Bulletin of the American Physical Society
APS April Meeting 2020
Volume 65, Number 2
Saturday–Tuesday, April 18–21, 2020; Washington D.C.
Session D15: Numerical Relativity: Algorithms and Code DevelopmentLive
|
Hide Abstracts |
Sponsoring Units: DGRAV DCOMP Chair: Carlos Lousto, Rochester Institute of Technology Room: Virginia B |
Saturday, April 18, 2020 3:30PM - 3:42PM Live |
D15.00001: Progress toward simulating merging black holes with SpECTRE Geoffrey Lovelace SpECTRE is a next-generation numerical relativity code that is currently in development by the Simulating eXtreme Spacetimes collaboration. By combining a Discontinuous Galerkin method with task-based paralleism, SpECTRE will take advantage of future exascale computing to model merging black holes and neutron stars with significantly improved accuracy compared to today’s state-of-the-art. While the benefits of SpECTRE’s approach are most pronounced for simulations involving matter, they also will enable new numerical-relativity models of merging black holes that are longer and more accurate, particularly in regions of the parameter space that are especially computationally demanding, such as high mass ratios. In this talk, I will present an update on SpECTRE’s current capabilities for simulating dynamical, vacuum spacetimes, and I will discuss progress toward the goal of enabling SpECTRE to simulate merging black holes. [Preview Abstract] |
Saturday, April 18, 2020 3:42PM - 3:54PM Live |
D15.00002: SpECTRE Cauchy Characteristic Evolution Jordan Moxon, Mark Scheel, Saul Teukolsky I present advances and early results from the Cauchy Characteristic Evolution (CCE) development in SpECTRE. We have developed a number of mathematical refinements of the CCE system that improves spectral convergence and eases the computation of detailed dynamical spacetime information at scri+. The result is an efficient code, free from logarithmic pathologies, that rapidly computes full waveform information: news, strain, and all five Weyl scalars. I summarize the performance improvements in the SpECTRE implementation, highlighting key numerical techniques, and describe the battery of physical tests used to verify the precision of our CCE results. [Preview Abstract] |
Saturday, April 18, 2020 3:54PM - 4:06PM Live |
D15.00003: Computing the Electric Part of the Weyl Curvature Tensor with SpECTRE Sierra Thomas, Geoffrey Lovelace Extracting as much science as possible from the high signal-to-noise gravitational waves that next-generation detectors will observe requires model gravitational waveforms with substantially higher accuracy. In pursuit of this goal, the SXS Collaboration is developing a next-generation numerical-relativity code called SpECTRE. By using the Discontinuous Galerkin method to numerically solve differential equations and task-based parallelism, SpECTRE will be able to efficiently take advantage of future exascale computing (i.e., its performance will scale to tens of thousands of computer processors) to achieve much greater speed and accuracy. In this talk, I will discuss calculating the electric part of the Weyl curvature tensor using SpECTRE. The electric part of the Weyl tensor characterizes tidal deformations of an observer caused by spacetime curvature and is one ingredient for computing the emitted gravitational waves. I will present results computing the Weyl tensor for a SpECTRE simulation of a perturbed black hole, including a discussion of accuracy and performance. [Preview Abstract] |
Saturday, April 18, 2020 4:06PM - 4:18PM Live |
D15.00004: Numerical relativity with the new Nmesh code Wolfgang Tichy, Ananya Adhikari, Liwei Ji We introduce the new open-source Nmesh code, which is intended to efficiently run on large supercomputers to solve challenging relativistic astrophysics problems such as binary neutron star mergers. The aim of Nmesh is to achieve more accurate solutions by using a discontinuous Galerkin method. We explain the basic computational and parallelization methods we use. We also present first results for test problems such as shock tube tests, and simulations with single neutron stars and black holes. [Preview Abstract] |
Saturday, April 18, 2020 4:18PM - 4:30PM Live |
