The R Project SVN R

Rev

Rev 88553 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
42333 ripley 1 
% File src/library/stats/man/biplot.princomp.Rd
68948 ripley 2 
% Part of the R package, https://www.R-project.org
88553 hornik 3 
% Copyright 1995-2025 R Core Team
42333 ripley 4 
% Distributed under GPL 2 or later
5 
 
27474 ripley 6 
\name{biplot.princomp}
56186 murdoch 7 
\alias{biplot.princomp}
27474 ripley 8 
\alias{biplot.prcomp}
9 
\title{
10 
Biplot for Principal Components
11 
}
12 
\description{
13 
  Produces a biplot (in the strict sense) from the output of
14 
  \code{\link{princomp}} or \code{\link{prcomp}}
15 
}
16 
\usage{
27968 ripley 17 
\method{biplot}{prcomp}(x, choices = 1:2, scale = 1, pc.biplot = FALSE, \dots)
30915 ripley 18 
 
27474 ripley 19 
\method{biplot}{princomp}(x, choices = 1:2, scale = 1, pc.biplot = FALSE, \dots)
20 
}
21 
\arguments{
22 
  \item{x}{an object of class \code{"princomp"}.}
23 
  \item{choices}{
24 
    length 2 vector specifying the components to plot. Only the default
25 
    is a biplot in the strict sense.
26 
  }
27 
  \item{scale}{
28 
    The variables are scaled by \code{lambda ^ scale} and the
29 
    observations are scaled by \code{lambda ^ (1-scale)} where
30 
    \code{lambda} are the singular values as computed by
90060 hornik 31 
    \code{\link{princomp}}.
32 
    Normally \eqn{0 \le \code{scale} \le 1}, and a warning
27474 ripley 33 
    will be issued if the specified \code{scale} is outside this range.
34 
  }
35 
  \item{pc.biplot}{
88553 hornik 36 
    If true, use what \bibcitet{R:Gabriel:1971} refers to as a
37 
    \dQuote{principal component biplot},
38 
    with \code{lambda = 1} and observations scaled up by sqrt(n) and
27474 ripley 39 
    variables scaled down by sqrt(n).  Then inner products between
40 
    variables approximate covariances and distances between observations
41 
    approximate Mahalanobis distance.
42 
  }
43 
  \item{\dots}{optional arguments to be passed to
44 
    \code{\link{biplot.default}}.}
45 
}
46 
\section{Side Effects}{
88553 hornik 47 
  a plot is produced on the current graphics device.
27474 ripley 48 
}
49 
\details{
88553 hornik 50 
  This is a method for the generic function \code{biplot}.  There is
51 
  considerable confusion over the precise definitions: those of the
52 
  original paper, \bibcitet{R:Gabriel:1971}, are followed here.
53 
  \bibcitet{R:Gabriel+Odoroff:1990} use the same definitions, but their
54 
  plots actually correspond to \code{pc.biplot = TRUE}.
27474 ripley 55 
}
56 
\references{
88553 hornik 57 
  \bibshow{*}
27474 ripley 58 
}
59 
\seealso{
60 
    \code{\link{biplot}},
61 
    \code{\link{princomp}}.
62 
}
63 
\examples{
41508 ripley 64 
require(graphics)
27474 ripley 65 
biplot(princomp(USArrests))
66 
}
67 
\keyword{multivariate}
68 
\keyword{hplot}