more iterating on macd, need to get a better handle on how to test.

bollinger_band_series.go

@@ -37,7 +37,7 @@ func (bbs BollingerBandsSeries) GetWindowSize(defaults ...int) int {
 		if len(defaults) > 0 {
 			return defaults[0]
 		}
-		return DefaultMovingAverageWindowSize
+		return DefaultSimpleMovingAveragePeriod
 	}
 	return bbs.WindowSize
 }

bollinger_band_series_test.go

@@ -46,6 +46,6 @@ func TestBollingerBandLastValue(t *testing.T) {
 
 	x, y1, y2 := bbs.GetLastBoundedValue()
 	assert.Equal(100.0, x)
-	assert.Equal(100, math.Floor(y1))
+	assert.Equal(101, math.Floor(y1))
-	assert.Equal(95, math.Floor(y2))
+	assert.Equal(83, math.Floor(y2))
 }

ema_series.go

@@ -0,0 +1,98 @@
+package chart
+
+const (
+	// DefaultEMASigma is the default exponential smoothing factor.
+	DefaultEMASigma = 0.25
+)
+
+// EMASeries is a computed series.
+type EMASeries struct {
+	Name  string
+	Style Style
+	YAxis YAxisType
+
+	// Sigma is the 'smoothing factor' parameter.
+	Sigma       float64
+	Period      int
+	InnerSeries ValueProvider
+}
+
+// GetName returns the name of the time series.
+func (ema EMASeries) GetName() string {
+	return ema.Name
+}
+
+// GetStyle returns the line style.
+func (ema EMASeries) GetStyle() Style {
+	return ema.Style
+}
+
+// GetYAxis returns which YAxis the series draws on.
+func (ema EMASeries) GetYAxis() YAxisType {
+	return ema.YAxis
+}
+
+// GetPeriod returns the window size.
+func (ema EMASeries) GetPeriod(defaults ...int) int {
+	if ema.Period == 0 {
+		if len(defaults) > 0 {
+			return defaults[0]
+		}
+		return ema.InnerSeries.Len()
+	}
+	return ema.Period
+}
+
+// Len returns the number of elements in the series.
+func (ema EMASeries) Len() int {
+	return ema.InnerSeries.Len()
+}
+
+// GetSigma returns the smoothing factor for the serise.
+func (ema EMASeries) GetSigma(defaults ...float64) float64 {
+	if ema.Sigma == 0 {
+		if len(defaults) > 0 {
+			return defaults[0]
+		}
+		return DefaultEMASigma
+	}
+	return ema.Sigma
+}
+
+// GetValue gets a value at a given index.
+func (ema EMASeries) GetValue(index int) (x float64, y float64) {
+	if ema.InnerSeries == nil {
+		return
+	}
+	vx, _ := ema.InnerSeries.GetValue(index)
+	x = vx
+	y = ema.compute(ema.GetPeriod(), index)
+	return
+}
+
+// GetLastValue computes the last moving average value but walking back window size samples,
+// and recomputing the last moving average chunk.
+func (ema EMASeries) GetLastValue() (x float64, y float64) {
+	if ema.InnerSeries == nil {
+		return
+	}
+	lastIndex := ema.InnerSeries.Len() - 1
+	x, _ = ema.InnerSeries.GetValue(lastIndex)
+	y = ema.compute(ema.GetPeriod(), lastIndex)
+	return
+}
+
+func (ema EMASeries) compute(period, index int) float64 {
+	_, v := ema.InnerSeries.GetValue(index)
+	if period == 1 || index == 0 {
+		return v
+	}
+	sig := ema.GetSigma()
+	return sig*v + ((1.0 - sig) * ema.compute(period-1, index-1))
+}
+
+// Render renders the series.
+func (ema EMASeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
+	style := ema.Style.WithDefaultsFrom(defaults)
+	DrawLineSeries(r, canvasBox, xrange, yrange, style, ema)
+}

ema_series_test.go

@@ -7,7 +7,7 @@ import (
 	"github.com/blendlabs/go-assert"
 )
 
