Visualization Support at RZG

Transcription

1 Visualization Support at RZG Markus Rampp (RZG) MPA Computer Seminar, Jan 14, 2009

2 Outline Topics Overview Existing services Some example projects Software overview & demo Remote visualization Conclusion Discussion, feedback

3 Overview Context: Visualization support for the MPG & IPP activity recently inspired/resurrected/approved by RZG steering committee main targets: interactive, remote data exploration & analysis, presentation,... large datasets (i.e. exhausting the memory of typical desktop computers) variety of simulation codes, non-standardized, heterogeneous data formats, scientific contexts,... currently 2 dedicated positions (R. Bruckschen, ) General strategies/goals: provide: software and hardware infrastructure guidance for selection, adoption and usage of general-purpose tools support for adaptation and instrumentation of simulation codes dedicated support for individual visualization projects

4 Existing services Software & Documentation /afs/rzg/common/soft/visualization/ VisIt/silo, ParaView, VisIVO,..., idl, (Amira/Avizo),... Hardware graphics workstation: kandinsky.ipp.mpg.de (parallel) rendering: interactive Power6 node(s), Linux clusters,... procurement of specialized/dedicated visualization hardware ( graphics cluster ) is in progress (see below) Support visualization@rzg.mpg.de cf. several completed and ongoing projects: 3 examples with different levels of support

5 Thermonuclear Supernova Explosion Simulation by F. Röpke & W. Hillebrandt (MPA) Astrophysical scenario: thermonuclear deflagration of a white dwarf star simulation code: SUCCESs finite-volume hydrodynamics (high-order Godunov) level-set method for thermonuclear burning fronts Visualization approach (cf. Röpke & Bruckschen, NJP 10, 2008) Combined volume rendering of the complete time-dependent dataset: stellar structure (scalar density field on the moving, rectilinear grid) deflagration front (level set renderend as a semi-transparent cloud of points) out-of-core rendering hybrid display (point based/volume rendering) interactive preview, movie mode with high fidelity transparency

6 Core-collapse Supernova Simulations by A. Marek & H.-Th. Janka (MPA) simulation code: VERTEX (neutrino) radiation hydrodynamics in 2D output data: binary, many different quantities, nonequidistant in time conversion to silo format Visualization approach (with VisIt) use-case for VisIt (open source tool developed by LLNL) data: e.g zones on non-uniform, polar grid interactive data exploration, analysis and presentation remote rendering and data access (RZGs Power6 system) movie rendering

7 MHD Turbulence Simulation by W.C. Müller (IPP) fundamental research for fusion devices dataset: rectilinear (cartesian) grid remote visualization and interactive data exploration (S.K. Malapaka, IPP): volume rendering, isosurfaces,... Visualization approach (with VisIt): grid exhausts Amira/Avizo s capabilities migration to VisIt parallel, high quality ray casting on 32 Power6 cores no data conversion necessary for simple binary output, brick of values (metadata) TIME: 0.9 DATA_FILE: /u/xyz/frame.000.t DATA_SIZE: # Allowable values for DATA_FORMAT are: BYTE, INT, FLOAT, DOUBLE DATA_FORMAT: FLOAT VARIABLE: x DATA_ENDIAN: LITTLE CENTERING: zonal...

8 Software overview: tools for massive, multidim. datasets VisIt (LLNL, + free, open source, extensible, documented, active development + parallel rendering & remote data access + comprehensive functionality: plots, operators, expressions, animation, scripting - not completely matured - particle data less well supported (e.g. SPH) ParaView (Kitware/VTK, + free, open source + parallel rendering & remote data access + comprehensive functionality: plots, filters, animation, scripting + support for particle data in progress (see PV-meshless ) - documentation partly commercial to be investigated: Vapor, Amira/Avizo (for massive datasets),...

9 The VisIt visualization tool VisIt installation at RZG installed versions: 1.10, 1.11 (soon) platforms: amd64 sles9 (Linux x64, 64 bit) i386 sles9 (Linux, 32 bit) ia64 altix (GUI, compute engine) rs aix53 (compute engine only) installation directory: /afs/rzg/common/soft/visualization/visit/ extension: database plugin for reading GADGET output (adopted by release 1.11) silo library (C, FORTRAN): /afs/rzg/common/soft/visualisation/silo/

10 VisIt demo Basic functionalities interactive plots: Pseudocolor, Line, Volume operators: Transform (coordinate), Clip, Box, Revolve expressions: simple expression language animation: simple movie sessions: save/restore session remote data access and rendering (requires VPN): Compute engine not covered here: quantitative analysis, data conversion,... Hints remember the select open dialog for remote data access documentation: /afs/rzg/common/soft/visualization/visit/doc Getting started Getting data into VisIt User s manual

11 Remote Visualization basics The problem of (interactive) visualization how to access non-local data and/or compute resources? traditional X over ssh approach: transfer of 3D data to local X-server! Solution: server-side 3D rendering i.e. reduction 3D 2D on the server transfer only (compressed) 2D images and user interaction (mouse, etc.) basic idea: library captures OpenGL/GLX calls on the server (for in-depth background, see + additional features: collaborative visualization,... generic implementation/products (examples): Sun shared visualization software (free, OpenSource) HP Remote Graphics (commercial) SGI Remote Vue, Power Vue (very new, partly commercial) built-in remote capabilities: VisIt, ParaView,...

12 Remote Visualization Illustrative example: Sun shared visualization software (VirtualGL, TurboVNC) Two basic modes: (illustrations: L. Scheck, by courtesy of LRZ) a) VGL Image Transport (direct mode): recommended mode in high bandwidth/low latency networks without significant firewall barriers requires an X-server running on the client PC requires installation of VirtualGL on the client PC b) X11 Image Transport (raw mode): recommended mode in low bandwidth/high latency networks recommended mode for Windows clients does not require an X-server running on the client PC requires installation of TurboVNC on the client PC

13 Conclusion & Outlook Towards persistent visualization support at RZG hardware procurement: graphics cluster with main components: a number of compute nodes with graphics cards for interactive remote visualization (multiple sessions, multiple nodes per session) possibly some large SMP -node/frontend cluster filesystem (?) GPFS mount/federation (?) relevant vendors: Sun, HP, (SGI) software: analysis tools (VisIt, ParaView, Avizo,... ), remote visualization consulting: strategies for selecting data formats, I/O,... documentation: Visualisation... looking forward to help visualizing your data...