https://github.com/mgeisler/smawk

Rust functions for finding row-minima in monotone matrices.
https://github.com/mgeisler/smawk

matrices optimization rust smawk

Last synced: about 1 year ago
JSON representation

Rust functions for finding row-minima in monotone matrices.

Host: GitHub
URL: https://github.com/mgeisler/smawk
Owner: mgeisler
License: mit
Created: 2017-10-12T08:46:52.000Z (over 8 years ago)
Default Branch: master
Last Pushed: 2024-08-19T23:55:13.000Z (almost 2 years ago)
Last Synced: 2025-04-22T06:19:39.568Z (about 1 year ago)
Topics: matrices, optimization, rust, smawk
Language: Rust
Homepage:
Size: 159 KB
Stars: 6
Watchers: 2
Forks: 1
Open Issues: 5
Metadata Files:
- Readme: README.md
- License: LICENSE

Awesome Lists containing this project

README

          # SMAWK Algorithm in Rust

[![](https://github.com/mgeisler/smawk/workflows/build/badge.svg)][build-status]

[![](https://codecov.io/gh/mgeisler/smawk/branch/master/graph/badge.svg)][codecov]

[![](https://img.shields.io/crates/v/smawk.svg)][crates-io]

[![](https://docs.rs/smawk/badge.svg)][api-docs]

This crate contains an implementation of the [SMAWK algorithm][smawk] for

finding the smallest element per row in a totally monotone matrix.

The SMAWK algorithm allows you to lower the running time of some algorithms from

O(*n*²) to just O(_n_). In other words, you can turn a quadratic time complexity

(which is often too expensive) into linear time complexity.

Finding optimal line breaks in a paragraph of text is an example of an algorithm

which would normally take O(*n*²) time for _n_ words. With this crate, the

running time becomes linear. Please see the [textwrap crate][textwrap] for an

example of this.

## Usage

Add this to your `Cargo.toml`:

```toml

[dependencies]

smawk = "0.3"

```

You can now efficiently find row and column minima. Here is an example where we

find the column minima:

```rust

use smawk::Matrix;

let matrix = vec![

    vec![3, 2, 4, 5, 6],

    vec![2, 1, 3, 3, 4],

    vec![2, 1, 3, 3, 4],

    vec![3, 2, 4, 3, 4],

    vec![4, 3, 2, 1, 1],

];

let minima = vec![1, 1, 4, 4, 4];

assert_eq!(smawk::column_minima(&matrix), minima);

```

The `minima` vector gives the index of the minimum value per column, so

`minima[0] == 1` since the minimum value in the first column is 2 (row 1). Note

that the smallest row index is returned.

### Cargo Features

This crate has an optional dependency on the

[`ndarray` crate](https://docs.rs/ndarray/), which provides an efficient matrix

implementation. Enable the `ndarray` Cargo feature to use it.

## Documentation

**[API documentation][api-docs]**

## Changelog

### Version 0.3.2 (2023-09-17)

This release adds more documentation and renames the top-level SMAWK functions.

The old names have been kept for now to ensure backwards compatibility, but they

will be removed in a future release.

- [#65](https://github.com/mgeisler/smawk/pull/65): Forbid the use of unsafe

  code.

- [#69](https://github.com/mgeisler/smawk/pull/69): Migrate to the Rust 2021

  edition.

- [#73](https://github.com/mgeisler/smawk/pull/73): Add examples to all

  functions.

- [#74](https://github.com/mgeisler/smawk/pull/74): Add “mathematics” as a crate

  category.

- [#75](https://github.com/mgeisler/smawk/pull/75): Remove `smawk_` prefix from

  optimized functions.

### Version 0.3.1 (2021-01-30)

This release relaxes the bounds on the `smawk_row_minima`,

`smawk_column_minima`, and `online_column_minima` functions so that they work on

matrices containing floating point numbers.

- [#55](https://github.com/mgeisler/smawk/pull/55): Relax bounds to `PartialOrd`

  instead of `Ord`.

- [#56](https://github.com/mgeisler/smawk/pull/56): Update dependencies to their

  latest versions.

- [#59](https://github.com/mgeisler/smawk/pull/59): Give an example of what

  SMAWK does in the README.

### Version 0.3.0 (2020-09-02)

This release slims down the crate significantly by making `ndarray` an optional

dependency.

- [#45](https://github.com/mgeisler/smawk/pull/45): Move non-SMAWK code and unit

  tests out of lib and into separate modules.

- [#46](https://github.com/mgeisler/smawk/pull/46): Switch `smawk_row_minima`

  and `smawk_column_minima` functions to a new `Matrix` trait.

- [#47](https://github.com/mgeisler/smawk/pull/47): Make the dependency on the

  `ndarray` crate optional.

- [#48](https://github.com/mgeisler/smawk/pull/48): Let `is_monge` take a

  `Matrix` argument instead of `ndarray::Array2`.

- [#50](https://github.com/mgeisler/smawk/pull/50): Remove mandatory

  dependencies on `rand` and `num-traits` crates.

### Version 0.2.0 (2020-07-29)

This release updates the code to Rust 2018.

- [#18](https://github.com/mgeisler/smawk/pull/18): Make `online_column_minima`

  generic in matrix type.

- [#23](https://github.com/mgeisler/smawk/pull/23): Switch to the

  [Rust 2018][rust-2018] edition. We test against the latest stable and nightly

  version of Rust.

- [#29](https://github.com/mgeisler/smawk/pull/29): Drop strict Rust 2018

  compatibility by not testing with Rust 1.31.0.

- [#32](https://github.com/mgeisler/smawk/pull/32): Fix crash on overflow in

  `is_monge`.

- [#33](https://github.com/mgeisler/smawk/pull/33): Update `rand` dependency to

  latest version and get rid of `rand_derive`.

- [#34](https://github.com/mgeisler/smawk/pull/34): Bump `num-traits` and

  `version-sync` dependencies to latest versions.

- [#35](https://github.com/mgeisler/smawk/pull/35): Drop unnecessary Windows

  tests. The assumption is that the numeric computations we do are

  cross-platform.

- [#36](https://github.com/mgeisler/smawk/pull/36): Update `ndarray` dependency

  to the latest version.

- [#37](https://github.com/mgeisler/smawk/pull/37): Automate publishing new

  releases to crates.io.

### Version 0.1.0 — August 7th, 2018

First release with the classical offline SMAWK algorithm as well as a newer

online version where the matrix entries can depend on previously computed column

minima.

## License

SMAWK can be distributed according to the [MIT license][mit]. Contributions will

be accepted under the same license.

[build-status]: https://github.com/mgeisler/smawk/actions?query=branch%3Amaster+workflow%3Abuild

[crates-io]: https://crates.io/crates/smawk

[codecov]: https://codecov.io/gh/mgeisler/smawk

[textwrap]: https://crates.io/crates/textwrap

[smawk]: https://en.wikipedia.org/wiki/SMAWK_algorithm

[api-docs]: https://docs.rs/smawk/

[rust-2018]: https://doc.rust-lang.org/edition-guide/rust-2018/

[mit]: LICENSE

ecosyste.ms

Data

Tools

Indexes

Applications

Experiments

Awesome

https://github.com/mgeisler/smawk

Awesome Lists containing this project

README