Field ordering for GA(3,0)

[chrisjldoran]

We currently store a quaternion in a struct ordered (w, x ,y z).

Occasionally it is helpful to grab a component along axis labeled (1, 2, 3) which have been derived programmatically. This can be done efficiently with a getfield(vec, i) command, but the indices are all off by 1 because the first field is w. We could solve this by swapping the order to (x, y, z, w). This also feels a bit more natural (it is how we order things in projective geometry).