Natural Market Mirror

//@version=2
//coded in tradingview by kprsa
//idea by Jim Sloman (RIP) - see his book "Ocean theory"
// ------

study("Natural Market Mirror",shorttitle="NMM",overlay=false)
n=input(defval=40,title="Length",type=integer,minval=1,maxval=100,step=1)
s=input(defval=close,title="Source price")

nmm(src2) =>
    src=log(src2)
    sum=0.0
    for i=1 to n
        sum := sum+(src-src[i])/sqrt(i*1.0)
	nmm=sum/(n*1.0)

plot(nmm(s),color=red)