R/qqGamma.r

In qPharmetra/qpToolkit: qPharmetra R Tools

# ROXYGEN Documentation
#' Plot QQ Gamma distribution
#' @description Plot qq-plot for gamma distributed variable
#' @param x numeric vector suspected to be Gamma distributed
#' @param ylab y label
#' @param xlab x label
#' @param main main title of the plot
#' @param \dots passed to qqplot
#' @return character vector with the NONMEM output. Each element i the vector represents a line in the NONMEM output file
#' @export
#' @importFrom stats var
#' @importFrom stats rgamma
#' @importFrom stats qqplot
#' @importFrom graphics abline
#' @examples
#' qqGamma(rgamma(100,shape = 0.1,scale = 0.2))
#'
qqGamma <- function(x
                  , ylab = deparse(substitute(x))
                  , xlab = "Theoretical Quantiles"
                  , main = "Gamma Distribution QQ Plot",...)
{
    # Plot qq-plot for gamma distributed variable

    xx = x[!is.na(x)]
    aa = (mean(xx))^2 / var(xx)
    ss = var(xx) / mean(xx)
    test = rgamma(length(xx), shape = aa, scale = ss)

    qqplot(test, xx, xlab = xlab, ylab = ylab, main = main,...)
    abline(0,1, lty = 2)
}