VisIt TeamApril 24, 2012

VisIt Update, DOE CGF 2012

PySide GUI, H. KrishnanFTLE from tokamak, Childs, Krishnan, & Sugiyama (MIT)

Outline

Features released in the last year Projects impacted (partial list) Upcoming features Publications & Outreach

Outline

Features released in the last year Projects impacted (partial list) Upcoming features Publications & Outreach

Support for custom user interfaces written in Python via PySide.

PySide is a LGPL Python library that wraps Qt.

PySide is now distributed with VisIt and available from VisIt’s CLI.

Dynamically create and control Qt GUIs via Python.

Supports GUIs created with Qt’s Designer.

2D AMR based multi-resolution capability

Provide multi-resolution display of data from AMR meshes

Culling of data is at the patch level

Only data required for image is read

User specifies smallest cell size to display

Patches displayed are updated as the user pans and zooms the image

Un-zoomed viewcoarse patches

Highly zoomed viewvery fine patches

Example: 6 levels, 32819 patchesmesh refines as image zoomed

Level 5159

patches

Level 4140 patchesLevel 3

71 patches

Level 6121

patches

Multi-resolution demo

On Sequoia (and similar platforms) the available memory per core will constrain global data structures used for simulation restarts and graphics dumps.

Transition from global metadata to implicit, local, or distributed tree based data structures:

Support for Distributed Mesh Metadata

Current Global Constructs:• Multi-Domain Object Specification• Domain Boundary Information• AMR Nesting Hierarchies• Spatial Extents and Variable Extents

Particle Advection

Particle advection: displacing a massless particle tangent to the velocity field

System: Parallel Integral Curve System (PICS) See Hank’s talk on Thurs

Accomplishments: Continued work on hardening particle

advection infrastructure Including more robust pathlines and AMR

support Reverse pathlines Code sprint!

Particle Advection

Streamlines seeded by a separate plot, via VisIt’s

named selection mechanism.

Finite-Time Lyapunov Exponents (FTLE)

Visualize manifolds of maximal stretching in a flow, as indicated by dense particles

Finite-Time Lyapunov Exponent (FTLE)

Courtesy Garth

FTLE in VisIt

New FTLE operator available in V2.5

FTLE from tokamak, Childs, Krishnan, & Sugiyama

(MIT)

FTLE from ocean modeling, Ozgokmen (Univ. of Miami)

VTK 5.8 Upgrade

• VisIt updated to use new API• Faster renderer• Allowed some code to be removed

• Restored mangled Mesa support in VTK• Performance improvements in VTK’s renderer

• Don’t check GL state during render • 5x faster when displaying back from remote

computer• Fixed VTK text rendering bugs• Fixed VTK’s specular highlights with color

texturing• Need to migrate fixes back to VTK main

Enhanced Support for Windows

• Visual Studio 2010• Build programs without console• SSH tunneling through gateway computer• Parallel engine using MSMPI• Launch VisIt on Windows HPC clusters

• Allow parallel compute engine to launch in batch and start mdserver

Windows HPC

schedulermdserver

Compute engine

Local computer Remote computer

launch launch

Submit job

Outline

Features released in the last year Projects impacted (partial list) Upcoming features Publications & Outreach

Understanding laser beam interactions at the National Ignition Facility

The National Ignition Facility (NIF) is 3 football fields in size

192 lasers are focused on the target about a cm in size

The goal is to ignite the deuterium and tritium fuel in the target

The Nation Ignition Facility

A hohlraum

Simulated 2 beams to understand back scatter

Simulating 2 beams hitting the target to understand how much backscatter is present and if multiple beams impacts the results. Previous simulations could only simulate a single beam.

Simulation facts: Ran on 32k cores contained 220 billion zones

Visualization details: Interactively set up the movies Created the movies in batch Used either 1k or 2k cores 2 minutes to process a time state 5 hours to generate a movie

Effect of back scatter on input beams

Reduced input beam corresponds to high back scatter

Input beam Back scatter

Were able to demonstrate an oscillatory behavior where the back scatter intensity would increase, leading to a decrease in the input intensity, which lead to a decrease in the back scatter intensity, which lead to an increase in the input intensity, etc.

Outline

Features released in the last year Projects impacted (partial list) Upcoming features Publications & Outreach

Stream surfaces VRF OpenCL Staggered grids

Outline

Features released in the last year Projects impacted (partial list) Upcoming features Publications & Outreach

Publications D. Camp, C. Garth, H. Childs, D. Pugmire, and K. I. Joy. Streamline

Integration Using MPI-Hybrid Parallelism on a Large Multicore Architecture. IEEE Transactions on Visualization and Computer Graphics, 17:1702–1713, 2011

D. Camp, H. Childs, A. Chousaria, C. Garth, and K. I. Joy. Evaluating the Benefits of An Extended Memory Hierarchy for Parallel Streamline Algorithms. In Proceedings of the IEEE Symposium on Large Data Visualization and Analysis (LDAV), pages 57–64, October 2011

H. Childs, E. Brugger, B. Whitlock, J. Meredith, S. Ahern, K. Bonnell, M. Miller, G. H. Weber, C. Harrison, D. Pugmire, T. Fogal, C. Garth, A. Sanderson, E. W. Bethel, M. Durant, D. Camp, J. M. Favre, O. Ruebel, P. Navratil, M. Wheeler, P. Selby, and F. Vivodtzev. VisIt: An End-User Tool For Visualizing and Analyzing Very Large Data. In Proceedings of SciDAC 2011, July 2011

C. Harrison, H. Childs, and K. P. Gaither. Data-Parallel Mesh Connected Components Labeling and Analysis. In Proceedings of EuroGraphics Symposium on Parallel Graphics and Visualization, pages 131–140, April 2011

A.R. Sanderson, G. Chen, X. Tricoche, E. Cohen. “Understanding Quasi-Periodic Fieldlines and Their Topology in Toroidal Magnetic Fields,” In Proceedings of TopoInVis 2011, pp. (to appear). 2011.

B. Whitlock, J. Favre, J. Meredith, Parallel In Situ Coupling with a fully featured Visualization System. In Proceedings of EuroGraphics Symposium on Parallel Graphics and Visualization, pages 101-109, April 2011

Documentation and Training

• VisIt Tutorial:• ISC11, DOE ACTS, SciDAC, Boise State,

UCSC, HiPACC• Visualization with VisIt Class

• Materials updated• Materials created for 2nd day covering advanced

features• Taught at ARL in May 2011• Taught at LLNL in September 2011

• Python Interface Manual• Python doc strings updated & added for all

functions• Automatic generation from source code