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

[Jun-Hwan Choi]

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?

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
>> --------------------------------------------------------------
>>
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-- 
--------------------------------------------------------------
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
--------------------------------------------------------------