[Users] LORENE BHNS Initial Data

[Gwyneth Allwright]

Thanks Roland! This is going to be useful; I didn't know about that
parameter file.

I've been trying to compile Lorene, but am getting errors like:

Undefined symbols for architecture x86_64:
__gfortran_os_error", referenced from:
      _poiss2d_ in liblorenef77_g.a(poisson2d.o)
      _poiss2di_ in liblorenef77_g.a(poisson2di.o)

The initial "make" works fine. The errors only appear when I "make test" or
"make coal_ns_bh init_ns_bh lit_bin_ns_bh" in the Codes/Bin_ns_bh
directory. Did you by any chance run into something like this?

I'm using the MacPorts universal version of gcc 6.3.0 and am compiling with
g++ and gfortran. I've tried setting -m64 and -m32, but neither works. I
probably need to change something in my local settings file, but so far I
haven't been able to figure out what.

Gwyneth

On Thu, Mar 9, 2017 at 6:58 PM, Roland Haas <roland.haas at physics.gatech.edu>
wrote:

> Hello Gwyneth, Frank, all,
>
> > Thanks for all the comments! I'm looking forward to trying this out.
> >
> > Once I manage to compile Lorene and produce some data, I'll have a go at
> > importing the data into the toolkit. There's probably going to be a
> > learning curve, but I don't mind spending some time on this. If I manage
> to
> > get it working, I'll add to the wiki.
> I was pointed out to me by a kind person that there is indeed a simpler
> way to get at "some" bhns initial data. You can use a combination of
> the TOVSolver and TwoPunctures thorns to obtain such a one as shown in
> the test parfile
> arrangements/EinsteinInitialData/TwoPunctures/test/bhns_eval.par
>
> You will probably have to run with quite high values for npoints_A and
> npoints_B (easily >60) to obtain any reasonable value for the
> constraints.
>
> This will not generate great (or even good) initial data since at the
> very least the star will be out of hydrostatic equilibrium so will
> start to oscillate noticeably when the simulation stars. Second the
> example parfile has the star at rest. You can give it a velocity via
> TOVSolver's TOV_Velocity_x[0] etc parameters though then you will not
> even strictly satisfy the initial data constraints for the metric since
> TOVSolver does not take the fluid into account when solving for the
> momentum constraint. Finally there is no help provided to obtain
> quasicircular orbits at all, so you are stuck with eg starting from the
> Newtonian velocity and see what happens.
>
> As said, not great initial data for BHNS but something that you could
> at least play with while learning how to use LORENE or getting access
> to better data produced by other codes.
>
> Yours,
> Roland
>
> --
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>
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