[yt-users] A basic question how yt treat the intersect cell.

[Matthew Turk]

On Mon, May 7, 2012 at 2:50 PM, Jun-Hwan Choi <choi.junhwan at gmail.com> wrote:
> Thanks Matt,
>
> To make clear your statement, the cells are never interpolated when we make
> profile and objects.
> When yt compute the cell's location, it compute the center of the cell.
> Therefore, if I make r vs M(r) profile, the cell's mass goes to the radius
> bin with which the cell's center corresponds, regardless of the size of
> cell.
> Is it correct?

Yup.  If you want to have radial bins that are smaller than your cell
size, you could use the covering_grid functionality and manually
calculate your profiles.

-Matt

>
> Thank you,
> Junhwan
>
>
> On 05/07/12 13:10, Matthew Turk wrote:
>>
>> Hi Junhwan,
>>
>> On Mon, May 7, 2012 at 12:02 PM, Jun-Hwan Choi<jhchoi at pa.uky.edu>  wrote:
>>>
>>> Hi all,
>>>
>>> I have one conceptual question.
>>> When you make a profile, what happen one grid cell (finest cell) is
>>> bigger
>>> than one bin?
>>
>> Typically profiles do not get applied to spatial dimensions.  Profiles
>> bin cells based explicitly on the value of the profiled field; cells
>> contain one definitive field value for each field, not multiple, so it
>> will only get placed into a single bin.
>>
>>> Does yt interpolate the physical value (mass, density, velocity ...) and
>>> assign the appropriate value to the bins which the cell intersects?
>>> The very similar question is what happen one grid cell (finest)
>>> intersects
>>> with object boundary.
>>> For example, I define sphere and try to measure total mass of sphere.
>>> Does yt interpolate the mass of cell that intersects with the object's
>>> boundary and compute the partial mass of cell to assign to total mass of
>>> the
>>> sphere?
>>
>> No, cells are not interpolated.  Data objects apply a strict cutoff
>> based on cell-centers.  So if you have a sphere, and your sphere
>> intersects a cell center, that cell will be included in analysis of
>> that sphere.  If you want to apply additional cutoffs based on spatial
>> characteristics you can, but you will have to explicitly apply them.
>>
>> -Matt
>>
>>> If yt interpolate the cell, does yt use a particular weight?
>>> This issue may be important, when one need to compute fine physical
>>> quantities.
>>>
>>> Thanks in advance,
>>> Junhwan
>>>
>>> --
>>> --------------------------------------------------------------
>>> Jun-Hwan Choi, Ph.D.
>>> Department of Physics and Astronomy, University of Kentucky
>>> Tel: (859) 897-6737        Fax: (859) 323-2846
>>> Email: jhchoi at pa.uky.edu   URL: http://www.pa.uky.edu/~jhchoi
>>> --------------------------------------------------------------
>>>
>>> _______________________________________________
>>> 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
>
>
>
> --
> --------------------------------------------------------------
> Jun-Hwan Choi, Ph.D.
> Department of Physics and Astronomy, University of Kentucky
> Tel: (859) 897-6737        Fax: (859) 323-2846
> Email: jhchoi at pa.uky.edu   URL: http://www.pa.uky.edu/~jhchoi
> --------------------------------------------------------------
>
> _______________________________________________
> yt-users mailing list
> yt-users at lists.spacepope.org
> http://lists.spacepope.org/listinfo.cgi/yt-users-spacepope.org