Workshop on Interoperability of DOE Visualization Centers
Institution Report
Sandia National Laboratories
Constantine "Dino" Pavlakos
a. High-level directions and priorities
Programs which are contributing to visualization efforts at Sandia include
ASCI, Defense Programs, MICS, PRE (Product Realization Environment),
DISCOM2, and internal core computing. In the last couple of years,
ASCI has become increasingly prominent. The MICS work, however, continues
to play a vital role -- it provides for more fundamental research, that
has enabled development of technology which we are now leveraging for
other programs, such as ASCI.
Certain themes which are central to our visualization activities include:
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Large Data
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Distributed Computing/Visualization
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Human Computer Interfaces
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Interactivity
b. Broad views on future research activities for the next two years
Large Data Visualization -- The problem of visualizing very large data
continues to be an important area of research. This is because
conventional and/or commercial tools are generally inadequate for
handling of very large data, necessitating development of special
capabilities to address the unusual requirements of our very large-scale
scientific computations. Methods which we are investigating and/or
expect to incorporate to enable handling of large data include:
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Parallel Visualization Methods
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New Algorithms
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Hierarchical Data Management
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Data Simplification
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Out-of-core approaches
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Runtime Visualization (i.e. produce images as the result of
the simulation, or "computational experiment", instead of
traditional result databases)
Among recent successes, we have demonstrated the use of our
parallel visualization methods to volume render a one billion cell
data set at pseudo-interactive rates.
Distributed Computing/Visualization -- Sandia has a couple of key
projects in this area:
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"C-Plant" refers to a project which is exploring the construction
of next-generation, scalable, high-performance computers (and visualization
architectures) using "COTS" (Component-Off-The-Shelf) technologies,
such as PCs, high-speed interconnects, and low-cost graphics cards.
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"Distance Insensitive Visualization" -- This is an objective, more
than it is a single project. Sandia is investigating a variety of
approaches towards delivering a consistent level of performance for
visualization, independent of the distance between the large computational
infrastructure and any remote display. Among others, we will investigate
the use of image-based technologies (e.g. image-based rendering,
image distribution schemes, etc.). This objective carries special
significance for Sandia as a national laboratory, since Sandia has
geographically disparate sites in New Mexico and California.
Human Computer Interfaces -- We expect to continue building on
successful work already done at Sandia. In particular, work in this
area has resulted in the spin-off of MUSE Technologies, collaborations
with the High Performance Computing Center at Stuttgart (Germany), and
a new system which incorporates a haptic device for user interface
control as well as data interaction. Areas of continuing research
will include:
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Virtual Environments
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Collaborative environments
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Haptics
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Sonification
Interactivity -- This is a performance objective which transcends
our visualization activities. An implicit, if not explicit, goal
of all our efforts is to provide maximal interactivity, to enable
exploration, versus passive observation.
Information Visualization -- Some initial work in this area has
resulted in a prototype tool for discovering relationships in large
databases. Development of this tool will continue. This is an
emerging area which could result in other research opportunities.
Measurements to Insight -- This phrase describes work whose nature
is to extract geometric models from real world data (e.g. images,
medical scans, etc.) which are then processed somehow using
big computing to ultimately provide insight. An interesting
application of these techniques was used recently to try to recreate
the sound a
dinosaur may have once made.
c. Barriers or obstacles
One important challenge for those of us who are developing state-of-the-art
visualization tools is the delivery of those tools into real user
environments, for production use. This is an ongoing, day-to-day
struggle. At the laboratories, we are constantly being pushed by
somewhat opposite forces, one that demands attention to day-to-day
short term needs of application environments, while another demands
that we continue to demonstrate quality-and-quantity research. Our
research dollars are particularly scarce, so it is difficult to
justify use of research dollars/time to "productize" our research
tools. Programs like ASCI have helped alleviate this problem by providing both
funding and the demand for productization of many of our MICS-developed
tools. However, ASCI aside, it is important to note that
productization of research tools requires significant resources which
can detract from research efforts when resources are limited,
which they are. This issue is equally relevant to interoperability.
An issue which we face with regard to the parallel visualization tools
we are developing (which we believe are critical to solving some of our
large data visualization problems) relates to portability across the
range of MP/distributed architectures we are faced with. Certainly,
MPI has helped a great deal. However, today's massively parallel
computing systems present a variety of architectural diversities, as
well as system-software, storage, and networking inconsistencies, which
still present significant challenges for portable parallel tools,
particularly of an interactive nature.
A related issue is that of integrating separate parallel computing
software components to construct larger applications. Again, functional
constraints on certain MP systems make this difficult. If integration
can sometimes be difficult, general interoperability of parallel
software components is even more complex.
ASCI presents one of our most difficult challenges for
visualization as well as other tools. ASCI applications will require
an extremely high level of confidence in results. This, in turn, demands
an unprecedented level of confidence in the underlying tools.
d. Visualization Tools
Commercial(ASCI common tools):
In-House:
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MUSTAFA(AVS/Express-based) -- a finite-element visualization tool
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EIGEN/VR --
a synthetic environments tool
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FLIGHT -- a prototype system for data exploration which integrates a
SensAble Technologies PHANToM for haptic feedback
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PVR --
a Parallel Volume Rendering system
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Parallel Marching-cubes /
Decimation
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PMesa -- a sort-last, parallel implementation of the OpenGL-like
3D graphics library (under construction)
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VxInsight --
a tool for discovering relationships in large databases
Other:
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COVISE --
"COllaborative VIsualization and Simulation Environment"
Data Interfaces:
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Exodus II -- an API for writing/reading unstructured grid data
used by finite-element applications
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Viz files -- an API and underlying format developed for structured-grid,
shock-physics applications (specifically CTH/PCTH)
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ASCI CDF -- an emerging "Common Data Format"
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PDS (Parallel Data Set) -- a prototype, high-performance, data interface
which includes parallel i/o