On Nov 22, 2013 4:15 PM, "Marek Otahal" <[email protected]> wrote: > > > > > On Sat, Nov 23, 2013 at 12:25 AM, Scott Purdy <[email protected]> wrote: >> >> >> For some reason having trouble wrapping my head around that but I believe that all makes sense. I think you are saying that if your input space was varied enough that you saturate the SP, then the number of patterns you can represent is inversely proportional to the noise tolerance. The caveat to this is that even if you end up with a different SP representation because of a small amount of noise, the representation will still be very semantically similar to the previous. In fact, you most likely only have one or two columns that are different so the higher levels will see a very similar pattern. > > Yes, I wouldn't say it better ;) Thanks for rewording to make sense. (I was just talking noise at the output layer, where 10% noise would make 100 from a 1000 bits, that could easily change meaning if you're running on 20 ON bits). > > Btw, could this be an argument for reconstruction against classification? When I mess with 10% of the SDR, you'll train on a wrong pattern, if we use "back-propagation" the random-bits will have low permanences, so will reduce on the way down.
That would require hierarchy and feedback. Reconstruction doesn't affect active or predicted cells. > >>> >>> >>> >>> PS: >>> Is there a (lower bound) limit on the number of columns in SP? So would a 20 col SP work? That way, I could achieve the (20 choose 3) and reach the state of info-full SP. >> >> >> The theory relies on large numbers. Subutai's CLA quiz covers it very thoroughly. In your 20 choose 3 example, you lose fault tolerance/subsampling at higher levels, the ability to represent many different patterns (only 1140), and the ability to represent many simultaneous patterns. > > I know, the fault tolerance would be a problem. Lost ability to represent huge num. of patterns is what I want. Otherwise it's out of reach for anybody to experiment with a SP in nearly saturated state (input pattern wise). > > > > > -- > Marek Otahal :o) > > _______________________________________________ > nupic mailing list > [email protected] > http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org >
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