[HN Gopher] AI Overcomes Stumbling Block on Brain-Inspired Hardware
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       AI Overcomes Stumbling Block on Brain-Inspired Hardware
        
       Author : pseudolus
       Score  : 45 points
       Date   : 2022-02-18 10:30 UTC (12 hours ago)
        
 (HTM) web link (www.quantamagazine.org)
 (TXT) w3m dump (www.quantamagazine.org)
        
       | dr_dshiv wrote:
       | More generally, this is an amazing reference if you interested in
       | the field:
       | 
       | Csaba, G., & Porod, W. (2020). Coupled oscillators for computing:
       | A review and perspective. Applied Physics Reviews, 7(1), 011302.
       | 
       | Did you know Von Neumann posthumously patented a non-Von Neumann
       | architecture based on coupled oscillators?
        
         | [deleted]
        
       | slowmovintarget wrote:
       | Seems like this is also a mathematical explanation of why
       | Einstein's brain was so powerful. He was overparameterized in
       | similar fashion with more connections per neuron than the average
       | brain.
        
       | visarga wrote:
       | The idea would be great if it could scale to 100B weights. In the
       | loop training is cool - forward prop using the neuromorphic
       | hardware, network update using Pytorch.
       | 
       | But for now, they only get 98.7% on MNIST, state of the art is
       | 99.91%, a 14x lower error rate. You have to try hard to get under
       | 99%, just take a look. Maybe it's because they can't use
       | backprop. Backprop is so powerful it's hard to beat it.
       | 
       | https://paperswithcode.com/sota/image-classification-on-mnis...
       | 
       | https://www.kaggle.com/c/digit-recognizer/leaderboard
        
         | billlli wrote:
         | One of the authors here...
         | 
         | Scaling certainly is one of the next big challenges, the
         | current network sizes severely limit us in our inference
         | performance.
         | 
         | Just to clear things up: Our circuits were actually trained via
         | backprop. This is what allowed us to reach performance levels
         | very close to equivalently sized but simulated SNNs (and even
         | rather close to the accuracy of ANNs of the same size).
        
       | igorkraw wrote:
       | Having started my PhD originally in neuromorphics before I
       | switched lanes, no they didn't, at least not the important one.
       | 
       | They still perform gradient descent using a GPU. I love
       | BrainScaleS but until we have analog/neuromorphic training, the
       | elephant in the room of "why not make an ASIC for the prettrained
       | model" remains. We can do robust training on GPU already.
       | 
       | There is interesting work being done with predictive coding based
       | training that might fix it, but as far as I know it's still put
       | there.
        
         | orbifold wrote:
         | One of the co-authors here. Demonstrating inference on a
         | neuromorphic chip can already be challenging, especially if it
         | contains analog components. This is a way to make this kind of
         | hardware "useful" on a given task. Of course learning on chip
         | is the holy grail, but given that this kind of hardware has
         | potential latency and power-consumption advantages for small
         | (event-based) data, a general way of optimising the weights is
         | pretty cool, I think.
        
           | p1esk wrote:
           | So what advantages does implementing spiking NNs in hardware
           | vs implementing non-spiking NNs in hardware? Usually people
           | say "better power efficiency" but I have never seen apples to
           | apples comparisons. Is mixed signal chip running spiking NN
           | actually more efficient than a mixed signal chip running a
           | non-spiking (traditional, GEMM based) NN? Have such
           | comparisons been done in the literature? If not, where is
           | this claim coming from?
           | 
           | Also, why do people try to implement SNNs in hardware, when
           | they don't work well in software? Shouldn't we first try to
           | figure out how the brain actually does it (processes
           | information), and only then try to build expensive
           | specialized hardware for it?
        