-func TestExponentialMovingAverageSeries(t *testing.T) {
+func TestEMASeries(t *testing.T) {
 	assert := assert.New(t)
 
 	mockSeries := mockValueProvider{
@@ -16,7 +16,7 @@ func TestExponentialMovingAverageSeries(t *testing.T) {
 	}
 	assert.Equal(10, mockSeries.Len())
 
-	mas := &ExponentialMovingAverageSeries{
+	mas := &EMASeries{
 		InnerSeries: mockSeries,
 	}
 

exp_moving_average_series.go

@@ -1,94 +0,0 @@
-package chart
-
-const (
-	// DefaultExponentialMovingAverageSigma is the default exponential smoothing factor.
-	DefaultExponentialMovingAverageSigma = 0.25
-)
-
-// ExponentialMovingAverageSeries is a computed series.
-type ExponentialMovingAverageSeries struct {
-	Name  string
-	Style Style
-	YAxis YAxisType
-
-	// Sigma is the 'smoothing factor' parameter.
-	Sigma       float64
-	InnerSeries ValueProvider
-
-	valueBuffer []float64
-}
-
-// GetName returns the name of the time series.
-func (mas ExponentialMovingAverageSeries) GetName() string {
-	return mas.Name
-}
-
-// GetStyle returns the line style.
-func (mas ExponentialMovingAverageSeries) GetStyle() Style {
-	return mas.Style
-}
-
-// GetYAxis returns which YAxis the series draws on.
-func (mas ExponentialMovingAverageSeries) GetYAxis() YAxisType {
-	return mas.YAxis
-}
-
-// Len returns the number of elements in the series.
-func (mas *ExponentialMovingAverageSeries) Len() int {
-	return mas.InnerSeries.Len()
-}
-
-// GetSigma returns the smoothing factor for the serise.
-func (mas ExponentialMovingAverageSeries) GetSigma(defaults ...float64) float64 {
-	if mas.Sigma == 0 {
-		if len(defaults) > 0 {
-			return defaults[0]
-		}
-		return DefaultExponentialMovingAverageSigma
-	}
-	return mas.Sigma
-}
-
-// GetValue gets a value at a given index.
-func (mas *ExponentialMovingAverageSeries) GetValue(index int) (x float64, y float64) {
-	if mas.InnerSeries == nil {
-		return
-	}
-	if mas.valueBuffer == nil || index == 0 {
-		mas.valueBuffer = make([]float64, mas.InnerSeries.Len())
-	}
-	vx, vy := mas.InnerSeries.GetValue(index)
-	x = vx
-	if index == 0 {
-		mas.valueBuffer[0] = vy
-		y = vy
-		return
-	}
-
-	sig := mas.GetSigma()
-	mas.valueBuffer[index] = sig*vy + ((1.0 - sig) * mas.valueBuffer[index-1])
-	y = mas.valueBuffer[index]
-	return
-}
-
-// GetLastValue computes the last moving average value but walking back window size samples,
-// and recomputing the last moving average chunk.
-func (mas ExponentialMovingAverageSeries) GetLastValue() (x float64, y float64) {
-	if mas.InnerSeries == nil {
-		return
-	}
-
-	seriesLength := mas.InnerSeries.Len()
-	for index := 0; index < seriesLength; index++ {
-		x, _ = mas.GetValue(index)
-	}
-
-	y = mas.valueBuffer[seriesLength-1]
-	return
-}
-
-// Render renders the series.
-func (mas *ExponentialMovingAverageSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
-	style := mas.Style.WithDefaultsFrom(defaults)
-	DrawLineSeries(r, canvasBox, xrange, yrange, style, mas)
-}

macd_series.go

@@ -1,37 +1,45 @@
 package chart
 
 const (
-	// DefaultMACDWindowPrimary is the long window.
+	// DefaultMACDPeriodPrimary is the long window.
-	DefaultMACDWindowPrimary = 26
+	DefaultMACDPeriodPrimary = 26
-	// DefaultMACDWindowSecondary is the short window.
+	// DefaultMACDPeriodSecondary is the short window.
-	DefaultMACDWindowSecondary = 12
+	DefaultMACDPeriodSecondary = 12
+	// DefaultMACDSignalPeriod is the signal period to compute for the MACD.
+	DefaultMACDSignalPeriod = 9
 )
 
