Nastasha Wijers

Based on [pixelization_routines.pyx](https://github.com/yt-project/yt/tree/main/yt/utilities/lib/pixelization_routines.pyx), `interpolate_sph_grid_gather` (line 1361), I wouldn't expect exact mass conservation from this method: it is calculating the SPH density at cell centers by SPH interpolation to the cell...

I mean, my idea was the even more basic 'add a print statement to the function'

... ok, that's weird. It should be handled by the SPH backend, but maybe the octree stuff has its own routines? I'm not too familiar with those. Do you see...

@matthewturk Thanks! It agree it's best to be sure about this. I did add a test for Ray objects to this pull request. I don't think it's entirely complete; for...

pre-commit.ci autofix

@matthewturk @jzuhone @langmm @chummels could you take a look at this pull request and approve it or give me some feedback? This slipped my mind for quite a while, but...

@neutrinoceros can I ask what the 4.4.0 milestone means? The github docs didn't seem very helpful on this.

@jzuhone thanks!

Hi, I'm pretty new to YT, but I have been looking into SPH data projections for a different issue (#4788) that involves the `pixelize_sph_kernel_projection` function. The approach sounds reasonable enough...

I think basically the same issue also comes up in slices through SPH datasets: [pixelization_routines.pyx, line 1465 onwards](https://github.com/yt-project/yt/blob/8ef156989728d1b6af6c24c342974e3d352cdf9f/yt/utilities/lib/pixelization_routines.pyx#L1465): `pixelize_sph_kernel_slice`. The general approach here seems to be to evaluate the SPH...