pel: Generic function for `pel...`

Description

Generic function for pel...: probability distribution fitting with L-Moments

Usage

pel(
  distrib = c("exp", "gam", "gev", "glo", "gpa", "gno", "gum", "kap", "ln3", "nor",
    "pe3", "wak", "wei"),
  lmom = NULL,
  probability_distribution_attrname = "probability_distrib",
  x = NULL,
  nmom = 5,
  sort.data = TRUE,
  ratios = sort.data,
  trim = 0,
  indices = NULL,
  spi.scale = NA,
  correction = NULL,
  ...
)
pel_x(x, ...)
pel_lmom(lmom, ...)

Value

A numeric vector containing the parameters of the selected probability distribution. It is a list in case of selection of several probability distributions (i.e. length(distrib)>1).

Arguments

distrib: character string indicating the probability distribution to fit
lmom, ...: L-moments and further parameters for pel...
probability_distribution_attrname: attribute name for probability distribution
x: vector containg sample. It is utiled to calculete L-moments in case lmom is set equal to NULL.
nmom, sort.data, ratios, trim: arguments for samlmu (nmom=5 by default). Thay are utilized if argument lmom is NULL.
indices: optional index or tag character vector of the same length of x used as INDEX for tapply. It is used to fit different probability distribution in one sample time series (e. g. months in an year).
spi.scale: integer value or NA. If it is greater than 1, x is filtered with the sum of a generic element of x and the previous spi.scale-1 ones (e.g. SPI-3,SPI-6, etc. ). Default is NA (no filtering) which is equivalent to spi.scale=1.
correction: numeric value correction for the 3rd (and higher) L-moment estimation. Default is NULL , generally it is not used. It is used and suggested to be 10^(-10) in case of a massive function use with lmom=NULL (e.g. raster cell or zonal statistics).

Details

pel_x and pel_lmom are wrapper functions of pel whose first argument is x or lmom respectively.

Examples

Run this code


 # Sample L-moments of Ozone from the airquality data
 data(airquality)
 lmom <- samlmu(airquality$Ozone,nmom=6)
 distrib <- "gev"    
 # Fit a GEV distribution
 out_gev <- pel(distrib=distrib,lmom=lmom)

 distrib <- c("exp","gam","gev","glo","gpa","gno","gum","kap","ln3",
 "nor","pe3","wak","wei")

 out_list <- pel(distrib=distrib,lmom=lmom)