-// MACDSeries (or Moving Average Convergence Divergence) is a special type of series that
+// MACDSeries computes the difference between the MACD line and the MACD Signal line.
-// computes the difference between two different EMA values for a given index, as denoted by WindowPrimary(26) and WindowSecondary(12).
+// It is used in technical analysis and gives a lagging indicator of momentum.
 type MACDSeries struct {
 	Name        string
 	Style       Style
 	YAxis       YAxisType
 	InnerSeries ValueProvider
 
-	WindowPrimary   int
+	PrimaryPeriod   int
-	WindowSecondary int
+	SecondaryPeriod int
+	SignalPeriod    int
 
 	Sigma float64
 }
 
-// GetWindows returns the primary and secondary window sizes.
+// GetPeriods returns the primary and secondary periods.
-func (macd MACDSeries) GetWindows() (w1, w2 int) {
+func (macd MACDSeries) GetPeriods() (w1, w2, sig int) {
-	if macd.WindowPrimary == 0 {
+	if macd.PrimaryPeriod == 0 {
-		w1 = DefaultMACDWindowPrimary
+		w1 = DefaultMACDPeriodPrimary
 	} else {
-		w1 = macd.WindowPrimary
+		w1 = macd.PrimaryPeriod
 	}
-	if macd.WindowSecondary == 0 {
+	if macd.SecondaryPeriod == 0 {
-		w2 = DefaultMACDWindowSecondary
+		w2 = DefaultMACDPeriodSecondary
 	} else {
-		w2 = macd.WindowSecondary
+		w2 = macd.SecondaryPeriod
+	}
+	if macd.SignalPeriod == 0 {
+		sig = DefaultMACDSignalPeriod
+	} else {
+		sig = macd.SignalPeriod
 	}
 	return
 }
@@ -42,7 +50,7 @@ func (macd MACDSeries) GetSigma(defaults ...float64) float64 {
 		if len(defaults) > 0 {
 			return defaults[0]
 		}
-		return DefaultExponentialMovingAverageSigma
+		return DefaultEMASigma
 	}
 	return macd.Sigma
 }
@@ -68,7 +76,7 @@ func (macd MACDSeries) Len() int {
 		return 0
 	}
 
-	w1, _ := macd.GetWindows()
+	w1, _, _ := macd.GetPeriods()
 	innerLen := macd.InnerSeries.Len()
 	if innerLen > w1 {
 		return innerLen - w1
@@ -76,35 +84,250 @@ func (macd MACDSeries) Len() int {
 	return 0
 }
 
-// GetValue gets a value at a given index.
+// GetValue gets a value at a given index. For MACD it is the signal value.
 func (macd MACDSeries) GetValue(index int) (x float64, y float64) {
 	if macd.InnerSeries == nil {
 		return
 	}
 
-	w1, w2 := macd.GetWindows()
+	w1, w2, sig := macd.GetPeriods()
+	sigma := macd.GetSigma()
 
 	effectiveIndex := index + w1
 	x, _ = macd.InnerSeries.GetValue(effectiveIndex)
 
-	ema1 := macd.computeEMA(w1, effectiveIndex)
+	signal := EMASeries{
-	ema2 := macd.computeEMA(w2, effectiveIndex)
+		InnerSeries: MACDLineSeries{
+			InnerSeries:     macd.InnerSeries,
+			PrimaryPeriod:   w1,
+			SecondaryPeriod: w2,
+			Sigma:           sigma,
+		},
+		Sigma:  sigma,
+		Period: sig,
+	}
+
+	macdl := MACDLineSeries{
+		InnerSeries:     macd.InnerSeries,
+		PrimaryPeriod:   w1,
+		SecondaryPeriod: w2,
+		Sigma:           sigma,
+	}
+
+	_, sv := signal.GetValue(index)
+	_, lv := macdl.GetValue(index)
+	y = lv - sv
 
