Aggregation seems to crash with 6 partitions but not 5. Adding a couple print statements seems to suggest that `process_bounday()` is segfaulting. See [this branch](https://github.com/karthik-shanmugam/opaque/tree/agg-segfault) to recreate easily <img width="722" alt="screen shot 2017-03-14 at 6 55 27 pm" src="https://cloud.githubusercontent.com/assets/7821859/24067088/7aa5b0e2-0b35-11e7-989d-5aa256ba498f.png">
Aggregation seems to crash with 6 partitions but not 5.
Adding a couple print statements seems to suggest that
process_bounday()is segfaulting.See this branch to recreate easily