diff --git a/CHANGELOG b/CHANGELOG new file mode 100644 --- /dev/null +++ b/CHANGELOG @@ -0,0 +1,5 @@ +- 0.1.0.1 + * Extend cabal description, include CHANGELOG + +- 0.1.0.0 + * First release: diff --git a/psqueues.cabal b/psqueues.cabal --- a/psqueues.cabal +++ b/psqueues.cabal @@ -1,5 +1,5 @@ name: psqueues -version: 0.1.0.0 +version: 0.1.0.1 license: BSD3 license-file: LICENSE maintainer: haskell@better.com @@ -7,29 +7,51 @@ synopsis: Pure priority search queues category: Data Structures description: - A priority search queue manages a set of triples of the form - @(key, priority, value)@ and allows for efficient lookup by key, and - efficient lookup and removal of the element with minimal priority. This - package contains three, performant implementations of priority search - queues, which differ in the requirements on the type of keys. + The psqueues package provides + in + three different flavors. . - * 'IntPSQ's are the most efficient structure, but require the keys to be - of type 'Int'. + * @OrdPSQ k p v@, which uses the @Ord k@ instance to provide fast insertion, + deletion and lookup. This implementation is based on Ralf Hinze's + . + Hence, it is similar to the + library, although it is + considerably faster and provides a slightly different API. . - * 'OrdPSQ's just require the key to implement the `Ord` typeclass, but are - the slowest structures of the three. + * @IntPSQ p v@ is a far more efficient implementation. It fixes the key type + to @Int@ and uses a + (like @IntMap@) with an additional min-heap property. . - * 'HashPSQ's require the key to implement both the 'Ord' and 'Hashable' - typeclasses. They use an 'IntMap' over the hash of the keys combined - with a 'OrdPSQ' to manage collisions. Except for keys with a very fast - comparison and small smaps 'HashPSQ's are faster than 'OrdPSQ's. + * @HashPSQ k p v@ is a fairly straightforward extension of @IntPSQ@: it + simply uses the keys' hashes as indices in the @IntPSQ@. If there are any + hash collisions, it uses an @OrdPSQ@ to resolve those. The performance of + this implementation is comparable to that of @IntPSQ@, but it is more widely + applicable since the keys are not restricted to @Int@, but rather to any + @Hashable@ datatype. . - Typical use cases for priority search queues are LRU caches, where the - priority is the time of the last access, and timeout management, where the - priority is the time at which the timeout should trigger. + Each of the three implementations provides the same API, so they can be used + interchangeably. The benchmarks show how they perform relative to one + another, and also compared to the other Priority Search Queue + implementations on Hackage: + + and + . + . + <> + . + <> + . + Typical applications of Priority Search Queues include: + . + * Caches, and more specifically LRU Caches; + . + * Schedulers; + . + * Pathfinding algorithms, such as Dijkstra's and A*. build-type: Simple cabal-version: >=1.8 extra-source-files: + CHANGELOG source-repository head type: git