https://github.com/meooow25/samsort

A stable adaptive mergesort implementation
https://github.com/meooow25/samsort

haskell sorting

Last synced: 8 days ago
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A stable adaptive mergesort implementation

• Host: GitHub
• URL: https://github.com/meooow25/samsort
• Owner: meooow25
• License: bsd-3-clause
• Created: 2024-04-26T21:37:01.000Z (6 months ago)
• Default Branch: master
• Last Pushed: 2024-06-29T10:26:42.000Z (4 months ago)
• Last Synced: 2024-10-01T23:18:29.860Z (about 1 month ago)
• Topics: haskell, sorting
• Language: Haskell
• Homepage:
• Size: 55.7 KB
• Stars: 8
• Watchers: 3
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# samsort

[![Hackage](https://img.shields.io/hackage/v/samsort?logo=haskell&color=blue)](https://hackage.haskell.org/package/samsort)

[![Haskell-CI](https://github.com/meooow25/samsort/actions/workflows/haskell-ci.yml/badge.svg)](https://github.com/meooow25/samsort/actions/workflows/haskell-ci.yml)

A stable adapative mergesort implementation

## Features

This is a lightweight library offering two high performance sort functions:

* `sortArrayBy` sorts a GHC [`MutableArray#`](https://hackage.haskell.org/package/base-4.19.0.0/docs/GHC-Exts.html#t:MutableArray-35-)

  of boxed elements in place.

* `sortIntArrayBy` sorts a GHC [`MutableByteArray#`](https://hackage.haskell.org/package/base-4.19.0.0/docs/GHC-Exts.html#t:MutableByteArray-35-)

  of `Int#`s in place.

There are no dependencies outside of `base`. This means that this library is

not tied to array abstractions from any particular library. This also means

that you may need to write a few lines of code to get a `MutableArray#` or

`MutableByteArray#` from your data, which can then be sorted. See

[`HOWTO.md`](https://github.com/meooow25/samsort/blob/master/HOWTO.md)

for a guide.

If you need to use this library in an environment where you cannot depend on

other packages, you may simply copy the lone source file

[`src/Data/SamSort.hs`](https://github.com/meooow25/samsort/blob/master/src/Data/SamSort.hs)

to your project.

## Algorithm details

* The sort is a comparison-based $O(n \log n)$ mergesort.

* The sort is stable, i.e. the order of equal elements in the input is

  preserved.

* The sort is adaptive, i.e. the sort identifies and uses ascending and

  descending runs of elements occuring in the input to perform less work. As a

  result, the sort is $O(n)$ for already sorted inputs.

* The sort is the fastest among implementations from other libraries in most

  scenarios. [See the benchmarks](https://github.com/meooow25/samsort/tree/master/compare)

  for details.

## Known issues

Ideally, this library would offer only an algorithm, capable of sorting arrays

of any flavor. To support different arrays we would need to rely on some

abstraction, either from another library (like `vector`), or created here. We

cannot do either of those while also keeping the library as lightweight as it

is now.

## Contributing

Questions, bug reports, documentation improvements, code contributions welcome!

Please [open an issue](https://github.com/meooow25/samsort/issues) as the first

step. Slow performance counts as a bug!