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/HS.solution.R | 35 +++++++++++++++++++++++++++++------ 1 file changed, 29 insertions(+), 6 deletions(-) (limited to 'R/HS.solution.R') diff --git a/R/HS.solution.R b/R/HS.solution.R index 4651a6a8..890ad8ff 100644 --- a/R/HS.solution.R +++ b/R/HS.solution.R @@ -1,6 +1,29 @@ -HS.solution <- function(t, parent.0, k1, k2, tb) -{ - parent = ifelse(t <= tb, - parent.0 * exp(-k1 * t), - parent.0 * exp(-k1 * tb) * exp(-k2 * (t - tb))) -} +#' Hockey-Stick kinetics +#' +#' Function describing two exponential decline functions with a break point +#' between them. +#' +#' @param t Time. +#' @param parent.0 Starting value for the response variable at time zero. +#' @param k1 First kinetic constant. +#' @param k2 Second kinetic constant. +#' @param tb Break point. Before this time, exponential decline according to +#' \code{k1} is calculated, after this time, exponential decline proceeds +#' according to \code{k2}. +#' @return The value of the response variable at time \code{t}. +#' @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} +#' @examples +#' +#' plot(function(x) HS.solution(x, 100, 2, 0.3, 0.5), 0, 2, ylim=c(0,100)) +#' +#' @export +HS.solution <- function(t, parent.0, k1, k2, tb) +{ + parent = ifelse(t <= tb, + parent.0 * exp(-k1 * t), + parent.0 * exp(-k1 * tb) * exp(-k2 * (t - tb))) +} -- cgit v1.2.1