StreamingHistogram (apache-cassandra API)
Date: 2014-10-21

org.apache.cassandra.utils

## Class StreamingHistogram

- java.lang.Object
- - org.apache.cassandra.utils.StreamingHistogram

-     public class StreamingHistogram
      extends java.lang.Object

  Histogram that can be constructed from streaming of data. The algorithm is taken from following paper: Yael Ben-Haim and Elad Tom-Tov, "A Streaming Parallel Decision Tree Algorithm" (2010) http://jmlr.csail.mit.edu/papers/volume11/ben-haim10a/ben-haim10a.pdf

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `StreamingHistogram.StreamingHistogramSerializer`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static StreamingHistogram.StreamingHistogramSerializer` | `serializer`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `StreamingHistogram(int maxBinSize)` Creates a new histogram with max bin size of maxBinSize

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `boolean` | `equals(java.lang.Object o)`
    `java.util.Map<java.lang.Double,java.lang.Long>` | `getAsMap()`
    `int` | `hashCode()`
    `void` | `merge(StreamingHistogram other)` Merges given histogram with this histogram.
    `double` | `sum(double b)` Calculates estimated number of points in interval [-inf,b].
    `void` | `update(double p)` Adds new point p to this histogram.
    `void` | `update(double p, long m)` Adds new point p with value m to this histogram.

    - ### Methods inherited from class java.lang.Object

      `clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### serializer

          public static final StreamingHistogram.StreamingHistogramSerializer serializer

  - ### Constructor Detail

    - #### StreamingHistogram

          public StreamingHistogram(int maxBinSize)

      Creates a new histogram with max bin size of maxBinSize
      Parameters:
        `maxBinSize` - maximum number of bins this histogram can have

  - ### Method Detail

    - #### update

          public void update(double p)

      Adds new point p to this histogram.
      Parameters:
        `p` -

    - #### update

          public void update(double p,
                    long m)

      Adds new point p with value m to this histogram.
      Parameters:
        `p` -
        `m` -

    - #### merge

          public void merge(StreamingHistogram other)

      Merges given histogram with this histogram.
      Parameters:
        `other` - histogram to merge

    - #### sum

          public double sum(double b)

      Calculates estimated number of points in interval [-inf,b].
      Parameters:
        `b` - upper bound of a interval to calculate sum
      Returns:
        estimated number of points in a interval [-inf,b].

    - #### getAsMap

          public java.util.Map<java.lang.Double,java.lang.Long> getAsMap()

    - #### equals

          public boolean equals(java.lang.Object o)

      Overrides:
        `equals` in class `java.lang.Object`

    - #### hashCode

          public int hashCode()

      Overrides:
        `hashCode` in class `java.lang.Object`

Copyright © 2014 The Apache Software Foundation