Subject: General Tech | November 13, 2016 - 06:24 PM | Scott Michaud
Tagged: optical computing, HPC
We occasionally discuss photonic computers as news is announced, because we're starting to reach “can count the number of atoms with fingers and toes” sizes of features. For instance, we reported on a chip made by University of Colorado Boulder and UC Berkeley that had both electric and photonic integrated circuits on it.
This announcement from Optalysys is completely different.
The Optalysys GENESYS is a PCIe add-in board that is designed to accelerate certain tasks. For instance, light is fourier transformed when it passes through a lens, and reverse fourier transformed when it is refocused by a second lens. When I was taking fourth-year optics back in 2009, our professor mentioned that scientists used this trick to solve fourier transforms by flashing light through a 2D pattern, passing through a lens, and being projected upon film. This image was measured pixel by pixel, with each intensity corresponding to the 2D fourier transform's value of the original pattern. Fourier transforms are long processes to solve algebraically, especially without modern computers, so this was a huge win; you're solving a 2D grid of values in a single step.
These are the sort of tricks that the Optalysys GENESYS claims to use. They claim that this will speed up matrix multiplications, convolutions (fourier transforms -- see previous paragraph), and pattern recognition (such as for DNA sequencing). Matrix multiplications is a bit surprising to me, because it's not immediately clear how you can abuse light dynamics to calculate this, but someone who has more experience in this field will probably say “Scott, you dummy, we've been doing this since the 1800s” or something.
Image Credit: Tom Roelandts
The circles of the filter (center) correspond to the frequencies it blocks or permits.
The frequencies correspond to how quick an image changes.
This is often used for noise reduction or edge detection, but it's just a filter in fourier space.
You could place it between two lenses to modify the image in that way.
From a performance standpoint, their “first demonstrator system” operated at 20Hz with 500x500 resolution. However, their video claims they expect to have a “PetaFLOP-equivalent co-processor” by the end of the 2017. For comparison, modern GPUs are just barely in the 10s of TeraFLOPs, but that's about as useful as comparing a CPU core to a digital signal processor (DSP). (I'm not saying this is analogous to a DSP, but performance comparisons are about as useful.)
Optalysys expects to have a 1 PetaFLOP co-processor available by the end of the year.