qcomp {CompDist}

qcomp

Description

Returns a quantile function to the specifications of a user specified multisection composite distribution

Usage

qcomp(xx,dists,par,borders,par.pos,buffer)

Arguments

xx

Desired quantiles between 0 and 1

dists

A vector of strings stating the desired partial distributions in order

par

A list of parameters, a vector of parameters for each partial distribution, with the first two being the interval limits and the second argument being he weights to be used

borders

Optional: If the distribution has to have continuous and differentiable catentation points, the user specifies a list for each of area following the first, containing a range for a parameter of the following partial distribution to lie within.

par.pos

Optional: If 'borders' is non empty, e.g a smooth function is desired, here the vector of parameter positions that need to be changed is specified. Default value is 1, meaning the first parameter for each partial distribution is amended

buffer

Optional: A two dimensional vector, containing the values for upper and lower buffer from the respective catenation points during optimization

Value

An object of the same length as xx, giving the quantile values

Author(s)

Martin Wiegand, Saralees Nadarajah

Examples

par<-list()

distvec<-c("lnorm","gamma")

par[[1]]<-c(0,1,Inf)

par[[2]]<-c(1)

par[[3]]<-c(0,1)

par[[4]]<-c(1,1)


x<-seq(0.01,0.99,0.01)

# non-continuous case

y1<-qcomp(x,distvec,par)

# continuous case

y2<-qcomp(x,distvec,par,borders=list(c(0.00001,10)),buffer=c(10e-5,0))



par(mfrow=c(1,2),oma=rep(0,4))

xrange<-range(x)

yrange<-range(y1,y2)

plot(x,y1,type="l",xlab="x",ylab="Quantile function",xlim=xrange,ylim=yrange)

abline(h=1,lty=2)

plot(x,y2,type="l",xlab="x",ylab="Quantile function",xlim=xrange,ylim=yrange)

abline(h=1,lty=2)