[yt-users] Athena units

[Stephanie Tonnesen]

Thanks for all the tips/info, I got what I wanted using "z-velocity" and
defining my own variable "zkpc".

-Stephanie


On Tue, Oct 22, 2013 at 12:41 PM, John ZuHone <jzuhone at gmail.com> wrote:

> No worries--it just points to the importance of getting these things
> documented soon.
>
> On Oct 22, 2013, at 12:39 PM, Nathan Goldbaum <nathan12343 at gmail.com>
> wrote:
>
> Ah, sorry for the misinformation!
>
>
> On Tue, Oct 22, 2013 at 9:36 AM, John ZuHone <jzuhone at gmail.com> wrote:
>
>> But, "z-velocity" is a defined derived field in the Athena frontend, and
>> should give it in CGS units.
>>
>> On Oct 22, 2013, at 12:32 PM, Nathan Goldbaum <nathan12343 at gmail.com>
>> wrote:
>>
>> Yes, velocity_z is in code units as well because it's an athena field.
>>  You'll need to define a new x-velocity field (to match the naming scheme
>> elsewhere in yt) that converts the athena velocity field to CGS.
>>
>> This is all being fixed with our new sympy powered units system and will
>> be much easier in yt 3.0 or 3.1 (whichever version gets the new units
>> support).
>>
>> -Nathan
>>
>>
>> On Tue, Oct 22, 2013 at 9:23 AM, John ZuHone <jzuhone at gmail.com> wrote:
>>
>>> Hi Stephanie,
>>>
>>> First off, if I recall correctly we only support setting LengthUnits,
>>> DensityUnits, and TimeUnits. Everything else (such as mass, velocity,
>>> energy, etc.) should be derived from those.
>>>
>>> Secondly, the reason why you're seeing this for the grid "z" is that it
>>> always defaults to the code units (as well as "x" and "y", and the cell
>>> deltas). I don't think we have a built-in field for "z" in centimeters (or
>>> anything else other than code units), so I think you might have to define a
>>> field on your own for "z" in whatever units you want.
>>>
>>> Anyone else want to chime in?
>>>
>>> Best,
>>>
>>> John
>>>
>>> On Oct 22, 2013, at 11:31 AM, Stephanie Tonnesen <stonnes at gmail.com>
>>> wrote:
>>>
>>> Hi John,
>>>
>>> Thanks for this.  So I now have this in, and it is being applied to my
>>> SlicePlot and ProjectionPlot, but my pc.add_phase_object is still using
>>> code units.  There is an excerpt below.
>>>
>>> >pf =
>>> load("id0/rps."+outstring[i]+".vtk",parameters={"TimeUnits":9.78262,"LengthUnits":26.,"DensityUnits":9.999e-30,"VelocityUnits":2.6e3,"MassUnits":2.596e6})
>>> >pc = PlotCollection(pf)
>>> >tracerp25 = alld.cut_region(["grid['specific_scalar[0]'] > 0.25",
>>> "grid['z'] > 0.01"])
>>>
>>> >pc.add_phase_object(tracerp25,["z","velocity_z","CellMass"],weight=None,x_log=False,y_log=False)
>>>
>>> Can I force it to use physical units?
>>>
>>> Thanks,
>>> Stephanei
>>>
>>>
>>>
>>>
>>> On Mon, Oct 21, 2013 at 10:24 PM, John ZuHone <jzuhone at gmail.com> wrote:
>>>
>>>> Stephanie,
>>>>
>>>> You can set it up like this:
>>>>
>>>> pf = load("virgo_weak_mag.0054.vtk",
>>>>                  parameters={"TimeUnits":3.1557e13,
>>>>                                          "LengthUnits":3.0856e24,
>>>>
>>>>  "DensityUnits":6.770424595218825e-27})
>>>>
>>>> Sorry, this is a little-documented feature.
>>>>
>>>> Best,
>>>>
>>>> John
>>>>
>>>> On Oct 21, 2013, at 10:20 PM, Stephanie Tonnesen <stonnes at gmail.com>
>>>> wrote:
>>>>
>>>> > Hi Again, Everyone!
>>>> >
>>>> > So I would also like my figures to be in physical units, instead of
>>>> in my code units.  I *think* the Athena frontend doesn't read in what the
>>>> unit conversions are (and I am not sure how it would do that).  Can I just
>>>> do something simple like:
>>>> >
>>>> > DensityUnits = 3.
>>>> > density_physunits = grid['density'] * DensityUnits
>>>> >
>>>> > Then, of course, I don't know how I would do a SlicePlot,
>>>> ProjectionPlot or phaseplot in physical units...
>>>> >
>>>> > Any help/advice/direction is appreciated!
>>>> >
>>>> > Thanks,
>>>> > Stephanie
>>>> > _______________________________________________
>>>> > yt-users mailing list
>>>> > yt-users at lists.spacepope.org
>>>> > http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>>
>>>> _______________________________________________
>>>> yt-users mailing list
>>>> yt-users at lists.spacepope.org
>>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>>
>>>
>>> _______________________________________________
>>> yt-users mailing list
>>> yt-users at lists.spacepope.org
>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>
>>>
>>>
>>> _______________________________________________
>>> yt-users mailing list
>>> yt-users at lists.spacepope.org
>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>
>>>
>> _______________________________________________
>> yt-users mailing list
>> yt-users at lists.spacepope.org
>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>
>>
>>
>> _______________________________________________
>> yt-users mailing list
>> yt-users at lists.spacepope.org
>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>
>>
> _______________________________________________
> yt-users mailing list
> yt-users at lists.spacepope.org
> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>
>
>
> _______________________________________________
> yt-users mailing list
> yt-users at lists.spacepope.org
> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.spacepope.org/pipermail/yt-users-spacepope.org/attachments/20131022/38e0db64/attachment.html>