[R] Vector comparison to matrix

[Todd Remund]

I am looking for a fast way to count the number of rows in a matrix are 
identical to a pattern vector.  For example, if I am interested in counting 
the number of row vectors in a matrix that are identical to (1,2,3) what 
would I do?  I have tried the identical statement in a loop but this is far 
too slow.  I have a very large matrix and need to avoid loops at all costs.  
Thanks for any help.
Todd Remund