Graphframes

**Thanks to the many contributors to this release!**

release-0.5.0
**We *strongly* encourage all users to use this latest release because of the bug fix described below!**

**CRITICAL bug fix**
* All previous versions of GraphFrames had a bug which can affect ConnectedComponents and other algorithms.
* This fixes a bug in indexing vertices with non-Integer IDs.
* It can affect all algorithms which are wrappers around GraphX, including ConnectedComponents, PageRank, and others.
* The bug surfaces when the input DataFrame is non-deterministic. E.g., running an algorithm on a DataFrame just loaded from disk should be fine in previous releases, but running that algorithm on a DataFrame produced using shuffling, unions, and other operators can cause incorrect results. This issue is fixed in this release.

**New features**
* Python API for aggregateMessages for building custom graph algorithms
* Scala API for parallel personalized PageRank, wrapping the GraphX implementation. This is only available when using GraphFrames with Spark 2.1+.

**Contributors to this release**
* Felix Cheung
* Tuomas Sivula
* Xiangrui Meng
* Joseph Bradley
* Bagrat Amirbekian
* Santiago Castro
* Philip Yang


release-0.4.0
New release of GraphFrames for Apache Spark 2.0 and 2.1
* Minor fix for checkpointing issue in DataFrame-based connected components implementation (issue 160)

release-0.3.0
- DataFrame-based connected components implementation
- Users can fall back to GraphX implementation as needed
- removed support for Spark 1.4 and 1.5


release-0.2.0
**New methods** (in Scala, Java and Python APIs)
- cache, persist, unpersist
- triplets

**Improvements**
- Motif finding (find() method)
- Result DataFrame now orders the columns in the same order specified by the motif.
- more robust internals (intermediate column naming)
- Various documentation and example fixes
- Compatibility with Apache Spark 1.4, 1.5, 1.6, 2.0 (with Scala 2.10), as well as Apache Spark 2.0 with Scala 2.11

**Contributors to this release**
- Tim Hunter
- Felix Cheung
- Joseph Bradley
- Xiangrui Meng
- Shagun Sodhani
- Frederick Lefebvre
- Qingpeng "Q.P." Zhang
- Bill Chambers
- Reynold Xin