HyperLogLog (hyperloglog 1.1 API)

java.lang.Object
- com.github.prasanthj.hll.HyperLogLog

public class HyperLogLog
extends Object

 This is an implementation of the following variants of hyperloglog (HLL)
 algorithm 
 Original  - Original HLL algorithm from Flajolet et. al from
             http://algo.inria.fr/flajolet/Publications/FlFuGaMe07.pdf
 HLLNoBias - Google's implementation of bias correction based on lookup table
             http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/40671.pdf
 HLL++     - Google's implementation of HLL++ algorithm that uses SPARSE registers
             http://static.googleusercontent.com/media/research.google.com/en//pubs/archive/40671.pdf
             
 Following are the constructor parameters that determines which algorithm is
 used
 numRegisterIndexBits - number of LSB hashcode bits to be used as register index.
                        Default is 14. min = 4 and max = 16
 numHashBits - number of bits for hashcode. Default is 64. min = 32 and max = 128
 encoding - Type of encoding to use (SPARSE or DENSE). The algorithm automatically
            switches to DENSE beyond a threshold. Default: SPARSE
 enableBitPacking - To enable bit packing or not. Bit packing improves compression
                    at the cost of more CPU cycles. Default: true
 noBias - Use Google's bias table lookup for short range bias correction.
          Enabling this will highly improve the estimation accuracy for short
          range values. Default: true

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class HyperLogLog.EncodingType

static class HyperLogLog.HyperLogLogBuilder

Nested Classes
Modifier and Type	Class and Description
`static class`	`HyperLogLog.EncodingType`
`static class`	`HyperLogLog.HyperLogLogBuilder`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`add(long hashcode)`
`void`	`addBoolean(boolean val)`
`void`	`addByte(byte val)`
`void`	`addBytes(byte[] val)`
`void`	`addChar(char val)`
`void`	`addDouble(double val)`
`void`	`addFloat(float val)`
`void`	`addInt(int val)`
`void`	`addLong(long val)`
`void`	`addShort(short val)`
`void`	`addString(String val)` Java's default charset will be used for strings.
`void`	`addString(String val, Charset charset)`
`static HyperLogLog.HyperLogLogBuilder`	`builder()`
`long`	`count()`
`boolean`	`equals(Object obj)`
`HyperLogLog.EncodingType`	`getEncoding()`
`HLLDenseRegister`	`getHLLDenseRegister()`
`HLLSparseRegister`	`getHLLSparseRegister()`
`int`	`getNumRegisterIndexBits()`
`double`	`getStandardError()`
`int`	`hashCode()`
`void`	`merge(HyperLogLog hll)` Merge the specified hyperloglog to the current one.
`void`	`setCount(long count)`
`void`	`setEncoding(HyperLogLog.EncodingType encoding)`
`void`	`setHLLDenseRegister(byte[] reg)` Reconstruct dense registers from byte array
`void`	`setHLLSparseRegister(int[] reg)` Reconstruct sparse map from serialized integer list
`String`	`toString()`
`String`	`toStringExtended()`

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

Method Detail

builder

public static HyperLogLog.HyperLogLogBuilder builder()

addBoolean
```
public void addBoolean(boolean val)
```

addByte
```
public void addByte(byte val)
```

addBytes
```
public void addBytes(byte[] val)
```

addShort
```
public void addShort(short val)
```

addInt
```
public void addInt(int val)
```

addLong
```
public void addLong(long val)
```

addFloat
```
public void addFloat(float val)
```

addDouble
```
public void addDouble(double val)
```

addChar
```
public void addChar(char val)
```

addString
```
public void addString(String val)
```
Java's default charset will be used for strings.

Parameters:

val - - input string

addString

public void addString(String val,
                      Charset charset)

add
```
public void add(long hashcode)
```

count
```
public long count()
```

setCount
```
public void setCount(long count)
```

getStandardError
```
public double getStandardError()
```

getHLLDenseRegister

public HLLDenseRegister getHLLDenseRegister()

getHLLSparseRegister

public HLLSparseRegister getHLLSparseRegister()

setHLLSparseRegister
```
public void setHLLSparseRegister(int[] reg)
```
Reconstruct sparse map from serialized integer list

Parameters:

reg - - uncompressed and delta decoded integer list

setHLLDenseRegister
```
public void setHLLDenseRegister(byte[] reg)
```
Reconstruct dense registers from byte array

Parameters:

reg - - unpacked byte array

merge
```
public void merge(HyperLogLog hll)
```
Merge the specified hyperloglog to the current one. Encoding switches automatically after merge if the encoding switch threshold is exceeded.

Parameters:

hll - - hyperloglog to be merged

Throws:

IllegalArgumentException - - throw when incompatible HLL are tried to be merged

toString
```
public String toString()
```
Overrides:

toString in class Object

toStringExtended
```
public String toStringExtended()
```

getNumRegisterIndexBits
```
public int getNumRegisterIndexBits()
```

getEncoding

public HyperLogLog.EncodingType getEncoding()

setEncoding

public void setEncoding(HyperLogLog.EncodingType encoding)

equals
```
public boolean equals(Object obj)
```
Overrides:

equals in class Object

hashCode
```
public int hashCode()
```
Overrides:

hashCode in class Object

Class HyperLogLog

Nested Class Summary

Method Summary

Methods inherited from class java.lang.Object

Method Detail

builder

addBoolean

addByte

addBytes

addShort

addInt

addLong

addFloat

addDouble

addChar

addString

addString

add

count

setCount

getStandardError

getHLLDenseRegister

getHLLSparseRegister

setHLLSparseRegister

setHLLDenseRegister

merge

toString

toStringExtended

getNumRegisterIndexBits

getEncoding

setEncoding

equals

hashCode