Users April 2010

users@lists.einsteintoolkit.org

15 participants
22 discussions

Initial data documentation
by Erik Schnetter 17 Jun '10

17 Jun '10

As discussed in our telecon this morning, I wrote a wiki page about setting up an initial data thorn for <http:// docs.einsteintoolkit.org>. The last section (setting up and running with an example parameter file) is still missing. I would be happy if someone took the liberty to proofread, correct, simplify, and possibly complete my explanations. -erik -- Erik Schnetter <schnetter(a)cct.lsu.edu> http://www.cct.lsu.edu/~eschnett/

6 16

wrong linking address on EinsteinToolkit website
by Jian Tao 27 May '10

27 May '10

Hi, On the tutorial page, http://einsteintoolkit.org/info/documentation/tutorial.php The link to "thornlist for the Einstein Toolkit" doesn't work. Regards, Jian

6 8

Einstein Toolkit talk at GR19
by Erik Schnetter 13 May '10

13 May '10

I have just submitted an abstract for a talk at GR19 <http://www.gr19.com/ > in the session B2 Numerical Relativity and Astrophysical Applications. This talk will advertise the Einstein Toolkit to the community. Title: The Einstein Toolkit Authors: Erik Schnetter for the Einstein Toolkit Consortium Abstract: We introduce the Einstein Toolkit, a collection of software components and tools for simulating and analyzing general relativistic astrophysical systems. Such systems include gravitational wave space-times, collisions of compact objects such as black holes or neutron stars, accretion onto compact objects, core collapse supernovae and Gamma-Ray Bursts. This toolkit is developed as open software for relativistic astrophysics. Our aim is to provide the core computational tools that can enable new science, broaden our community, facilitate interdisciplinary research and take advantage of emerging petascale computers and advanced cyberinfrastructure. We believe that this toolkit can also be constructively used in teaching numerical relativity courses, and can help "getting started" in numerical relativity research. The Einstein Toolkit builds on numerous software efforts in the numerical relativity community including CactusEinstein, Whisky, and Carpet. The Einstein Toolkit currently uses the Cactus Framework as the underlying computational infrastructure that provides large-scale parallelization, general computational components, and a model for collaborative, portable code development. We give a brief overview over the toolkit, its goals, and its current state, and show examples of scientific results obtained by various research groups employing this toolkit as basis of their research codes. -- Erik Schnetter <schnetter(a)cct.lsu.edu> http://www.cct.lsu.edu/~eschnett/

5 14

Schedule change in Exact.
by Eloisa Bentivegna 04 May '10

04 May '10

Hello, I'd like to propose the following patch for the schedule.ccl of thorn Exact: ------------------------------------------------------ 135a136,140 > > schedule Exact__initialize in MoL_PostStep > { > LANG: Fortran > } "Set data from exact solution on an exact slice" ------------------------------------------------------ This should ensure that Exact__initialize is executed after regridding, in the same way that Exact__gauge already is. Thanks! Eloisa

5 9

possible CVS server issues
by Roland Haas 03 May '10

03 May '10

Hello all, the cvs server at cvs.cct.lsu.edu seems to have become unaccessible from outside of LSU (I can still ping it from is.cct.lsu.edu). Trying to check out a thorn from LSUThorns I get: Updating module: LSUThorns/QuasiLocalMeasures from repository: :pserver:cvs.cct.lsu.edu/numrel located in: whisky/arrangements ERROR: Could not update module LSUThorns/QuasiLocalMeasures Died at ./GetComponents line 1353. Yours, Roland -- My email is as private as my paper mail. I therefore support encrypting and signing email messages. Get my PGP key from http://keys.gnupg.net.

3 3

unable to build documentation due to change in data format
by Roland Haas 29 Apr '10

29 Apr '10

Hello all, it seems the move from CVS to subversion has had the side effect of changing the date field in checked out files from \def\CA@styledate{\CA@getcvsdate $Date: 2009/02/13 15:45:19 $} to \def\CA@styledate{\CA@getcvsdate $Date: 2009-02-13 10:45:19 -0500 (Fri, 13 Feb 2009) $} in doc/latex/cactus.sty this causes \CA@getcvsdate (line 36) in \CA@styledate to fail. This in turn prevents me from building documentation (at least for the HydroBase thorn). Changing the \def line back to what it looked like before the move fixes this. Yours, Roland -- My email is as private as my paper mail. I therefore support encrypting and signing email messages. Get my PGP key from http://keys.gnupg.net.

