
Returns void
Inherited from AbstractSubject.removeParameter
- Defined in lab/util/AbstractSubject.ts:226

`Protected` setBroadcast

setBroadcast(value): boolean
Sets whether this Subject will broadcast events, typically used to temporarily disable broadcasting. Intended to be used in situations where a subclass overrides a method that broadcasts an event. This allows the subclass to prevent the superclass broadcasting that event, so that the subclass can broadcast the event when the method is completed.
Parameters
- value: boolean
  whether this Subject should broadcast events
Returns boolean
the previous value
Inherited from AbstractSubject.setBroadcast
- Defined in lab/util/AbstractSubject.ts:238

setDamping

setDamping(value): void
Sets the strength of the damping force.
Parameters
- value: number
  strength of the damping force
Returns void
- Defined in lab/model/DampingLaw.ts:214

setRotateRatio

setRotateRatio(value): void
Sets the ratio used to calculate rotational damping, as fraction of translational damping.
Parameters
- value: number
  ratio used to calculate rotational damping
Returns void
- Defined in lab/model/DampingLaw.ts:223

toString

toString(): string
Returns string
Inherit Doc
Overrides AbstractSubject.toString
- Defined in lab/model/DampingLaw.ts:92

toStringShort

toStringShort(): string
Returns a minimal string representation of this object, usually giving just identity information like the class name and name of the object.

For an object whose main purpose is to represent another Printable object, it is recommended to include the result of calling toStringShort on that other object. For example, calling toStringShort() on a DisplayShape might return something like this:
```
DisplayShape{polygon:Polygon{'chain3'}}
```
Returns string
a minimal string representation of this object.
Implementation of ForceLaw.toStringShort
Overrides AbstractSubject.toStringShort
- Defined in lab/model/DampingLaw.ts:100

Class DampingLaw

Parameters Created

Hierarchy (view full)

Implements

Index

Constructors

Properties

Methods

Constructors

constructor

Parameters

damping: number

Optional rotateRatio: number

Optional opt_simList: SimList

Returns DampingLaw

Properties

Private rotateRatio_

Methods

addBodies

Parameters

bodies: SimObject[]

Returns void

addBody

Parameters

obj: SimObject

Returns void

addObserver

Parameters

observer: Observer

Returns void

addParameter

Parameters

parameter: Parameter

Returns void

Throws

broadcast

Parameters

evt: SubjectEvent

Returns void

broadcastParameter

Parameters

name: string

Returns void

Throws

calculateForces

Returns Force[]

connect

Parameters

simList: SimList

Returns void

disconnect

Returns void

getBodies

Returns MassObject[]

Protected getBroadcast

Returns boolean

getClassName

Returns string

getDamping

Returns number

getName

Returns string

getObservers

Returns Observer[]

getParameter

Parameters

name: string

Returns Parameter

Throws

getParameterBoolean

Parameters

name: string

Returns ParameterBoolean

Throws

getParameterNumber

Parameters

name: string

Returns ParameterNumber

Throws

getParameterString

`Optional` rotateRatio: number

`Optional` opt_simList: SimList

`Private` rotateRatio_

`Protected` getBroadcast

`Protected` setBroadcast