diff --git a/pkg/strategy/factorzoo/correlation.go b/pkg/strategy/factorzoo/correlation.go new file mode 100644 index 000000000..0c47de9ee --- /dev/null +++ b/pkg/strategy/factorzoo/correlation.go @@ -0,0 +1,103 @@ +package factorzoo + +import ( + "fmt" + "github.com/c9s/bbgo/pkg/indicator" + "github.com/c9s/bbgo/pkg/types" + "math" + "time" +) + +var zeroTime time.Time + +//var zeroTime time.Time +type KLineValueMapper func(k types.KLine) float64 + +//go:generate callbackgen -type CORRELATION +type CORRELATION struct { + types.IntervalWindow + Values types.Float64Slice + EndTime time.Time + + UpdateCallbacks []func(value float64) +} + +func (inc *CORRELATION) Last() float64 { + if len(inc.Values) == 0 { + return 0.0 + } + return inc.Values[len(inc.Values)-1] +} + +func (inc *CORRELATION) calculateAndUpdate(klines []types.KLine) { + if len(klines) < inc.Window { + return + } + + var end = len(klines) - 1 + var lastKLine = klines[end] + + if inc.EndTime != zeroTime && lastKLine.GetEndTime().Before(inc.EndTime) { + return + } + + var recentT = klines[end-(inc.Window-1) : end+1] + + correlation, err := calculateCORRELATION(recentT, inc.Window, KLineAmplitudeMapper, indicator.KLineVolumeMapper) + if err != nil { + log.WithError(err).Error("can not calculate correlation") + return + } + inc.Values.Push(correlation) + + if len(inc.Values) > indicator.MaxNumOfVOL { + inc.Values = inc.Values[indicator.MaxNumOfVOLTruncateSize-1:] + } + + inc.EndTime = klines[end].GetEndTime().Time() + + inc.EmitUpdate(correlation) +} + +func (inc *CORRELATION) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) { + if inc.Interval != interval { + return + } + + inc.calculateAndUpdate(window) +} + +func (inc *CORRELATION) Bind(updater indicator.KLineWindowUpdater) { + updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate) +} + +func calculateCORRELATION(klines []types.KLine, window int, valA KLineValueMapper, valB KLineValueMapper) (float64, error) { + length := len(klines) + if length == 0 || length < window { + return 0.0, fmt.Errorf("insufficient elements for calculating VOL with window = %d", window) + } + + sumA, sumB, sumAB, squareSumA, squareSumB := 0., 0., 0., 0., 0. + for _, k := range klines { + // sum of elements of array A + sumA += valA(k) + // sum of elements of array B + sumB += valA(k) + + // sum of A[i] * B[i]. + sumAB = sumAB + valA(k)*valB(k) + + // sum of square of array elements. + squareSumA = squareSumA + valA(k)*valA(k) + squareSumB = squareSumB + valB(k)*valB(k) + } + // use formula for calculating correlation coefficient. + corr := (float64(window)*sumAB - sumA*sumB) / + math.Sqrt((float64(window)*squareSumA-sumA*sumA)*(float64(window)*squareSumB-sumB*sumB)) + + return corr, nil +} + +func KLineAmplitudeMapper(k types.KLine) float64 { + return k.High.Div(k.Low).Float64() +} diff --git a/pkg/strategy/factorzoo/correlation_callbacks.go b/pkg/strategy/factorzoo/correlation_callbacks.go new file mode 100644 index 000000000..829426e86 --- /dev/null +++ b/pkg/strategy/factorzoo/correlation_callbacks.go @@ -0,0 +1,15 @@ +// Code generated by "callbackgen -type CORRELATION"; DO NOT EDIT. + +package factorzoo + +import () + +func (inc *CORRELATION) OnUpdate(cb func(value float64)) { + inc.UpdateCallbacks = append(inc.UpdateCallbacks, cb) +} + +func (inc *CORRELATION) EmitUpdate(value float64) { + for _, cb := range inc.UpdateCallbacks { + cb(value) + } +}