D15.00005: Shock-capturing discontinuous Galerkin schemes in SpECTRE Francois Hebert We present an update on limiters — shock-capturing schemes for discontinuous Galerkin — in the SpECTRE code (https://github.com/sxs-collaboration/spectre). In general, a limiter provides a prescription for correcting the unphysical solutions that can arise when the high-order discontinuous Galerkin solution becomes oscillatory near shocks. The development of limiters for discontinuous Galerkin methods is ongoing, with recent efforts from the community pushing to increase their robustness and accuracy. We implement different limiters, from simple slope limiters to more recent, higher-order WENO-based limiters. We compare their performance on standard shock problems and single-star evolutions. [Preview Abstract] |
Saturday, April 18, 2020 4:30PM - 4:42PM Live |
D15.00006: BlackHoles@Home Status Report Zach Etienne BlackHoles@Home fits numerical-relativity-based black hole binary calculations on a consumer-grade desktop computer, enabling gravitational waveform catalogs and follow-ups at unprecedentedly large scales on volunteer computers. It owes its efficiency to a new reference-metric formulation of BSSN in bispherical coordinates. While the original approach (reported last year) was extremely efficient in memory usage, the high gridpoint density near coordinate foci (and correspondingly tiny CFL-limited timestep) made the approach impractically slow by about a factor of 10. We report on improvements to the underlying infrastructure (NRPy+) and advances in our techniques that both maintain the memory efficiency and increase the performance by well over an order of magnitude, enabling BlackHoles@Home to be launched worldwide in the very near future. [Preview Abstract] |
Saturday, April 18, 2020 4:42PM - 4:54PM Not Participating |
D15.00007: Toward moving puncture simulations with the GHG system Liwei Ji, Ananya Adhikari, Wolfgang Tichy We present a new conformal rescaling of the GHG system. With this rescaling it should be possible to evolve black holes without excising the black hole interior, by using a puncture method similar to the one used for standard moving puncture simulations with the BSSNOK system. The rescaled system is first order in both time and space, and thus amenable for use with a discontinuous Galerkin method. We present first results for single black hole evolutions using the Nmesh code. [Preview Abstract] |
Saturday, April 18, 2020 4:54PM - 5:06PM Not Participating |
D15.00008: Discontinuous Galerkin Methods for Turbulent Flow Simulations Cristobal Armaza Turbulence is thought to be a fundamental ingredient in the mechanism that governs core-collapse supernovae explosions as well as other astrophysical phenomena. Previous work has shown that for core collapse, finite-difference methods need unattainable resolutions to satisfactorily resolve the small-scale features and correctly capture the physics. We investigate whether the high resolution achievable in principle with discontinuous Galerkin (DG) methods can deal with this problem. We present results from the new SpECTRE DG code for the model turbulence problem previously studied with finite-difference methods. [Preview Abstract] |
Saturday, April 18, 2020 5:06PM - 5:18PM Not Participating |
D15.00009: Visualizing relativistic astrophysics simulations using YT Denyz Melchor, Saul Teukolsky, Nils Deppe Visualizations of numerical-relativity simulations are important both for helping scientists gain insight into numerical results and for helping to share the excitement of gravitational-wave science with the public. In this talk, I present results using new tools to visualize simulations from the Simulating eXtreme Spacetimes (SXS) Collaboration. Specifically, I updated and extended an existing python code, using the YT Project package, for visualizing gravitational waves from simulations of merging black holes. A major contribution was made to generalize the code to support visualizing both gravitational waves at a specific radius away from the binary and gravitational waves after they have been extrapolated to infinity. I also present results for a new YT-based tool to visualize simulations with matter in them, such as binary neutron stars, binary neutron star-black hole, and accretion disk simulations. SXS simulations output data as a collection of hexahedral elements, but these need to be reinterpreted as a collection of tetrahedral elements for YT to visualize them. I present results from an algorithm that I developed and implemented to perform this reinterpretation. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700