[Users] About cctk_time
Bruno Giacomazzo
bruno.giacomazzo at unimib.it
Wed Nov 11 15:43:12 CST 2020
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
>
--
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/20201111/4a9aa5bb/attachment.html
More information about the Users
mailing list