Recent Advances in VisIt: AMR Streamlines and Query-Driven Visualization

NUMERICAL MODELING OF SPACE PLASMA FLOWS// ASTRONUM-2009 Proceedings of the 4th International Conference ASP Conference Series, Vol. 407, 2010 *NAMES OF EDITORS** Recent Advances in VisIt: AMR Streamlines and Query-driven Visualization G. H. Weber, 1,2 S. Ahern, 3 E. W. Bethel, 1 S. Borovikov, 4 H. R. Childs, 1,2 E. Deines, 2 C. Garth, 2 H. Hagen, 5,2 B. Hamann, 2,1 K. I. Joy, 2,1 D. Martin, 1 J. Meredith, 3 Prabhat, 1 D. Pugmire, 3 O. R¨ bel, 1,2,5 B. Van Straalen, 1 and K. Wu 1 u 1 Computational Research Division, Lawrence Berkeley National Laboratory, One Cyclotron Road, Berkeley, CA 94720, USA 2 Institute for Data Analysis and Visualization, Department of Computer Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA 3 Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6016, USA 4 Center for Space Plasma and Aeronomic Research, The University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 5 International Research Training Group 1131, Technische Universit¨ t a Kaiserslautern, Erwin-Schro¨ dinger Strase, D-67653 Kaiserslautern, o Germany Abstract. Adaptive Mesh Refinement (AMR) is a highly effective method for simulations spanning a large range of spatiotemporal scales such as those en- countered in astrophysical simulations. Combining research in novel AMR visu- alization algorithms and basic infrastructure work, the Department of Energy’s (DOEs) Science Discovery through Advanced Computing (SciDAC) Visualiza- tion and Analytics Center for Enabling Technologies (VACET) has extended VisIt, an open source visualization tool that can handle AMR data without converting it to alternate representations. This paper focuses on two recent advances in the development of VisIt. First, we have developed streamline com- putation methods that properly handle multi-domain data sets and utilize ef- fectively multiple processors on parallel machines. Furthermore, we are working on streamline calculation methods that consider an AMR hierarchy and detect transitions from a lower resolution patch into a finer patch and improve inter- polation at level boundaries. Second, we focus on visualization of large-scale particle data sets. By integrating the DOE Scientific Data Management (SDM) Center’s FastBit indexing technology into VisIt, we are able to reduce parti- cle counts effectively by thresholding and by loading only those particles from disk that satisfy the thresholding criteria. Furthermore, using FastBit it be- comes possible to compute parallel coordinate views efficiently, thus facilitating interactive data exploration of massive particle data sets. Introduction Adaptive Mesh Refinement (AMR) (Berger & Colella 1989) plays an increasingly important role in astrophysical simulations. In general, AMR techniques have