com.twitter.algebird

AveragedValue

case class AveragedValue(count: Long, value: Double) extends Product with Serializable

Tracks the count and mean value of Doubles in a data stream.

Adding two instances of AveragedValue with + is equivalent to taking an average of the two streams, with each stream weighted by its count.

The mean calculation uses a numerically stable online algorithm suitable for large numbers of records, similar to Chan et. al.'s variance algorithm on Wikipedia. As long as your count doesn't overflow a Long, the mean calculation won't overflow.

count

the number of aggregated items

value

the average value of all aggregated items

See also

MomentsGroup.getCombinedMean for implementation of +

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Instance Constructors

  1. new AveragedValue(count: Long, value: Double)

    count

    the number of aggregated items

    value

    the average value of all aggregated items

Value Members

  1. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  2. final def !=(arg0: Any): Boolean

    Definition Classes
    Any

  3. final def ##(): Int

    Definition Classes
    AnyRef → Any

  4. def +[N](that: N)(implicit num: Numeric[N]): AveragedValue

    Returns a new instance that averages that into this instance.

    Returns a new instance that averages that into this instance.

    that

    value to average into this instance

    returns

    an instance representing the mean of this instance and that.

  5. def +(that: Double): AveragedValue

    Returns a new instance that averages that into this instance.

    Returns a new instance that averages that into this instance.

    that

    value to average into this instance

    returns

    an instance representing the mean of this instance and that.

  6. def +(r: AveragedValue): AveragedValue

    Averages this instance with another AveragedValue instance.

    Averages this instance with another AveragedValue instance.

    r

    the other instance

    returns

    an instance representing the mean of this instance and r.

  7. def -(r: AveragedValue): AveragedValue

    Averages this instance with the *opposite* of the supplied AveragedValue instance, effectively subtracting out that instance's contribution to the mean.

    Averages this instance with the *opposite* of the supplied AveragedValue instance, effectively subtracting out that instance's contribution to the mean.

    r

    the instance to subtract

    returns

    an instance with r's stream subtracted out

  8. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  9. final def ==(arg0: Any): Boolean

    Definition Classes
    Any

  10. final def asInstanceOf[T0]: T0

    Definition Classes
    Any

  11. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  12. val count: Long

    the number of aggregated items

  13. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  14. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )

  15. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any

  16. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any

  17. final def ne(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  18. final def notify(): Unit

    Definition Classes
    AnyRef

  19. final def notifyAll(): Unit

    Definition Classes
    AnyRef

  20. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef

  21. def unary_-: AveragedValue

    Returns a copy of this instance with a negative value.

    Returns a copy of this instance with a negative value. Note that

    a + -b == a - b

  22. val value: Double

    the average value of all aggregated items

  23. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  24. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  25. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

Inherited from Serializable

Inherited from Serializable

Inherited from Product

Inherited from Equals

Inherited from AnyRef

Inherited from Any

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