[HN Gopher] A Closer Look at LightSolver's Laser-Based Processin...
       ___________________________________________________________________
        
       A Closer Look at LightSolver's Laser-Based Processing Unit (LPU)
        
       Author : giuliomagnifico
       Score  : 32 points
       Date   : 2023-06-18 14:22 UTC (1 days ago)
        
 (HTM) web link (www.allaboutcircuits.com)
 (TXT) w3m dump (www.allaboutcircuits.com)
        
       | gnramires wrote:
       | Hm, they seem to be making huge theoretical claims: it seems
       | they're claiming it outperforms classical Turing machine methods
       | by an exponential (non-polynomial) factor. I think this would be
       | a violation of Church-Turing thesis and in of itself quite
       | revolutionary. It's odd this conclusion didn't receive more
       | attention.
       | 
       | On the surface, since they're not using full quantum coherence
       | properties, it seems this should be possible to simulate in a
       | classical computer just fine (in "polynomial time" in some sense)
       | which make it unclear to me why the exponential speedup should
       | exist.
       | 
       | Nonetheless, I think this kind of machine could be useful and
       | more efficient even without any exponential advantages (which to
       | be frank I'm dubious of).
        
         | [deleted]
        
       | stncls wrote:
       | > In three recent trials testing the performance and accuracy of
       | the new LPU, the device showed promise against its supercomputing
       | and quantum computing counterparts in the following ways:
       | 
       | They proceed to cite three not-yet-peer-reviewed manuscripts by
       | the co-founders [1,2,3]. In all three papers, they use a
       | _simulation_ of their LPU (that runs on CPU or GPU), and compare
       | to some classical heuristics on an AWS instance.
       | 
       | I read [1] and the results are... preliminary at best. They
       | compare their simulation to a single deep-learning-based
       | heuristic called RUN-CSP on tiny MAX-2-SAT instances (<350
       | variables). Deep learning is great but it is generally not SOTA
       | on combinatorial problems. Still, RUN-CSP is not bad, and its
       | authors seem more reasonable; in their paper, they write:
       | "Despite being generic, we show that [RUN-CSP] matches or
       | surpasses most greedy and semi-definite programming based
       | algorithms and sometimes even outperforms state-of-the-art
       | heuristics for the specific problems." Note that RUN-CSP is
       | indeed generic and was by no mean fine-tuned for MAX-2-SAT.
       | 
       | In summary, LightSolver only exists as a simulator on GPUs, that
       | simulator was only tested on very niche problems, and even then
       | probably not against the state-of-the-art. I am trying to be
       | polite here, but to be clear: the BS-o-meter is strongly in the
       | red.
       | 
       | [1] https://arxiv.org/pdf/2302.06926.pdf
       | 
       | [2] https://arxiv.org/pdf/2207.09517.pdf
       | 
       | [3] https://arxiv.org/pdf/2209.03788.pdf
        
       | light_hue_1 wrote:
       | LightSolver are shameless charlatans and scammers of the highest
       | order. We may one day see both founders in jail for defrauding
       | their investors.
       | 
       | Let's just look at two of their false claims:
       | 
       | > Taking on the "3-Regular 3-XORSAT Challenge," LightSolver
       | solved the problem in polynomial time, while all other state-of-
       | the art classical and quantum computers solved it in exponential
       | time.
       | 
       | That is absolutely 100% false in numerous ways.
       | 
       | First of all, they solved this in a simulation, not on their
       | actual LightSolver hardware. So that means that classical
       | computers can solve this problem in polynomial time just fine.
       | Their hardware is totally superflous.
       | 
       | That's not at all surprising because 3R3X is solvable in cubic
       | time with Gaussian elimination or conjugate gradient methods!
       | It's a thorny problem for a class of optimizers, but it poses no
       | problems in general.
       | 
       | Everything they say is just a lie. For example "Faster than
       | TensorFlow". Then you click, and it's a paper comparing their
       | method to one particular max-sat solver implemented in TF, RUN-
       | CSP. And they implement a totally different approach, again, as a
       | simulator on a classical computer. Which then turns out to be
       | faster (not surprising, RUN-CSP is not state of the art in
       | performance, nowhere near). In no sense does this mean they're
       | faster than TF. They're just lying.
        
         | tromp wrote:
         | > 3R3X is solvable in cubic time with Gaussian elimination
         | 
         | As explained on Wikipedia [1].
         | 
         | [1]
         | https://en.wikipedia.org/wiki/Boolean_satisfiability_problem...
        
       ___________________________________________________________________
       (page generated 2023-06-19 23:01 UTC)