             | orbifold wrote:
             | The chip under discussion is able to do both (analog matrix
             | multiplication and SNN operation). Briefly there are a
             | bunch of "nano"-devices which are more amendable to spike
             | based operation. Moreover analog computation is hard to
             | scale up so the layer wise digitalization and weight
             | loading and communication wipe out a lot of the potential
             | benefit in the case of analog matrix accelerators. Part of
             | the advances in recent years make SNN work "well enough" in
             | software, especially considering the relative smaller
             | overall investment in them.
        
               | p1esk wrote:
               | But BrainScale chip was built to run spiking ops, so even
               | when it does analog matmul, it's not optimized to do it
               | exclusively and end to end, right? How about we compare
               | it to a chip that was designed to perform analog matmul,
               | for example, this one: https://www.mythic-
               | ai.com/product/m1076-analog-matrix-proces...
               | 
               | If we measured the forward pass time to run something
               | like Resnet-50 on Imagenet, taking into account any
               | accuracy degradation, and compared to what BrainScale can
               | do with the SNN equivalent of Resnet-50 - that would be
               | interesting.
               | 
               | Don't get me wrong, what you did there is nice (chip in
               | the loop with SNNs), I'm just struggling a bit with
               | understanding the motivation. What does "works well
               | enough" mean? Shouldn't it work much better than anything
               | else to deserve building custom hardware for it?
               | Especially if a regular matmul based NNs work better and
               | might actually run faster and be more power efficient
               | (when run on state of the art custom hw)?
               | 
               | I mean, this would be a no-brainer :) if you told me
               | "this is how our brain works, and we want to emulate it
               | in hardware to speed up neuroscience experiments", but
               | that's just not true, is it? We don't know how the brain
               | processes information, even such basic things like how
               | the information is actually encoded, or what kind of
               | computation a neuron performs.
               | 
               | Or if you don't care about the brain, it would make sense
               | if the SNN algos produced state of the art results, and
               | everyone would want to run them in their iphones. Or ok,
               | if no state of the art results, at least good results
               | with the best speed/efficiency. But if you have neither
               | best results, nor best hw performance, I'm really
               | scratching my head here...
        
           | igorkraw wrote:
           | Yes, it is pretty cool, please don't think I'm bashing your
           | paper. If anything, I'm bashing Quanta and popscience for
           | overhype and the literature _in general_ for mainly avoiding
           | the difficult question for the more tractable one - while
           | fully understanding why.
           | 
           | As I said in a sister comment, I fully believe in
           | neuromorphics inspired inference engines. It's just that we
           | have some of them already, and while your paper _is_ novel,
           | people should take this in the appropriate context.
        
         | xpuente wrote:
         | The second elephant is don't split training from inference.
         | There is no such thing as inference in biological systems. All
         | these efforts are futile as long as we do not get rid of the
         | GD.
        
         | 16890c wrote:
         | To your point of on-chip analog neuromorphic training, there is
         | some recent work with one of the same authors [1] on event-
         | based backprop in spiking neural networks. So far they only
         | have simulations, but this is likely an important step toward
         | fully integrated, scalable training of SNNs on neuromorphic
         | hardware.
         | 
         | [1] https://www.nature.com/articles/s41598-021-91786-z
        
           | igorkraw wrote:
           | This is part of the research I find more exciting, but the
           | challenge is to actually make this work for things which
           | aren't MNIST. I might be wrong on this, but I haven't seen
           | any novel learning rules deal with Fashion MNIST or CIFAR so
           | far. MNIST can be solved based only on image statistics and
           | is a bad check in this regard - almost everything can learn
           | MNIST
        
         | mpfundstein wrote:
         | i think one needs to let go of those questions. this is
         | fundamental research that might yield enormous benefits. yesz
         | there are more efficient ways currently(!) available , but that
         | frankly doesn't matter yet. we are now busy figuring out the
         | fundamentals.
         | 
         | i personally think this research yielded a very cool insight.
         | namely that you can fix the problem of decreased performance
         | when transferring a learned model on a supercomputer to a
         | neuromorphic chip. this is very cool
        
