Erlang Priority Queue Implementation
====================================

The priority queue implementations implement a subset of the stdlib Erlang queue interface as seen in the implementation used by both [Riak and RabbitMQ](https://github.com/basho/riak_core/blob/master/src/riak_core_priority_queue.erl).

The implementations:

* `priority_queue` (fastest for any priorities when only using a single priority at a time)
* `pqueue` (fastest for 41 priorities, -20 (high) to 20 (low), when using 2 or more priorities at the same time)
* `pqueue2` (slower heap implementation)
* `pqueue3` (faster than `pqueue2` and `priority_queue` when using 64 or more priorities at the same time)
* `pqueue4` (slightly slower than `pqueue` but fastest for allowing 257 priorities, -128 (high) to 128 (low), i.e., fastest when using 42 or more priorities at the same time)

[The latest results are here](http://okeuday.livejournal.com/19539.html), with [the benchmark here](http://github.com/okeuday/erlbench).

Author
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Michael Truog (mjtruog at protonmail dot com)

Thanks
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* Jesper Louis andersen (PropEr integration and testing)
* Ulf Wiger (suggestions and insight)

License
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MIT License