Initial discussion of the fic under a Harry Potter and the Methods of Rationality thread is here. The first dedicated threads: Part 1, Part 2. See also the luminosity sequence which contains some of the concepts that the Luminosity fic is intended to illustrate. (Disclaimer: in the fic, the needs of the story take precedence over the needs for didactic value where the two are in tension.)
Spoilers are OK to post without ROT-13 for canon, all of Book 1, and Radiance up to the current chapter. Note which chapter (let's all use the numbering on my own webspace, rather than fanfiction.net, for consistency) you're about to spoil in your comment if it's big. People who know extra stuff (my betas and people who have requested specific spoilers) should keep mum about unpublished information they have. If you wish to join the ranks of the betas or the spoiled, contact me individually.