Rescaling rows of a matrix

["Walter R. Paczkowski" <dataanalytics@earthlink.net>]

Hi,

I hope someone can help me.  I'm trying to do the following:

Let X be an Nxn matrix (n<N).  The rows are people and the columns are 
their ratings on a product.  I want to create a matrix Z by subtracting 
each person's mean from their row of X (I can do this using sweep) and 
then rescaling each row to have sum of squares of one.  Then R = ZZ' is 
the NxN correlation matrix among the persons.  The matrix Z will be used 
later for further analysis.
My question: how do I rescale X after sweeping out the means to create Z?

Thanks for any help.

Walt Paczkowski