<div dir="ltr">Roland,<div> thank you very much for the information. Sorry that I was not able to join the telecon, but Jay informed me about the discussion.</div><div><br></div><div>Thanks,</div><div>Bruno</div><div><br></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno gio 12 nov 2020 alle ore 16:38 Roland Haas <<a href="mailto:rhaas@illinois.edu">rhaas@illinois.edu</a>> ha scritto:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Hello Bruno, Jay, (to mark this email as "responded")<br>
<br>
Jay brought this up in today's ET call:<br>
<br>
<a href="http://lists.einsteintoolkit.org/pipermail/users/2020-November/007670.html" rel="noreferrer" target="_blank">http://lists.einsteintoolkit.org/pipermail/users/2020-November/007670.html</a><br>
<br>
and Peter, Zach, I responded:<br>
<br>
--8<--<br>
Jay Kalinani: TOV simulation using new Spritz code. When adding a dipolar<br>
magnetic field to the star, there is some confusion about the behavior of<br>
cctk_time. There's a desire to not store RK intermediate values of<br>
cctk_time to cctk_time itself.<br>
Zach suggested that a local variable could be defined that simply outputs<br>
cctk_iteration*dt if desired.<br>
Roland had some comments about scheduling such a routine.<br>
--8<--<br>
<br>
basically: "this is as designed in case the RHS in has an explicit<br>
dependency on time".<br>
<br>
Yours,<br>
Roland<br>
<br>
> Hi Erik,<br>
> those should be internal steps of the Runge-Kutta integrator when going<br>
> from t to t+dt. Why is the cctk_time changed in those intermediate steps?<br>
> Shouldn't cctk_time be set only at each iteration in time?<br>
> <br>
> Thanks,<br>
> Bruno<br>
> <br>
> <br>
> Il giorno mer 11 nov 2020 alle ore 15:11 Erik Schnetter <<br>
> <a href="mailto:schnetter@cct.lsu.edu" target="_blank">schnetter@cct.lsu.edu</a>> ha scritto: <br>
> <br>
> > Jay<br>
> ><br>
> > This intermediate step comes from the time integrator. The Einstein<br>
> > Toolkit usually uses Runge-Kutta type time integrators that perform<br>
> > multiple sub-steps for each time step. These time integrators are<br>
> > provided by the "Methods of Lines" thorn ("MoL"). The respective<br>
> > documentation should have further pointers, and the respective<br>
> > parameter settings should also tell you more. (See also e.g.<br>
> > <<a href="https://en.wikipedia.org/wiki/Runge%E2%80%93Kutta_methods" rel="noreferrer" target="_blank">https://en.wikipedia.org/wiki/Runge–Kutta_methods</a>>).<br>
> ><br>
> > -erik<br>
> ><br>
> > On Tue, Nov 10, 2020 at 12:20 PM Jay Vijay Kalinani<br>
> > <<a href="mailto:jayvijay.kalinani@phd.unipd.it" target="_blank">jayvijay.kalinani@phd.unipd.it</a>> wrote: <br>
> > ><br>
> > > Dear all,<br>
> > ><br>
> > > I am trying to perform a magnetised TOV simulation using Einstein <br>
> > Toolkit and Spritz GRMHD code. In particular, currently I have a subroutine<br>
> > that adds a dipolar magnetic field to the TOV star after its initial data<br>
> > has been generated via TOVSolver thorn. <br>
> > > Within this subroutine, I have added the following lines that print the <br>
> > 'cctk_time' value as: <br>
> > ><br>
> > > character(len=200) warnline<br>
> > > WRITE( warnline, '( "cctk_time: ", g16.7)' ) cctk_time<br>
> > > call CCTK_INFO(warnline)<br>
> > ><br>
> > > This subroutine is scheduled in HydroBase_Con2Prim after Con2Prim step. <br>
> > And I get the following lines in the .out file as: <br>
> > > .........<br>
> > ><br>
> > > INFO (TOVSolver): Integrated TOV equation<br>
> > ><br>
> > > INFO (TOVSolver): Information about the TOVs used:<br>
> > ><br>
> > > INFO (): TOV radius mass bary_mass mass(g) cent.rho rho(cgi) <br>
> > K K(cgi) Gamma <br>
> > ><br>
> > > INFO (): 1 8.12502 1.40016 1.50618 2.78e+33 0.00128 7.92e+14 <br>
> > 100 1.45e+05 2 <br>
> > ><br>
> > > INFO (TOVSolver): Not using old matter initial data<br>
> > ><br>
> > > INFO (TOVSolver): Done interpolation.<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.000000<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): Adding a poloidal magnetic field to the TOV <br>
> > star on reflevel 0 <br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): Adding atmo to the TOV star on reflevel = <br>
> > '0' <br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.000000<br>
> > ><br>
> > > <br>
> > ----------------------------------------------------------------------------------------------------------------------------------- <br>
