FVE (Volatility Modified)

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//  Copyright by HPotter v1.0 02/06/2014
// This is another version of FVE indicator that we have posted earlier 
// in this forum.
// This version has an important enhancement to the previous one that`s 
// especially useful with intraday minute charts.
// Due to the volatility had not been taken into account to avoid the extra 
// complication in the formula, the previous formula has some drawbacks:
// The main drawback is that the constant cutoff coefficient will overestimate 
// price changes in minute charts and underestimate corresponding changes in 
// weekly or monthly charts.
// And now the indicator uses adaptive cutoff coefficient which will adjust to 
// all time frames automatically.
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study(title="Volatility Finite Volume Elements", shorttitle="FVI")
Samples = input(22, minval=1)
Perma = input(40, minval=1)
Cintra = input(0.1)
Cinter = input(0.1)
xhl2 = hl2
xhlc3 = hlc3
xClose = close
xIntra = log(high) - log(low)
xInter = log(xhlc3) - log(xhlc3[1])
xStDevIntra = stdev(sma(xIntra, Samples) , Samples)
xStDevInter = stdev(sma(xInter, Samples) , Samples)
xVolume = volume
TP = xhlc3
TP1 = xhlc3[1]
Intra = xIntra
Vintra = xStDevIntra
Inter = xInter
Vinter = xStDevInter
CutOff = Cintra * Vintra + Cinter * Vinter
MF = xClose - xhl2 + TP - TP1
FveFactor = iff(MF > CutOff * xClose, 1, 
             iff(MF < -1 * CutOff * xClose, -1,  0))
xVolumePlusMinus = xVolume * FveFactor
Fvesum = sum(xVolumePlusMinus, Samples)
VolSum = sum(xVolume, Samples)
xFVE = (Fvesum / VolSum) * 100
xEMAFVE = ema(xFVE, Perma)
plot(xFVE, color=green, title="FVI")
plot(xEMAFVE, color=blue, title="FVI EMA")