Reddit 'Ask Me Anything' recap: Mike Papka

Mike Papka is the Director of the Argonne Leadership Computing Facility. On Aug. 12, 2013, he took time off from running the facility that houses the fifth-fastest supercomputer in the world, Mira, to chat with Redditors about everything from grand discoveries to basic multiplication.


  1. Ever wonder what a super smart supercomputer scientist looks like? Just another reason why the "proof shot" is one of the best parts of an "AMA":
  2. Mike Papka - Reddit "Ask Me Anything"
    Mike Papka - Reddit "Ask Me Anything"
  3. Minutes after the chat opened, questions started streaming in from curious Redditors. One of the early questions dealt with high-performance computing (HPC) and how it is applied:
  4. I know you guys aren't a weapons lab, so what other kinds of things do you need a supercomputer for in science? What are the fields that benefit most?
  5. Many disciplines require HPC to make progress and virtually any process or problem can be advanced with HPC. Ongoing investigations range from the basic to the applied - everything from understanding water to designing better jet engines. Anyone from the science or engineering community whose research requires HPC can apply for time on DOE leadership computing machines.
  6. 'Turbulent Mixing Noise from Jet Exhaust Nozzle'
    'Turbulent Mixing Noise from Jet Exhaust Nozzle'
  7. Researchers used supercomputers at Argonne to study the complex mixing noises that jet exhaust nozzles produce. This research will help develop the next generation of "green," low-noise jet engines. 
  8. It didn't take long for Mira to enter the conversation:
  9. Can you give a brief overview of the large scale computing systems that Argonne has in place? I know for a time it was the fastest in the world, but I don't know if this is still true.
  10. Answer to Q1: Argonne's current largest machine is Mira ( " class=""> ). Its theoretical peak performance is 10 petaflops. It has 768,000 compute cores and 768 terabytes of memory, all housed within 48 computing racks that weigh 2 tons each. It's water cooled. To give you an idea of Mira’s computational power, it is capable of carrying out 10 quadrillion calculations per second. It debuted as third-fastest in the world in 2012. Our current position is fifth-fastest in the world.
  11. Mira: Argonne's 10-petaflop supercomputer
  12. After Mike provided a few details on the mind-boggling capabilities of Mira, another chat participant - with a good sense of humor - decided to put the machine to the test:
  13. Can your computer work out what 9999999999999999999999999999 x 999999999999999999999999999 is?
  14. Mike politely vouched for Mira's ability to handle the problem:
  15. I'm pretty sure it can. :)
  16. Just for good measure, shortly after, Mike used his MacBook Pro - a slightly less powerful machine - to find the answer...
  17. Obviously, a multiplication problem is not how supercomputers are measured. The true measure of the impact these engineering marvels make is the discoveries to which they contribute:
  18. Hi Mike, thanks for doing this. What are some of the most important discoveries that have come as a result of supercomputing at Argonne recently?
  19. Mike said that while computational research is ongoing, projects examining concrete and the dark universe have produced exciting results:
  20. High-Fidelity Simulation of Complex Suspension Flow for Practical Rheometry
    High-Fidelity Simulation of Complex Suspension Flow for Practical Rheometry
  21. Concrete is a complex material, comprised of a suspension of rocks and sand embedded in cement paste. It is actually a fluid that changes its properties over time. Researchers used HPC to learn more about this complex material in order to make concrete a more sustainable material by finding new ways to recycle it, and by changing its ingredients in order to reduce the amount of greenhouse gas resulting from its production.
  22. Supercomputing Sheds Light on the Dark Universe