FRAMA Rate of Change

//@version=2
study("FRAMA Rate of Change",shorttitle="FRAMA RoC",overlay=false)
price = input(hl2)
len = input(defval=16,minval=1)
FC = input(defval=1,minval=1)
SC = input(defval=198,minval=1)
len1 = len/2
w = log(2/(SC+1))
H1 = highest(high,len1)
L1 = lowest(low,len1)
N1 = (H1-L1)/len1
H2 = highest(high,len)[len1]
L2 = lowest(low,len)[len1]
N2 = (H2-L2)/len1
H3 = highest(high,len)
L3 = lowest(low,len)
N3 = (H3-L3)/len
dimen1 = (log(N1+N2)-log(N3))/log(2)
dimen = iff(N1>0 and N2>0 and N3>0,dimen1,nz(dimen1[1]))
alpha1 = exp(w*(dimen-1))
oldalpha = alpha1>1?1:(alpha1<0.01?0.01:alpha1)
oldN = (2-oldalpha)/oldalpha
N = (((SC-FC)*(oldN-1))/(SC-1))+FC
alpha_ = 2/(N+1)
alpha = alpha_<2/(SC+1)?2/(SC+1):(alpha_>1?1:alpha_)
out = (1-alpha)*nz(out[1]) + alpha*price
roc_len=input(12,title="RoC Length")
roc=((out-out[roc_len])/out[roc_len])*100
plot(roc,color=roc>0?(roc>roc[1]?lime:green):(roc>roc[1]?maroon:red),style=histogram,linewidth=3)