  We study the problem of determining whether a given frame is scalable, and
when it is, understanding the set of all possible scalings. We show that for
most frames this is a relatively simple task in that the frame is either not
scalable or is scalable in a unique way, and to find this scaling we just have
to solve a linear system. We also provide some insight into the set of all
scalings when there is not a unique scaling. In particular, we show that this
set is a convex polytope whose vertices correspond to minimal scalings.