-	y = ema1 - ema2
 	return
 }
 
-func (macd MACDSeries) computeEMA(windowSize int, index int) float64 {
+// MACDSignalSeries computes the EMA of the MACDLineSeries.
-	_, v := macd.InnerSeries.GetValue(index)
+type MACDSignalSeries struct {
-	if windowSize == 1 {
+	Name        string
-		return v
+	Style       Style
+	YAxis       YAxisType
+	InnerSeries ValueProvider
+
+	PrimaryPeriod   int
+	SecondaryPeriod int
+	SignalPeriod    int
+
+	Sigma float64
+}
+
+// GetPeriods returns the primary and secondary periods.
+func (macds MACDSignalSeries) GetPeriods() (w1, w2, sig int) {
+	if macds.PrimaryPeriod == 0 {
+		w1 = DefaultMACDPeriodPrimary
+	} else {
+		w1 = macds.PrimaryPeriod
 	}
-	sig := macd.GetSigma()
+	if macds.SecondaryPeriod == 0 {
-	return sig*v + ((1.0 - sig) * macd.computeEMA(windowSize-1, index-1))
+		w2 = DefaultMACDPeriodSecondary
+	} else {
+		w2 = macds.SecondaryPeriod
+	}
+	if macds.SignalPeriod == 0 {
+		sig = DefaultMACDSignalPeriod
+	} else {
+		sig = macds.SignalPeriod
+	}
+	return
+}
+
+// GetSigma returns the smoothing factor for the serise.
+func (macds MACDSignalSeries) GetSigma(defaults ...float64) float64 {
+	if macds.Sigma == 0 {
+		if len(defaults) > 0 {
+			return defaults[0]
+		}
+		return DefaultEMASigma
+	}
+	return macds.Sigma
+}
+
+// GetName returns the name of the time series.
+func (macds MACDSignalSeries) GetName() string {
+	return macds.Name
+}
+
+// GetStyle returns the line style.
+func (macds MACDSignalSeries) GetStyle() Style {
+	return macds.Style
+}
+
+// GetYAxis returns which YAxis the series draws on.
+func (macds MACDSignalSeries) GetYAxis() YAxisType {
+	return macds.YAxis
+}
+
+// Len returns the number of elements in the series.
+func (macds MACDSignalSeries) Len() int {
+	if macds.InnerSeries == nil {
+		return 0
+	}
+
+	w1, _, _ := macds.GetPeriods()
+	innerLen := macds.InnerSeries.Len()
+	if innerLen > w1 {
+		return innerLen - w1
+	}
+	return 0
+}
+
+// GetValue gets a value at a given index. For MACD it is the signal value.
+func (macds MACDSignalSeries) GetValue(index int) (x float64, y float64) {
+	if macds.InnerSeries == nil {
+		return
+	}
+
+	w1, w2, sig := macds.GetPeriods()
+	sigma := macds.GetSigma()
+
+	effectiveIndex := index + w1
+	x, _ = macds.InnerSeries.GetValue(effectiveIndex)
+
+	signal := EMASeries{
+		InnerSeries: MACDLineSeries{
+			InnerSeries:     macds.InnerSeries,
+			PrimaryPeriod:   w1,
+			SecondaryPeriod: w2,
+			Sigma:           sigma,
+		},
+		Sigma:  sigma,
+		Period: sig,
+	}
+
+	_, y = signal.GetValue(index)
+	return
 }
 
