(I'm the author of the original blog post/algorithm) For Google, this makes sense, although I see now it's a weird idiosyncrasy outside of the Googleplex :) G

(I'm the author of the original blog post/algorithm) For Google, this makes sense, although I see now it's a weird idiosyncrasy outside of the Googleplex :) Google has changes all year round, so "now" always represents a day of some changes. The algorithm is run on the entire code base, so now is a perfectly normal spot to go with. It didn't occur to me that really what now represents is "last time of changes". This is a good spot, and I'll put it in the paper I'm writing! Thanks! A reasonable/desirable modification is probably for now to be changed to represent the last change, just like the first change is when the normalization window begins. (0 = time of first change, 1 = time of last change). HTH.