RANDN('state',0) resets the generator to its initial state.
RANDN('state',J), for integer J, resets the generator to its J-th state.
RANDN('state',sum(100*clock)) resets it to a different state each time.
MATLAB Version 4.x used random number generators with a single seed.
RANDN('seed',0) and RANDN('seed',J) cause the MATLAB 4 generator
to be used.