 // Render renders the series.
-func (macd MACDSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
+func (macds MACDSignalSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
-	style := macd.Style.WithDefaultsFrom(defaults)
+	style := macds.Style.WithDefaultsFrom(defaults)
-	DrawLineSeries(r, canvasBox, xrange, yrange, style, macd)
+	DrawLineSeries(r, canvasBox, xrange, yrange, style, macds)
+}
+
+// MACDLineSeries is a series that computes the inner ema1-ema2 value as a series.
+type MACDLineSeries struct {
+	Name        string
+	Style       Style
+	YAxis       YAxisType
+	InnerSeries ValueProvider
+
+	PrimaryPeriod   int
+	SecondaryPeriod int
+
+	Sigma float64
+}
+
+// GetName returns the name of the time series.
+func (macdl MACDLineSeries) GetName() string {
+	return macdl.Name
+}
+
+// GetStyle returns the line style.
+func (macdl MACDLineSeries) GetStyle() Style {
+	return macdl.Style
+}
+
+// GetYAxis returns which YAxis the series draws on.
+func (macdl MACDLineSeries) GetYAxis() YAxisType {
+	return macdl.YAxis
+}
+
+// GetPeriods returns the primary and secondary periods.
+func (macdl MACDLineSeries) GetPeriods() (w1, w2 int) {
+	if macdl.PrimaryPeriod == 0 {
+		w1 = DefaultMACDPeriodPrimary
+	} else {
+		w1 = macdl.PrimaryPeriod
+	}
+	if macdl.SecondaryPeriod == 0 {
+		w2 = DefaultMACDPeriodSecondary
+	} else {
+		w2 = macdl.SecondaryPeriod
+	}
+	return
+}
+
+// Len returns the number of elements in the series.
+func (macdl MACDLineSeries) Len() int {
+	if macdl.InnerSeries == nil {
+		return 0
+	}
+
+	w1, _ := macdl.GetPeriods()
+	innerLen := macdl.InnerSeries.Len()
+	if innerLen > w1 {
+		return innerLen - w1
+	}
+	return 0
+}
+
+// GetSigma returns the smoothing factor for the serise.
+func (macdl MACDLineSeries) GetSigma(defaults ...float64) float64 {
+	if macdl.Sigma == 0 {
+		if len(defaults) > 0 {
+			return defaults[0]
+		}
+		return DefaultEMASigma
+	}
+	return macdl.Sigma
+}
+
+// GetValue gets a value at a given index. For MACD it is the signal value.
+func (macdl MACDLineSeries) GetValue(index int) (x float64, y float64) {
+	if macdl.InnerSeries == nil {
+		return
+	}
+
+	w1, w2 := macdl.GetPeriods()
+
+	effectiveIndex := index + w1
+	x, _ = macdl.InnerSeries.GetValue(effectiveIndex)
+
+	ema1 := EMASeries{
+		InnerSeries: macdl.InnerSeries,
+		Period:      w1,
+		Sigma:       macdl.GetSigma(),
+	}
+
+	ema2 := EMASeries{
+		InnerSeries: macdl.InnerSeries,
+		Period:      w2,
+		Sigma:       macdl.GetSigma(),
+	}
+
+	_, emav1 := ema1.GetValue(index)
+	_, emav2 := ema2.GetValue(index)
+
+	y = emav1 - emav2
+	return
+}
+
+// Render renders the series.
+func (macdl MACDLineSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
+	style := macdl.Style.WithDefaultsFrom(defaults)
+	DrawLineSeries(r, canvasBox, xrange, yrange, style, macdl)
 }

