| % File src/library/stats/man/biplot.princomp.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2018 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{biplot.princomp} |
| \alias{biplot.princomp} |
| \alias{biplot.prcomp} |
| \title{ |
| Biplot for Principal Components |
| } |
| \description{ |
| Produces a biplot (in the strict sense) from the output of |
| \code{\link{princomp}} or \code{\link{prcomp}} |
| } |
| \usage{ |
| \method{biplot}{prcomp}(x, choices = 1:2, scale = 1, pc.biplot = FALSE, \dots) |
| |
| \method{biplot}{princomp}(x, choices = 1:2, scale = 1, pc.biplot = FALSE, \dots) |
| } |
| \arguments{ |
| \item{x}{an object of class \code{"princomp"}.} |
| \item{choices}{ |
| length 2 vector specifying the components to plot. Only the default |
| is a biplot in the strict sense. |
| } |
| \item{scale}{ |
| The variables are scaled by \code{lambda ^ scale} and the |
| observations are scaled by \code{lambda ^ (1-scale)} where |
| \code{lambda} are the singular values as computed by |
| \code{\link{princomp}}. Normally \code{0 <= scale <= 1}, and a warning |
| will be issued if the specified \code{scale} is outside this range. |
| } |
| \item{pc.biplot}{ |
| If true, use what Gabriel (1971) refers to as a "principal component |
| biplot", with \code{lambda = 1} and observations scaled up by sqrt(n) and |
| variables scaled down by sqrt(n). Then inner products between |
| variables approximate covariances and distances between observations |
| approximate Mahalanobis distance. |
| } |
| \item{\dots}{optional arguments to be passed to |
| \code{\link{biplot.default}}.} |
| } |
| \section{Side Effects}{ |
| a plot is produced on the current graphics device. |
| } |
| \details{ |
| This is a method for the generic function \code{biplot}. There is |
| considerable confusion over the precise definitions: those of the |
| original paper, Gabriel (1971), are followed here. Gabriel and |
| Odoroff (1990) use the same definitions, but their plots actually |
| correspond to \code{pc.biplot = TRUE}. |
| } |
| \references{ |
| Gabriel, K. R. (1971). |
| The biplot graphical display of matrices with applications to |
| principal component analysis. |
| \emph{Biometrika}, \bold{58}, 453--467. |
| \doi{10.2307/2334381}. |
| |
| Gabriel, K. R. and Odoroff, C. L. (1990). |
| Biplots in biomedical research. |
| \emph{Statistics in Medicine}, \bold{9}, 469--485. |
| \doi{10.1002/sim.4780090502}. |
| } |
| \seealso{ |
| \code{\link{biplot}}, |
| \code{\link{princomp}}. |
| } |
| \examples{ |
| require(graphics) |
| biplot(princomp(USArrests)) |
| } |
| \keyword{multivariate} |
| \keyword{hplot} |