RAVI [Albert]

//
// @author LazyBear
// If you use this code in its orignal/modified form, do drop me a note. 
// 
study(title = "RAVI [Albert]", shorttitle="RAVI_A")
short=input(7)
long=input(65)
src=close
ravi=(sma(src, short) - sma(src, long)) / sma(src,long)
hline(0)
plot(ravi, style=area)