VISUALIZATION:
New Ways to Understand the Data

The Visualization Laboratory and the Science Visualization Facility at CCS enable researchers to understand and convey the significance of a supercomputer's calculation results.

Atoms are so close and stars are so far away. In both cases, we cannot really "see" how they behave when various forces act on them. Fortunately, technologies exist to transform supercomputers into microscopes and telescopes that possess ultrahigh resolution. Using experimental data, scientists can make calculations on supercomputers to predict how atoms and stars change under different conditions.

Graphical representation of a molecular orbital of the benzene dimer with the underlying adaptive computational mesh.

Thanks to techniques for visualizing data, suddenly "pictures" worth a thousand gigabytes can be produced. Scientists can "see" in vivid colors images of an alloy's electrons pointing in different directions— like a compass needle—as a metallic alloy's magnetic field shifts because of changes in alloy composition. They can "observe" explosions in a star as it synthesizes and disperses elements that make life possible on our planet. These images give researchers insights into scientific processes and phenomena.

Computational science generates, processes and interprets nearly unfathomable quantities of data from scientific simulations of, for example, galactic supernovae, proteins, nanostructures, and fusion energy devices. Because researchers have vast amounts of data to be analyzed, they often prefer to examine data in a compact form that is accurate, reliable, and readily understandable. Viewing the results as pictures is immensely more efficient. This is where the science of visualization demonstrates its value, and why visualization must keep pace with advances in scientific computing.

Visualization is a discipline that develops computer graphics, interaction devices, three-dimensional (3D) imaging, and realistic rendering techniques. The tools use simulation data as input and create a scientifically accurate representation.

The Visualization Laboratory and the Science Visualization Facility in the Department of Energy's Center for Computational Sciences (CCS) at ORNL offer Laboratory and visiting researchers the ability to visually analyze and compare results of computer simulations. The ability to see an image of the results may reveal intricacies and flaws otherwise concealed in a haystack of data.

For example, in an image produced computationally from huge amounts of data, researchers can see up close the dimensions and structure of an engineered molecule. They can observe pulses of currents and winds in a simulated weather event or climate map. They can also witness the events leading to a supernova explosion and understand how it may create chemical elements.

At CCS researchers working with high-performance computers and increasing volumes of data will be able to view quickly the results of their work in a lab, office or conference room setting. With virtual-lab capabilities, these collaborations can involve researchers in the same room or in offices throughout the world. Researchers can compare their latest work with previous data through applications that are intuitively designed and customized to the user.

The Science Visualization Facility of CCS is a large-scale, immersive venue for data exploration and analysis. The new research tool is a 30-ft wide by 8-ft high display comparable in size to 150 standard computer displays with a resolution of more than 11,000 by 3,000 pixels, creating a total space of 35 million pixels. The immersive qualities of this environment create a powerful discovery tool for research groups and collaborations. The Science Visualization Facility provides a premier data analysis and visualization capability and facility in DOE's Office of Science.

The Visualization Laboratory houses display venues of different sizes and capabilities. The reCAVE offers a seamless integration of multiple projections into a large, reconfigurable, and inexpensive virtual environment. Because screens are mounted on movable frames with their respective projectors and mirrors, scientific images can be projected and viewed in different geometries, from a long wall, to "L"-shapes, boxes, or other shapes that best present the data.

An array of liquid-crystal display, flat-screen monitors, currently 6 tiles in a 3 x 2 grid, can fit in an office—either hung from the ceiling or on a wall. This portable array can display 12 megapixels of information. Another display, the IBM T221 monitor, can display images in photographic resolution of 9 megapixels, much higher than high-definition television, which has a 2-megapixel capability.

The visualization facilities are integrated with CCS through a high-band-width network between large-scale, high-performance computers and large-scale data visualization computers and displays. Images displayed on each venue are rendered using a group of commodity PCs with high-end graphics capabilities—a low-cost, high-performance Beowulf-type visualization cluster. Workload is distributed among the PCs in a parallel fashion for high-performance and real-time interactions.

Viewing Changes in Climate, Stars, and Materials

The Science Visualization Facility is used to investigate the intricacies of global climate change simulations. Through projected climate simulations portrayed as maps of the globe, color-coding helps deliver an understanding of parameters such as surface temperature and carbon dioxide concentrations. Such simulations may involve hundreds of parameters. Because of highly interconnected and complex interrelationships among variables, subtle changes in one variable can have significant long-term effects. Large, tiled displays provide an ideal environment for observing such sensitivities between multiple simulations and variables and can be experienced by as many as 20 participants.

Researchers can examine virtual stellar explosions—complex hydrodynamics from near the stellar core to the turbulent shock front. As the models are refined, scientists can observe parameters such as temperature, density, and velocity in the supernovae simulations and compare results from both theoretical and observational data. Eventually, it may be possible to understand how the elements that make life possible are synthesized and dispersed by such explosions.

Materials science research is conducted at the atomic level as researchers build and study the dynamics of custom engineered materials. ORNL's visualization facilities offer scientists the ability to zoom in to the atomistic scale and observe spin dynamics and vibrational modes or zoom back out to determine bulk material properties, say, in a magnetic alloy whose composition is being changed. Visualization venues such as those in the Science Visualization Lab enable researchers to learn what works, as well as what fails—filling in the missing pieces of scientific understanding.

Visual Mural for Visitors

In addition to providing researchers with an indispensable visual tool for comprehending and communicating their research, ORNL's visualization facilities have repeatedly proven their effectiveness at communicating and demonstrating the value of ORNL research to the public. Collectively, the facilities comprise a visual mural for Laboratory visitors ranging from the nation's highest elected officials to local school groups. The Science Visualization Facility was a highlight of the recent Laboratory tour by science writers attending the New Horizons in Science Briefing sponsored by the Council for the Advancement of Science Writing.

Scientific visualization is a rapidly moving discipline as research and technology evolves. As computers advance in power and speed and scientific models become more complex, the art and science of visualization and its underlying analytical process must advance in step. As scientific computing closes in on its 100-teraflop goal, visualization researchers will be pressed to keep pace with the progress. But the resulting discoveries from images on the screen and the understanding they provide will be worth the investment.

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