Sequoia, currently the world's most powerful supercomputer, was built for upkeep of nuclear weaponry. But researchers have put it to work on a groundbreaking simulation of something a bit more salutary: the human heart.
Lawrence Livermore National Laboratory, already well-known for work in high-performance computing, has commandeered the Sequoia supercomputer during what is known as its "shakedown period," when it's being set up and tested but isn't quite ready to for its intended purpose. LLNL and other organizations were given time-share access to the computer to do approved non-classified research.
Supercomputing is a competitive field, but for the moment Sequoia is the fastest on Earth: with more than 1.5 million computing cores producing 20 quintillion operations per second, it allows the researchers to simulate the heart at a far greater fidelity than ever before.
LLNL computational scientist Art Mirin describes the project: "Our heart code work has been a great opportunity to demonstrate Sequoia’s power with an application that most people consider important to society, in this case, cardiac modeling." So it's not just about digitizing the heart, but also about humanizing the computer.
The simulations divide the heart into thousands of little digital pieces, each composed of mathematical models that take input from and send data to other pieces. Their interactions require an enormous amount of calculations, even though the model only simulates electrical activity, not physical.
The best that could be done before was to simulate pieces about 0.2mm across, and it could take 45 minutes or so to simulate a single beat. With new software called Cardioid running on the Sequoia supercomputer, not only can they simulate more accurately (the pieces are 0.1mm across, about the size of an actual heart cell), but also hundreds of times faster: now a virtual heartbeat only takes 10 seconds to create.
This huge increase in performance makes many things practical: virtually testing arrhythmia drugs, for instance, or establishing baseline patterns against which real hearts can be compared. And since heart disease is such a major health risk, especially in the U.S., an accurate electromechanical model of the heart is essential for future research in many other fields.
LLNL researcher David Richards described the potential benefits to Popular Mechanics:
At a very coarse level of resolution, everyone’s heart looks the same. The details that differentiate individual hearts can be very fine, and our ability to model at extraordinarily high resolution, currently a factor of eight greater than previously, that allows us to capture very fine differences.
The time at Sequoia is running out, and the supercomputer will be running programs for the Stockpile Stewardship program, intended to ensure the country's nuclear warheads remain "safe, secure, and reliable well into the future." The researchers will have to fall back on less-powerful machines — still far faster than even the fastest desktop, but not quite world-class — to continue their research. But the powerful Cardioid simulation code will still allow for faster and more accurate simulation than before.
Further developments in the heart-simulation department at LLNL, as well as other applications of supercomputing power, should appear in their internal Science & Technology publication.
Devin Coldewey is a contributing writer for NBC News Digital. His personal website is coldewey.cc.