           | igorkraw wrote:
           | I addressed this in some sister comments(including similar
           | work tbsz transferred to other types of devices), but
           | specifically for your comment: in my view, science has higher
           | standards for presentation and communication than start-up
           | submarine posts, and the fact that we are still relying on
           | GPUs to train and other avenues to do this exist _is_
           | relevant to asses it. I am happy about basic research being
           | done and do not think every paper needs to set a SotA or
           | change the world - but overhype is exactly _why_ every paper
           | needs to try selling it as such, because if you don 't go
           | viral and make a big impact on main media, your career might
           | suffer. Hence install of being able to say "we made something
           | cool, a lot of work left to be done", papers need to conjure
           | up a paradigm shift put of every publication (again, not
           | bashing the authors, just the system)
        
           | AussieWog93 wrote:
           | Are you intimate with the literature the way GP is?
           | 
           | I studied a different field (application of machine learning
           | to brain-machine interfaces), but I would (and still do)
           | regularly see completely mundane research presented as
           | something groundbreaking by a person/institution seeking
           | clout.
           | 
           | I've actually pointed out the bullshit a couple of times
           | here, and received very similar responses to yours.
           | 
           | I think it's a case of cutting-edge, not-widely-deployed
           | technology seeming really exciting to someone hearing about
           | it for the first time, even if the research itself does
           | nothing particularly new compared to a few years ago.
        
             | mpfundstein wrote:
             | I feel your pain. seriously! i worked 2 years on deep
             | learning for crowd counting and 99% of all papers (and
             | corresponding press releases) were utter crap. Super minor
             | improvements were presented as the big new thing. But thats
             | how the field is. Everyone trying to get tenure, so people
             | need to scream loudly from the trees what assume shit they
             | are doing.
             | 
             | I for one just learned to ignore it and just look at the
             | merit of a paper and what it contributes.
        
         | billlli wrote:
         | Thanks for your comment, one of the authors here...
         | 
         | Fully self-learning systems are certainly one of the
         | overarching goals of our field. Unsurprisingly, there are many
         | challenges to be solved along the way.
         | 
         | > why not make an ASIC for the prettrained model
         | 
         | Our paper does not really touch the topic of deployment (except
         | for the study on post-deployment degradation of the circuits,
         | maybe). Model-specific ASICs, however, would likely not pose an
         | economically viable solution.
         | 
         | > We can do robust training on GPU already.
         | 
         | We certainly can! Deploying those trained models on novel,
         | "imperfect" hardware is the challenge.
        
           | igorkraw wrote:
           | I hope you I did not cause offense, for neuromorphics this is
           | a wonderful paper and it's important to do basic research
           | like this! I'm just a bit jaded after 5 years of following
           | the literature and seeing most papers sidestep what I see as
           | the _big_ road block.
           | 
           | We can now train sparse, quantized, robust neural networks
           | which are _already_ specified in terms of primitives for
           | which ASIC macros can easily be designed. If we are going to
           | make a new chip that anyway, IP like this is a benchmark I
           | compare to in my mind.
           | 
           | If we want flexibility,FPGAs are being integrated with modern
           | CPUs and will allow you to program precise weights if you
           | want them, making it more feasible to do complex tasks.
           | 
           | So this is regarding the point of ASICS. I don't want to bash
           | your paper, but to me this is the competition to beat and why
           | I reacted to the title given by quanta with context that I
           | think I'd important for people not familiar with the
           | literature.
           | 
           | I fully believe neuromorphic or neuromorphic inspired
           | inference engines will (continue to) have their place.
           | 
           | As for the deployment of robust weights to imperfect
           | hardware, an ex colleagues of mine started this line of
           | research when I did my internship at IBM
           | https://www.nature.com/articles/s41467-020-16108-9
           | 
           | So I meant robust in this sense, robust to deployment to real
           | devices
        
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