[mindcrime]

Don't forget SystemML[1] and Singa[2], as well as venerable systems like Mahout[3] and SAMOA[4].

[1]: http://systemml.apache.org/

[2]: https://singa.incubator.apache.org/

[3]: http://mahout.apache.org/

[4]: https://samoa.incubator.apache.org/