Chcek the integrity of the two datasets by checking:
(1) That the low-d set is at least 2 dimensions
(2) That the low d space is lower dimensional than the hi d space
(3) That both datasets have the same number of points
Project Coordinate is perhaps the simplest possible projection algorithm; It
simply takes two specificed dimensions in the high dimensional space, and uses these
as the basis for the low-dimensional space.
Settings stores gauge parameters which must persist when the projection algorithm is changed,
but which should not be static (which must be different when different instances of the Gauge
class are created).