class_docstr: Defined by J. Welles Wilder, Jr. in 1978 in his book *"New Concepts in
  Technical Trading Systems"* for the RSI
  
  Records days which have been "up", i.e.: the close price has been
  higher than the day before.
  
  Formula:
    - upday = max(close - close_prev, 0)
  
  See:
    - http://en.wikipedia.org/wiki/Relative_strength_index
class_docstr_tok: ["Defined","by","J.","Welles","Wilder",",","Jr.","in","1978","in","his","book","*","''","New","Concepts","in","Technical","Trading","Systems","''","*","for","the","RSI","Records","days","which","have","been","``","up","''",",","i.e",".",":","the","close","price","has","been","higher","than","the","day","before",".","Formula",":","-","upday","=","max","(","close","-","close_prev",",","0",")","See",":","-","http",":","\/\/en.wikipedia.org\/wiki\/Relative_strength_index"]
code: def __init__(self):
      self.lines.upday = Max(self.data - self.data(-self.p.period), 0.0)
      super(UpDay, self).__init__()
  
imports: from __future__ import absolute_import, division, print_function, unicode_literals
  from .None import Indicator, Max, MovAv
  from .None import DivZeroByZero
label_desc: Use image node_id 1 to create a new UpDay object from inherited base classes: Indicator with example: obj = UpDay()