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java.lang.Objectcern.colt.PersistentObject
cern.jet.stat.quantile.EquiDepthHistogram
Read-only equi-depth histogram for selectivity estimation. Assume you have collected statistics over a data set, among them a one-dimensional equi-depth histogram (quantiles). Then an applications or DBMS might want to estimate the selectivity of some range query [from,to], i.e. the percentage of data set elements contained in the query range. This class does not collect equi-depth histograms but only space efficiently stores already produced histograms and provides operations for selectivity estimation. Uses linear interpolation.
This class stores a list l of float values for which holds:
| Field Summary | 
| Fields inherited from class cern.colt.PersistentObject | 
| serialVersionUID | 
| Constructor Summary | |
| EquiDepthHistogram(float[] quantileElements)Constructs an equi-depth histogram with the given quantile elements. | |
| Method Summary | |
|  int | binOfElement(float element)Returns the bin index of the given element. | 
|  int | bins()Returns the number of bins. | 
|  float | endOfBin(int binIndex)Returns the end of the range associated with the given bin. | 
|  double | percentFromTo(float from,
              float to)Returns the percentage of elements in the range (from,to]. | 
|  double | phi(float element)Returns how many percent of the elements contained in the receiver are <= element. | 
|  int | size()Deprecated. Deprecated. Returns the number of bin boundaries. | 
|  float | startOfBin(int binIndex)Returns the start of the range associated with the given bin. | 
| static void | test(float element)Not yet commented. | 
| Methods inherited from class cern.colt.PersistentObject | 
| clone | 
| Methods inherited from class java.lang.Object | 
| equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait | 
| Constructor Detail | 
public EquiDepthHistogram(float[] quantileElements)
| Method Detail | 
public int binOfElement(float element)
element - the element to search for.
IllegalArgumentException - if the element is not contained in any bin.public int bins()
public float endOfBin(int binIndex)
ArrayIndexOutOfBoundsException - if binIndex < 0 || binIndex >= bins().
public double percentFromTo(float from,
                            float to)
from - the start point (exclusive).to - the end point (inclusive).public double phi(float element)
public int size()
public float startOfBin(int binIndex)
ArrayIndexOutOfBoundsException - if binIndex < 0 || binIndex >= bins().public static void test(float element)
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