[Yt-dev] Column Density derived field

[Stephen Skory]

Cameron & Matt,

What it's called isn't a big concern to me, but I see what you're
saying, Cameron.

> The issue about field detector is an interesting one.  I guess I don't
> understand why asking for 'x' is a problem.  Your solution sounds good
> to me.

When I wasn't looking for the field detector as I am now, what was
happening is data['x' or 'y' or 'z'] would return some values that
weren't cell centers, which when passed to the interpolation stuff
would not work. So asking for 'x' wasn't a problem, but the values it
returned were not what I wanted.

> How fast is the code?  It looks to me like it probably does quite a
> few expensive operations

Running on a 40^3 dataset on my 2.0Ghz i7 lappy on battery power gives
about 300,000 cells/second for the whole process (HEALPix with 5
surfaces + interpolation). I think I'm close to making it parallel,
but some weird stuff is popping up that I don't quite understand just
yet.

>... would you be willing at some point in the
> future to explore replacing it with an actual adaptive healpix
> operation?

Perhaps. It seems to me before you said that that would be quite a bit
more difficult, which looking at the source is true. Everything in
this current attempt is using numpy vectorization, so I don't know how
much more speed can be squeezed out of this method.

-- 
Stephen Skory
s at skory.us
http://stephenskory.com/
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