Thank's Michael.
2014-01-30 Michael Ferrier <[email protected]> > Hi Christian, > > What you describe is done in lines 58-60: > > 58. else if predictiveState(c, i, t) == 0 and predictiveState(c, i, > t-1)==1 then > 59. adaptSegments (segmentUpdateList(c,i), false) > 60. segmentUpdateList(c, i).delete() > > If the cell was predictive at t-1 but is no longer predictive (and we know > that it's not active either, because otherwise it would be a learning cell > since it was previously predictive), then adaptSegments() is called with > positiveReinforcement set to false, causing the synapses that were active > (that made the cell predictive at t-1) to be decremented. > > -Mike > > _____________ > Michael Ferrier > Department of Cognitive, Linguistic and Psychological Sciences, Brown > University > [email protected] > > > On Wed, Jan 29, 2014 at 9:10 PM, Christian Cleber Masdeval Braz < > [email protected]> wrote: > >> >> Hi >> >> I was studying the TP algorithm and didn't understand one point. >> >> In the beginning, permanence values are assigned aleatory to distal >> dendrites segments of all cells (as in the initialization of the SP). >> >> In time t, the region predicts a bunch of cells based on the activation >> of their segments. A segment is active if it have a minimum number of >> active synapses connected with active cells in time t. In time t + 1, the >> cells that were predicted and are in active columns (and just that in >> active columns) will have their synapses permanence values updated >> according. >> >> But, what about the false positives, the cells that were predicted >> ocasionaly just because they had an active segment that fit well with input >> in time t, but they never occur. Don't they will be predicted again and >> again when the input in time t occur? I couldn't see where the algorithm >> treat this issue. >> >> In the last part, it does >> >> for c, i in cells >> 55. if learnState(c, i, t) == 1 then => >> update just the cells that are in an active column >> 56. adaptSegments (segmentUpdateList(c, i), true) >> 57. segmentUpdateList(c, i).delete() >> >> Doesn't necessary to decrement the permanence value of those connected >> synapses in the distal dentrite segments of cells that don't occur? >> >> >> Christian >> >> >> >> >> >> >> >> >> >> >> _______________________________________________ >> nupic mailing list >> [email protected] >> http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org >> >> > > _______________________________________________ > nupic mailing list > [email protected] > http://lists.numenta.org/mailman/listinfo/nupic_lists.numenta.org > >
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