Tag Archives: ramsey numbers

Dust to dust – Science for Science

No, this is not an obituary for D-Wave.

But the reporting of the latest news connected to D-Wave just doesn’t sit well with me.

Ever tried to strike up a conversation about Ramsey numbers around the water cooler, or just before a business meeting started? No? I wouldn’t think so.

I don’t mean to denigrate the scientific feat of calculating Ramsey numbers on D-Wave’s machine, but the way this news is reported, is entirely science for science’s sake.

It puts D-Wave squarely into the ghetto of specialized scientific computation. Although, I am convinced that quantum computing will be fantastic for science, and having a physics background I am quite excited about this, I nevertheless strongly believe that this is not a big enough market for D-Wave.

It is one thing to point to the calculation of numbers that less than one out of ten CIOs will ever have heard of. It is another matter entirely not to milk this achievement for every drop of marketing value.

In all the news articles I perused, it is simply stated that calculating Ramsey numbers is notoriously difficult. What this exactly means is left to the reader’s imagination.

If your goal is to establish that you are making an entirely new type of super-computer then you need an actual comparison or benchmark. From Wikipedia we can learn the formula for how many graphs have to be searched to determine a Ramsey number.

For R(8,2) D-Wave’s machine required 270 milliseconds. This comes to more than 68,719 million search operations. For a conventional computer one graph search will take multiple operations – depending on the size of the graph. (The largest graph will be 8 nodes requiring about 1277 operations).  Assuming the graph complexity grows with O(2n) I estimate about 800 operations on average.

Putting this together – assuming I calculated this correctly – the D-Wave machine performs at the equivalent of about 55 million MIPS.   For comparison: This is more than what a cluster of 300 Intel i7 Hex core CPUs could deliver.

Certainly some serious computational clout. But why do I have to waste my spare time puzzling this out?  At the time of writing I cannot find a press release about this on the company’s web site. Why? This needs to be translated into something that your average CIO can comprehend and then shouted from the rooftops.

D-Wave used to be good at performing marketing stunts and the company was harshly criticized for this from some academic quarters. Did these critics finally get under D-Wave’s skin?

…. I hope not.

Update: Courtesy of Geordie Rose from D-Wave (lifted from the comment section) here is a link to a very informative presentation on the Ramsey number paper.  While you’re at it you may also want to check out his talk. That one definitely makes for better water cooler  conversation material – less steeped in technicalities but with lots of apples and Netflix thrown in for good measure. Neat stuff.

Update 2: More videos from the same event now available on D-Wave’s blog.