SP columns activating without input when using topology

rhyolight · August 22, 2016, 5:54pm

Thanks @Vovchik, you got me looking in the right place. I think the problem can be fixed quite simply by adding one more condition to the if statement below:

github.com

numenta/nupic/blob/f1dd3ca676891f7370cf5404b3bbe432ac503f75/src/nupic/research/spatial_pooler.py#L1471


  @return list with indices of the winning columns
  """
  winners = []
  addToWinners = max(overlaps)/1000.0
  overlaps = numpy.array(overlaps, dtype=realDType)
  for i in xrange(self._numColumns):
    maskNeighbors = self._getNeighborsND(i, self._columnDimensions, self._inhibitionRadius)
    overlapSlice = overlaps[maskNeighbors]
    numActive = int(0.5 + density * (len(maskNeighbors) + 1))
    numBigger = numpy.count_nonzero(overlapSlice > overlaps[i])
    if numBigger < numActive:
      winners.append(i)
      overlaps[i] += addToWinners
  return numpy.array(winners, dtype=uintType)




@staticmethod
def _getNeighbors1D(columnIndex, dimensions, radius, wrapAround=False):
  """
  Returns a list of indices corresponding to the neighbors of a given column.
  In this variation of the method, which only supports a one dimensional

As-is, this condition will select winner columns that have no overlap with the input vector. I believe one more condition needs to be added so the code looks like this:

  if overlaps[i] > 0 and numBigger < numActive:

See it working with this change:

Topic		Replies	Views
NuPIC Topology Notes NuPIC spatial-pooling , topology	9	1356	August 23, 2016
Details needed on spatial pooler algo NuPIC spatial-pooling	2	694	June 25, 2017
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SP columns activating without input when using topology

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