Hi, Dan,

Yes, this is what I want. Is there better way to solve this?

Cindy

On Mon, Aug 10, 2009 at 2:52 PM, Nordlund, Dan (DSHS/RDA) <
NordlDJ@dshs.wa.gov> wrote:

>  > -----Original Message-----
> > From: r-help-bounces@r-project.org [mailto:r-help-bounces@r-project.org]
> On
> > Behalf Of cindy Guo
> > Sent: Monday, August 10, 2009 2:32 PM
> > To: r-help@r-project.org
> > Subject: [R] matrix power
> >
> > Hi, All,
> >
> > If I  have a symmetric matrix, how can I get the negative square root of
> the
> > matrx, ie. X^(-1/2) ?
> >
> > Thanks,
> >
> > Cindy
> >
>
> Cindy,
>
> Just to be sure we are all on the same page.  Are saying you have a matrix
> X, and you want to find the a matrix A such that
>
> X = A %*% A
>
> And you want to then find the matrix inverse of A ?
>
> Dan
>
> Daniel J. Nordlund
> Washington State Department of Social and Health Services
> Planning, Performance, and Accountability
> Research and Data Analysis Division
> Olympia, WA  98504-5204
>
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html>
> and provide commented, minimal, self-contained, reproducible code.
>

	[[alternative HTML version deleted]]


