I got some satisfying research time in on the emission-line archetype project. I wrote a detailed description of the
representation relationship such that we can say that spectrum i represents spectrum j. It is then a matter of computing all the representation relationships and finally an integer programming problem to find the minimum-sized subset of the spectra such that every spectrum is represented. Integer programming is NP-hard (I think) in general, but damn the open source glpk toolkit is pretty incredible (fast, and often finds the global minimum for problems of interest).
In the spirit of
always having synchronized documents and code (documents say what the code does, code does what the documents say), I worked on the code to catch up with where I am in the document.