Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!snorkelwacker.mit.edu!bloom-beacon!eru!hagbard!sunic!news.funet.fi!polaris.utu.fi!magi From: magi@utu.fi (Marko Gronroos) Newsgroups: comp.ai.philosophy Subject: Re: CoOntinuous vs discrete Message-ID: Date: 28 Mar 91 18:13:53 GMT References: <91082.223501DOCTORJ@SLACVM.SLAC.STANFORD.EDU> <1991Mar25.141743.21124@news.larc.nasa.gov> <19175@ogicse.ogi.edu> Sender: usenet@polaris.utu.fi (Usenet News) Organization: University of Turku, Finland Lines: 51 In-Reply-To: maxwebb@ogicse.ogi.edu's message of 27 Mar 91 00:44:46 GMT maxwebb@ogicse.ogi.edu (Max G. Webb) said: > The 'apparent' continuity in the response of neurons is not too > relevant, due to the low precision in the device. Whatever each > neuron is computing, it is not computing it to 32 bits accuracy! 32 bits? Integer? Not floating point? How about sight? You can see the Sun, which is -27 magnitudes, and a galaxy that is +6 magnitudes. The brigthness difference is 32 magnitudes ==> approx. 10^13 ==> 10 000 000 000 000. 32 bits is only 4 294 967 296. Ok, ok, neurons don't fire 10 000 000 000 000 times as fast when watching the Sun than when watching a star, but this is just an example of dangers of using fixed-range numbers. How about using floats?? What happends if you put your fancy CCD-camera in direct sunlight? Your Cray blows up? :-) > Having infinite precision in one number is equivalent in power > to having infinite # of (sequentially accessible) bits of memory. > (of course) Yes, of course! What a scientific breakthrough! WOW! But exactly becouse of this they use a rotated '8' - symbol in mathematics and exponents for smaller numbers. B-> > Hence, discrete devices should have no problem simulating such > neurons. ARGH! Not again! There is a BIG difference between discrete in quantity and discrete in time/space, computers are f*cking discrete in time/space!!!!!!! > Simply set the smallest delta between two numbers in > your representation to 1/2 the relative inaccuracy of the neuron > between two different presentations of the same stimuli. How can you assume that we would have the same accuracy (smallest delta) in the first (test) and the second (actual use) representation/simulation? Why represent the same stimuli to the both simulations if the first one already has processed it? I can understand why someone wants to run speed tests in computers, but this sounds suspicious... Did I understand your message clearly or why does it sound so suspicious? Sorry about flames, but I'm sorry if I misunderstood you (hopefully...). ------------------------------------------------------------------------------- Marko Gronroos ! Tel. +358-21-445613 ! Karvataskunkatu 10 H 100 ! ! Computer Scientists do it 20610 Turku ! ! with bigger hardware. Finland ! ! ------------------------------------------------------------------------------