bbgo/pkg/indicator/rsi.go

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package indicator
import (
"math"
"time"
"git.qtrade.icu/lychiyu/bbgo/pkg/datatype/floats"
"git.qtrade.icu/lychiyu/bbgo/pkg/types"
)
// rsi implements Relative Strength Index (RSI)
// https://www.investopedia.com/terms/r/rsi.asp
//
// The Relative Strength Index (RSI) is a technical analysis indicator that is used to measure the strength of a security's price. It is
// calculated by taking the average of the gains and losses of the security over a specified period of time, and then dividing the average gain
// by the average loss. This resulting value is then plotted as a line on the price chart, with values above 70 indicating overbought conditions
// and values below 30 indicating oversold conditions. The RSI can be used by traders to identify potential entry and exit points for trades,
// or to confirm other technical analysis signals. It is typically used in conjunction with other indicators to provide a more comprehensive
// view of the security's price.
//go:generate callbackgen -type RSI
type RSI struct {
types.SeriesBase
types.IntervalWindow
Values floats.Slice
Prices floats.Slice
PreviousAvgLoss float64
PreviousAvgGain float64
EndTime time.Time
updateCallbacks []func(value float64)
}
func (inc *RSI) Update(price float64) {
if len(inc.Prices) == 0 {
inc.SeriesBase.Series = inc
}
inc.Prices.Push(price)
if len(inc.Prices) < inc.Window+1 {
return
}
var avgGain float64
var avgLoss float64
if len(inc.Prices) == inc.Window+1 {
priceDifferences := inc.Prices.Diff()
avgGain = priceDifferences.PositiveValuesOrZero().Abs().Sum() / float64(inc.Window)
avgLoss = priceDifferences.NegativeValuesOrZero().Abs().Sum() / float64(inc.Window)
} else {
difference := price - inc.Prices[len(inc.Prices)-2]
currentGain := math.Max(difference, 0)
currentLoss := -math.Min(difference, 0)
avgGain = (inc.PreviousAvgGain*13 + currentGain) / float64(inc.Window)
avgLoss = (inc.PreviousAvgLoss*13 + currentLoss) / float64(inc.Window)
}
rs := avgGain / avgLoss
rsi := 100 - (100 / (1 + rs))
inc.Values.Push(rsi)
inc.PreviousAvgGain = avgGain
inc.PreviousAvgLoss = avgLoss
}
func (inc *RSI) Last(i int) float64 {
return inc.Values.Last(i)
}
func (inc *RSI) Index(i int) float64 {
return inc.Last(i)
}
func (inc *RSI) Length() int {
return len(inc.Values)
}
var _ types.SeriesExtend = &RSI{}
func (inc *RSI) PushK(k types.KLine) {
inc.Update(k.Close.Float64())
}
func (inc *RSI) CalculateAndUpdate(kLines []types.KLine) {
for _, k := range kLines {
if inc.EndTime != zeroTime && !k.EndTime.After(inc.EndTime) {
continue
}
inc.PushK(k)
}
inc.EmitUpdate(inc.Last(0))
inc.EndTime = kLines[len(kLines)-1].EndTime.Time()
}
func (inc *RSI) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) {
if inc.Interval != interval {
return
}
inc.CalculateAndUpdate(window)
}
func (inc *RSI) Bind(updater KLineWindowUpdater) {
updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate)
}