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Einstein Toolkit Meeting Reminder
by Frank Loeffler 19 Jan '14

19 Jan '14

Hi Please consider joining the weekly Einstein Toolkit phone call at 10 am US central time on Mondays. As usual, you can find instructions how to join on the following web site: http://einsteintoolkit.org/community/support/ In short: the number is (+1) 225-578-4942 or (+1) 866-573-0359 and the conference id is 118682#. One of the likely topics will be SPH within Cactus. Happy MLK day, Frank

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Sync a single variable
by Steven R. Brandt 16 Jan '14

16 Jan '14

Frank tells me there was a ticket, maybe even a patch, at some point allowing one to specify a single variable (rather than a group) for syncing in a ccl file. Does anyone know what's become of it? Cheers, Steve

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SPH Idea and your Feedback
by sruehe＠astrophysik.uni-kiel.de 16 Jan '14

16 Jan '14

Hallo, first of all i want to thank you for your feedback. It's much more than i expected. Because i havn't read up on every part of the EinsteinToolkit (most of the last days i read the theoretical background to the BSSN formalism) i can't say much about programming concepts up to now. I think the implantation of a particle based structure is one of the biggest part for a SPH implementation. I'm glad about this interest and would try to join the phone call on the next Monday, which Frank Loeffler suggested. Stefan Ruehe

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Some more Questions from a new User
by sruehe＠astrophysik.uni-kiel.de 15 Jan '14

15 Jan '14

Hello EinsteinToolkit-Community, first of all i want thank you very much for the fast and helpful answer to my last Email. I mentioned i'm at the beginning of my phd. So before i'm wasting too much time on working at something an other already knows, i want to ask some perhaps a little bit naively sounding questions. I have studied smoothed particle hydrodynamics on a fixed spacetime, so i get the idea devolping a sph based thorn. I found no publications, so is perhaps anybody already working on this problem, or has one shown that this isn't possible? Because this is an community based development, it is quite interesting whether it could be an useful thorn. I'm not sure whether my questions are answerable, but perhaps you can help me a second time. Thank you very much, Stefan Ruehe

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Point relase of ET_2013_11 "Noether"
by Frank Loeffler 13 Jan '14

13 Jan '14

Since its release, a few important corrections have been added to the current version ET_2013_11 "Noether". In fact, one error in particular can lead silently to wrong results, so we strongly suggest to update checkouts. Updating is easy: from within your Cactus checkout (cd into it), execute ./bin/GetComponents -u New tags for this "point release" have been created: ET_2013_11_v1, but it is not recommended to use these for a checkout, to be able to easily receive possible future updates. The tar ball has been updated as well. In the following we briefly describe the changes included in this update. The ET_2013_11 "Noether" release of the Einstein Toolkit contained an error in Carpet which was introduced since the previous ET_2013_05 "Gauss" release. The problem was related to synchronising ghost zones after data is restricted (copied from fine grids to coarse grids). The problem has been observed to result in incorrect data on coarse grids for multi-process runs with more than 2 refinement levels, and data on coarse grids which depends on the number of processes used. This problem has now been fixed in the ET_2013_11 release branch. The MoL integrator RK87 was not functional in the Noether release, triggering an error message instead. This message was meant to warn that RK87 is not implemented for grid arrays. However, this error message and abort was always triggered, even for evolutions of only grid functions (the usual case). This has been corrected, and now only triggers if evolutions of grid arrays are requested with RK87. In IDLinearWaves the calculation of one coeffient for the m=2 mode of the Teukolsky waves was missing, resulting in usage of uninitialized memory for that mode. This is not a regression from a previous release, but was included in the point release because of its trivial and non-invasive fix. Frank Loeffler for the Einstein Toolkit maintainers

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Meeting Minutes
by Roland Haas 13 Jan '14

13 Jan '14

Present: Frank, Roland, Peter, Steve, Yosef, Zach, Josh, Matt, Ian backporting changes: * urgently want to create new release tag and send out announcement for restriction bug that was fixed and backported * policy for backporting: ** backport all regression fixes ** backport all fixes that would have silently produced incorrect results ** backport fixes that cleanly apply, backport fixes which are requested by a user IllinoisGRMHD: * progress made checking for regressions, now agrees with previous Illinois code for 100 steps when using AMR and no symmetries * will be proposed for inclusion * Philipp and Zach to add edge centered prolongation operators for magnetic vector potentials * need to interface with current BC scheme in CactusBase/Boundary * code repository is at: https://svn.einsteintoolkit.org/cactus/EinsteinEvolve/IllinoisGRMHD Yours, Roland

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New User, Questions
by sruehe＠astrophysik.uni-kiel.de 13 Jan '14

