Class/Object

com.twitter.algebird

AveragedValue

Related Docs: object AveragedValue | package algebird

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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 parallel 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)

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    count

    the number of aggregated items

    value

    the average value of all aggregated items

Value Members

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

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    Definition Classes
    AnyRef → Any

  2. final def ##(): Int

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    AnyRef → Any

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

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    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.

  4. def +(that: Double): AveragedValue

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    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 +(r: AveragedValue): AveragedValue

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    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.

  6. def -(r: AveragedValue): AveragedValue

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    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

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

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    Definition Classes
    AnyRef → Any

  8. final def asInstanceOf[T0]: T0

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    Any

  9. def clone(): AnyRef

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    Attributes
    protected[java.lang]
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    @throws( ... )

  10. val count: Long

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    the number of aggregated items

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

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    AnyRef

  12. def finalize(): Unit

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    protected[java.lang]
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    @throws( classOf[java.lang.Throwable] )

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

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  14. final def isInstanceOf[T0]: Boolean

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    Any

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

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    AnyRef

  16. final def notify(): Unit

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  17. final def notifyAll(): Unit

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

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    Definition Classes
    AnyRef

  19. def unary_-: AveragedValue

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    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

  20. val value: Double

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    the average value of all aggregated items

  21. final def wait(): Unit

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    @throws( ... )

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

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    @throws( ... )

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

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    @throws( ... )

Inherited from Serializable

Inherited from Serializable

Inherited from Product

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Inherited from AnyRef

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