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authorJohannes Ranke <jranke@uni-bremen.de>2019-10-25 00:37:42 +0200
committerJohannes Ranke <jranke@uni-bremen.de>2019-10-25 02:03:54 +0200
commit0a3eb0893cb4bd1b12f07a79069d1c7f5e991495 (patch)
tree1bf0ffeb710b3438fee224d0a657606b4c36b495 /R/DFOP.solution.R
parent053bf27d3f265c7a7378e2df3e00cf891e0d1bb2 (diff)
Use roxygen for functions and methods
Diffstat (limited to 'R/DFOP.solution.R')
-rw-r--r--R/DFOP.solution.R32
1 files changed, 27 insertions, 5 deletions
diff --git a/R/DFOP.solution.R b/R/DFOP.solution.R
index 8531cfed..608e7e18 100644
--- a/R/DFOP.solution.R
+++ b/R/DFOP.solution.R
@@ -1,5 +1,27 @@
-DFOP.solution <- function(t, parent.0, k1, k2, g)
-{
- parent = g * parent.0 * exp(-k1 * t) +
- (1 - g) * parent.0 * exp(-k2 * t)
-}
+#' Double First-Order in Parallel kinetics
+#'
+#' Function describing decline from a defined starting value using the sum of
+#' two exponential decline functions.
+#'
+#' @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 g Fraction of the starting value declining according to the first
+#' kinetic constant.
+#' @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) DFOP.solution(x, 100, 5, 0.5, 0.3), 0, 4, ylim = c(0,100))
+#'
+#' @export
+DFOP.solution <- function(t, parent.0, k1, k2, g)
+{
+ parent = g * parent.0 * exp(-k1 * t) +
+ (1 - g) * parent.0 * exp(-k2 * t)
+}

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