13 Jan '14

Hallo Einsteintoolkit-Community, i'm a phd-student in my first year at University zu Kiel, Germany. I've read many papers and saw the Toolkit for simulating relativistic hydrodynamics at black holes. First i have some important qustions and hope you can help me. Does the BSSN-algorithm regard the hydrodynamic mass as source function in the current timestep to calculate the hypersurface of the next timestep? Does this work via the TmunuBase? Is the self-gravitation of the hydrodynamics calculated by the perturbation of the spacetime? I hope you can help me, thank you very much. Stefan Ruehe

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PAPI on stampede/mic
by Roland Haas 12 Jan '14

12 Jan '14

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello Erik, all, it seems that PAPI 5.3 has options to compile for the mics. One only has to pass --with-mic to configure. Are you aware of incompatibilities of PAPI 5.3 or should it be fine to update the tarball in ExternalLibraries? (CC'd to users(a)einsteintoolkit.org) I can compile PAPI 5.3 on stampede and run the papi.par test in ExternalLibraries/PAPI and get Cache misses (but no timing, but lots of event-does-not exist warnings): INFO (PAPI): PAPI_register_clock INFO (PAPI): Running local single-threaded DGEMM benchmark with N=1000... INFO (PAPI): Floating point operations: 2 Gflop over 1 threads INFO (PAPI): Pure performance: 0.651531 Gflop/sec INFO (PAPI): Overall performance: 0.643122 Gflop/sec INFO (PAPI): Running local multi-threaded DGEMM benchmark with N=1000... INFO (PAPI): Floating point operations: 488 Gflop over 244 threads INFO (PAPI): Pure performance: 36.7471 Gflop/sec INFO (PAPI): Overall performance: 27.8211 Gflop/sec INFO (PAPI): NOTE: These performance numbers do not have to be large, but they need to agree with what PAPI reports INFO (PAPI): PAPI Statistics: CPU time 5042.929817665 sec CPU cycles 5520.440487605 Gcyc PAPI_TOT_CYC 0.324841654 cyc^(-1) PAPI_TOT_INS 0.027041240 cyc^(-1) PAPI_L1_ICA 0.033998239 cyc^(-1) PAPI_L1_ICM 0.000011858 cyc^(-1) PAPI_L1_DCA 0.011631986 cyc^(-1) PAPI_L1_DCM 0.000893145 cyc^(-1) PAPI_LD_INS 562.116089268 cyc^(-1) PAPI_SR_INS 0.001194933 cyc^(-1) INFO (PAPI): PAPI Statistics: CPU time 4.165410795 sec CPU cycles 4.559431145 Gcyc PAPI_TOT_CYC 393.906331451 cyc^(-1) PAPI_TOT_INS 32.842575465 cyc^(-1) PAPI_L1_ICA 41.205762993 cyc^(-1) PAPI_L1_ICM 0.014362943 cyc^(-1) PAPI_L1_DCA 14.119073876 cyc^(-1) PAPI_L1_DCM 1.093455247 cyc^(-1) PAPI_LD_INS 680595.542337835 cyc^(-1) PAPI_SR_INS 1.448845164 cyc^(-1) 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. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iEYEARECAAYFAlLTVN0ACgkQTiFSTN7SboWomACfURwvejhjIUlgpqaquQrIQSrG E9sAoJAwcpVKzYOvLxH8obmRRPLSPWKv =67bw -----END PGP SIGNATURE-----

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Einstein Toolkit Meeting Reminder
by Frank Loeffler 10 Jan '14

10 Jan '14

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Meeting Minutes
by Roland Haas 06 Jan '14

06 Jan '14

Present: Frank, Roland, Peter, Steve, Yosef, Zach, Philipp current release bugfixes: * Frank will create v1 tags * will update the release tarball * backported fixes are: #1499 #1504 * possibly backport for to 1512 GRHydro changes: * lots of changes since US Thanksgiving. Large parts of code ported to C++ from F90 (often by copying routines and translating the language). * new code uses template arguments for boolean/enum parameters inside of innermost loop * considerable speedup for ppm, hlle and prim2con routines * increases object size due to number of template instantiations * hidden behind parameter GRHydro::use_cxx_code * will propose to push into svn repository for testing/compiling * separate call by Roland and Frank and whoever is interested to review code * transition code to new C++ routines over the next couple releases. Usual procedure: add code in next release but do not make default, make default and deprecate old code in next to next release, move old code into archive after that * verify that published results can still be run with new code * further planned changes: reconstruct pressure instead of eps (seem to behave better when a contact discontinuity is present) EOS_Omni changes: * rewrite of nuclear EOS backend * much faster * internal changes, no externally visible change IllinoisGRMHD: * progress made checking for regressions, now agrees with previous Illinois code for 100 steps when using AMR and no symmetries * will be proposed for inclusion * Philipp and Zach to add edge centered prolongation operators for magnetic vector potentials * code review once code is deemed ready (requirements for inclusion: http://einsteintoolkit.org/documentation/contribute/) * code repository is at: https://svn.einsteintoolkit.org/cactus/EinsteinEvolve/IllinoisGRMHD Yours, Roland

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