| % File src/library/stats/man/screeplot.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2007 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{screeplot} |
| \alias{screeplot} |
| \alias{screeplot.default} |
| \title{Screeplots} |
| \usage{ |
| \method{screeplot}{default}(x, npcs = min(10, length(x$sdev)), |
| type = c("barplot", "lines"), |
| main = deparse1(substitute(x)), \dots) |
| } |
| \arguments{ |
| \item{x}{an object containing a \code{sdev} component, such as that |
| returned by \code{\link{princomp}()} and \code{\link{prcomp}()}.} |
| \item{npcs}{the number of components to be plotted.} |
| \item{type}{the type of plot. Can be abbreviated.} |
| \item{main, \dots}{graphics parameters.} |
| } |
| \description{ |
| \code{screeplot.default} plots the variances against the number of the |
| principal component. This is also the \code{plot} method for classes |
| \code{"princomp"} and \code{"prcomp"}. |
| } |
| \references{ |
| Mardia, K. V., J. T. Kent and J. M. Bibby (1979). |
| \emph{Multivariate Analysis}, London: Academic Press. |
| |
| Venables, W. N. and B. D. Ripley (2002). |
| \emph{Modern Applied Statistics with S}, Springer-Verlag. |
| } |
| \seealso{ |
| \code{\link{princomp}} and \code{\link{prcomp}}. |
| } |
| \examples{ |
| require(graphics) |
| |
| ## The variances of the variables in the |
| ## USArrests data vary by orders of magnitude, so scaling is appropriate |
| (pc.cr <- princomp(USArrests, cor = TRUE)) # inappropriate |
| screeplot(pc.cr) |
| |
| fit <- princomp(covmat = Harman74.cor) |
| screeplot(fit) |
| screeplot(fit, npcs = 24, type = "lines") |
| } |
| \keyword{multivariate} |