Re: Boxsize of 3 Mpc simulates EXACTLY the same regions as Boxsize = 10 Mpc

From: Hassan Fathivavsari <h.fathie_at_gmail.com>
Date: Thu, 8 Jul 2021 12:02:01 +0200

Dear Tiago,

Thank you for your response and your helpful clarification.

Best regards,
Hassan


On Thu, Jul 8, 2021 at 11:46 AM Tiago Castro <tiagobscastro_at_gmail.com>
wrote:

> Dear Hassan,
>
> By exactly, I will assume that you mean that by visual inspection, they
> look alike, right? For such a small box, the initial power spectrum is
> close to a power law for both of them and the initial phases will basically
> set the structure formation. If you keep the seed and number of particles,
> you are sampling the phases with respect to the box size in the same way.
> To run a sub-set of a box, you have to guarantee that the phases are
> distributed spatially (and not with respect to the box size) the same way .
> In fact, this operation is not simple.
>
> I hope I understood and answer your question.
> Kind Regards,
> ---
>
> Em qui., 8 de jul. de 2021 às 10:54, Hassan Fathivavsari <
> h.fathie_at_gmail.com> escreveu:
>
>> Dear all,
>>
>> I have changed the BoxSize in the param.txt file in
>> the /examples/DM-L50-N128 folder
>> to BoxSize = 10 Mpc and ran the simulation.
>>
>> I then changed the BoxSize to BoxSize = 3 Mpc and ran the simulation
>> again.
>>
>> When I compare the snapshots of the two simulations, I see that they
>> represent
>> the same regions with the same structures, sub structures, ... etc.
>>
>> But I expected the simulation with BoxSize = 3 to represent only a
>> sub-section
>> of the simulation with BoxSize = 10. But this is not the case and the two
>> simulations
>> almost exactly look like each other (with some minor variations).
>>
>> I would be grateful for any clarification in this issue.
>>
>> Many thanks.
>> Best regards,
>> Hassan
>>
>>
>>
>>
>>
Received on 2021-07-08 12:02:19