Implement CDLDOJISTAR

cdldojistar.go

@@ -0,0 +1,69 @@
+package talibcdl
+
+import "log"
+
+// DojiStart implements ta-lib function TA_CDLDOJISTAR.
+//
+//     |       Up:              36%
+//     ▓       Down:            64%
+//     ▓       Common Rank:     F+
+//     |       Efficiency Rank: E-
+//      +      Source:          feedroll.com
+func DojiStar(series Series) []int {
+	es := enhancedSeries{series}
+	outInteger := make([]int, es.Len())
+
+	// Identify the minimum number of price bar needed to calculate at least one output.
+	startIdx := intMax(settingBodyDoji.avgPeriod, settingBodyLong.avgPeriod) + 1
+
+	// Make sure there is still something to evaluate.
+	if startIdx >= es.Len() {
+		log.Printf("too few input len(%d) want(%d)", es.Len(), startIdx)
+		return outInteger
+	}
+
+	// Do the calculation using tight loops.
+	// Add-up the initial period, except for the last value.
+	bodyLongPeriodTotal := 0.0
+	bodyDojiPeriodTotal := 0.0
+	bodyLongTrailingIdx := startIdx - 1 - settingBodyLong.avgPeriod
+	bodyDojiTrailingIdx := startIdx - settingBodyDoji.avgPeriod
+
+	for i := bodyLongTrailingIdx; i < startIdx-1; i++ {
+		bodyLongPeriodTotal += es.rangeOf(settingBodyLong, i)
+	}
+
+	for i := bodyDojiTrailingIdx; i < startIdx; i++ {
+		bodyDojiPeriodTotal += es.rangeOf(settingBodyDoji, i)
+	}
+
+	/* Proceed with the calculation for the requested range.
+	 * Must have:
+	 * - first candle: long real body
+	 * - second candle: star (open gapping up in an uptrend or down in a downtrend) with a doji
+	 * The meaning of "doji" and "long" is specified with TA_SetCandleSettings
+	 * outInteger is positive (1 to 100) when bullish or negative (-1 to -100) when bearish;
+	 * it's defined bullish when the long candle is white and the star gaps up, bearish when the long candle
+	 * is black and the star gaps down; the user should consider that a doji star is bullish when it appears
+	 * in an uptrend and it's bearish when it appears in a downtrend, so to determine the bullishness or
+	 * bearishness of the pattern the trend must be analyzed
+	 */
+	for i := startIdx; i < es.Len(); i++ {
+		if es.realBody(i-1) > es.average(settingBodyLong, bodyLongPeriodTotal, i-1) && // 1st: long real body
+			es.realBody(i) <= es.average(settingBodyDoji, bodyDojiPeriodTotal, i) && // 2nd: doji
+			((es.candleColor(i-1).isWhite() && es.realBodyGapUp(i, i-1)) || // that gaps up if 1st is white
+				(es.candleColor(i-1).isBlack() && es.realBodyGapDown(i, i-1))) { // or down if 1st is black
+			outInteger[i] = -int(es.candleColor(i-1)) * 100
+		} else {
+			outInteger[i] = 0
+		}
+		// add the current range and subtract the first range: this is done after the pattern recognition
+		// when avgPeriod is not 0, that means "compare with the previous candles" (it excludes the current candle)
+		bodyLongPeriodTotal += es.rangeOf(settingBodyLong, i-1) - es.rangeOf(settingBodyLong, bodyLongTrailingIdx)
+		bodyDojiPeriodTotal += es.rangeOf(settingBodyDoji, i) - es.rangeOf(settingBodyDoji, bodyDojiTrailingIdx)
+		bodyLongTrailingIdx++
+		bodyDojiTrailingIdx++
+	}
+
+	return outInteger
+}

cdldojistar_test.go

@@ -0,0 +1,18 @@
+package talibcdl
+
+import (
+	"testing"
+)
+
+func TestDojiStar(t *testing.T) {
+	d := SimpleSeries{
+		Highs:  []float64{21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 165, 13},
+		Opens:  []float64{11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 160, 12},
+		Closes: []float64{20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 110, 11},
+		Lows:   []float64{10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 105, 10},
+	}
+	cs := DojiStar(d)
+	t.Log(cs)
+
+	compareInts(t, d, cs, "result = talib.CDLDOJISTAR(testOpen,testHigh,testLow,testClose)")
+}