Relative Strength to index as used by Leaf_West. If you follow his methods be aware of the different moving averages for the different time periods. From Leaf_West: "on my weekly and monthly R/S charts, I include a 13 EMA of the R/S (brown dash line) and an 8 SMA of the 13 EMA (pink solid line). The indicator on the bottom of the weekly/monthly charts is an 8 period momentum indicator of the R/S line. The red horizontal line is drawn at the zero line. For daily or 130-minute time periods (or shorter), my R/S charts are slightly different - the moving averages of the R/S line include a 20EMA (brown dash line), a 50 EMA (blue dash line) and an 8 SMA of the20 EMA (pink solid line). The momentum indicator is also slightly different from the weekly/monthly charts – here I use a 12 period calculation (vs 8 SMA period for the weekly/monthly charts)." Leaf's methods do evolve and so watch for any changes to the preferred MAs etc..
I have updated this script to handle the weekly and monthly. I have noticed that recently working with another symbol on a chart seems to cause a hang. Others have commented on this as well in their scripts. Sometimes it works and sometimes it won't. In any case this script automatically adjusts the MAs to suit the chart period. Just copy the following and paste into a blank script:
// Relative Strength to index as used by Leaf_West
//On Leaf's weekly and monthly R/S charts, he uses a 13EMA of the R/S (brown dash line)
//and an 8SMA of the 13EMA (pink solid line).
//For daily or 130-minute time periods, R/S charts are slightly different -
//the moving averages of the R/S line include a 20EMA (brown dash line), a 50EMA (blue dash line)
//and an 8SMA of the20EMA (pink solid line).
//The momentum indicator is also slightly different from the weekly/monthly charts
//here he uses a 12 period calculation (vs 8 period for the weekly/monthly charts).
study(shorttitle = " Rel Strength to index Leaf_West", title=" Relative strength to Index", overlay=false)
sym = input(title="Symbol", type=symbol, defval="AMEX:SPY")
src = input(title="Source", type=source, defval=close)
lenemarsh = input (20, title=" smoothing period for intraday and daily short ema")
lenemarlo = input (13, title=" smoothing period for weekly and monthly short ema")
lensma_ema = input (8, title="smoothing period for sma of ema")
lenemalong=input(50, title=" smoothing period for intraday and daily long ema")
shoemalong= input(false, title= "show 50 ema on weekly and monthly R/S")
lenemars= isintraday or period=='D' or period=='390' ? lenemarsh:lenemarlo
s = security("sym", period, src)
s3= close/s*100
emars= ema(s3,lenemars)//s3,lenemars
sma_ema= sma(emars, lensma_ema)
emalong= ema(s3, lenemalong)
plot(s3, color=black,title=" rel chart strength")
plot (emars, color=maroon, title="e moving avg of rel chart strength")
plot (sma_ema, color=fuchsia, title="s moving avg of e moving avg ")
plot(emalong, color=shoemalong or (isintraday or period=='D')?blue:na)