def printActiveIndices(self, state, andValues=False):
    """Print the list of [column, cellIdx] indices for each of the active
    cells in state. """
    (cols, cellIdxs) = state.nonzero()

    if len(cols) == 0:
      print "NONE"
      return

    prevCol = -1
    for (col,cellIdx) in zip(cols, cellIdxs):
      if col != prevCol:
        if prevCol != -1:
          print "] ",
        print "Col %d: [" % (col),
        prevCol = col

      if andValues:
        print "%d: %s," % (cellIdx, state[col,cellIdx]),
      else:
        print "%d," % (cellIdx),
    print "]"
Print the list of [column, cellIdx] indices for each of the active
    cells in state.