> The primary use case for mahout collections is directly *inside* of > our Vector interface. Which is to say, it's not directly exposed to > most users, and we don't really expose the ability to do guava collections > stuff on them at all: We Do Math. :) So in particular, we don't expose
Fair enough. But you might want to expose some of it at some point and if this happens it may just be ready for you. > Question is whether there's anything to be gained by just swapping > our own collections *out* for something else, like HPPC or fastutil. Depends. Speed optimizations may be one reason -- you'd need to check if the code gains anything by using these libraries compared to Mahout collections. While microbenchmarks may show large differences my bet is that overall results, taking into account computations and, God forbid, I/O, will be within noise range unless you're really using these data structures a *lot* in tight loops. The only practical benefit I see is getting rid of a chunk of code you don't wish to maintain (like you said: missing features, unit tests, etc.). But I don't negate there is some entertainment value in going back to such fundamental data structures and trying to squeeze the last bit of performance out of them. :) Dawid
