[lab · T2] Indexing & Retrieval — track thread

[akash-coded]

L.A.B. track thread. One per track. Ask here rather than opening a new thread — the
answers accumulate where the next person will look.

Labs: L03, L04 · Lifecycle stage: Design · the method

What this track is about

IDF is a log-odds ratio, not a frequency penalty — and it goes negative. L04 then shows what happens when the analyzer quietly re-partitions the term space underneath a scoring function that is working perfectly.

Where people get stuck

If L03's negative branch surprises you, that is the lab working. A term in more than half the collection is evidence against relevance, and that is the principled version of a stop list. Do not floor it at zero; the sign is the lesson.

How to ask here

Paste the check that failed and its message. The messages are written to be actionable — if
one is not, that is a bug in the lab and saying so is a useful contribution.

python scripts/lab.py run <id>            # public checks
python scripts/lab.py run <id> --hidden   # everything

Submitting

Fork, fill in starter.py, open a pull request. The
Labs workflow posts your results as a comment and
edits it in place on each push. It will not fail the build on red checks — the comment says
what failed.

What this track hands to the next one

Design produces the artefact the following stage needs. If you finish L03, L04 and cannot say what
that artefact is for your own corpus, the track is not done — that is the point of the lifecycle
running underneath the pathway rather than beside it.