1% Generated by roxygen2: do not edit by hand
2% Please edit documentation in R/priceBands.R
3\name{PBands}
4\alias{PBands}
5\alias{priceBands}
6\title{Construct (optionally further smoothed and centered ) volatility bands around
7prices}
8\usage{
9PBands(
10  prices,
11  n = 20,
12  maType = "SMA",
13  sd = 2,
14  ...,
15  fastn = 2,
16  centered = FALSE,
17  lavg = FALSE
18)
19}
20\arguments{
21\item{prices}{A univariate series of prices.}
22
23\item{n}{Number of periods to average over.}
24
25\item{maType}{A function or a string naming the function to be called.}
26
27\item{sd}{The number of standard deviations to use.}
28
29\item{\dots}{any other pass-thru parameters, usually for function named by
30\code{maType}.}
31
32\item{fastn}{Number of periods to use for smoothing higher-frequency 'noise'.}
33
34\item{centered}{Whether to center the bands around a series adjusted for high
35frequency noise, default \code{FALSE}.}
36
37\item{lavg}{Whether to use a longer \code{(n*2)} smoothing period for
38centering, default \code{FALSE}.}
39}
40\value{
41A object of the same class as \code{prices} or a matrix (if
42\code{try.xts} fails) containing the columns:
43\describe{
44   \item{ dn }{ The lower price volatility Band. }
45   \item{ center }{ The smoothed centerline (see details). }
46   \item{ up }{ The upper price volatility Band. }
47}
48}
49\description{
50John Bollinger's famous adaptive volatility bands most often use the typical
51price of an HLC series, or may be calculated on a univariate price series
52(see \code{\link{BBands}}).
53}
54\details{
55This function applies a second moving average denoted by \code{fastn} to
56filter out higher-frequency noise, making the bands somewhat more stable to
57temporary fluctuations and spikes.
58
59If \code{centered} is \code{TRUE}, the function also further smoothes and
60centers the bands around a centerline adjusted to remove this higher
61frequency noise.  If \code{lavg} is also \code{TRUE}, the smoothing applied
62for the middle band (but not the volatility bands) is doubled to further
63smooth the price-response function.
64
65If you have multiple different price series in \code{prices}, and want to use
66this function, call this functions using \code{lapply(prices,PBands,...)}.
67}
68\examples{
69
70  data(ttrc)
71  pbands.close <- PBands( ttrc[,"Close"] )
72
73}
74\seealso{
75\code{\link{BBands}}
76}
77\author{
78Brian G. Peterson
79}
80\keyword{ts}
81