code: public Vec getTopicVec(int k)
      {
          return new ScaledVector(1.0/lambda.get(k).sum(), lambda.get(k));
      }
docs: Returns the topic vector for a given topic. The vector should not be
  altered, and is scaled so that the sum of all term weights sums to one.
  @param k the topic to get the vector for
  @return the raw topic vector for the requested topic.