ApproximateHistogram (io.druid:druid 0.8.1 API)

java.lang.Object
- io.druid.query.aggregation.histogram.ApproximateHistogram

public class ApproximateHistogram
extends Object

Field Summary

Fields
Modifier and Type Field and Description

long[] bins

static int DEFAULT_BUCKET_SIZE

static int DEFAULT_HISTOGRAM_SIZE

float[] positions

Fields
Modifier and Type	Field and Description
`long[]`	`bins`
`static int`	`DEFAULT_BUCKET_SIZE`
`static int`	`DEFAULT_HISTOGRAM_SIZE`
`float[]`	`positions`

Constructor Summary

Constructors
Constructor and Description
`ApproximateHistogram()`
`ApproximateHistogram(int size)`
`ApproximateHistogram(int binCount, float[] positions, long[] bins, float min, float max)`
`ApproximateHistogram(int size, float[] positions, long[] bins, int binCount, float min, float max, long count, float lowerLimit, float upperLimit)`
`ApproximateHistogram(int size, float lowerLimit, float upperLimit)`

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`binCount()`
`long[]`	`bins()`
`boolean`	`canStoreCompact()` Checks whether this approximate histogram can be stored in a compact form
`int`	`capacity()`
`ApproximateHistogram`	`copy(ApproximateHistogram h)` Copies histogram h into the current histogram.
`long`	`count()`
`boolean`	`equals(Object o)`
`ApproximateHistogram`	`fold(ApproximateHistogram h)`
`ApproximateHistogram`	`fold(ApproximateHistogram h, float[] mergedPositions, long[] mergedBins, float[] deltas)`
`ApproximateHistogram`	`foldFast(ApproximateHistogram h)`
`ApproximateHistogram`	`foldFast(ApproximateHistogram h, float[] mergedPositions, long[] mergedBins)`
`protected ApproximateHistogram`	`foldMin(ApproximateHistogram h, float[] mergedPositions, long[] mergedBins, float[] deltas)`
`protected ApproximateHistogram`	`foldRule(ApproximateHistogram h, float[] mergedPositions, long[] mergedBins)`
`static ApproximateHistogram`	`fromBytes(byte[] bytes)` Constructs an Approximate Histogram object from the given byte-array representation
`static ApproximateHistogram`	`fromBytes(ByteBuffer buf)` Constructs an ApproximateHistogram object from the given byte-buffer representation
`static ApproximateHistogram`	`fromBytesCompact(ByteBuffer buf)` Constructs an ApproximateHistogram object from the given compact byte-buffer representation
`static ApproximateHistogram`	`fromBytesDense(ByteBuffer buf)` Constructs an ApproximateHistogram object from the given dense byte-buffer representation
`static ApproximateHistogram`	`fromBytesSparse(ByteBuffer buf)` Constructs an ApproximateHistogram object from the given dense byte-buffer representation
`protected String`	`getBinsString()`
`int`	`getCompactStorageSize()`
`int`	`getDenseStorageSize()`
`long`	`getExactCount()`
`float`	`getMax()`
`int`	`getMaxStorageSize()`
`float`	`getMin()`
`int`	`getMinStorageSize()` Returns the minimum number of bytes required to store this ApproximateHistogram object
`float[]`	`getQuantiles(float[] probabilities)` Returns the approximate quantiles corresponding to the given probabilities.
`int`	`getSparseStorageSize()`
`int`	`hashCode()`
`float`	`max()`
`protected void`	`merge(int index)` Merges the bin in the given position with the next bin
`protected void`	`mergeInsert(int mergeAt, int insertAt, float v, long c)` Merges the bin in the mergeAt position with the bin in position mergeAt+1 and simultaneously inserts the given bin (v,c) as a new bin at position insertAt
`float`	`min()`
`protected int`	`minDeltaIndex()`
`void`	`offer(float value)` Adds the given value to the histogram
`float[]`	`positions()`
`protected int`	`ruleCombineBins(int leftBinCount, float[] leftPositions, long[] leftBins, int rightBinCount, float[] rightPositions, long[] rightBins, float[] mergedPositions, long[] mergedBins)`
`void`	`setLowerLimit(float lowerLimit)`
`void`	`setUpperLimit(float upperLimit)`
`protected void`	`shiftLeft(int start, int end)` Shifts the given range of histogram bins one slot to the left
`protected void`	`shiftRight(int start, int end)` Shifts the given range the histogram bins one slot to the right
`double`	`sum(float b)` Returns the approximate number of items less than or equal to b in the histogram
`byte[]`	`toBytes()` Returns a byte-array representation of this ApproximateHistogram object
`void`	`toBytes(ByteBuffer buf)` Writes the representation of this ApproximateHistogram object to the given byte-buffer
`void`	`toBytesCompact(ByteBuffer buf)` Returns a compact byte-buffer representation of this ApproximateHistogram object storing actual values as opposed to histogram bins Requires 3 + 4 * count bytes of storage with count <= 127
`void`	`toBytesDense(ByteBuffer buf)` Writes the dense representation of this ApproximateHistogram object to the given byte-buffer Requires 16 + 12 * size bytes of storage
`void`	`toBytesSparse(ByteBuffer buf)` Writes the sparse representation of this ApproximateHistogram object to the given byte-buffer Requires 16 + 12 * binCount bytes of storage
`Histogram`	`toHistogram(float[] breaks)` Computes a visual representation of the approximate histogram with bins laid out according to the given breaks
`Histogram`	`toHistogram(float bucketSize, float offset)` Computes a visual representation given an initial breakpoint, offset, and a bucket size.
`Histogram`	`toHistogram(int size)` Computes a visual representation of the approximate histogram with a given number of equal-sized bins
`String`	`toString()`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - DEFAULT_HISTOGRAM_SIZE
```
public static final int DEFAULT_HISTOGRAM_SIZE
```
    See Also:
    Constant Field Values
  - DEFAULT_BUCKET_SIZE
```
public static final int DEFAULT_BUCKET_SIZE
```
    See Also:
    Constant Field Values
  - positions
```
public float[] positions
```
  - bins
```
public long[] bins
```
- Constructor Detail
  - ApproximateHistogram
```
public ApproximateHistogram(int size,
                    float[] positions,
                    long[] bins,
                    int binCount,
                    float min,
                    float max,
                    long count,
                    float lowerLimit,
                    float upperLimit)
```
  - ApproximateHistogram
```
public ApproximateHistogram()
```
  - ApproximateHistogram
```
public ApproximateHistogram(int size)
```
  - ApproximateHistogram
```
public ApproximateHistogram(int size,
                    float lowerLimit,
                    float upperLimit)
```
  - ApproximateHistogram
```
public ApproximateHistogram(int binCount,
                    float[] positions,
                    long[] bins,
                    float min,
                    float max)
```
- Method Detail
  - equals
```
public boolean equals(Object o)
```
    Overrides:
    
