SC07: day 2 recap

Well, for day 2 had very little in the way of looking at demos. It was a day of meetings. That and a BOF. Ok, I did get to see the D-Wave systems stuff and ask some questions. It is not precisely what I thought it was. In short, they map problems onto an Ising model, and then cool the chip. The mapping onto the Ising model may be understood in terms of constraints on the “spin” state of the model. Their software handles the conversion of constraints into Hamiltonians. I know some programmers can handle FPGAs using VHDL. Not sure how many can handle writing a potential function. D-Wave will handle that for you using a modified SQL statement. It is quite clever.

I sat in on the Cell BOF and listened to most of the presentations before running out to dinner with some friends and colleagues.
Cell is an interesting beast. You likely have heard of it by now. It is a quintessential accelerator system. Huge amounts of computing power, and some tiny internal components (scratch rams) that you have to manage. Coding is not a straight port of your C/Fortran code (yes, some people in the world still use Fortran, I suspect it will still be compliing/working long after I retire).
This said, the presentations were often “we ported this over” or “we are building this machine” (an IBM person gave an account of RoadRunner). One person, Vipin Sachadeva (probably mis-spelled his name) gave an analysis of how a particular workload mapped onto the processor. It was quite interesting. Jack Dongara gave a talk on iterative refinement for using lower precision calculations to seed correctors for higher precision. Which will work well in specific cases. He had just come from judging the cluster challenge, so he was wearing a baseball cap with a blue led pattern doing some blinking.
All the talks were 5 minutes in length.
Ran out to dinner with a former colleague, a current colleague, and some other people the former colleague works with. Started down the memory lane … SGI and Cray. Lots of head shaking, disbelief, who was where and doing what these days.
Today is truncated. We have to leave for the airport by noon. I will look again for demos, and I have a few meetings.
If you are there and see a guy with a JackRabbit shirt (black with a yellow/white logo), please say “hi”. And yes, shirts are available to those who buy these units.