[R] How to repeat vectors ?

[Tong Wang]

Hi,
    If I have a matrix  , say       a11   a12
                                                   a21  a22
    Is there a routine to get:      a11  a12
                                                     a11  a12
                                                     a21   a22
                                                     a21   a22

     Thanks a lot for any help.

best