rephrased a comment
Topics() is passed both the topic file and the qid file. Topics.query() reads in the qids for the qid file and scopes its topic list by it. This makes exp*.py cleaner.
Experiment definitions are different. The rtags itags and test collection references are shorter and cleaner. Redundancy has been removed. A matrix{} dict encapsulates the experiment set-up.
Written using the new experiment layout.