Merge pull request #171 from pik-piam/patch

convergence documentation

Author: tscheypidi

R/convergence.R

@@ -14,15 +14,16 @@
 #' @param direction NULL, "up" or "down". NULL means normal convergence in both
 #' directions, "up" is only a convergence if origin<aim, "down" means only a
 #' convergence if origin>aim
-#' @param type "smooth", "s", "linear" or "decay". Describes the type of
-#' convergence: linear means a linear conversion , s is an s-curve which starts
-#' from origin in start_year and reaches aim precisely in end_year. After 50
-#' percent of the convergence time, it reaches about the middle of the two
-#' values. Its based on the function min(1, pos^4/(0.07+pos^4)*1.07) smooth is
-#' a conversion based on the function x^3/(0.1+x^3).  In the latter case only
-#' 90\% of convergence will be reached in the end year, because full
-#' convergence is reached in infinity.  decay is a conversion based on the
-#' function x/(1.5 + x)*2.5.
+#' @param type "smooth", "s", "linear" or "decay". Describes the function used
+#' for convergence (x starts at 0 and ends at 1):
+#' "linear" means linear interpolation.
+#' "s" is an s-curve which starts from origin in start_year and reaches aim
+#' precisely in end_year. After 50\% of the convergence time, it reaches about
+#' the middle of the two values. It's using the function x^4/(0.07+x^4)*1.07).
+#' "smooth" is a conversion based on the function x^3/(0.1+x^3). With "smooth"
+#' only 90\% of convergence will be reached in the end year, full
+#' convergence is approached as x approaches infinity.
+#' "decay" is a conversion based on the function x / (par + x) * (par + 1).
 #' @param par parameter value for convergence function; currently only used for
 #' type="decay"
 #' @return returns a time-series with the same timesteps as origin, which