simple

Documentation

Overview

Package simple implements an unweighted reservoir sampling algorithm.

Index

• type Simple
  • func New(capacity int, rnd *rand.Rand) *Simple
  • func (s *Simple) Add(span varopt.Sample)
  • func (s *Simple) Count() int
  • func (s *Simple) Get(i int) varopt.Sample
  • func (s *Simple) Size() int
  • func (s *Simple) Weight() float64

Types

type Simple

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

Simple implements unweighted reservoir sampling using Algorithm R from "Random sampling with a reservoir" by Jeffrey Vitter (1985) https://en.wikipedia.org/wiki/Reservoir_sampling#Algorithm_R

func New

func New(capacity int, rnd *rand.Rand) *Simple

New returns a simple reservoir sampler with given capacity (i.e., reservoir size) and random number generator.

func (*Simple) Add

func (s *Simple) Add(span varopt.Sample)

Add considers a new observation for the sample. Items have unit weight.

func (*Simple) Count

func (s *Simple) Count() int

Count returns the number of items that were observed.

func (*Simple) Get

func (s *Simple) Get(i int) varopt.Sample

Get returns the i'th selected item from the sample.

func (*Simple) Size

func (s *Simple) Size() int

Get returns the number of items in the sample. If the reservoir is full, Size() equals Capacity().

func (*Simple) Weight

func (s *Simple) Weight() float64

Weight returns the adjusted weight of each item in the sample.