bbgo_origin/pkg/indicator/atr.go

104 lines
2.1 KiB
Go

package indicator
import (
"math"
"time"
"github.com/c9s/bbgo/pkg/types"
)
//go:generate callbackgen -type ATR
type ATR struct {
types.IntervalWindow
Values types.Float64Slice
TrueRanges types.Float64Slice
PercentageVolatility types.Float64Slice
PriviousClose float64
EndTime time.Time
UpdateCallbacks []func(value float64)
}
func (inc *ATR) Update(high, low, cloze float64) {
if inc.Window <= 0 {
panic("window must be greater than 0")
}
if inc.PriviousClose == 0 {
inc.PriviousClose = cloze
return
}
// calculate true range
trueRange := types.Float64Slice{
high - low,
math.Abs(high - inc.PriviousClose),
math.Abs(low - inc.PriviousClose),
}.Max()
inc.TrueRanges.Push(trueRange)
inc.PriviousClose = cloze
// apply rolling moving average
if len(inc.TrueRanges) < inc.Window {
return
}
if len(inc.TrueRanges) == inc.Window {
atr := inc.TrueRanges.Mean()
inc.Values.Push(atr)
inc.PercentageVolatility.Push(atr / cloze)
return
}
lambda := 1 / float64(inc.Window)
atr := inc.Values.Last()*(1-lambda) + inc.TrueRanges.Last()*lambda
inc.Values.Push(atr)
inc.PercentageVolatility.Push(atr / cloze)
}
func (inc *ATR) Last() float64 {
if len(inc.Values) == 0 {
return 0.0
}
return inc.Values[len(inc.Values)-1]
}
func (inc *ATR) Index(i int) float64 {
length := len(inc.Values)
if length == 0 || length-i-1 < 0 {
return 0
}
return inc.Values[length-i-1]
}
func (inc *ATR) Length() int {
return len(inc.Values)
}
var _ types.Series = &ATR{}
func (inc *ATR) calculateAndUpdate(kLines []types.KLine) {
for _, k := range kLines {
if inc.EndTime != zeroTime && !k.EndTime.After(inc.EndTime) {
continue
}
inc.Update(k.High.Float64(), k.Low.Float64(), k.Close.Float64())
}
inc.EmitUpdate(inc.Last())
inc.EndTime = kLines[len(kLines)-1].EndTime.Time()
}
func (inc *ATR) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) {
if inc.Interval != interval {
return
}
inc.calculateAndUpdate(window)
}
func (inc *ATR) Bind(updater KLineWindowUpdater) {
updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate)
}