ptolemy.actor.util
Class RealDependency

java.lang.Object
  ptolemy.actor.util.RealDependency

All Implemented Interfaces:

java.lang.Comparable<Dependency>, Dependency

public class RealDependency
extends java.lang.Object
implements Dependency

This dependency represents causal relationships that have a real value or are infinite. Infinity represents the lack of a causal relationship. A finite positive real value represents a causal dependency with (typically) a time delay. A zero value represents an immediate causal relationship. See the paper "Causality Interfaces for Actor Networks" by Ye Zhou and Edward A. Lee, ACM Transactions on Embedded Computing Systems (TECS), April 2008, as available as Technical Report No. UCB/EECS-2006-148, November 16, 2006.

Since:

Ptolemy II 8.0

Version:

$Id: RealDependency.java 57044 2010-01-27 22:41:05Z cxh $

Author:

Edward A. Lee

Accepted Rating:

Red (eal)

Proposed Rating:

Yellow (eal)

Field Summary

private double	_value The value.
static RealDependency	OPLUS_IDENTITY The additive identity.
static RealDependency	OTIMES_IDENTITY The multiplicative identity.

Fields inherited from interface ptolemy.actor.util.Dependency

EQUALS, GREATER_THAN, INCOMPARABLE, LESS_THAN

Constructor Summary

private

RealDependency(double value) Construct a dependency with the specified value.

Method Summary

int	compareTo(Dependency dependency) Return Dependency.LESS_THAN, EQUALS, or GREATER_THAN depending on whether the argument is less than, equal to, or greater than this dependency.
boolean	equals(java.lang.Object object) Return true if the value of this dependency equals that of the specified one, and the specified one is an instance of RealDepedency.
int	hashCode() Return the same hashCode that that Java Double object would return had it the same value.
Dependency	oPlus(Dependency d) Return a dependency that results from parallel composition of this one and the specified one.
Dependency	oPlusIdentity() Return the dependency that when added to any other dependency using oPlus() yields the other dependency.
Dependency	oTimes(Dependency d) Return a dependency that results from serial composition of this one and the specified one.
Dependency	oTimesIdentity() Return the dependency that when multiplied by any other dependency using oTimes() yields the other dependency.
java.lang.String	toString() Return a string representation in the form "RealDependency(value)".
double	value() Return the double value of the dependency.
static RealDependency	valueOf(double value) Return an instance of RealDependency with the specified value.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

OPLUS_IDENTITY

public static final RealDependency OPLUS_IDENTITY

The additive identity.

OTIMES_IDENTITY

public static final RealDependency OTIMES_IDENTITY

The multiplicative identity.

_value

private double _value

The value.

Constructor Detail

RealDependency

private RealDependency(double value)

Construct a dependency with the specified value. The constructor is private. Use valueOf() to construct an instance.

Parameters:

value - The value.

Method Detail

compareTo

public int compareTo(Dependency dependency)

Return Dependency.LESS_THAN, EQUALS, or GREATER_THAN depending on whether the argument is less than, equal to, or greater than this dependency. Real dependencies are totally ordered, so this never returns Dependency.INCOMPARABLE. The order is the usual numerical ordering of doubles, with Double.POSITIVE_INFINITY on top.

Specified by:

compareTo in interface java.lang.Comparable<Dependency>

Parameters:

dependency - The dependency to compare against.

Returns:

The result of comparison.

Throws:

java.lang.ClassCastException - If the argument is not an instance of RealDependency.

equals

public boolean equals(java.lang.Object object)

Return true if the value of this dependency equals that of the specified one, and the specified one is an instance of RealDepedency.

Overrides:

equals in class java.lang.Object

Parameters:

object - The object to compare against.

Returns:

true if this object is the same as the object argument.

hashCode

public int hashCode()

Return the same hashCode that that Java Double object would return had it the same value.

Overrides:

hashCode in class java.lang.Object

oPlus

public Dependency oPlus(Dependency d)

Return a dependency that results from parallel composition of this one and the specified one.

Specified by:

oPlus in interface Dependency

Parameters:

d - The dependency to add.

Returns:

A dependency whose value is the minimum of the two dependency values.

Throws:

java.lang.ClassCastException - if d is not a RealDependency.

oPlusIdentity

public Dependency oPlusIdentity()

Return the dependency that when added to any other dependency using oPlus() yields the other dependency.

Specified by:

oPlusIdentity in interface Dependency

Returns:

The additive identity.

oTimes

public Dependency oTimes(Dependency d)

Return a dependency that results from serial composition of this one and the specified one.

Specified by:

oTimes in interface Dependency

Parameters:

d - The dependency to multiply.

Returns:

A dependency whose value is the sum of the value of this one and the specified one.

Throws:

java.lang.ClassCastException - if d is not a RealDependency.

oTimesIdentity

public Dependency oTimesIdentity()

Return the dependency that when multiplied by any other dependency using oTimes() yields the other dependency.

Specified by:

oTimesIdentity in interface Dependency

Returns:

The multiplicative identity.

toString

public java.lang.String toString()

Return a string representation in the form "RealDependency(value)".

Overrides:

toString in class java.lang.Object

Returns:

A string representation.

value

public double value()

Return the double value of the dependency.

Returns:

The value of the dependency.

valueOf

public static RealDependency valueOf(double value)

Return an instance of RealDependency with the specified value. This is preferable to use over the constructor because it uses the same instances for the most common values.

Parameters:

value - The value used to determine the RealDependency to be returned.

Returns:

an instance of RealDependency, if value is 0.0, then OTIMES_IDENTITY is returned, if value is Double.POSITIVE_INFINITY, then OPLUS_IDENTITY is returned. Otherwise the RealDependency constructor is called.