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93 lines
1.9 KiB
Go
93 lines
1.9 KiB
Go
package indicator
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import (
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"time"
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log "github.com/sirupsen/logrus"
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"github.com/c9s/bbgo/pkg/types"
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)
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/*
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vwma implements the volume weighted moving average (VWMA) indicator:
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Calculation:
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pv = element-wise multiplication of close prices and volumes
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VWMA = SMA(pv, window) / SMA(volumes, window)
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Volume Weighted Moving Average
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- https://www.motivewave.com/studies/volume_weighted_moving_average.htm
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*/
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//go:generate callbackgen -type VWMA
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type VWMA struct {
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types.IntervalWindow
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Values types.Float64Slice
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EndTime time.Time
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UpdateCallbacks []func(value float64)
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}
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func (inc *VWMA) Last() float64 {
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if len(inc.Values) == 0 {
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return 0.0
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}
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return inc.Values[len(inc.Values)-1]
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}
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func KLinePriceVolumeMapper(k types.KLine) float64 {
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return k.Close * k.Volume
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}
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func KLineVolumeMapper(k types.KLine) float64 {
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return k.Volume
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}
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func (inc *VWMA) calculateAndUpdate(kLines []types.KLine) {
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if len(kLines) < inc.Window {
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return
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}
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var index = len(kLines) - 1
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var kline = kLines[index]
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if inc.EndTime != zeroTime && kline.EndTime.Before(inc.EndTime) {
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return
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}
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var recentK = kLines[index-(inc.Window-1) : index+1]
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pv, err := calculateSMA(recentK, inc.Window, KLinePriceVolumeMapper)
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if err != nil {
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log.WithError(err).Error("price x volume SMA error")
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return
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}
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v, err := calculateSMA(recentK, inc.Window, KLineVolumeMapper)
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if err != nil {
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log.WithError(err).Error("volume SMA error")
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return
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}
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vwma := pv / v
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inc.Values.Push(vwma)
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if len(inc.Values) > MaxNumOfSMA {
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inc.Values = inc.Values[MaxNumOfSMATruncateSize-1:]
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}
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inc.EndTime = kLines[index].EndTime.Time()
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inc.EmitUpdate(vwma)
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}
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func (inc *VWMA) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) {
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if inc.Interval != interval {
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return
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}
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inc.calculateAndUpdate(window)
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}
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func (inc *VWMA) Bind(updater KLineWindowUpdater) {
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updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate)
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}
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