bbgo/pkg/strategy/fmaker/S2.go

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package fmaker
import (
"fmt"
"math"
"time"
"git.qtrade.icu/lychiyu/bbgo/pkg/datatype/floats"
"git.qtrade.icu/lychiyu/bbgo/pkg/indicator"
"git.qtrade.icu/lychiyu/bbgo/pkg/types"
)
//go:generate callbackgen -type S2
type S2 struct {
types.IntervalWindow
Values floats.Slice
EndTime time.Time
UpdateCallbacks []func(value float64)
}
func (inc *S2) Last(int) float64 {
if len(inc.Values) == 0 {
return 0.0
}
return inc.Values[len(inc.Values)-1]
}
func (inc *S2) 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 := calculateS2(recentT, inc.Window, types.KLineOpenPriceMapper, types.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 *S2) handleKLineWindowUpdate(interval types.Interval, window types.KLineWindow) {
if inc.Interval != interval {
return
}
inc.CalculateAndUpdate(window)
}
func (inc *S2) Bind(updater indicator.KLineWindowUpdater) {
updater.OnKLineWindowUpdate(inc.handleKLineWindowUpdate)
}
func calculateS2(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 += valB(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
}