2017-06-22 19:49 GMT+02:00 Uwe Ligges <lig...@statistik.tu-dortmund.de>: > On 22.06.2017 17:11, Bernd Funovits wrote: >> >> Hello, >> >> I experienced some unexpected behaviour while determining the rank of >> matrices (sometimes 1x1 matrices): >> base::qr(matrix(1e-20))$rank returns 1 (incorrect) >> base::qr(diag(c(1, 1e-20)))$rank returns 2 (incorrect) > > > Why do you believe this is incorrect? > > 0 != 1e-20 > > and 1e-20 is well representable without significant rounding errors given > > > .Machine$double.xmin > [1] 2.225074e-308 > > > Best, > Uwe Ligges
qr() has a tolerance argument which by default is tol=1e-07. Regards, Iñaki ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
