[R] generating symmetric matrices

[Ben Bolker]

Gregory Gentlemen <gregory_gentlemen <at> yahoo.ca> writes:

> 
> Greetings,
> 
> I have a seemingly simple task which I have not been able to solve today. I
want to construct a symmetric
> matrix of arbtriray size w/o using loops. The following I thought would do it:
>
 
 [snip]

p <- 6
Rmat <- diag(p)
vals <- rnorm(p*(p-1)/2)
Rmat[lower.tri(Rmat)] <- vals
Rmat[upper.tri(Rmat)] <- t(Rmat)[upper.tri(Rmat)]

  appears to work.