We had a lot of legacy code that we are refactoring and cleaning up before pushing to the open source repositories. The biggest set of functionality that is missing is Linear Algebra. This is because ArrayFire 2.1 depended on other closed source libraries that we can not use when we are open source. We'll be looking into adding similar functionality as time goes on. There are a couple of other functions that are missing, but they should be implemented soon. Is there anything in particular you are missing?