# RSI

0th

Percentile

##### Relative Strength Index

The Relative Strength Index (RSI) calculates a ratio of the recent upward price movements to the absolute price movement. Developed by J. Welles Wilder.

Keywords
ts
##### Usage
RSI(price, n = 14, maType, ...)
##### Arguments
price

Price series that is coercible to xts or matrix.

n

Number of periods for moving averages.

maType

Either:

1. A function or a string naming the function to be called.

2. A list with the first component like (1) above, and additional parameters specified as named components. See Examples.

Other arguments to be passed to the maType function in case (1) above.

##### Details

The RSI calculation is RSI = 100 - 100 / ( 1 + RS ), where RS is the smoothed ratio of 'average' gains over 'average' losses. The 'averages' aren't true averages, since they're divided by the value of n and not the number of periods in which there are gains/losses.

##### Value

A object of the same class as price or a vector (if try.xts fails) containing the RSI values.

##### Note

The RSI is usually interpreted as an overbought/oversold (over 70 / below 30) indicator. Divergence with price may also be useful. For example, if price is making new highs/lows, but RSI is not, it could indicate a reversal.

You can calculate a stochastic RSI by using the function stoch on RSI values.

##### References

The following site(s) were used to code/document this indicator: Relative Strength Index: http://www.fmlabs.com/reference/RSI.htm http://www.equis.com/Customer/Resources/TAAZ/?c=3&p=100 http://linnsoft.com/tour/techind/rsi.htm http://stockcharts.com/education/IndicatorAnalysis/indic_RSI.html Stochastic RSI: http://www.fmlabs.com/reference/StochRSI.htm http://stockcharts.com/education/IndicatorAnalysis/indic_stochRSI.html

See EMA, SMA, etc. for moving average options; and note Warning section. See CMO for a variation on RSI.
library(TTR) # NOT RUN { data(ttrc) price <- ttrc[,"Close"] # Default case rsi <- RSI(price) # Case of one 'maType' for both MAs rsiMA1 <- RSI(price, n=14, maType="WMA", wts=ttrc[,"Volume"]) # Case of two different 'maType's for both MAs rsiMA2 <- RSI(price, n=14, maType=list(maUp=list(EMA,ratio=1/5), maDown=list(WMA,wts=1:10))) # }