[Users] problems of reproducing the simulation of binary neutron star with different mass

Mon May 14 13:46:15 CDT 2018

Hello Chia-Hui,

ok that would make the distance from the origin ~38 units (Msun)
which is certainly not what the parameter file is designed to handle.

The code only flips the x and y coordinates, not z as well so (x,y,z)
and (-x,-y,z) thought this will not make a difference for you as the
center of the stars is at z=0 anyway.

You have to edit the .par file and there are two lines in there that
read:

CarpetRegrid2::position_x_1 = 15.1875

and

CarpetRegrid2::position_x_2 = -15.1875

You have to change 15.1875 to the initial x position of one of the stars (measured in solar masses ie about 1.48 km) and the -15.1875 to that of the other one.

You then have to restart your simulation from the beginning. Note that I expect this to still fail since even if you initially give the code:

CarpetRegrid2::position_x_1 = 42.
CarpetRegrid2::position_x_2 = -17

it will very soon set the centers to be

x_1 = 17, x_2 = -17 

since the star at x_2 = -17 is the heavier one (and thus has larger
central density).

There is a thorn that Zach Etienne is proposing for inclusion in the
Einstein Toolkit: https://trac.einsteintoolkit.org/ticket/1974 that he
says can track two unequal mass stars. The thorn in question would seem
to be VolumeIntegrals_GRMHD .