    equals in class Object
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class Object
  - count
```
public long count()
```
  - min
```
public float min()
```
  - max
```
public float max()
```
  - binCount
```
public int binCount()
```
  - capacity
```
public int capacity()
```
  - positions
```
public float[] positions()
```
  - bins
```
public long[] bins()
```
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
  - getExactCount
```
public long getExactCount()
```
  - getMin
```
public float getMin()
```
  - getMax
```
public float getMax()
```
  - getBinsString
```
protected String getBinsString()
```
    Returns:
    a string representation of the actual bin counts
  - setLowerLimit
```
public void setLowerLimit(float lowerLimit)
```
  - setUpperLimit
```
public void setUpperLimit(float upperLimit)
```
  - offer
```
public void offer(float value)
```
    Adds the given value to the histogram
    
    Parameters:
    value - the value to be added
  - minDeltaIndex
```
protected int minDeltaIndex()
```
  - merge
```
protected void merge(int index)
```
    Merges the bin in the given position with the next bin
    
    Parameters:
    index - index of the bin to merge, index must satisfy 0 <= index < binCount - 1
  - mergeInsert
```
protected void mergeInsert(int mergeAt,
               int insertAt,
               float v,
               long c)
```
    Merges the bin in the mergeAt position with the bin in position mergeAt+1 and simultaneously inserts the given bin (v,c) as a new bin at position insertAt
    
