code: def accuracy(current, predicted):
      
    acc = 0
    if np.count_nonzero(predicted) > 0:
      acc = float(np.dot(current, predicted))/float(np.count_nonzero(predicted))
    return acc
docs: Computes the accuracy of the TM at time-step t based on the prediction
    at time-step t-1 and the current active columns at time-step t.
    
    @param current (array) binary vector containing current active columns
    @param predicted (array) binary vector containing predicted active columns  
    @return acc (float) prediction accuracy of the TM at time-step t