[Users] [Commits] [svn:einsteintoolkit] TOVSolver/trunk/ (Rev. 137)

[Christian D. Ott]

Hi Roland,

the EOS is universal. If one of the stars has a smaller mass, then it
has a smaller central density. If one wants to do exotic physics, then
one needs a different evolution code than GRHydro anyways. I see no
reason why the TOV solver should support something that can't be evolved
by the ET in any case and just adds complication and can trick users
that do not have sufficient experience into doing something massively
stupid.

Also, we are in a development phase, so it's expected that things break
once in a while.

 - Christian


On 7/7/13 11:06 AM, Roland Haas wrote:
> Hello all,
> 
>> Log:
>>  * remove option to have different gamma and K for different
>>    stars. That's physically impossible.
>>  * adjust test par files (will do so with GRHydro next)
>>  * modify the way solutions are added so that atmosphere cuts
>>    are applied after solutions are added. Otherwise one of the
>>    stars will have the atmosphere added to it. This breaks symmetry.
> This commit (and the following ones) make the tests fail, at least in
> subversion (Zelmani is ok since the author *does* provide updated tests,
> just not in GRHydr/svn, so I could port over the change).
> 
> I am personally generally unhappy about commits that require everybody
> to change/update their paramater files unless the change is required to
> prevent a bug from manifesting. Removing "[0]" from ones parameter file
> is not hard, but will break each and every single one of them. One of
> the nice things about Cactus has been that (some parts of it) are fairly
> stable and developers take care to not introduce changes that require
> each user to update their parameter files (unless the user wants/needs
> new features).
> 
> I am also not sure I agree with the statement that one cannot have
> different Gama or K for different stars. Even if the same Gamma and K
> would be needed for all neutron stars (which I also don't fully
> understand, why should not a different Gamam or K be a better
> approximiation to NS of different massses?) there is still the
> possiblilty of setting up two different sorts of stars and evolve those.
> Note that I make no statement how to proceed with such an evolution past
> the point where the stars would touch. To my knowledge only Ian Hawke
> did such simulations in the past, and Ian effective advected the EOS
> parameters with the fluid if I remember correctly. If someone with more
> expterise would comment that would be helpful.
> 
> I would like to revert parts of this patch (keeping the atmosphere
> treatment that prevents asymetries in the data setup and seems to be
> currently buggy) and restore the possibility to have different K and
> Gamma (indep of whether this is physical I don't see a point in removing
> this functionality).
> 
> Please comment (in private or on the mailing list).
> 
> Yours,
> Roland
> 
> 
> 
> 
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