> -----Original Message----- > From: r-help-boun...@r-project.org > [mailto:r-help-boun...@r-project.org] On Behalf Of Nikhil Kaza > Sent: Tuesday, August 03, 2010 8:56 AM > To: Ron Michael > Cc: r-help@r-project.org > Subject: Re: [R] Need help on upper.tri() > > > try using Matrix package instead > > mat <- Matrix(rnorm(25),5,5) > forceSymmetric(mat) > > The reason your method does not work is because matrix is > effectively > a vector and the indices increase along rows within a column.
To copy the transpose of the upper triangle to the lower triangle using only base R functions try mat[lower.tri(mat)] <- t(mat)[lower.tri(mat)] Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > > Nikhil > > On Aug 3, 2010, at 7:36 AM, Ron Michael wrote: > > > HI, I am really messing up to make a symmetrical matrix using > > upper.tri() & lower.tri() function. Here is my code: > > > >> set.seed(1) > >> mat = matrix(rnorm(25), 5, 5) > >> mat > > [,1] [,2] [,3] [,4] [,5] > > [1,] -0.6264538 -0.8204684 1.5117812 -0.04493361 0.91897737 > > [2,] 0.1836433 0.4874291 0.3898432 -0.01619026 0.78213630 > > [3,] -0.8356286 0.7383247 -0.6212406 0.94383621 0.07456498 > > [4,] 1.5952808 0.5757814 -2.2146999 0.82122120 -1.98935170 > > [5,] 0.3295078 -0.3053884 1.1249309 0.59390132 0.61982575 > >> mat[lower.tri(mat)] = mat[upper.tri(mat)] > >> mat > > [,1] [,2] [,3] [,4] [,5] > > [1,] -0.62645381 -0.82046838 1.51178117 -0.04493361 0.91897737 > > [2,] -0.82046838 0.48742905 0.38984324 -0.01619026 0.78213630 > > [3,] 1.51178117 -0.01619026 -0.62124058 0.94383621 0.07456498 > > [4,] 0.38984324 0.94383621 0.78213630 0.82122120 -1.98935170 > > [5,] -0.04493361 0.91897737 0.07456498 -1.98935170 0.61982575 > > > > > > Which is not coming as symmetrical function. Can anyone > point me on > > the correct way of using upper, lower.try() function to get a > > symmetrical matrix? > > > > Thanks, > > > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > > and provide commented, minimal, self-contained, reproducible code. > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