simple_moving_average_series.go

@@ -1,105 +0,0 @@
-package chart
-
-const (
-	// DefaultMovingAverageWindowSize is the default number of values to average.
-	DefaultMovingAverageWindowSize = 5
-)
-
-// SimpleMovingAverageSeries is a computed series.
-type SimpleMovingAverageSeries struct {
-	Name  string
-	Style Style
-	YAxis YAxisType
-
-	WindowSize  int
-	InnerSeries ValueProvider
-
-	valueBuffer *RingBuffer
-}
-
-// GetName returns the name of the time series.
-func (mas SimpleMovingAverageSeries) GetName() string {
-	return mas.Name
-}
-
-// GetStyle returns the line style.
-func (mas SimpleMovingAverageSeries) GetStyle() Style {
-	return mas.Style
-}
-
-// GetYAxis returns which YAxis the series draws on.
-func (mas SimpleMovingAverageSeries) GetYAxis() YAxisType {
-	return mas.YAxis
-}
-
-// Len returns the number of elements in the series.
-func (mas *SimpleMovingAverageSeries) Len() int {
-	return mas.InnerSeries.Len()
-}
-
-// GetValue gets a value at a given index.
-func (mas *SimpleMovingAverageSeries) GetValue(index int) (x float64, y float64) {
-	if mas.InnerSeries == nil {
-		return
-	}
-	if mas.valueBuffer == nil || index == 0 {
-		mas.valueBuffer = NewRingBufferWithCapacity(mas.GetWindowSize())
-	}
-	if mas.valueBuffer.Len() >= mas.GetWindowSize() {
-		mas.valueBuffer.Dequeue()
-	}
-	px, py := mas.InnerSeries.GetValue(index)
-	mas.valueBuffer.Enqueue(py)
-	x = px
-	y = mas.getAverage(mas.valueBuffer)
-	return
-}
-
-// GetLastValue computes the last moving average value but walking back window size samples,
-// and recomputing the last moving average chunk.
-func (mas SimpleMovingAverageSeries) GetLastValue() (x float64, y float64) {
-	if mas.InnerSeries == nil {
-		return
-	}
-	windowSize := mas.GetWindowSize()
-	seriesLength := mas.InnerSeries.Len()
-	startAt := seriesLength - windowSize
-	if startAt < 0 {
-		startAt = 0
-	}
-	vb := NewRingBufferWithCapacity(windowSize)
-	for index := startAt; index < seriesLength; index++ {
-		xn, yn := mas.InnerSeries.GetValue(index)
-		vb.Enqueue(yn)
-		x = xn
-	}
-	y = mas.getAverage(vb)
-	return
-}
-
-// GetWindowSize returns the window size.
-func (mas SimpleMovingAverageSeries) GetWindowSize(defaults ...int) int {
-	if mas.WindowSize == 0 {
-		if len(defaults) > 0 {
-			return defaults[0]
-		}
-		return DefaultMovingAverageWindowSize
-	}
-	return mas.WindowSize
-}
-
-func (mas SimpleMovingAverageSeries) getAverage(valueBuffer *RingBuffer) float64 {
-	var accum float64
-	valueBuffer.Each(func(v interface{}) {
-		if typed, isTyped := v.(float64); isTyped {
-			accum += typed
-		}
-	})
-	return accum / float64(valueBuffer.Len())
-}
-
-// Render renders the series.
-func (mas *SimpleMovingAverageSeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
-	style := mas.Style.WithDefaultsFrom(defaults)
-	DrawLineSeries(r, canvasBox, xrange, yrange, style, mas)
-}

sma_series.go

@@ -0,0 +1,90 @@
+package chart
+
+const (
+	// DefaultSimpleMovingAveragePeriod is the default number of values to average.
+	DefaultSimpleMovingAveragePeriod = 16
+)
+
+// SMASeries is a computed series.
+type SMASeries struct {
+	Name  string
+	Style Style
+	YAxis YAxisType
+
+	Period      int
+	InnerSeries ValueProvider
+}
+
+// GetName returns the name of the time series.
+func (sma SMASeries) GetName() string {
+	return sma.Name
+}
+
+// GetStyle returns the line style.
+func (sma SMASeries) GetStyle() Style {
+	return sma.Style
+}
+
+// GetYAxis returns which YAxis the series draws on.
+func (sma SMASeries) GetYAxis() YAxisType {
+	return sma.YAxis
+}
+
+// Len returns the number of elements in the series.
+func (sma SMASeries) Len() int {
+	return sma.InnerSeries.Len()
+}
+
+// GetValue gets a value at a given index.
+func (sma SMASeries) GetValue(index int) (x float64, y float64) {
+	if sma.InnerSeries == nil {
+		return
+	}
+	px, _ := sma.InnerSeries.GetValue(index)
+	x = px
+	y = sma.getAverage(index)
+	return
+}
+
+// GetLastValue computes the last moving average value but walking back window size samples,
+// and recomputing the last moving average chunk.
+func (sma SMASeries) GetLastValue() (x float64, y float64) {
+	if sma.InnerSeries == nil {
+		return
+	}
+	seriesLen := sma.InnerSeries.Len()
+	px, _ := sma.InnerSeries.GetValue(seriesLen - 1)
+	x = px
+	y = sma.getAverage(seriesLen - 1)
+	return
+}
+
+// GetPeriod returns the window size.
+func (sma SMASeries) GetPeriod(defaults ...int) int {
+	if sma.Period == 0 {
+		if len(defaults) > 0 {
+			return defaults[0]
+		}
+		return DefaultSimpleMovingAveragePeriod
+	}
+	return sma.Period
+}
+
+func (sma SMASeries) getAverage(index int) float64 {
+	period := sma.GetPeriod()
+	floor := MaxInt(0, index-period)
+	var accum float64
+	var count float64
+	for x := index; x >= floor; x-- {
+		_, vy := sma.InnerSeries.GetValue(x)
+		accum += vy
+		count += 1.0
+	}
+	return accum / count
+}
+
+// Render renders the series.
+func (sma *SMASeries) Render(r Renderer, canvasBox Box, xrange, yrange Range, defaults Style) {
+	style := sma.Style.WithDefaultsFrom(defaults)
+	DrawLineSeries(r, canvasBox, xrange, yrange, style, sma)
+}

