def _generateFeatures(self):
    """
    Generates a pool of features to be used for the experiments.

    For each index, numColumns SDR's are created, as locations for the same
    feature should be different for each column.
    """
    size = self.sensorInputSize
    bits = self.numInputBits

    self.features = []
    for _ in xrange(self.numColumns):
      self.features.append(
        [self._generatePattern(bits, size) for _ in xrange(self.numFeatures)]
    )
Generates a pool of features to be used for the experiments.

    For each index, numColumns SDR's are created, as locations for the same
    feature should be different for each column.