My $0.02 since I’m working with a lot of java and scala lately, including the interaction between the two:
Please keep in mind the more complex dependency issues that will be introduced by requiring Java users to now have to pull in a large scala dependency base. In addition, a lot is Scala is compiler-dependent with different jars for 2.10,2.12,etc. and so they’re in different places than the regular jars and having a Java person suddenly have to deal with this is a good way to make him say “no thanks”. My day job build and runtime environment systems, for instance, don’t handle the mixing very well without having to hack a bunch of build files and even then it causes problems from time to time. Scala experts won’t have problems but it’s a steep learning curve for Java (or C++) folks. On Thu, Sep 27, 2018 at 6:14 PM YiZhi Liu <eazhi....@gmail.com> wrote: > I vote for "2.) Leave the existing macro in place and add another > which generates a Java friendly version" > > @Qing @Andrew, could you give some examples, so that people can better > understand how it provides "best possible experience" to Java users. > > I have no strong preference between having JavaShape & JavaContext or not. > On Thu, Sep 27, 2018 at 5:56 PM Andrew Ayres <andrew.f.ay...@gmail.com> > wrote: > > > > That's not really the conversation I'm wanting to have. I want a > discussion > > about the macros with respect to NDArray so that we can get agreement on > > our path forward with respect to implementing the NDArray wrapper. > > > > The design that was put forth and agreed to was for a a Java wrapper > around > > the Scala API. Adding a bunch of Java friendly methods inside the Scala > > code would create a mess for users. Maintenance would be essentially the > > same for both because either way you're going to be updating Java methods > > when you make Scala changes. > > > > Let's please stick with the issue in the original email. > > > > Thanks, > > Andrew > > > > On Thu, Sep 27, 2018 at 5:22 PM Qing Lan <lanking...@live.com> wrote: > > > > > I would like to loop this back a layer. Current, there is a discussion > in > > > the MXNet Scala community on the ways to implement the Java APIs. > Currently > > > there are two thoughts: > > > > > > 1. Make Scala Java Friendly (Create Java compatible methods in the > Scala > > > Class. such as NDArray with Java compatible constructor) > > > 2. Make Java friendly wrappers in Scala (Andrew's explanation below) > > > > > > The first approach require minimum input from our side to implement > > > however bring user a bunch of useless api they may not want to use. It > also > > > makes Scala package heavier. The good thing is these two packages > require > > > minimum maintenance cost. As a tradeoff, if any time in the future we > want > > > to make Java big (make Java as the primary language supported by > MXNet), > > > then the migration from Scala to Java will be harmful. Spark consider > this > > > carefully and decide not to change much on their Scala code base to > make it > > > more Java. > > > > > > The second approach will make unique NDArray, Shape, Context and more. > The > > > good thing about this is we can always holds a version control on Java. > > > Some breaking changes on Scala may not influence much on Java. It did > the > > > best way to decouple the module and good for us to build unique > pipeline > > > for Java. The bad thing with this design is the maintenance cost as we > need > > > to keep two code bases, but it also make Java side easy to change to > make > > > it better compatible with users. > > > > > > Thanks, > > > Qing > > > > > > On 9/27/18, 3:25 PM, "Andrew Ayres" <andrew.f.ay...@gmail.com> wrote: > > > > > > Hi, > > > > > > Currently, we're working to implement a new Java API and would like > > > some > > > feedback from the community on an implementation detail. In short, > the > > > new > > > Java API will use the existing Scala API (in a manner similar to > how > > > the > > > current Clojure API works). This basically means that we're making > Java > > > friendly wrappers to call the existing Scala API. > > > > > > The feedback we're looking for is on the implementation of NDArray. > > > Scala's > > > NDArray has a significant amount of code which is generated via > macros > > > and > > > we've got two viable paths to move forward: > > > > > > 1.) Change the macro to generate Java friendly methods - To do > this > > > we'll > > > modify the macro so that the generated methods won't have > > > default/optional > > > arguments. There may also have to be some changes to parameter > types to > > > make them Java friendly. The big advantage here is that ongoing > > > maintenance > > > will easier. The disadvantages are that we'll be changing the > existing > > > Scala NDArray Infer API (it's marked experimental) and Scala users > will > > > lose the ability to use the default and optional arguments. > > > > > > 2.) Leave the existing macro in place and add another which > generates a > > > Java friendly version - The biggest issue here is that we'll be > > > doubling > > > the number of macros that we've got to maintain. It'll become even > more > > > overhead once we start expanding the Java API with more classes > that > > > use > > > generated code like this. The advantages are that the existing > Scala > > > NDArray Infer API would remain unchanged for Scala users and that > the > > > new > > > macro could be optimized to give the best possible experience to > the > > > Java > > > API. > > > > > > Thanks, > > > Andrew > > > > > > > > > > > > > -- > Yizhi Liu > DMLC member > Amazon Web Services > Vancouver, Canada >
