Chips That Flow With Probabilities, Not Bits 153
holy_calamity writes "Boston company Lyric Semiconductor has taken the wraps off a microchip designed for statistical calculations that eschews digital logic. It's still made from silicon transistors. But they are arranged gates that compute with analogue signals representing probabilities, not binary bits. That makes it easier to implement calculations of probabilities, says the company, which has a chip for correcting errors in flash memory claimed to be 30 times smaller than a digital logic-based equivalent."
Analog Computers (Score:4, Insightful)
It would seem that they have reinvented the analog computer, but this time entirely on a chip. And probably (hopefully) with some logic that prevents errors due to natural processes like capacitive coupling.
Re:Analog Computers (Score:3, Insightful)
Being able to do it on silicon should mean they can make them cheaply and quickly with existing fab gear. I could see these being a lot of fun for tinkerers.
Analog computers live again!! (Score:1, Insightful)
Probability in computers: it's called a float (Score:5, Insightful)
The article mentions Bayesian calculations. Can these computers really speed up those calculations? Nowadays Bayesian calculations usually involve thousands of iterations of a technique called Markov Chain Monte Carlo [wikipedia.org] (MCMC) unless the distributions in question are conjugate priors [wikipedia.org]. The simulation then converges to the right answer.
The issue I see is that all these techniques are just math. They are either analytic (conjugate priors) or require strict error bounds in order get sensible answers (MCMC). There's no separate system of math that Bayesians use. Like many others, Bayesians just need quick reliable floating point mathematics. So anyway, I don't see how this can help Bayesian statisticians, unless it also revolutionizes engineering, physics, etc.
Analogue Computing (Score:2, Insightful)
This is potentially a great advance. Everyone knows that analogue computing can greatly outperform digital computing (now each bit has a continuum of states so stores infinitely more data, each operation on 2 'bits'....you get the idea)....but there are many issues to resolve i.e.
1) Error correction - every 'bit' is in an erroneous state
2) Writing code for the thing - anyone got analogue algorithm design on their CVs?
Douglas Adams would be proud. (Score:1, Insightful)
Re:1 AND 1 = 1 : 0.8 AND 0.6 = 0.7 (Score:5, Insightful)
If 0.8 AND 0.6 = 0.7 (I assume you're taking the average here), then 1 AND 0 would be 0.5, when it's supposed to be 0. The only answers I would accept for 0.8 AND 0.6 are 0.6 (min) and 0.48 (multiplication). An OR gate is constructed by attaching NOT (1 - x here) gates to the inputs and output of an AND gate, yielding 0.8 or 0.92 depending on which rule you go with.
Re:Analog Computers (Score:1, Insightful)
It's not analog in the sense that we use op amps, we still use gates
What's the difference? A gate is just a high speed high gain ultra high distortion opamp.
Re:Mod shit down (Score:3, Insightful)
"[A]nalog devices working with analog values" does actually imply it is an analog computer, at least in part. Still, the overall usage sounds does novel, through the usage of Bayesian statistics "operations" logic as an alternative to the better known Boolean logic operations used in binary digital computers.
I have to disagree with you here. An analog computer is not the same thing as analog electronics in general. As an analogy, using a few digital gates to control an alarm doesn't mean you just built a digital computer.
An analog computer is a special system that uses analog circuits to solve systems of differential equations. It is uniquely analog in the sense that it is continuous-time and has a continuously-variable output (not quantized). In the 40s and 50s, it was cheaper, more accurate (usually) and certainly required less equipment to do simulations using analog computers versus digital computers. Those days are long, long gone.
Sure, analog electronics more than "still exist". The analog IC market is growing faster than it ever has. But I would be hard pressed to call the analog subtractor in a Pipelined ADC an "analog computer", nor would I call the mixer in a mobile phone (a circuit that multiplies two analog waveforms) an "analog computer" either.
Re:The actual thesis (Score:3, Insightful)
I'm a bit worried about them being completely fabless. I'm sure all their circuits work in SPICE, but how is this going to deal with real world noise, especially embedded on some other digital chip? The powerpoint explicitly states that is adversely affected especially by the sudden spikes caused by digital noise...
I wouldn't worry too much. More companies than not are fabless you know. They are going to deal with noise the way all analog designers deal with noise. They are going to use a deep n-well with guard rings. They are going to bypass the hell out of their supplies. They are going to run their signals on high metal with shields beneath. The same things we all do.