Hi,
  If you see the link http://www.stata.com/help.cgi?drawnorm, and you can
see an example,
#draw a sample of 1000 observations from a bivariate standard
normal distribution, with correlation 0.5.
#drawnorm x y, n(1000) corr(0.5)
 This is what Stata software did. What i hope to do in R should be similar
as that.
  It will be better to only need us to specify the correlation matrix, mean
values and possible variances. One of my aim is to simulate random fields.
  Thanks.


2010/8/23 Ben Bolker <bbolker@gmail.com>

> rusers.sh <rusers.sh <at> gmail.com> writes:
>
> >   rmvnorm()can be used to generate the random numbers from a multivariate
> > normal distribution with specified means and covariance matrix, but i
> want
> > to specify the correlation matrix instead of covariance matrix for the
> > multivariate
> > normal distribution.
> > Does anybody know how to generate the random numbers from a multivariate
> > normal distribution with specified correlation matrix? What about
> > other non-normal
> > distribution?
>
>   What do you want the variances to be?  If you don't mind that they're
> all equal to 1, then using your correlation matrix as the Sigma argument
> to the mvrnorm() [sic] function in MASS should work fine.  They have to
> be defined as *something* ....
>  If you want multivariate distributions with non-normal marginal
> distributions, consider the 'copula' package, but be prepared to do
> some reading -- this is a fairly big/deep topic.
>
>  good luck.
>
> ______________________________________________
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
-----------------
Jane Chang
Queen's

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