105 lines
2.6 KiB
Go
105 lines
2.6 KiB
Go
package chart
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const (
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// DefaultMovingAverageWindowSize is the default number of values to average.
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DefaultMovingAverageWindowSize = 5
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)
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// MovingAverageSeries is a computed series.
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type MovingAverageSeries struct {
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Name string
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Style Style
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YAxis YAxisType
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WindowSize int
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InnerSeries ValueProvider
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valueBuffer *RingBuffer
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}
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// GetName returns the name of the time series.
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func (mas MovingAverageSeries) GetName() string {
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return mas.Name
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}
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// GetStyle returns the line style.
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func (mas MovingAverageSeries) GetStyle() Style {
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return mas.Style
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}
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// GetYAxis returns which YAxis the series draws on.
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func (mas MovingAverageSeries) GetYAxis() YAxisType {
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return mas.YAxis
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}
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// Len returns the number of elements in the series.
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func (mas *MovingAverageSeries) Len() int {
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return mas.InnerSeries.Len()
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}
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// GetValue gets a value at a given index.
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func (mas *MovingAverageSeries) GetValue(index int) (x float64, y float64) {
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if mas.InnerSeries == nil {
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return
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}
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if mas.valueBuffer == nil || index == 0 {
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mas.valueBuffer = NewRingBufferWithCapacity(mas.GetWindowSize())
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}
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if mas.valueBuffer.Len() >= mas.GetWindowSize() {
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mas.valueBuffer.Dequeue()
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}
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px, py := mas.InnerSeries.GetValue(index)
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mas.valueBuffer.Enqueue(py)
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x = px
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y = mas.getAverage(mas.valueBuffer)
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return
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}
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// GetLastValue computes the last moving average value but walking back window size samples,
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// and recomputing the last moving average chunk.
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func (mas MovingAverageSeries) GetLastValue() (x float64, y float64) {
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if mas.InnerSeries == nil {
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return
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}
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windowSize := mas.GetWindowSize()
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seriesLength := mas.InnerSeries.Len()
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startAt := seriesLength - windowSize
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if startAt < 0 {
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startAt = 0
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}
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vb := NewRingBufferWithCapacity(windowSize)
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for index := startAt; index < seriesLength; index++ {
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xn, yn := mas.InnerSeries.GetValue(index)
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vb.Enqueue(yn)
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x = xn
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}
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y = mas.getAverage(vb)
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return
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}
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// GetWindowSize returns the window size.
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func (mas MovingAverageSeries) GetWindowSize(defaults ...int) int {
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if mas.WindowSize == 0 {
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if len(defaults) > 0 {
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return defaults[0]
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}
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return DefaultMovingAverageWindowSize
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}
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return mas.WindowSize
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}
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func (mas MovingAverageSeries) getAverage(valueBuffer *RingBuffer) float64 {
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var accum float64
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valueBuffer.Each(func(v interface{}) {
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if typed, isTyped := v.(float64); isTyped {
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accum += typed
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}
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})
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return accum / float64(valueBuffer.Len())
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}
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// Render renders the series.
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func (mas *MovingAverageSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
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style := mas.Style.WithDefaultsFrom(defaults)
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DrawLineSeries(r, canvasBox, xrange, yrange, style, mas)
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}
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