[RS]Kaufman Adaptive Moving Average V0

study(title="[RS]Kaufman Adaptive Moving Average", shorttitle="[RS]KAMA.V0", overlay=true)
//
length0 = input(4)
src0 = input(close)
//  ||----------------------------------------------------------------------------------------------------------------------------||
//  ||---    Kaufman Adaptive Moving Average Function:   -------------------------------------------------------------------------||
kama(src, length)=>
    _ER = abs(change(src, length) / sum(abs(src-src[1]), length))
    _alpha = pow((_ER * 0.6015 + 0.0645), 2)
    _previous = nz(_return[1], src)
    _return = (_alpha * src) + (1-_alpha) * _previous
    _return
//  ||----------------------------------------------------------------------------------------------------------------------------||
plot(kama(src0, length0))