109 lines
3.1 KiB
Go
109 lines
3.1 KiB
Go
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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// vwap implements the volume weighted average price (VWAP) indicator:
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//
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// Volume Weighted Average Price (VWAP) Definition
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// - https://www.investopedia.com/terms/v/vwap.asp
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//
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// Volume-Weighted Average Price (VWAP) Explained
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// - https://academy.binance.com/en/articles/volume-weighted-average-price-vwap-explained
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//
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// The Volume Weighted Average Price (VWAP) is a technical analysis indicator that is used to measure the average price of a security
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// over a specified period of time, with the weighting factors determined by the volume of the security. It is calculated by taking the
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// sum of the product of the price and volume for each trade, and then dividing that sum by the total volume of the security over the
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// specified period of time. This resulting average is then plotted on the price chart as a line, which can be used to make predictions
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// about future price movements. The VWAP is typically more accurate than other simple moving averages, as it takes into account the
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// volume of the security, but may be less reliable in markets with low trading volume.
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//go:generate callbackgen -type VWAP
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type VWAP struct {
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types.SeriesBase
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types.IntervalWindow
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Values floats.Slice
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Prices floats.Slice
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Volumes floats.Slice
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WeightedSum float64
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VolumeSum 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 *VWAP) Update(price, volume float64) {
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if len(inc.Prices) == 0 {
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inc.SeriesBase.Series = inc
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}
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inc.Prices.Push(price)
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inc.Volumes.Push(volume)
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if inc.Window != 0 && len(inc.Prices) > inc.Window {
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popIndex := len(inc.Prices) - inc.Window - 1
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inc.WeightedSum -= inc.Prices[popIndex] * inc.Volumes[popIndex]
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inc.VolumeSum -= inc.Volumes[popIndex]
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}
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inc.WeightedSum += price * volume
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inc.VolumeSum += volume
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vwap := inc.WeightedSum / inc.VolumeSum
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inc.Values.Push(vwap)
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}
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func (inc *VWAP) Last(i int) float64 {
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return inc.Values.Last(i)
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}
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func (inc *VWAP) Index(i int) float64 {
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return inc.Last(i)
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}
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func (inc *VWAP) Length() int {
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return len(inc.Values)
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}
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var _ types.SeriesExtend = &VWAP{}
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func (inc *VWAP) PushK(k types.KLine) {
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inc.Update(types.KLineTypicalPriceMapper(k), k.Volume.Float64())
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}
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func (inc *VWAP) CalculateAndUpdate(allKLines []types.KLine) {
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for _, k := range allKLines {
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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 = allKLines[len(allKLines)-1].EndTime.Time()
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}
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func (inc *VWAP) 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 *VWAP) Bind(updater KLineWindowUpdater) {
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updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate)
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}
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func calculateVWAP(klines []types.KLine, priceF types.KLineValueMapper, window int) float64 {
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vwap := VWAP{IntervalWindow: types.IntervalWindow{Window: window}}
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for _, k := range klines {
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vwap.Update(priceF(k), k.Volume.Float64())
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}
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return vwap.Last(0)
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}
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