Kaufman Moving Average Adaptive

Kaufman Moving Average Adaptive

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//  
// Everyone wants a short-term, fast trading trend that works without large
// losses. That combination does not exist. But it is possible to have fast
// trading trends in which one must get in or out of the market quickly, but
// these have the distinct disadvantage of being whipsawed by market noise
// when the market is volatile in a sideways trending market. During these
// periods, the trader is jumping in and out of positions with no profit-making
// trend in sight. In an attempt to overcome the problem of noise and still be
// able to get closer to the actual change of the trend, Kaufman developed an
// indicator that adapts to market movement. This indicator, an adaptive moving
// average (AMA), moves very slowly when markets are moving sideways but moves
// swiftly when the markets also move swiftly, change directions or break out of
// a trading range.
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study(title="Kaufman Moving Average Adaptive (KAMA)", shorttitle="Kaufman Moving Average Adaptive (KAMA)", overlay = true)
Length = input(21, minval=1)
xPrice = close
xvnoise = abs(xPrice - xPrice[1])
nfastend = 0.666
nslowend = 0.0645
nsignal = abs(xPrice - xPrice[Length])
nnoise = sum(xvnoise, Length)
nefratio = iff(nnoise != 0, nsignal / nnoise, 0)
nsmooth = pow(nefratio * (nfastend - nslowend) + nslowend, 2) 
nAMA = nz(nAMA[1]) + nsmooth * (xPrice - nz(nAMA[1]))
plot(nAMA, color=blue, title="KAMA")