# Zero Lag EMA (Using an Error Correcting Filter) 
# Mobius 
# Ported to TOS 08.31.2016 from Article by John Ehlers 
# Using an EMA error term, the current price – EMA[1], the amplitude of the error term is altered by multiplying the error by a gain term. The new filter is an EC or Error Corrected EMA. 

# Inputs: 
input Length = 20; 
input GainLimit = 50; 
input LabelsOn = yes; 

 

# Vars: 
def alpha; 
def BestGain; 
def EC1; 
def Gain; 
def EC; 
def Error; 
def LeastError; 
def EMA; 

alpha = 2 / (Length + 1); 
EMA = alpha * close + (1 - alpha) * EMA[1]; 
plot EMAdata = EMA; 
EMAdata.SetDefaultColor(Color.Yellow); 
Gain = fold g = -GainLimit to GainLimit 
       do getValue(g / 10, g); 

EC1 = fold V = -GainLimit to GainLimit 
      do alpha * (EMA + (fold i = -GainLimit to GainLimit 
                         do i / 10) * (Close - EC1[1])) + (1 - alpha) * EC1[1]; 

Error = AbsValue(Close - EC1); 
If Error < 1000000 
Then { 
LeastError = Error; 
BestGain = Gain; 
} else { 
LeastError = LeastError[1]; 
BestGain = 0; 
} 

EC = alpha * (EMA + BestGain * (Close - EC1)) + (1 - alpha) * EC1; 

Plot ECdata = EC; 
ECdata.SetDefaultColor(Color.Cyan); 
AddLabel(LabelsOn, "Standard EMA", color.yellow); 
AddLabel(LabelsOn, "Error Corrected EMA", color.cyan); 
#End Code Error Corrected EMA