Re: Compute Local density for No Gas particles

From: Arman Khalatyan <arm2arm_at_gmail.com>
Date: Thu, 22 Nov 2012 20:23:24 +0100

I just read them from parameter file if you calculate all particles not a
region you can put Rc=BoxSiye,

On Thu, Nov 22, 2012 at 1:29 AM, Magda Guglielmo
<magda.guglielmo_at_gmail.com>wrote:

> Hi Arman,
>
> thank you very much for the code.
> I am trying it, but I have some question about.
> In the function in InSubBox the code will call inbox using header.BoxSize
> and All.Rc, the question is where does the code assign value to All.Rc?
> Thank you in advance for your help.
> Regards
> Magda
>
>
>
> On Mon, Oct 15, 2012 at 10:00 PM, Arman Khalatyan <arm2arm_at_gmail.com>wrote:
>
>> Hi Magda, there is no simple way to calculate density with Gadget2, but
>> you can make it work with a few changes.
>>
>> please check the attachment . I have my modified version of read_io.c
>> In Makefile you need to define which particles to move to SPH slot:
>> for example add this lines to calculate density of DM particles.
>> OPT +=-DDM_ONLY # calculate density only for DM or STARS
>> OPT += -DALL_RHO
>>
>> In main.c:
>> comment out run(); routine then:
>>
>> ngb_treebuild();
>> savepositions(1);
>>
>> Probably you need to change io.c to save results into some another block
>> instead of RHO, let say:
>> #ifdef DM_ONLY
>> strcpy(RHONAME, "RHO1");
>> strcpy(HSMLNAME,"H1 ");
>> #endif
>>
>>
>> Then in function fill_Tab_IO_Labels() in switch statement:
>> case IO_RHO:
>> strncpy(Tab_IO_Labels[IO_RHO], RHONAME, 4);
>> break;
>> case IO_HSML:
>> strncpy(Tab_IO_Labels[IO_HSML]
>> , HSMLNAME, 4);
>> break;
>>
>>
>> Thats it.
>>
>> Arman.
>>
>>
>> On Mon, Oct 15, 2012 at 8:59 AM, Yves Revaz <yves.revaz_at_epfl.ch> wrote:
>>
>>> **
>>> Dear Magda,
>>>
>>> This is not trivial to do in Gagdget2, as to compute the density
>>> (and hydro) you need to use the SphP structure. But this structure
>>> exists by default only for type 0 (gas) particles.
>>>
>>> If you don't use the hydro part, one very easy way to implement what
>>> you need is to move your type 2 particles into time 0, and disable the
>>> hydro forces.
>>>
>>> If this is not sufficient for your purpose, you need to extend the SphP
>>> structure to
>>> other particles. This is of course possible, but much more tricky.
>>>
>>> yves
>>>
>>>
>>>
>>> On 10/15/2012 08:42 AM, Magda Guglielmo wrote:
>>>
>>> Dear gadget list,
>>>
>>> I need Gadget2 to compute the local density and the number of
>>> neighbours in the current smoothing radius for particles of type 2 (disk
>>> particles). My understanding is that Gadget normally does only for gas
>>> particles (SPH), so I need to modify the density.c routine. I am not
>>> running any SPH Hydro simulation, so I don't use this routine, but I would
>>> like to keep the Gadget structure unchanged so that it will keep working.
>>> I saw that a similar topic has been posted the web archive, but I did
>>> not find any answer or suggestions.
>>> Does anyone has any suggestion on how I can do this in the simplest way
>>> possible?
>>>
>>>
>>> Thank you in advance
>>> Best Regards
>>>
>>>
>>>
>>> --
>>> (o o)
>>> --------------------------------------------oOO--(_)--OOo-------
>>> Dr. Yves Revaz
>>> Laboratory of Astrophysics
>>> Ecole Polytechnique Fédérale de Lausanne (EPFL)
>>> Observatoire de Sauverny Tel : ++ 41 22 379 24 28
>>> 51. Ch. des Maillettes Fax : ++ 41 22 379 22 05
>>> 1290 Sauverny e-mail : Yves.Revaz_at_epfl.ch
>>> SWITZERLAND Web : http://www.lunix.ch/revaz/
>>> ----------------------------------------------------------------
>>>
>>>
>>>
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>>
>>
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>
>
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Received on 2012-11-22 20:23:26

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