2 2

FW: HydroBase description
by Aaryn Tonita 27 Apr '10

27 Apr '10

I believe the best place to have mass and temperature units set is in the equation of state thorns and to have the magnetic field units set by the code implementing the particular implementation of the Maxwell equations. This goes into one of your original questions about whether there were other dimensions left to specify, but in principle one could measure temperature using a completely different unit system--for instance taking c=MeV=k_b=1 and using MeV to measure temperature. Since this would only affect the equation of state thorn (the hydro equations don't see temperature directly) it wouldn't introduce any inconsistency if one was measuring the density in units where c=G=M_sun=1. The equation of state thorn would need to do some internal bookkeeping on the two different unit systems, is all. This would be useful if one was working internally with some statistical physics expressions directly so that you would not need to continuously convert the temperature. As I see it now, when using the ideal fluid equation of state (or polytrope), one is free to interpret the units. Always. This is really unavoidable: there is no microphysical interpretation of kappa or gamma. This changes when you use a realistic (or a fit) equation of state, the units would then be specified by the particular thorn which is implementing the functions needed by EOS_Base. In short: I believe the units to be best specified in the particular equation of state thorns. Cheers, Aaryn -----Original Message----- From: Roland Haas [mailto:roland.haas@physics.gatech.edu] Sent: Tuesday, April 27, 2010 4:16 PM To: Aaryn Tonita Subject: Re: [Users] HydroBase description Hello all, > Actually, the units of "Whisky" is a myth I have been trying to dispel from > some of the people at the AEI for a while now. In the hydro equations, the > only place that a mass scale enters is through the equation of state. So > HydroBase will work with any choice of mass unit (defined through the > equation of state) so long as G=c=1 is used consistently. I have run quite > successfully using polytropic units and kilometres. Well it should certainly possible to remove these statements from documentation and interface.ccl. I agree that in particular fixing the mass unit is awkward (Tanja Bode here has simulations where the natural mass unit is 10^8 M_sun) for some simulations. Is there a strong preference for fixing all (or only G=c=eps0=mu0=1, maybe k_B=1?) units or should they be left unspecified? > As for the ideal magnetohydrodynamic equations, Whisky_Exp chooses > div(Faraday) = 4-current without any constant of nature, so this is > equivalent to choosing the permeability of free space (\mu_0) to be unity. Hmm, mostly I was curious about factors of \sqrt{4\pi} in B^i. I believe that B^i as defined in HydroBase is Anton's et. al. (astro-ph/0506063v1) b^\mu after the rescaling by \sqrt{4\pi} in Eq (29). > However, this would not be defined by HydroBase unless HydroBase sets the > stress energy tensor. HydroBase does not set Tmunu. Fully determining the units might be useful for some analysis thorns. Another option might be to add parameters defining the units/describing the fluid to HydroBase or EOS_Base, though this did not seem to be very popular when it was suggested before. Eg. the unit mass in gramms, unit length in cm etc. Yours, Roland -- My email is as private as my paper mail. I therefore support encrypting and signing email messages. Get my PGP key from http://keys.gnupg.net.

1 0

HydroBase description
by Roland Haas 27 Apr '10

27 Apr '10

Hello all, I have put a short description of HydroBase, its grid-variables and the units used into the wiki. It is really just what can be found in the documentation (currently out of date) and interface.ccl. Since I have never done MHD and don't know the conventions used in that field would someone who is knowledgeable mind reading through it and checking in particular the units I give for B and its definition in terms of the (dual) Faraday tensor, please? One could also add descriptions for the parameters, but these would really be just copies of what is in param.ccl. Also it would be nice to note if these choices for units of the various quantities exhaust the freedom to choose units (I would think that with temperature and specific entropy they should, even determine the mass of the (ideal gas) particle that makes up the fluid). Yours, Roland -- My email is as private as my paper mail. I therefore support encrypting and signing email messages. Get my PGP key from http://keys.gnupg.net.

4 3

GetComponents
by Roland Haas 22 Apr '10

22 Apr '10

Hello all, I had played around with converting our codebase to the new directory layout (so far it compiles without problems) and found it useful to add darcs support to GetComponents. For this I copied the git routines and did a s/git/darcs/ (almost literally just that). Also slightly changed how git, darcs and hg create links by using Perl's File::Spec->abs2rel function to create relative paths. This avoids the hard-coded assumption that git-repos is two directory levels above the target. Finally I added close($output) statements to run_command which seem to be necessary to catch the return value of 'which'. Otherwise GetComponents does not seem to detect that there is no darcs eg. on Ranger. If these seem like good things to have, would it be possible to add them to GetComponents? Yours, Roland

2 1

Fwd: GetComponents description
by Eric Seidel 20 Apr '10

20 Apr '10

Just realized this didn't go to the users list. Begin forwarded message: > From: Eric Seidel <eric(a)eseidel.org> > Date: April 20, 2010 3:05:22 PM EDT > To: Bruno Coutinho Mundim <bcmsma(a)astro.rit.edu> > Subject: Re: [Users] GetComponents description > > Thanks for pointing this out, I updated the documentation to include !NAME. > > Eric > > > On Apr 20, 2010, at 2:58 PM, Bruno Coutinho Mundim wrote: > >> Hi, >> >> reading the GetComponents description again, I noticed that >> the !NAME directive is not described there (at the end of >> the file all required and optional directives are described). >> >> Bruno. >> _______________________________________________ >> Users mailing list >> Users(a)einsteintoolkit.org >> http://lists.einsteintoolkit.org/mailman/listinfo/users >

1 0

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

Users April 2010