[yt-users] Recenter Halo

Chen Jingjing chenjj235 at gmail.com
Wed Apr 1 06:47:36 PDT 2015


Works perfectly! Thank you so much!

Jingjing

2015-03-31 4:12 GMT-04:00 Britton Smith <brittonsmith at gmail.com>:

> Hi Jingjing,
>
> This is a bug that I thought I had fixed already.  The file is just
> missing an import of that function.  I have issued a pull request to fix
> this and it should be incorporated shortly.  Sorry about that.
>
> Britton
>
> On Tue, Mar 31, 2015 at 1:55 AM, Chen Jingjing <chenjj235 at gmail.com>
> wrote:
>
>> Hi Britton,
>> I tried to use the iterative_center_of_mass callback like this. Since you
>> said it does not require a sphere callback, I assumed that I don't need to
>> specify a sphere.
>>
>> data_ds = yt.load('RD0008/RedshiftOutput0008')
>>
>> hc = HaloCatalog(data_ds=data_ds, finder_method='hop')
>>
>> hc.add_callback("iterative_center_of_mass")
>>
>> hc.add_filter("quantity_value", "particle_mass", ">", 1e11, "Msun")
>>
>> hc.create()
>>
>> I got a error
>>
>> NameError: global name 'periodic_distance' is not defined
>>
>> So can you tell me what would be the right way?
>>
>> Thanks,
>> Jingjing
>>
>> 2015-03-30 15:08 GMT-04:00 Britton Smith <brittonsmith at gmail.com>:
>>
>> Hi Jingjing,
>>>
>>> To add that function to the HaloCatalog analysis, you need to do the
>>> following:
>>>
>>> hc.add_callback("sphere_field_max_recenter", "density")
>>>
>>> Note, this callback recenters an existing sphere, so you will need to
>>> have added a sphere with:
>>>
>>> hc.add_callback("sphere")
>>>
>>> Make sure you add the sphere first.  Additionally, you might try the
>>> "iterative_center_of_mass" callback, which will calculate new centers by
>>> calculating the center of mass on a continually smaller sphere.  This one
>>> does not require a sphere callback and will actually write out the
>>> recentered positions.
>>>
>>> Britton
>>>
>>> On Mon, Mar 30, 2015 at 7:27 PM, Chen Jingjing <chenjj235 at gmail.com>
>>> wrote:
>>>
>>>> Dear yt-users,
>>>> I am having a little problem on finding the exact center of a halo. I
>>>> used to do
>>>>
>>>> "hc = HaloCatalog(data_ds=data_ds, finder_method='hop')"
>>>>
>>>> to create a halo catalog. But I think the position in the catalog is a
>>>> little bit off the exact center judging from the plots I made. I need the
>>>> exact center to compute the angular momentum so the off-center result could
>>>> cause some problem. I tried to recenter at the maximum gas density by
>>>> adding this line
>>>>
>>>> "hc.sphere_field_max_recenter('density')"
>>>>
>>>> But I got an error, AttributeError: 'HaloCatalog' object has no
>>>> attribute 'sphere_field_max_recenter'.
>>>>
>>>> Can anyone tell me what is the right way to find the center as the
>>>> location of maximum gas density?
>>>>
>>>> Thanks,
>>>> Jingjing
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> Jingjing Chen [ chenjj235 at gmail.com ]
>>>> Department of Astronomy
>>>> Columbia University
>>>> 550 West 120th Street
>>>> New York, New York 10027
>>>> Cell Phone: +1(347)5746709
>>>>
>>>>
>>>> _______________________________________________
>>>> yt-users mailing list
>>>> yt-users at lists.spacepope.org
>>>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>>>
>>>>
>>>
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>>>
>>
>>
>> --
>>
>> Jingjing Chen [ chenjj235 at gmail.com ]
>> Department of Astronomy
>> Columbia University
>> 550 West 120th Street
>> New York, New York 10027
>> Cell Phone: +1(347)5746709
>>
>>
>> _______________________________________________
>> yt-users mailing list
>> yt-users at lists.spacepope.org
>> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>>
>>
>
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>


-- 

Jingjing Chen [ chenjj235 at gmail.com ]
Department of Astronomy
Columbia University
550 West 120th Street
New York, New York 10027
Cell Phone: +1(347)5746709
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