    Parameters:
    mergeAt - index of the bin to be merged
    insertAt - index to insert the new bin at
    v - bin position
    c - bin count
  - shiftRight
```
protected void shiftRight(int start,
              int end)
```
    Shifts the given range the histogram bins one slot to the right
    
    Parameters:
    start - index of the first bin to shift
    end - index of the rightmost bin to shift into
  - shiftLeft
```
protected void shiftLeft(int start,
             int end)
```
    Shifts the given range of histogram bins one slot to the left
    
    Parameters:
    start - index of the leftmost empty bin to shift into
    end - index of the last bin to shift left
  - fold
```
public ApproximateHistogram fold(ApproximateHistogram h)
```
  - fold
```
public ApproximateHistogram fold(ApproximateHistogram h,
                        float[] mergedPositions,
                        long[] mergedBins,
                        float[] deltas)
```
  - foldFast
```
public ApproximateHistogram foldFast(ApproximateHistogram h)
```
  - foldFast
```
public ApproximateHistogram foldFast(ApproximateHistogram h,
                            float[] mergedPositions,
                            long[] mergedBins)
```
    Parameters:
    h - histogram to be merged into the current histogram
    mergedPositions - temporary buffer of size greater or equal to this.capacity()
    mergedBins - temporary buffer of size greater or equal to this.capacity()
    
    Returns:
    returns this histogram with h folded into it
  - copy
```
public ApproximateHistogram copy(ApproximateHistogram h)
```
    Copies histogram h into the current histogram.
    
    Parameters:
    h - ApproximateHistogram to copy
    
    Returns:
    this histogram
  - foldMin
```
protected ApproximateHistogram foldMin(ApproximateHistogram h,
                           float[] mergedPositions,
                           long[] mergedBins,
                           float[] deltas)
```
  - foldRule
```
protected ApproximateHistogram foldRule(ApproximateHistogram h,
                            float[] mergedPositions,
                            long[] mergedBins)
```
  - ruleCombineBins
```
protected int ruleCombineBins(int leftBinCount,
                  float[] leftPositions,
                  long[] leftBins,
                  int rightBinCount,
                  float[] rightPositions,
                  long[] rightBins,
                  float[] mergedPositions,
                  long[] mergedBins)
```
  - toBytes
```
public byte[] toBytes()
```
    Returns a byte-array representation of this ApproximateHistogram object
    
    Returns:
    byte array representation
  - getDenseStorageSize
```
public int getDenseStorageSize()
```
  - getSparseStorageSize
```
public int getSparseStorageSize()
```
  - getCompactStorageSize
```
public int getCompactStorageSize()
```
  - getMaxStorageSize
```
public int getMaxStorageSize()
```
  - getMinStorageSize
```
public int getMinStorageSize()
```
    Returns the minimum number of bytes required to store this ApproximateHistogram object
    
    Returns:
    required number of bytes
  - canStoreCompact
```
public boolean canStoreCompact()
```
    Checks whether this approximate histogram can be stored in a compact form
    
    Returns:
    true if yes, false otherwise
  - toBytes
```
public void toBytes(ByteBuffer buf)
```
    Writes the representation of this ApproximateHistogram object to the given byte-buffer
    
    Parameters:
    buf - ByteBuffer to write the ApproximateHistogram to
  - toBytesDense
```
public void toBytesDense(ByteBuffer buf)
```
    Writes the dense representation of this ApproximateHistogram object to the given byte-buffer Requires 16 + 12 * size bytes of storage
    
    Parameters:
    buf - ByteBuffer to write the ApproximateHistogram to
  - toBytesSparse
```
public void toBytesSparse(ByteBuffer buf)
```
    Writes the sparse representation of this ApproximateHistogram object to the given byte-buffer Requires 16 + 12 * binCount bytes of storage
    
    Parameters:
    buf - ByteBuffer to write the ApproximateHistogram to
  - toBytesCompact
```
public void toBytesCompact(ByteBuffer buf)
```
    Returns a compact byte-buffer representation of this ApproximateHistogram object storing actual values as opposed to histogram bins Requires 3 + 4 * count bytes of storage with count <= 127
    
    Parameters:
    buf - ByteBuffer to write the ApproximateHistogram to
  - fromBytes
```
public static ApproximateHistogram fromBytes(byte[] bytes)
```
    Constructs an Approximate Histogram object from the given byte-array representation
    
