generate.data           Data generation function for simulation and
                        demonstration There are three settings.
lprq0                   A supporting function that return the local
                        polynomial regression quantile. This estimates
                        the quantile and its derivative at the point
                        x.0
plot.siqr               plot function of siqr
siqr                    Main estimation function of single index
                        quantile regression model. a two step method.
summary.siqr            Function to print summary
