# Quantile Smoothing Splines
# Toy example of rqss using the Ruppert, Wand Carroll LIDAR data

require(SemiPar)
require(quantreg)
data(lidar)
attach(lidar)

taus <- c(.05,.25,.5,.75,.95)

par(mfrow = c(1,2))
plot(range,logratio,cex = .5)
for(i in 1:length(taus)){
        plot(rqss(logratio ~ qss(range,lambda = 10),tau = taus[i]),col="red")
        }
plot(range,logratio,cex = .5)
for(i in 1:length(taus)){
        plot(rqss(logratio ~ qss(range,lambda = 10,constraint = "D"),tau = taus[i]),col="red")
        }