Yours,
Roland

> Dear Roland,
> 
> Yes, I did use the parameter file from gallery page and use unequal mass initial data from Lorene.
> 
> I just check the initial location of the binary star is (-34.59 km , 45.41 km).However you said it makes the hard-coded assumption that if one of the stars is at (x,y,z) the other one is at (-x,-y,z) .How should I set CarpetRegrid2::position_x_1 and CarpetRegrid2::position_x_2 ?
> 
> Thank you.
> 
> Best regards,
> 
> Chia-Hui
> 
> ________________________________
> 寄件者: Roland Haas <rhaas at illinois.edu>
> 寄件日期: 2018年5月15日 上午 02:13:06
> 收件者: 林家暉
> 副本: Einstein Toolkit Users
> 主旨: Re: [Users] problems of reproducing the simulation of binary neutron star with different mass
> 
> Hello Chia-Hui,
> 
> thank you for the attached file.
> 
> Yes, the error is related to the grid structure:
> 
> WARNING level 0 from host nid05920 process 0
>   while executing schedule bin (none), routine (no thorn)::(no routine)
>   in thorn CarpetLib, file /global/u1/c/chlin/Cactus/arrangements/Carpet/CarpetLib/src/gh.cc:178:
>   -> The refinement hierarchy is not properly nested.  
> 
> This is for the run where you used the parameter file from the gallery
> page but used unequal mass initial data from LORENE?
> 
> I am asking because, given that the parameter file specifies
> Rotating180 symmetry, the evolution will be as if equal mass NS were
> given in the initial data file (it will duplicate the right hand NS and
> ignore the left hand one). So the error that you saw should not be due
> to the unequal mass per-se. It could be if the location of the stars
> changed initially (eg for unequal mass the more massive one will be
> closer to the origin than the other one). This still should not give
> you this particular error (it would be wrong in other ways though)
> since the parameter file uses CarpetRegrid2::ensure_proper_nesting   =
> "yes" which should avoid this particular error.
> 
> Looking at the plot from your initial email it may be that there was an
> error in the initial setups as it looks to me as if the neutron stars
> have actually drifted apart. At least the gallery examples has the NS
> initially at ~+/-15 units from the origin but in you plot it looks like
> much more.
> 
> Wen you added the new ID you must make sure to adjust the initial
> location in the parfile in the lines reading:
> 
> CarpetRegrid2::position_x_1 = 15.1875
> CarpetRegrid2::position_x_2 = -15.1875
> 
> The binary black hole example does not have the restriction of
> assuming 180 degree symmetry, no.
> 
> Yours,
> Roland
> 
> > Dear Roland,
> > Thank you for your reply.
> > The attached file is .err file corresponding to the simulation of binary star with different central enthalpy.  Can you have a look at it ?Thank you.
> > For not able to track multiple stars, does it occur in binary blackhole case(http://einsteintoolkit.org/gallery/bbh/index.html) ?
> > Best regards,
> > Chia-Hui
> > ________________________________
> > 寄件者: Roland Haas <rhaas at illinois.edu>
> > 寄件日期: 2018年5月13日 下午 09:28:51
> > 收件者: 林家暉
> > 副本: Einstein Toolkit Users
> > 主旨: Re: [Users] problems of reproducing the simulation of binary neutron star with different mass
> >
> > Hello Chia-Hui Lin,
> >
> > changing the central enthalpy seems like the right thing to do to
> > change masses in LORENE since it prescribes the central enthalpy of
> > each star.
> >
> > The backtrace that you showed and the error message is unfortunately
> > not detailed enough to make a guess as to what could have gone wrong.
> > This output is produced by a call to CCTK_Error() however the
> > CCTK_Error function takes an error string as an argument which is not
> > present in the lines that you have copied. It is likely in the *.err
> > file that the simulation produced and you should try and include that
> > file as an attachment in your email.
> >
> > If you have non-equal mass stars then you have to remove the 180 degree
> > rotation symmetry from the parameter files. Ie you have to change the
> > lines (these are scattered throughout throughout the par file)
> >
> > ActiveThorns = "RotatingSymmetry180 ReflectionSymmetry"
> > CoordBase::xmin =    0.00
> > CoordBase::boundary_shiftout_x_lower = 1
> > CarpetRegrid2::symmetry_rotating180    = "yes"
> > Hydro_Analysis::Hydro_Analysis_rho_max_loc_only_positive_x = "true"
> > Hydro_Analysis::Hydro_Analysis_average_multiple_maxima_locations = "yes"
> >
> > to
> >
> > ActiveThorns = "ReflectionSymmetry"
> > CoordBase::xmin = 396.00
> > CoordBase::boundary_shiftout_x_lower = 0
> > CarpetRegrid2::symmetry_rotating180    = "no"
> > Hydro_Analysis::Hydro_Analysis_rho_max_loc_only_positive_x = "false"
> > Hydro_Analysis::Hydro_Analysis_average_multiple_maxima_locations = "no"
> >
> > Please note though that currently the thorn NSTracker and HydroAnalysis *cannot* properly track multiple stars. It makes the hard-coded assumption that if one of the stars is at (x,y,z) the other one is at (-x,-y,z) which is only true for equal mass neutron stars. This will mean that one of the stars will eventually leave the box that is supposed to track it.
> >
> > Yours,
> > Roland
> >  
> > > Dear whom it may concern,
> > >
> > > I am trying to reproduce the simulation of binary neutron star (http://einsteintoolkit.org/gallery/bns/index.html) with different mass. I use Lorene code to produce the initial data . The parameter files I used is locate in /Lorene/Codes/Bin_star/Parameters/Polytrope_irrot/Test_GR . And I changed  central enthalpy of each star in par_init.d to get different mass (Is there other way I can get different mass?). And then I simulate with the ET. However I met some problems:
> > >
> > > 1.I requested 48 cores with 10 hours to run the code , however the code terminated after running ~4 hours. And the end of .err file reads:
> > >
> > >
> > >
> > > cactus_sim: /global/u1/c/chlin/Cactus/arrangements/Carpet/Carpet/src/helpers.cc:275: int Carpet::Abort(const _cGH *, int): Assertion `0' failed.
> > >
> > > cactus_sim: /global/u1/c/chlin/Cactus/arrangements/Carpet/Carpet/src/helpers.cc:275: int Carpet::Abort(const _cGH *, int): Assertion `0' failed.
> > >
> > > Rank 0 with PID 47930 received signal 6
> > >
> > > Writing backtrace to nsnstohmns/backtrace.0.txt
> > >
> > > Rank 1 with PID 47931 received signal 6
> > >
> > > Writing backtrace to nsnstohmns/backtrace.1.txt
> > >
> > > cactus_sim: /global/u1/c/chlin/Cactus/arrangements/Carpet/Carpet/src/helpers.cc:275: int Carpet::Abort(const _cGH *, int): Assertion `0' failed.
> > >
> > > cactus_sim: /global/u1/c/chlin/Cactus/arrangements/Carpet/Carpet/src/helpers.cc:275: int Carpet::Abort(const _cGH *, int): Assertion `0' failed.
> > >
> > > Rank 2 with PID 13239 received signal 6
> > >
> > > Rank 3 with PID 13240 received signal 6
> > >
> > > Writing backtrace to nsnstohmns/backtrace.2.txt
> > >
> > > Writing backtrace to nsnstohmns/backtrace.3.txt
> > >
> > > srun: error: nid05930: tasks 2-3: Aborted
> > >
> > > srun: Terminating job step 9192104.0
> > >
> > > srun: error: nid05920: tasks 0-1: Aborted
> > >
> > >
> > > The code is aborted without completing the whole process until the merger. How can I perform the complete process?
> > >
> > > 2. When I use visit to do the visualization ,I found the file rho.xy.h5 only has half of the whole simulation as :
> > >
> > > [cid:e66a53d5-d406-4599-997f-00e90a864dc0]
> > >
> > >
> > >
> > >
> > >
> > > The tutorial(scripts.tar.gz<http://einsteintoolkit.org/gallery/bns/scripts.tar.gz>) tells that I should use symmetric reflection to perform the whole visualization. However I cannot use this method since I simulated binary star with different mass . So there is no symmetry. How can I get the whole picture instead of only half ?
> > >
> > >
> > > Thank you.
> > >
> > > Best regards,
> > >
> > > Chia-Hui Lin  
> >
> >
> >
> > --
> > My email is as private as my paper mail. I therefore support encrypting
> > and signing email messages. Get my PGP key from http://pgp.mit.edu .  
> 
> 
> 
> --
> My email is as private as my paper mail. I therefore support encrypting
> and signing email messages. Get my PGP key from http://pgp.mit.edu .

-- 
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