> Presumably, the help file wording goes back to S-PLUS which > (to my recollection) didn't allow zero-extent matrices.
Splus (and S) started having reasonable support for zero-extent matrices in May 2001 (i.e., Splus 6.0, which I think corresponds to S version 4-m of June 2, 1999), Splus5.0 (Nov 20, 1998, corresponding to S version 4-? of Oct 26, 1998) have very partial support for them. % Splus6.0 S-PLUS : Copyright (c) 1988, 2001 Insightful Corp. S : Copyright Lucent Technologies, Inc. Version 6.0.1 Release 1 for Linux 2.2.12 : 2001 Working data will be in .Data > library(MASS) > Null(diag(3)) numeric matrix: 3 rows, 0 columns. > load.date() [1] "Fri May 4 01:09:06 PDT 2001" Bill Dunlap TIBCO Software wdunlap tibco.com On Mon, Nov 10, 2014 at 5:47 AM, peter dalgaard <pda...@gmail.com> wrote: > There is a maintainer for this contributed package... > > However, a zero column vector _is_ numeric(0) -- with dimension attributes > c(3,0). > > structure(numeric(0),dim=c(3,0)) > c(Null(diag(3))) > > I.e., the ambiguity is pretty slight. > > Presumably, the help file wording goes back to S-PLUS which (to my > recollection) didn't allow zero-extent matrices. The actual behaviour is a > clear improvement. > > - Peter D. > > > > On 10 Nov 2014, at 13:49 , Georgi Boshnakov < > georgi.boshna...@manchester.ac.uk> wrote: > > > Hi, > > > > Function Null from package MASS seems to return a matrix with zero > columns and the expected number of rows when > > the null space of the argument contains only the zero vector, e.g. > > > >> library(MASS) > >> diag(nrow=3) > > [,1] [,2] [,3] > > [1,] 1 0 0 > > [2,] 0 1 0 > > [3,] 0 0 1 > > > >> Null(diag(nrow=3)) > > > > [1,] > > [2,] > > [3,] > > > > But the documentation of Null seems to imply that the result is > numeric(0): > > > > ----------------------------------------------- > > > > Value: > > > > The matrix 'N' with the basis for the null space, or an empty > > vector if the matrix 'M' is square and of maximal rank. > > > > ----------------------------------------------- > > > > (R version 3.1.1 Patched (2014-09-21 r66653) -- "Sock it to Me") > > > > Georgi > > > > ______________________________________________ > > R-devel@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-devel > > -- > Peter Dalgaard, Professor, > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Email: pd....@cbs.dk Priv: pda...@gmail.com > > ______________________________________________ > R-devel@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-devel > [[alternative HTML version deleted]] ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