> > ><br>
> > > Iteration Time | ADMBASE::alp | <br>
> > HYDROBASE::rho | HYDROBASE::press | SPRITZ::B_norm <br>
> > ><br>
> > > | minimum maximum | minimum <br>
> > maximum | minimum maximum | minimum maximum <br>
> > ><br>
> > > <br>
> > ----------------------------------------------------------------------------------------------------------------------------------- <br>
> > ><br>
> > > 0 0.000 | 0.6698612 0.9603815 | 5.827798e-11 <br>
> > 0.0012800 | 0.0000000 0.0001638 | 8.399814e-09 0.0000399 <br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.3906250E-01<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.3906250E-01<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.7812500E-01<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.7812500E-01<br>
> > ><br>
> > > 1 0.078 | 0.6698612 0.9603833 | 5.827814e-11 <br>
> > 0.0012799 | 0.0000000 0.0001638 | 8.294987e-09 0.0000395 <br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1171875<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1171875<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1562500<br>
> > ><br>
> > > INFO (Spritz_DipoleAndAtmo): cctk_time: 0.1562500<br>
> > ><br>
> > > 2 0.156 | 0.6698612 0.9603850 | 5.827829e-11 <br>
> > 0.0012797 | 0.0000000 0.0001638 | 8.294994e-09 0.0000390 <br>
> > ><br>
> > > ..........<br>
> > ><br>
> > ><br>
> > ><br>
> > ><br>
> > > The simulation is performed in uniform grid with dx=dy=dz=0.3125, <br>
> > time::dtfac = 0.25 and HydroBase::timelevels = 2. <br>
> > > As you may see from the output lines, in between iteration 0 which is at <br>
> > cctk_time=0.0 and iteration 1 which is at cctk_time=0.078125, there is an<br>
> > intermediate time step with 'cctk_time=0.0390625' when the subroutine is<br>
> > called. <br>
> > ><br>
> > > I was hoping to understand better why this intermediate time step exists <br>
> > between two consecutive iterations, and if there is any documentation I<br>
> > could look at. <br>
> > > Any help would be much appreciated.<br>
> > ><br>
> > > Thank you very much.<br>
> > > Sincerely,<br>
> > > Jay Kalinani<br>
> > > _______________________________________________<br>
> > > Users mailing list<br>
> > > <a href="mailto:Users@einsteintoolkit.org" target="_blank">Users@einsteintoolkit.org</a><br>
> > > <a href="http://lists.einsteintoolkit.org/mailman/listinfo/users" rel="noreferrer" target="_blank">http://lists.einsteintoolkit.org/mailman/listinfo/users</a> <br>
> ><br>
> ><br>
> ><br>
> > --<br>
> > Erik Schnetter <<a href="mailto:schnetter@cct.lsu.edu" target="_blank">schnetter@cct.lsu.edu</a>><br>
> > <a href="http://www.perimeterinstitute.ca/personal/eschnetter/" rel="noreferrer" target="_blank">http://www.perimeterinstitute.ca/personal/eschnetter/</a><br>
> > _______________________________________________<br>
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> > <br>
> <br>
> <br>
<br>
<br>
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</blockquote></div><br clear="all"><div><br></div>-- <br><div dir="ltr" class="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><p><font color="#000000">Pr<font face="arial, sans-serif">of. Bruno Giacomazzo<br>Department of Physics<br>University of Milano-Bicocca<br></font></font><span style="color:rgb(0,0,0)"><font face="arial, sans-serif">Piazza della Scienza 3<br></font></span><span style="color:rgb(0,0,0)"><font face="arial, sans-serif">20126 Milano<br></font></span><span style="font-size:12.8px;color:rgb(0,0,0)">Italy</span></p><p><font color="#000000"><span style="font-size:12.8px">email: </span><span style="font-size:12.8px"><a href="mailto:bruno.giacomazzo@unimib.it" target="_blank">bruno.giacomazzo@unimib.it</a><br></span><span style="font-size:12.8px">phone: (+39) 02 6448 2321</span></font><br><font color="#000000"><span style="font-size:12.8px">web: </span></font><span style="color:rgb(0,0,0);font-size:12.8px"><a href="http://www.brunogiacomazzo.org/" style="font-size:12.8px" target="_blank">http://www.brunogiacomazzo.org</a></span></p><p><font color="#000000">----------------------------------------------------------------------<br><span style="font-size:12.8px">There are only 10 types of people in the world:<br></span><span style="font-size:12.8px">Those who understand binary, and those who don't<br></span><span style="font-size:12.8px">----------------------------------------------------------------------<br></span></font></p></div></div></div></div></div></div></div>