Function to choose method for quantile regression
rq.fit(x, y, tau=0.5, method="br", ...)
the design matrix
the response variable
the quantile desired, if tau lies outside (0,1) the whole process is estimated.
method of computation: "br" is Barrodale and Roberts exterior point "fn" is the Frisch-Newton interior point method.
Optional arguments passed to fitting routine.
rq
rq.fit.br
rq.fit.fnb