[yt-users] field gradients / vorticity / ghost cells

[Andrew Cunningham]

Related to this, I'd also like to query the group for thoughts the 
best approach to a specific kind of analysis I have in mind with this.

I'd like to know what the azimuthally averaged radiation flux is at some 
fixed distance r from the star plotted as a function of polar angle.

My plan is to create a radiation flux derived quantity (which is why I 
need a derivative), then create a flux dot rhat quantity and then extract 
to a fixed interpolated grid and then proceed with the extracting, 
averaging, plotting.

Does that sound like the correct approach or is there some yt 
functionality that I don't yet know about that might be more elegant? - 
ie) some way to extract the field on a spherical count our and return that 
as a list of values and positions.