    Parameters:
    bytes - byte array to construct an ApproximateHistogram from
    
    Returns:
    ApproximateHistogram constructed from the given byte array
  - fromBytesDense
```
public static ApproximateHistogram fromBytesDense(ByteBuffer buf)
```
    Constructs an ApproximateHistogram object from the given dense byte-buffer representation
    
    Parameters:
    buf - ByteBuffer to construct an ApproximateHistogram from
    
    Returns:
    ApproximateHistogram constructed from the given ByteBuffer
  - fromBytesSparse
```
public static ApproximateHistogram fromBytesSparse(ByteBuffer buf)
```
    Constructs an ApproximateHistogram object from the given dense byte-buffer representation
    
    Parameters:
    buf - ByteBuffer to construct an ApproximateHistogram from
    
    Returns:
    ApproximateHistogram constructed from the given ByteBuffer
  - fromBytesCompact
```
public static ApproximateHistogram fromBytesCompact(ByteBuffer buf)
```
    Constructs an ApproximateHistogram object from the given compact byte-buffer representation
    
    Parameters:
    buf - ByteBuffer to construct an ApproximateHistogram from
    
    Returns:
    ApproximateHistogram constructed from the given ByteBuffer
  - fromBytes
```
public static ApproximateHistogram fromBytes(ByteBuffer buf)
```
    Constructs an ApproximateHistogram object from the given byte-buffer representation
    
    Parameters:
    buf - ByteBuffer to construct an ApproximateHistogram from
    
    Returns:
    ApproximateHistogram constructed from the given ByteBuffer
  - sum
```
public double sum(float b)
```
    Returns the approximate number of items less than or equal to b in the histogram
    
    Parameters:
    b - the cutoff
    
    Returns:
    the approximate number of items less than or equal to b
  - getQuantiles
```
public float[] getQuantiles(float[] probabilities)
```
    Returns the approximate quantiles corresponding to the given probabilities. probabilities = [.5f] returns [median] probabilities = [.25f, .5f, .75f] returns the quartiles, [25%ile, median, 75%ile]
    
    Parameters:
    probabilities - array of probabilities
    
    Returns:
    an array of length probabilities.length representing the the approximate sample quantiles corresponding to the given probabilities
  - toHistogram
```
public Histogram toHistogram(float[] breaks)
```
    Computes a visual representation of the approximate histogram with bins laid out according to the given breaks
    
    Parameters:
    breaks - breaks defining the histogram bins
    
    Returns:
    visual representation of the histogram
  - toHistogram
```
public Histogram toHistogram(int size)
```
    Computes a visual representation of the approximate histogram with a given number of equal-sized bins
    
    Parameters:
    size - number of equal-sized bins to divide the histogram into
    
    Returns:
    visual representation of the histogram
  - toHistogram
```
public Histogram toHistogram(float bucketSize,
                    float offset)
```
    Computes a visual representation given an initial breakpoint, offset, and a bucket size.
    
    Parameters:
    bucketSize - the size of each bucket
    offset - the location of one breakpoint
    
    Returns:
    visual representation of the histogram

Class ApproximateHistogram

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_HISTOGRAM_SIZE

DEFAULT_BUCKET_SIZE

positions

bins

Constructor Detail

ApproximateHistogram

ApproximateHistogram

ApproximateHistogram

ApproximateHistogram

ApproximateHistogram

Method Detail

equals

hashCode

count

min

max

binCount

capacity

positions

bins

toString

getExactCount

getMin

getMax

getBinsString

setLowerLimit

setUpperLimit

offer

minDeltaIndex

merge

mergeInsert

shiftRight

shiftLeft

fold

fold

foldFast

foldFast

copy

foldMin

foldRule

ruleCombineBins

toBytes

getDenseStorageSize

getSparseStorageSize

getCompactStorageSize

getMaxStorageSize

getMinStorageSize

canStoreCompact

toBytes

toBytesDense

toBytesSparse

toBytesCompact

fromBytes

fromBytesDense

fromBytesSparse

fromBytesCompact

fromBytes

sum

getQuantiles

toHistogram

toHistogram

toHistogram