Hi other approach is to use embed
embed(c(rhsel,rhsel),length(rhsel))[-1,] which is a little bit quicker rhsel<-rnorm(1000) n <- length(rhsel) system.time({ i <- sapply(1:n, function(i) (1:n - i)%%n + 1) x2<-matrix(rhsel[i], n, n) }) system.time(x1<-embed(c(rhsel,rhsel),length(rhsel))[-1,]) all.equal(x1,x2) HTH Petr On 21 Sep 2006 at 14:53, Sundar Dorai-Raj wrote: Date sent: Thu, 21 Sep 2006 14:53:52 -0500 From: Sundar Dorai-Raj <[EMAIL PROTECTED]> Organization: PDF Solutions, Inc. To: kone <[EMAIL PROTECTED]> Copies to: r-help@stat.math.ethz.ch Subject: Re: [R] Matrix from a vector? > > > kone said the following on 9/21/2006 2:30 PM: > > Hi, > > > > Is there some function, which generates this kind of n x n -matrix > > from a vector? > > > > > rhset > > [1] 1792 256 13312 512 1024 2048 8192 4096 > > > m=matrix(nrow=length(rhset),ncol=length(rhset)) > > > for(i in 1:length(rhset)) > > + { > > + m[,i]=rhset > > + rhset=c(rhset[length(rhset)], rhset[2:length(rhset)-1]) > > + } > > > m > > [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] > > [1,] 1792 4096 8192 2048 1024 512 13312 256 > > [2,] 256 1792 4096 8192 2048 1024 512 13312 > > [3,] 13312 256 1792 4096 8192 2048 1024 512 > > [4,] 512 13312 256 1792 4096 8192 2048 1024 > > [5,] 1024 512 13312 256 1792 4096 8192 2048 > > [6,] 2048 1024 512 13312 256 1792 4096 8192 > > [7,] 8192 2048 1024 512 13312 256 1792 4096 > > [8,] 4096 8192 2048 1024 512 13312 256 1792 > > > > > > Atte Tenkanen > > University of Turku, Finland > > > > ______________________________________________ > > R-help@stat.math.ethz.ch 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. > > > Does this work for you? > > rhsel <- c(1792, 256, 13312, 512, 1024, 2048, 8192, 4096) > n <- length(rhsel) > i <- sapply(1:n, function(i) (1:n - i)%%n + 1) > matrix(rhsel[i], n, n) > > HTH, > > --sundar > > ______________________________________________ > R-help@stat.math.ethz.ch 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. Petr Pikal [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch 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.