46 lines
743 B
Go
46 lines
743 B
Go
package stats
|
|
|
|
import (
|
|
"sort"
|
|
)
|
|
|
|
type Percentile struct {
|
|
percentile float64
|
|
values sort.Float64Slice
|
|
offset int
|
|
}
|
|
|
|
func NewPercentile(percentile float64, sampleWindow int) *Percentile {
|
|
return &Percentile{
|
|
percentile: percentile,
|
|
values: make([]float64, 0, sampleWindow),
|
|
}
|
|
}
|
|
|
|
func (p *Percentile) AddSample(sample float64) {
|
|
p.values = append(p.values, sample)
|
|
sort.Sort(p.values)
|
|
}
|
|
|
|
func (p *Percentile) Value() float64 {
|
|
if len(p.values) == 0 {
|
|
return 0
|
|
}
|
|
|
|
return p.values[round(p.index())]
|
|
}
|
|
|
|
func (p *Percentile) index() float64 {
|
|
return float64(len(p.values)) * p.percentile - float64(p.offset)
|
|
}
|
|
|
|
func round(value float64) int64 {
|
|
if value < 0.0 {
|
|
value -= 0.5
|
|
} else {
|
|
value += 0.5
|
|
}
|
|
|
|
return int64(value)
|
|
}
|