[Yt-dev] simple quantities

Hi all, after my conversation on -users with Matt, and the recent investigations of inline yt, a thought occurs to me. The whole point of the conversation was that I would like to do some inline analysis of a simulation with star(s). As a zero-order test, the analysis shouldn't run if there are no stars, so I wanted to find out how many stars there are. But as the conversation revealed, it isn't simple/blindingly obvious to do that kind of calculation in a way that works in serial, parallel, and inline, e.g. with derived quantities. How do we feel about my writing a set of convenience functions that make these simple calculations easy? This shouldn't be comprehensive, just things that might come up often. Thoughts? Stephen Skory stephenskory(a)yahoo.com http://stephenskory.com/ 510.621.3687 (google voice)