diff --git a/pkg/indicator/alma.go b/pkg/indicator/alma.go new file mode 100644 index 000000000..885e90f55 --- /dev/null +++ b/pkg/indicator/alma.go @@ -0,0 +1,95 @@ +package indicator + +import ( + "math" + + "github.com/c9s/bbgo/pkg/types" +) + +// Refer: Arnaud Legoux Moving Average +// Refer: https://capital.com/arnaud-legoux-moving-average +// Also check https://github.com/DaveSkender/Stock.Indicators/blob/main/src/a-d/Alma/Alma.cs +// @param offset: Gaussian applied to the combo line. 1->ema, 0->sma +// @param sigma: the standard deviation applied to the combo line. This makes the combo line sharper +//go:generate callbackgen -type ALMA +type ALMA struct { + types.IntervalWindow + Offset float64 + Sigma int + Weight []float64 + Sum float64 + input []float64 + Values types.Float64Slice + UpdateCallbacks []func(value float64) +} + +const MaxNumOfALMA = 5_000 +const MaxNumOfALMATruncateSize = 100 + +func (inc *ALMA) Update(value float64) { + if inc.Weight == nil { + inc.Weight = make([]float64, inc.Window) + m := inc.Offset * (float64(inc.Window) - 1.) + s := float64(inc.Window) / float64(inc.Sigma) + inc.Sum = 0. + for i := 0; i < inc.Window; i++ { + diff := float64(i) - m + wt := math.Exp(-diff*diff/2./s/s) + inc.Sum += wt + inc.Weight[i] = wt + } + } + inc.input = append(inc.input, value) + if len(inc.input) >= inc.Window { + weightedSum := 0.0 + inc.input = inc.input[len(inc.input) - inc.Window:] + for i := 0; i < inc.Window; i++ { + weightedSum += inc.Weight[i] * inc.input[i] + } + inc.Values.Push(weightedSum / inc.Sum) + if len(inc.Values) > MaxNumOfALMA { + inc.Values = inc.Values[MaxNumOfALMATruncateSize-1:] + } + } +} + +func (inc *ALMA) Last() float64 { + if len(inc.Values) == 0 { + return 0 + } + return inc.Values[len(inc.Values)-1] +} + +func (inc *ALMA) Index(i int) float64 { + if i >= len(inc.Values) { + return 0 + } + return inc.Values[len(inc.Values)-i-1] +} + +func (inc *ALMA) Length() int { + return len(inc.Values) +} + +func (inc *ALMA) calculateAndUpdate(allKLines []types.KLine) { + if inc.input == nil { + for _, k := range allKLines { + inc.Update(k.Close.Float64()) + inc.EmitUpdate(inc.Last()) + } + return + } + inc.Update(allKLines[len(allKLines)-1].Close.Float64()) + inc.EmitUpdate(inc.Last()) +} + +func (inc *ALMA) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) { + if inc.Interval != interval { + return + } + inc.calculateAndUpdate(window) +} + +func (inc *ALMA) Bind(updater KLineWindowUpdater) { + updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate) +} diff --git a/pkg/indicator/alma_callbacks.go b/pkg/indicator/alma_callbacks.go new file mode 100644 index 000000000..52d2b2f73 --- /dev/null +++ b/pkg/indicator/alma_callbacks.go @@ -0,0 +1,15 @@ +// Code generated by "callbackgen -type ALMA"; DO NOT EDIT. + +package indicator + +import () + +func (inc *ALMA) OnUpdate(cb func(value float64)) { + inc.UpdateCallbacks = append(inc.UpdateCallbacks, cb) +} + +func (inc *ALMA) EmitUpdate(value float64) { + for _, cb := range inc.UpdateCallbacks { + cb(value) + } +}