87 lines
2.2 KiB
Go
87 lines
2.2 KiB
Go
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package indicator
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import (
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"time"
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"git.qtrade.icu/lychiyu/qbtrade/pkg/datatype/floats"
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"git.qtrade.icu/lychiyu/qbtrade/pkg/types"
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)
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/*
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obv implements on-balance volume indicator
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On-Balance Volume (OBV) Definition
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- https://www.investopedia.com/terms/o/onbalancevolume.asp
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On-Balance Volume (OBV) is a technical analysis indicator that uses volume information to predict changes in stock price.
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The idea behind OBV is that volume precedes price: when the OBV is rising, it means that buyers are becoming more aggressive and
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that the stock price is likely to follow suit. When the OBV is falling, it indicates that sellers are becoming more aggressive and
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that the stock price is likely to decrease. OBV is calculated by adding the volume on days when the stock price closes higher and
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subtracting the volume on days when the stock price closes lower. This running total forms the OBV line, which can then be used
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to make predictions about future stock price movements.
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*/
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//go:generate callbackgen -type OBV
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type OBV struct {
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types.SeriesBase
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types.IntervalWindow
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Values floats.Slice
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PrePrice float64
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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 *OBV) Update(price, volume float64) {
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if len(inc.Values) == 0 {
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inc.SeriesBase.Series = inc
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inc.PrePrice = price
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inc.Values.Push(volume)
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return
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}
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if volume < inc.PrePrice {
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inc.Values.Push(inc.Last(0) - volume)
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} else {
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inc.Values.Push(inc.Last(0) + volume)
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}
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}
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func (inc *OBV) Last(i int) float64 {
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return inc.Values.Last(i)
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}
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func (inc *OBV) Index(i int) float64 {
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return inc.Last(i)
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}
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var _ types.SeriesExtend = &OBV{}
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func (inc *OBV) PushK(k types.KLine) {
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inc.Update(k.Close.Float64(), k.Volume.Float64())
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}
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func (inc *OBV) CalculateAndUpdate(kLines []types.KLine) {
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for _, k := range kLines {
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if inc.EndTime != zeroTime && !k.EndTime.After(inc.EndTime) {
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continue
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}
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inc.PushK(k)
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}
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inc.EmitUpdate(inc.Last(0))
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inc.EndTime = kLines[len(kLines)-1].EndTime.Time()
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}
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func (inc *OBV) 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 *OBV) Bind(updater KLineWindowUpdater) {
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updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate)
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}
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