Here is part of the specification of an algorithm I'm implementing that shows the reason for my original query:
vid = w * vid + c1 * rand( ) * ( pid – xid ) + c2 * Rand( ) * (pgd –xid ) (1a) xid = xid + vid (1b) where c1 and c2 are two positive constants, rand() and Rand() are two random functions in the range [0,1], ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ and w is the inertia weight. -- http://mail.python.org/mailman/listinfo/python-list
