[yt-dev] Orientation vectors

[John ZuHone]

Hi all, and specifically to those of you with experience with the Orientation vectors...

Doing some testing, I set up an orienter like this:

orient = Orientation([0.0,0.0,1.0])

and the output of orient.unit_vectors is:

[array([ 0., -1.,  0.]), array([ 1.,  0., -0.]), array([ 0.,  0.,  1.])]

which I would have expected

[array([ 1., 0.,  0.]), array([ 0.,  1., 0.]), array([ 0.,  0.,  1.])]

although I know I could fix this by specifying a north_vector, why would the latter not be the default?

I'm asking because I was attempting to set up new coordinates like so:

orient = Orientation(L)

x_hat = orient.unit_vectors[0]
y_hat = orient.unit_vectors[1]
z_hat = orient.unit_vectors[2]
        
xsky = x*x_hat[0] + y*x_hat[1] + z*x_hat[2]
ysky = x*y_hat[0] + y*y_hat[1] + z*y_hat[2]
zsky = x*z_hat[0] + y*z_hat[1] + z*z_hat[2]

but this will rotate the x,y plane by 90 degrees. 

Best,

John