Date: Tue, 24 Feb 1998 13:22:56 -0800 (PST) From: Thomas Lumley <thomas@biostat.washington.edu> To: Bertram Zinner <zinnebe@mail.auburn.edu> Subject: Re: R-beta: qr(A)$rank In-Reply-To: <199802242105.PAA02418@mallard.duc.auburn.edu> On Tue, 24 Feb 1998, Bertram Zinner wrote: > I would like to find the rank of a matrix using R. Looking through a list > of commands it seems that the command qr should do the job. Checking a > simple example gave me the wrong answer. Here is the example: > > > A <- c(1,2,3,4,5,6) > > A <- matrix(A, nrow=2, ncol=3) > > A > [,1] [,2] [,3] > [1,] 1 3 5 > [2,] 2 4 6 > > qr(A)$rank > [1] 3 > > The correct answer is two. I think this is due to the mac version being so out of date. I don't have access to it, but qr(A)$rank does work on 0.50a2 and 0.61.1 (at least ignoring the question of whether the rank is well-defined numerically). What does the rest of qr(A) look like? This might help in deciding what to do, especially as a large chunk of the Mac expertise on R is temporarily unavailable due to power failures in New Zealnd. -thomas Thomas Lumley ------------------------------------------------------+------ Biostatistics : "Never attribute to malice what : Uni of Washington : can be adequately explained by : Box 357232 : incompetence" - Hanlon's Razor : Seattle WA 98195-7232 : : ------------------------------------------------------------ -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-help-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._