[yt-users] Basic units quesions

[John Wise]

> I'll say off the bat, I think I like the convention that the lowercase
> values (particle_position_[xyz]) are in the domain units.  This could
> still be used for things like the kD-tree and whatnot, where the
> values are easier if kept in some normalized fashion.  But then the
> uppercase: "ParticlePositionX" could be in cm, where the 0,0,0 point
> is the standard 0,0,0 of the cube.  (We could do the same for the
> field "x", "y", "z", which are currently in domain units, but then
> "X", "Y", "Z" could be in cm.)
>
> What do you, and the others, think?  I'd like to move away from domain
> units on the whole except where explicitly asked for; it requires
> knowing too much about yt internals to write fields and to handle
> data.  Additionally, in the future I anticipate we'll be modifying the
> mechanism for accessing particles to allow for accessing directly by
> particle type.

Hi Matt,

I like your proposal to have the lower-case coordinate fields to be in 
the [0,1] domain and the CamelCase in cm.  Mainly because I'm used to 
particle_position_[xyz] being in code units :)

I'm willingly to help with the reading specific particle types.  I have 
a standalone parallel Python code that reads only the star particles 
when OutputParticleTypeGrouping is turned on in Enzo.

John