class_docstr: Defined by Jack Hutson in the 80s and shows the Rate of Change (%) or slope
  of a triple exponentially smoothed moving average
  
  Formula:
    - ema1 = EMA(data, period)
    - ema2 = EMA(ema1, period)
    - ema3 = EMA(ema2, period)
    - trix = 100 * (ema3 - ema3(-1)) / ema3(-1)
  
    The final formula can be simplified to: 100 * (ema3 / ema3(-1) - 1)
  
  The moving average used is the one originally defined by Wilder,
  the SmoothedMovingAverage
  
  See:
    - https://en.wikipedia.org/wiki/Trix_(technical_analysis)
    - http://stockcharts.com/school/doku.php?id=chart_school:technical_indicators:trix
code: def __init__(self):
      ema1 = self.p._movav(self.data, period=self.p.period)
      ema2 = self.p._movav(ema1, period=self.p.period)
      ema3 = self.p._movav(ema2, period=self.p.period)
  
      # 1 period Percentage Rate of Change
      self.lines.trix = 100.0 * (ema3 / ema3(-self.p._rocperiod) - 1.0)
  
      super(Trix, self).__init__()
  
file_path: backtrader/backtrader/indicators/trix.py
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from .None import Indicator, MovAv
label_desc: Use image node_id 2 to create a new Trix object from inherited base classes: Indicator with example: obj = Trix()