package indicator import ( "math" "time" "github.com/c9s/bbgo/pkg/datatype/floats" "github.com/c9s/bbgo/pkg/types" ) // ATRP is the average true range percentage // See also https://www.fidelity.com/learning-center/trading-investing/technical-analysis/technical-indicator-guide/atrp // // The Average True Range Percentage (ATRP) is a technical analysis indicator that measures the volatility of a security's price. It is // calculated by dividing the Average True Range (ATR) of the security by its closing price, and then multiplying the result by 100 to convert // it to a percentage. The ATR is a measure of the range of a security's price, taking into account gaps between trading periods and any limit // moves (sharp price movements that are allowed under certain exchange rules). The ATR is typically smoothed using a moving average to make it // more responsive to changes in the underlying price data. The ATRP is a useful indicator for traders because it provides a way to compare the // volatility of different securities, regardless of their individual prices. It can also be used to identify potential entry and exit points // for trades based on changes in the security's volatility. // // Calculation: // // ATRP = (Average True Range / Close) * 100 // //go:generate callbackgen -type ATRP type ATRP struct { types.SeriesBase types.IntervalWindow PercentageVolatility floats.Slice PreviousClose float64 RMA *RMA EndTime time.Time UpdateCallbacks []func(value float64) } func (inc *ATRP) Update(high, low, cloze float64) { if inc.Window <= 0 { panic("window must be greater than 0") } if inc.RMA == nil { inc.SeriesBase.Series = inc inc.RMA = &RMA{ IntervalWindow: types.IntervalWindow{Window: inc.Window}, Adjust: true, } inc.PreviousClose = cloze return } // calculate true range trueRange := high - low hc := math.Abs(high - inc.PreviousClose) lc := math.Abs(low - inc.PreviousClose) if trueRange < hc { trueRange = hc } if trueRange < lc { trueRange = lc } // Note: this is the difference from ATR trueRange = trueRange / inc.PreviousClose * 100.0 inc.PreviousClose = cloze // apply rolling moving average inc.RMA.Update(trueRange) atr := inc.RMA.Last() inc.PercentageVolatility.Push(atr / cloze) } func (inc *ATRP) Last() float64 { if inc.RMA == nil { return 0 } return inc.RMA.Last() } func (inc *ATRP) Index(i int) float64 { if inc.RMA == nil { return 0 } return inc.RMA.Index(i) } func (inc *ATRP) Length() int { if inc.RMA == nil { return 0 } return inc.RMA.Length() } var _ types.SeriesExtend = &ATRP{} func (inc *ATRP) PushK(k types.KLine) { inc.Update(k.High.Float64(), k.Low.Float64(), k.Close.Float64()) } func (inc *ATRP) 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()) inc.EndTime = kLines[len(kLines)-1].EndTime.Time() } func (inc *ATRP) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) { if inc.Interval != interval { return } inc.CalculateAndUpdate(window) } func (inc *ATRP) Bind(updater KLineWindowUpdater) { updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate) }