[R] creating a symmetric matrix

[David L Carlson]

You asked for existing functions, but I was more intrigued by trying to
create one:

symmat <- function(n) {
     x <- matrix(1:n, nrow=n, ncol=n)
     abs(x-col(x))+1
}

> symmat(4)
     [,1] [,2] [,3] [,4]
[1,]    1    2    3    4
[2,]    2    1    2    3
[3,]    3    2    1    2
[4,]    4    3    2    1

----------------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77843-4352


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Erin Hodgess
> Sent: Thursday, September 06, 2012 8:11 PM
> To: R help
> Subject: [R] creating a symmetric matrix
> 
> Dear R People:
> 
> Suppose I have the following:
> 
> x <- 1:4
> 
> And I want to create the following matrix:
> 
> 1 2 3 4
> 2 1 2 3
> 3 2 1 2
> 4 3 2 1
> 
> Is there a function in place for this, please?  I looked at  symMatrix
> in micEcon and some of the items in Matrix, but they didn't quite do
> it.
> 
> I can put together something quickly, of course, but it seems likely
> that this would exist.
> 
> Thanks,
> Erin
> 
> 
> --
> Erin Hodgess
> Associate Professor
> Department of Computer and Mathematical Sciences
> University of Houston - Downtown
> mailto: erinm.hodgess at gmail.com
> 
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