Re: boxSize_Z in 2D hydro runs

From: Sander Valcke <Sander.Valcke_at_UGent.be>
Date: Tue, 29 Sep 2009 10:17:17 +0200

And to add to the problem: boxSize_Z is only declared for periodic
simulations. Using hinv3 and hinv4 as listed below the code does not
compile with TWODIMS set but PERIODIC not set.

Sander Valcke wrote:
>
> Dear gadget list,
>
> I have a small question about 2D hydro simulations in GadgetII. In
> hydra.c and density.c the following lines are used to get the inverse
> of the 2nd or 3rd power (2D) of the smoothing length:
>
> hinv3 = hinv * hinv / boxSize_Z;
> hinv4 = hinv * hinv * hinv / boxSize_Z;
>
> I do not understand why the boxSize_Z is there, why would the Z
> boxsize have any influence at all in a 2D simulation? I ran some tests
> and when commenting out the boxSize_Z the simulation results do
> differ, although the initial differences are quite small and the
> long-term qualitative evolution seems to remain the same.
>
> So, I would like to understand why that term is there, and whether I
> can safely remove it (the 2D particle densities written in the
> snapshots are the real 2D densities divided by boxSize_Z, which is a
> bit confusing).
>
> Cheerz,
>
> Sander
>

-- 
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| Sander Valcke                                  |
| Sterrenkundig Observatorium, Universiteit Gent |
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| phone +32-9-264-4796  |  fax +32-9-264-4989    |
| https://sourceforge.net/projects/hyplot/       |
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Sometimes the best medicine is to stop taking something.
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Received on 2009-09-29 10:12:06

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