So, there's this function. It's called a lot. More importantly, all those calls are on the critical path of a key user interaction. Let's talk about making it fast. Spoiler: it's a dot product. Some background (or skip to the juicy stuff) At Sourcegraph, we're working on a Code AI tool named Cody. In order for Cody to answer questions well, we need to give them enough context to work with. One of the ways we do this is by leveraging embeddings. For our purposes, an embedding is a vector represen...