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- // Copyright 2010 Petar Maymounkov. All rights reserved.
- // Use of this source code is governed by a BSD-style
- // license that can be found in the LICENSE file.
- package llrb
- import "math"
- // avgVar maintains the average and variance of a stream of numbers
- // in a space-efficient manner.
- type avgVar struct {
- count int64
- sum, sumsq float64
- }
- func (av *avgVar) Init() {
- av.count = 0
- av.sum = 0.0
- av.sumsq = 0.0
- }
- func (av *avgVar) Add(sample float64) {
- av.count++
- av.sum += sample
- av.sumsq += sample * sample
- }
- func (av *avgVar) GetCount() int64 { return av.count }
- func (av *avgVar) GetAvg() float64 { return av.sum / float64(av.count) }
- func (av *avgVar) GetTotal() float64 { return av.sum }
- func (av *avgVar) GetVar() float64 {
- a := av.GetAvg()
- return av.sumsq/float64(av.count) - a*a
- }
- func (av *avgVar) GetStdDev() float64 { return math.Sqrt(av.GetVar()) }
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