[R] generating symmetric matrices
Benilton Carvalho
bcarvalh at jhsph.edu
Mon Jul 30 15:55:22 CEST 2007
after dat.cor use:
Rmat[lower.tri(Rmat)] <- dat.cor
Rmat <- t(Rmat)
Rmat[lower.tri(Rmat)] <- dat.cor
b
On Jul 27, 2007, at 11:28 PM, Gregory Gentlemen wrote:
> 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:
>
> p <- 6
> Rmat <- diag(p)
> dat.cor <- rnorm(p*(p-1)/2)
> Rmat[outer(1:p, 1:p, "<")] <- Rmat[outer(1:p, 1:p, ">")] <- dat.cor
>
> However, the problem is that the matrix is filled by column and so
> the resulting matrix is not symmetric.
>
> I'd be grateful for any adive and/or solutions.
>
> Gregory
>
>
>
>
> ---------------------------------
>
>
>
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