#*********************************************
#*********************************************
#' Plots a histogram of 'x' added a line of the maximum likelihood fitted gamma distribution to 'x'.
#'
#'
#' @return
#'
#' @examples
#' \dontrun{}
#'
#' @export
#' @rdname histgamma
#'
histgamma<-function(x,breaks="Sturges",coll="red",lengthx=1000,lwd=1.5,add=FALSE,plot=TRUE,...){
############ AUTHOR(S): ############
# Arne Johannes Holmin
############ LANGUAGE: #############
# English
############### LOG: ###############
# Start: 2009-04-04 - Finished.
########### DESCRIPTION: ###########
# Plots a histogram of 'x' added a line of the maximum likelihood fitted gamma distribution to 'x'.
########## DEPENDENCIES: ###########
#
############ VARIABLES: ############
# - 'x' is the data.
# - 'coll' is the colour for the gamma line.
# - 'breaks' is used in hist().
# - 'lengthx' is the length of the gamma line.
# - 'lwd' is the line width of the gamma line.
# - 'add' is TRUE if the gamma line is to be added to a plot.
# - '...' variables passed on to hist().
##################################################
##################################################
##### Preparation #####
# Remove missing values:
x=x[!is.na(x)]
# Fit the data to the gamma distribution (scale to resonable values):
par=fitdistr(x/mean(x),densfun=dgamma,list(shape = 1, rate = 1))$est
par[2]=par[2]/mean(x)
##### Execution and output #####
gammax=seq(min(x),max(x),length.out=lengthx)
gammay=dgamma(gammax,par[1],par[2])
if(!add){
hh=suppressWarnings(hist(x,plot=FALSE,breaks=breaks,...))
# Adjusting for the total area of the histogram:
area=sum(hh$counts*diff(hh$breaks))
hh$counts=hh$counts/area
if(plot){
if(any(names(list(...))=="ylim")){
plot(hh,...)
}
else{
plot(hh,ylim=range(c(hh$density,gammay)),...)
}
}
# Reverting hh to its original scale:
hh$counts=hh$counts*area
}
else{
hh=hist(x,plot=FALSE,breaks=breaks,...)
}
if(plot){
lines(gammax,gammay,col=coll,lwd=lwd,...)
}
invisible(list(h=hh,gammax=gammax,gammay=gammay,par=c(shape=par[1],rate=par[2])))
##################################################
##################################################
}
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