bbgo_origin/pkg/indicator/vwap.go

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package indicator
import (
"time"
"github.com/c9s/bbgo/pkg/types"
)
/*
vwap implements the volume weighted average price (VWAP) indicator:
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Volume Weighted Average Price (VWAP) Definition
- https://www.investopedia.com/terms/v/vwap.asp
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Volume-Weighted Average Price (VWAP) Explained
- https://academy.binance.com/en/articles/volume-weighted-average-price-vwap-explained
*/
//go:generate callbackgen -type VWAP
type VWAP struct {
types.IntervalWindow
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Values types.Float64Slice
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Prices types.Float64Slice
Volumes types.Float64Slice
WeightedSum float64
VolumeSum float64
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EndTime time.Time
UpdateCallbacks []func(value float64)
}
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func (inc *VWAP) Last() float64 {
if len(inc.Values) == 0 {
return 0.0
}
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return inc.Values[len(inc.Values)-1]
}
func (inc *VWAP) 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 *VWAP) Length() int {
return len(inc.Values)
}
var _ types.Series = &VWAP{}
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func (inc *VWAP) Update(kLine types.KLine, priceF KLinePriceMapper) {
price := priceF(kLine)
volume := kLine.Volume.Float64()
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inc.Prices.Push(price)
inc.Volumes.Push(volume)
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if inc.Window != 0 && len(inc.Prices) > inc.Window {
popIndex := len(inc.Prices) - inc.Window - 1
inc.WeightedSum -= inc.Prices[popIndex] * inc.Volumes[popIndex]
inc.VolumeSum -= inc.Volumes[popIndex]
}
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inc.WeightedSum += price * volume
inc.VolumeSum += volume
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vwap := inc.WeightedSum / inc.VolumeSum
inc.Values.Push(vwap)
}
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func (inc *VWAP) calculateAndUpdate(kLines []types.KLine) {
var priceF = KLineTypicalPriceMapper
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for _, k := range kLines {
if inc.EndTime != zeroTime && k.EndTime.Before(inc.EndTime) {
continue
}
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inc.Update(k, priceF)
}
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inc.EmitUpdate(inc.Last())
inc.EndTime = kLines[len(kLines)-1].EndTime.Time()
}
func (inc *VWAP) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) {
if inc.Interval != interval {
return
}
inc.calculateAndUpdate(window)
}
func (inc *VWAP) Bind(updater KLineWindowUpdater) {
updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate)
}
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func CalculateVWAP(klines []types.KLine, priceF KLinePriceMapper, window int) float64 {
vwap := VWAP{IntervalWindow: types.IntervalWindow{Window: window}}
for _, k := range klines {
vwap.Update(k, priceF)
}
return vwap.Last()
}