[Users] About cctk_time
Bruno Giacomazzo
bruno.giacomazzo at unimib.it
Thu Nov 12 11:12:38 CST 2020
Roland,
thank you very much for the information. Sorry that I was not able to
join the telecon, but Jay informed me about the discussion.
Thanks,
Bruno
Il giorno gio 12 nov 2020 alle ore 16:38 Roland Haas <rhaas at illinois.edu>
ha scritto:
> Hello Bruno, Jay, (to mark this email as "responded")
>
> Jay brought this up in today's ET call:
>
> http://lists.einsteintoolkit.org/pipermail/users/2020-November/007670.html
>
> and Peter, Zach, I responded:
>
> --8<--
> Jay Kalinani: TOV simulation using new Spritz code. When adding a dipolar
> magnetic field to the star, there is some confusion about the behavior of
> cctk_time. There's a desire to not store RK intermediate values of
> cctk_time to cctk_time itself.
> Zach suggested that a local variable could be defined that simply outputs
> cctk_iteration*dt if desired.
> Roland had some comments about scheduling such a routine.
> --8<--
>
> basically: "this is as designed in case the RHS in has an explicit
> dependency on time".
>
> Yours,
> Roland
>
> > Hi Erik,
> > those should be internal steps of the Runge-Kutta integrator when going
> > from t to t+dt. Why is the cctk_time changed in those intermediate steps?
> > Shouldn't cctk_time be set only at each iteration in time?
> >
> > Thanks,
> > Bruno
> >
> >
> > Il giorno mer 11 nov 2020 alle ore 15:11 Erik Schnetter <
> > schnetter at cct.lsu.edu> ha scritto:
> >
> > > Jay
> > >
> > > This intermediate step comes from the time integrator. The Einstein
> > > Toolkit usually uses Runge-Kutta type time integrators that perform
> > > multiple sub-steps for each time step. These time integrators are
> > > provided by the "Methods of Lines" thorn ("MoL"). The respective
> > > documentation should have further pointers, and the respective
> > > parameter settings should also tell you more. (See also e.g.
> > > <https://en.wikipedia.org/wiki/Runge–Kutta_methods>).
> > >
> > > -erik
> > >
> > > On Tue, Nov 10, 2020 at 12:20 PM Jay Vijay Kalinani
> > > <jayvijay.kalinani at phd.unipd.it> wrote:
> > > >
> > > > Dear all,
> > > >
> > > > I am trying to perform a magnetised TOV simulation using Einstein
> > > Toolkit and Spritz GRMHD code. In particular, currently I have a
> subroutine
> > > that adds a dipolar magnetic field to the TOV star after its initial
> data
> > > has been generated via TOVSolver thorn.
> > > > Within this subroutine, I have added the following lines that print
> the
> > > 'cctk_time' value as:
> > > >
> > > > character(len=200) warnline
> > > > WRITE( warnline, '( "cctk_time: ", g16.7)' ) cctk_time
> > > > call CCTK_INFO(warnline)
> > > >
> > > > This subroutine is scheduled in HydroBase_Con2Prim after Con2Prim
> step.
> > > And I get the following lines in the .out file as:
> > > > .........
> > > >
> > > > INFO (TOVSolver): Integrated TOV equation
> > > >
> > > > INFO (TOVSolver): Information about the TOVs used:
> > > >
> > > > INFO (): TOV radius mass bary_mass mass(g) cent.rho rho(cgi)
> > > K K(cgi) Gamma
> > > >
> > > > INFO (): 1 8.12502 1.40016 1.50618 2.78e+33 0.00128 7.92e+14
> > > 100 1.45e+05 2
> > > >
> > > > INFO (TOVSolver): Not using old matter initial data
> > > >
> > > > INFO (TOVSolver): Done interpolation.
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.000000
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): Adding a poloidal magnetic field to the
> TOV
> > > star on reflevel 0
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): Adding atmo to the TOV star on reflevel
> =
> > > '0'
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.000000
> > > >
> > > >
> > >
> -----------------------------------------------------------------------------------------------------------------------------------
>
> > > >
> > > > Iteration Time | ADMBASE::alp |
> > > HYDROBASE::rho | HYDROBASE::press |
> SPRITZ::B_norm
> > > >
> > > > | minimum maximum | minimum
> > > maximum | minimum maximum | minimum maximum
> > > >
> > > >
> > >
> -----------------------------------------------------------------------------------------------------------------------------------
>
> > > >
> > > > 0 0.000 | 0.6698612 0.9603815 | 5.827798e-11
> > > 0.0012800 | 0.0000000 0.0001638 | 8.399814e-09 0.0000399
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.3906250E-01
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.3906250E-01
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.7812500E-01
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.7812500E-01
> > > >
> > > > 1 0.078 | 0.6698612 0.9603833 | 5.827814e-11
> > > 0.0012799 | 0.0000000 0.0001638 | 8.294987e-09 0.0000395
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1171875
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1171875
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1562500
> > > >
> > > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1562500
> > > >
> > > > 2 0.156 | 0.6698612 0.9603850 | 5.827829e-11
> > > 0.0012797 | 0.0000000 0.0001638 | 8.294994e-09 0.0000390
> > > >
> > > > ..........
> > > >
> > > >
> > > >
> > > >
> > > > The simulation is performed in uniform grid with dx=dy=dz=0.3125,
> > > time::dtfac = 0.25 and HydroBase::timelevels = 2.
> > > > As you may see from the output lines, in between iteration 0 which
> is at
> > > cctk_time=0.0 and iteration 1 which is at cctk_time=0.078125, there is
> an
> > > intermediate time step with 'cctk_time=0.0390625' when the subroutine
> is
> > > called.
> > > >
> > > > I was hoping to understand better why this intermediate time step
> exists
> > > between two consecutive iterations, and if there is any documentation I
> > > could look at.
> > > > Any help would be much appreciated.
> > > >
> > > > Thank you very much.
> > > > Sincerely,
> > > > Jay Kalinani
> > > > _______________________________________________
> > > > Users mailing list
> > > > Users at einsteintoolkit.org
> > > > http://lists.einsteintoolkit.org/mailman/listinfo/users
> > >
> > >
> > >
> > > --
> > > Erik Schnetter <schnetter at cct.lsu.edu>
> > > http://www.perimeterinstitute.ca/personal/eschnetter/
> > > _______________________________________________
> > > Users mailing list
> > > Users at einsteintoolkit.org
> > > http://lists.einsteintoolkit.org/mailman/listinfo/users
> > >
> >
> >
>
>
> --
> 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 .
>
--
Prof. Bruno Giacomazzo
Department of Physics
University of Milano-Bicocca
Piazza della Scienza 3
20126 Milano
Italy
email: bruno.giacomazzo at unimib.it
phone: (+39) 02 6448 2321
web: http://www.brunogiacomazzo.org
----------------------------------------------------------------------
There are only 10 types of people in the world:
Those who understand binary, and those who don't
----------------------------------------------------------------------
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.einsteintoolkit.org/pipermail/users/attachments/20201112/3600092a/attachment.html
More information about the Users
mailing list