egcd 0.2.0

Easy-to-import Python module with a basic, efficient, native implementation of the extended Euclidean algorithm.

Easy-to-import Python module with a basic, efficient, native implementation of the extended Euclidean algorithm.

Package Installation and Usage

The package is available on PyPI:

python -m pip install egcd

The library can be imported in the usual way:

from egcd import egcd

The function egcd is an efficient implementation of the extended Euclidean algorithm. It accepts two integer inputs b and n, returning a tuple of the form (gcd(b, n), a, m) where the three integers in the tuple satisfy the identity (a * b) + (n * m) = gcd(b, n):

>>> egcd(1, 1)
(1, 0, 1)
>>> egcd(12, 8)
(4, 1, -1)
>>> egcd(23894798501898, 23948178468116)
(2, 2437250447493, -2431817869532)
>>> egcd(pow(2, 50), pow(3, 50))
(1, -260414429242905345185687, 408415383037561)

Testing and Conventions

All unit tests are executed and their coverage is measured when using nose (see setup.cfg for configuration details):

python -m pip install nose coverage
nosetests --cover-erase

Alternatively, all unit tests are included in the module itself and can be executed using doctest:

python egcd/egcd.py -v

Style conventions are enforced using Pylint:

python -m pip install pylint
pylint egcd

Contributions

In order to contribute to the source code, open an issue or submit a pull request on the GitHub page for this library.

Versioning

Beginning with version 0.1.0, the version number format for this library and the changes to the library associated with version number increments conform with Semantic Versioning 2.0.0.