Random is not really a load-balancing algorithm,
and should be used only for testing!
It takes each object and randomly assigns it to a new part.
Via a parameter, one can alternatively choose to randomly perturb
only a fraction of the objects. The random method does not use weights
and does not attempt to achieve load balance.
The fraction of objects to randomly move.
1.0 = move all; 0.0 = move nothing