Hello, For a few large set of points, whenever I use a "CI" constraint in the qss term, I get the following error message: Warning message: In rq.fit.sfnc(x, y, tau = tau, ...) : tiny diagonals replaced with Inf when calling blkfct Without any constraint, these sets work well. Does anyone know how to solve this problem? Thank you very much, TDB -- View this message in context: http://www.nabble.com/R-Quantreg-package%3A-%22CI%22-constraint-in-qss-tp16227572p16227572.html Sent from the R help mailing list archive at Nabble.com.