sma_series_test.go

@@ -16,12 +16,18 @@ func (m mockValueProvider) Len() int {
 }
 
 func (m mockValueProvider) GetValue(index int) (x, y float64) {
+	if index < 0 {
+		panic("negative index at GetValue()")
+	}
+	if index > MinInt(len(m.X), len(m.Y)) {
+		panic("index is outside the length of m.X or m.Y")
+	}
 	x = m.X[index]
 	y = m.Y[index]
 	return
 }
 
-func TestSimpleMovingAverageSeriesGetValue(t *testing.T) {
+func TestSMASeriesGetValue(t *testing.T) {
 	assert := assert.New(t)
 
 	mockSeries := mockValueProvider{
@@ -30,9 +36,9 @@ func TestSimpleMovingAverageSeriesGetValue(t *testing.T) {
 	}
 	assert.Equal(10, mockSeries.Len())
 
-	mas := &SimpleMovingAverageSeries{
+	mas := &SMASeries{
 		InnerSeries: mockSeries,
-		WindowSize:  10,
+		Period:      10,
 	}
 
 	var yvalues []float64
@@ -52,7 +58,7 @@ func TestSimpleMovingAverageSeriesGetValue(t *testing.T) {
 	assert.Equal(6.0, yvalues[8])
 }
 
-func TestSimpleMovingAverageSeriesGetLastValueWindowOverlap(t *testing.T) {
+func TestSMASeriesGetLastValueWindowOverlap(t *testing.T) {
 	assert := assert.New(t)
 
 	mockSeries := mockValueProvider{
@@ -61,9 +67,9 @@ func TestSimpleMovingAverageSeriesGetLastValueWindowOverlap(t *testing.T) {
 	}
 	assert.Equal(10, mockSeries.Len())
 
-	mas := &SimpleMovingAverageSeries{
+	mas := &SMASeries{
 		InnerSeries: mockSeries,
-		WindowSize:  15,
+		Period:      15,
 	}
 
 	var yvalues []float64
@@ -78,7 +84,7 @@ func TestSimpleMovingAverageSeriesGetLastValueWindowOverlap(t *testing.T) {
 	assert.Equal(yvalues[len(yvalues)-1], ly)
 }
 
-func TestSimpleMovingAverageSeriesGetLastValue(t *testing.T) {
+func TestSMASeriesGetLastValue(t *testing.T) {
 	assert := assert.New(t)
 
 	mockSeries := mockValueProvider{
@@ -87,9 +93,9 @@ func TestSimpleMovingAverageSeriesGetLastValue(t *testing.T) {
 	}
 	assert.Equal(100, mockSeries.Len())
 
-	mas := &SimpleMovingAverageSeries{
+	mas := &SMASeries{
 		InnerSeries: mockSeries,
-		WindowSize:  10,
+		Period:      10,
 	}
 
 	var yvalues []float64
@@ -100,6 +106,6 @@ func TestSimpleMovingAverageSeriesGetLastValue(t *testing.T) {
 
 	lx, ly := mas.GetLastValue()
 	assert.Equal(100.0, lx)
-	assert.Equal(5.5, ly)
+	assert.Equal(6, ly)
 	assert.Equal(yvalues[len(yvalues)-1], ly)
 }