From 0a3eb0893cb4bd1b12f07a79069d1c7f5e991495 Mon Sep 17 00:00:00 2001 From: Johannes Ranke Date: Fri, 25 Oct 2019 00:37:42 +0200 Subject: Use roxygen for functions and methods --- R/FOMC.solution.R | 40 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 36 insertions(+), 4 deletions(-) (limited to 'R/FOMC.solution.R') diff --git a/R/FOMC.solution.R b/R/FOMC.solution.R index 8bd13d6b..f5e6a7ea 100644 --- a/R/FOMC.solution.R +++ b/R/FOMC.solution.R @@ -1,4 +1,36 @@ -FOMC.solution <- function(t, parent.0, alpha, beta) -{ - parent = parent.0 / (t/beta + 1)^alpha -} +#' First-Order Multi-Compartment kinetics +#' +#' Function describing exponential decline from a defined starting value, with +#' a decreasing rate constant. +#' +#' The form given here differs slightly from the original reference by +#' Gustafson and Holden (1990). The parameter \code{beta} corresponds to 1/beta +#' in the original equation. +#' +#' @param t Time. +#' @param parent.0 Starting value for the response variable at time zero. +#' @param alpha Shape parameter determined by coefficient of variation of rate +#' constant values. +#' @param beta Location parameter. +#' @return The value of the response variable at time \code{t}. +#' @note The solution of the FOMC kinetic model reduces to the +#' \code{\link{SFO.solution}} for large values of \code{alpha} and +#' \code{beta} with \eqn{k = \frac{\beta}{\alpha}}{k = beta/alpha}. +#' @references FOCUS (2006) \dQuote{Guidance Document on Estimating Persistence +#' and Degradation Kinetics from Environmental Fate Studies on Pesticides in +#' EU Registration} Report of the FOCUS Work Group on Degradation Kinetics, +#' EC Document Reference Sanco/10058/2005 version 2.0, 434 pp, +#' \url{http://esdac.jrc.ec.europa.eu/projects/degradation-kinetics} +#' +#' Gustafson DI and Holden LR (1990) Nonlinear pesticide dissipation in soil: +#' A new model based on spatial variability. \emph{Environmental Science and +#' Technology} \bold{24}, 1032-1038 +#' @examples +#' +#' plot(function(x) FOMC.solution(x, 100, 10, 2), 0, 2, ylim = c(0, 100)) +#' +#' @export +FOMC.solution <- function(t, parent.0, alpha, beta) +{ + parent = parent.0 / (t/beta + 1)^alpha +} -- cgit v1.2.1