[Yt-dev] pHOP in YT question

[Stephen Skory]

Geoffrey,

> In addition to the particle count cutoff, currently I am also discarding all haloes that have C (the smallest axis) less than a cell width similar to what is done with spheres in YT.  I think this is a pretty problem dependent number that can vary depending on what the user want, but I was wondering if there's a general consensus on how many cells constitute a good enough ellipsoid?  I can throw in a switch for user to define this number as well.

You're the ellipsoid expert around these parts, I think you need to
decide what's the best way to go. But I would argue that any linear
quantity you're measuring that's smaller than a cell is suspect.

> As an alternative to cell count, I was thinking maybe if the volume of the "perfect" ellipsoid is a "close enough" fraction of the cell volume, then to keep the ellipsoid, else discard it.  This would be useful for keeping poorly resolve objects that exist in a couple cells and you'd think that it is big enough to consider all cells part of the object. In this case, the user would input the fraction instead of the cell count, what do you guys think?

This sounds like another reasonable way to limit things. See my
comment above about who's the expert around these parts :)

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Stephen Skory
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