In 2000, Lawrence Livermore National Laboratory researchers set out run a simulation and allow visualization and analysis, all on the same computer. No small feat.
“The simulations were producing data sets so large that they had to be run on massive parallel-processing supercomputers,” recalls Hank Childs, then a visualization researcher at the lab. Meanwhile, “the visualization and analysis work that followed was done on smaller, serially computing desktop machines,” but the data were exceeding the desktops’ capacity.
With support from the Department of Energy’s Advanced Simulation and Computing program, he and colleagues from Livermore and other institutions created VisIt. With its open-source code, VisIt eliminates the need to move data from one machine to others. Its client-server design still allows portability to the desktop when needed – for instance, when experts want to enhance visualizations by employing graphics cards like those in video games.
VisIt’s name is somewhat misleading because “it’s really for a lot more than visualization,” says Childs, the software’s chief architect. “It makes a lot of pretty pictures, but some people also use visualization to debug what’s going on in their software.” VisIt enlists several techniques that let users see what is in their datasets.
In 2006, DOE’s Visualization and Analytics Center for Enabling Technologies made VisIt the center of its strategy to deliver a production-capable visualization and analysis tool. Since then, universities and other national laboratories have taken up its continuing development and funding.
VisIt received a 2005 R&D 100 award from R&D Magazine. And in 2009, it was the first non-simulation code to be certified for scalability – the capacity to sustain performance levels as work demands and processor numbers increase – under an ASCR program for code improvement and scaling.
VisIt has been downloaded hundreds of thousands of times, Childs says – a separate measure of success.