hyperloglog

README

Fork from original Axiom's HyperLogLog with serializing features.

Documentation

Index

• Variables
• type Sketch
  • func DeSerialize(data []byte) (*Sketch, error)
  • func New() *Sketch
  • func New14() *Sketch
  • func New16() *Sketch
  • func New16NoSparse() *Sketch
  • func NewNoSparse() *Sketch
  • func (sk *Sketch) Clone() *Sketch
  • func (sk *Sketch) Estimate() uint64
  • func (sk *Sketch) Insert(e []byte) bool
  • func (sk *Sketch) InsertHash(x uint64) bool
  • func (sk *Sketch) MarshalBinary() (data []byte, err error)
  • func (sk *Sketch) Merge(other *Sketch) error
  • func (sk *Sketch) Serialize() ([]byte, error)
  • func (sk *Sketch) UnmarshalBinary(data []byte) error
• type SketchOps

Variables

var ErrorTooShort = errors.New("too short binary")

ErrorTooShort is an error that UnmarshalBinary try to parse too short binary.

Types

type Sketch

type Sketch struct {
	// contains filtered or unexported fields
}

Sketch is a HyperLogLog data-structure for the count-distinct problem, approximating the number of distinct elements in a multiset.

func DeSerialize

func DeSerialize(data []byte) (*Sketch, error)

func New

func New() *Sketch

New returns a HyperLogLog Sketch with 2^14 registers (precision 14)

func New14

func New14() *Sketch

New14 returns a HyperLogLog Sketch with 2^14 registers (precision 14)

func New16

func New16() *Sketch

New16 returns a HyperLogLog Sketch with 2^16 registers (precision 16)

func New16NoSparse

func New16NoSparse() *Sketch

New16NoSparse returns a HyperLogLog Sketch with 2^16 registers (precision 16) that will not use a sparse representation

func NewNoSparse

func NewNoSparse() *Sketch

NewNoSparse returns a HyperLogLog Sketch with 2^14 registers (precision 14) that will not use a sparse representation

func (*Sketch) Clone

func (sk *Sketch) Clone() *Sketch

Clone returns a deep copy of sk.

func (*Sketch) Estimate

func (sk *Sketch) Estimate() uint64

Estimate returns the cardinality of the Sketch

func (*Sketch) Insert

func (sk *Sketch) Insert(e []byte) bool

Insert adds element e to sketch

func (*Sketch) InsertHash

func (sk *Sketch) InsertHash(x uint64) bool

InsertHash adds hash x to sketch

func (*Sketch) MarshalBinary

func (sk *Sketch) MarshalBinary() (data []byte, err error)

MarshalBinary implements the encoding.BinaryMarshaler interface.

func (*Sketch) Merge

func (sk *Sketch) Merge(other *Sketch) error

Merge takes another Sketch and combines it with Sketch h. If Sketch h is using the sparse Sketch, it will be converted to the normal Sketch.

func (*Sketch) Serialize

func (sk *Sketch) Serialize() ([]byte, error)

func (*Sketch) UnmarshalBinary

func (sk *Sketch) UnmarshalBinary(data []byte) error

UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.

type SketchOps

type SketchOps struct {
	P          uint8
	B          uint8
	M          uint32
	Alpha      float64
	TmpSet     map[uint32]struct{}
	SparseList *struct {
		Count uint32
		Last  uint32
		B     []uint8
	}
	Regs *struct {
		T  []reg
		NZ uint32
	}
}