R/plot_obsfa.R

In fhernanb/model: This Package Contains Useful Functions for Modeling Regresion

#' Plot observations in the coordinate plane Fi-Fj.
#' 
#' This function plots the original observations in the coordinate plane Fi-Fj from a factor analysis.
#' 
#' @param scores a matrix obtained from \code{\link{factanal}} function.
#' @param fx a number to indicate the factor to plot in x axis.
#' @param fy a number to indicate the factor to plot in y axis.
#' @param lchar the number of first characters to identify points, by default is 3.
#' @param ... arguments to be passed to methods, such as graphical parameters (see par).
#' 
#' @example examples/examples_plot_obsfa.R
#' @return \code{plot_obsfa} function returns a plot with the 
#' observations in the coordinate plane Fi-Fj from a factor analysis.
#' 
#' @details The number in \code{fx} and \code{fy} must be less or equal
#' number of factors in \code{factanal} function.
#' 
#' @importFrom graphics plot text abline
#' @export
plot_obsfa <- function(scores, fx=1, fy=2, lchar=3, ...) {
  stopifnot(any(class(scores) == 'matrix'))
  if (is.null(rownames(scores))) {
    n <- dim(scores)[1]
    rownames(scores) <- 1:n
    lchar <- nchar(n)
  }
  plot(x=scores[, fx], y=scores[, fy],
       xlab=bquote(.('Factor') ~ .(fx)),
       ylab=bquote(.('Factor') ~ .(fy)), ...)
  Names <- substr(rownames(scores), start = 1, stop = lchar)
  text(scores[, c(fx, fy)], labels = Names, adj = c(0, 0))
  abline(h = 0, col = "gray60", lty = "longdash")
  abline(v = 0, col = "gray60", lty = "longdash")
}