[yt-users] Getting error in Worked Example of Halo Analysis

[Nathan Goldbaum]

On Mon, Jun 22, 2015 at 1:11 PM, Chen Jingjing <chenjj235 at gmail.com> wrote:

> Thanks! And I just got an error from this line:
>
> hc.add_callback('virial_quantities',['radius'],critical_density=500)
>
> The error is:
>
> TypeError: virial_quantities() got an unexpected keyword argument
> 'critical_density'
>
> Do you know what might be wrong?
>

They keyword is "critical_overdensity", not "critical_density":

https://bitbucket.org/yt_analysis/yt/src/dc2467c4eae70b9f185adf2cba8f61b95f65fea0/yt/analysis_modules/halo_analysis/halo_callbacks.py?at=yt#cl-385

It looks like the docstring is incorrect.


> Thanks,
>
> Jingjing
>
> 2015-06-22 16:09 GMT-04:00 Britton Smith <brittonsmith at gmail.com>:
>
>> Hi Jingjing,
>>
>> It's 500 times the critical density.
>>
>> Britton
>>
>> On Mon, Jun 22, 2015 at 8:41 PM, Chen Jingjing <chenjj235 at gmail.com>
>> wrote:
>>
>>> Hi Britton,
>>> When I set critical_density=500, does it mean 500 times of the average
>>> density, or 500 times of the critical density?
>>>
>>> Thanks,
>>> Jingjing
>>>
>>> 2015-03-20 4:22 GMT-04:00 Britton Smith <brittonsmith at gmail.com>:
>>>
>>>> Hi Reju,
>>>>
>>>> It looks like the version of the notebook you are working from is a
>>>> little out of date as the syntax for some of those callbacks has changed.
>>>> Please, have a look here for an updated version:
>>>> http://yt-project.org/doc/cookbook/halo_analysis_example.html
>>>> I just ran this myself and confirmed everything to be working.
>>>>
>>>> As for your other questions:
>>>>
>>>> 1) How to find the center of mass of the halos(
>>>>> hc.add_quantity('center_of_mass') is not working )
>>>>>
>>>>
>>>> By default, the halo catalog is storing the center of the halo as
>>>> calculated by the halo finder that you used.  If you reload the halo
>>>> catalog that you produce, the x, y, and z position of each halo are the
>>>> "particle_position_x", "particle_position_y", "particle_position_z"
>>>> fields.  For example, you could do:
>>>> ds = yt.load(your_halo_catalog)
>>>> ad = ds.all_data()
>>>> print ad["particle_position_x"]
>>>>
>>>> Additionally, the halo catalog has a callback called
>>>> "iterative_center_of_mass" which starts from the original center and
>>>> iteratively recalculates the center of mass while reducing the radius of
>>>> the sphere.  I have found this to work very well for calculating halo
>>>> centers.  If you use this callback, it will rewrite the particle_position
>>>> fields to contain the new center for each halo.  To get more information on
>>>> this callback, do the following:
>>>>
>>>> from yt.analysis_modules.halo_analysis.halo_callbacks import *
>>>> help(iterative_center_of_mass)
>>>>
>>>>
>>>>> 2) How to find virial mass (both M_500 and M_200 ) of the halas
>>>>>
>>>>
>>>> You can find these using the virial_quantities callback.  In the
>>>> example you are working from, you can add another field to the
>>>> virial_quantities callback you use and it would calculate the value of that
>>>> field where the overdensity = 200.  For total mass, the field you want is
>>>> called "matter_mass".  To get M_500 instead of M_200, you can call the
>>>> virial_quantities callback again and give the keyword argument
>>>> critical_density=500.
>>>>
>>>> Britton
>>>>
>>>> _______________________________________________
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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
>
>
> _______________________________________________
> yt-users mailing list
> yt-users at lists.spacepope.org
> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org
>
>
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