Re: Glass ICs and "TILING" option in Gadget4

From: Volker Springel <vspringel_at_MPA-Garching.MPG.DE>
Date: Sun, 18 Dec 2022 15:48:10 +0100

Dear Zhao,

In principle, the tiling option should work with a glass file. However, the code was not automatically scaling the boxsize of the input glass file when TILING is used, and I suspect your problem originates from this. I have now added such a scaling of the boxsize in the most recent commit, i.e. one should in principle now be able to use a Gadget2 glass file for arbitrary boxsizes in Gadget4, and to use TILING to enlarge the glass file to a larger particle load. (I haven't had a chance to explicitly test this yet, however).

Best regards,

> On 29. Nov 2022, at 17:42, 陈钊 <> wrote:
> Dear all,
> I am trying to use Gadget to generate the initial conditions (ICs) by using glass file. I noticed that “TILING” option is provided for scaling test. While I wondering that if this option can be used to scale the glass file with low number of particles. So I used glass file with 32**3 particles generated by Gadget-2 to produce IC with 256**3 particles and set the "TILING=8” in the However, I got a very strange power spectrum shown by the green line in the following figure. The red line is the result from the glass file with the same number 256**3 and no TILING in the which is right relative to my input power spectrum (magenta line).
> <tt4.png>
> So, this means that I should not use “TILING” option to rescale the input glass file? And I should always provide the glass with same number of IC to the Gadget-4 NGENIC? This is not very convenient when the particle number is extremely large.
> I don’t know if I lacked some key points for this option. Is there a solution for this?
> Thanks for your time in advance!
> Best,
> Zhao
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Received on 2022-12-18 15:48:10

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