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Efficient native Python implementation of the integer square root function.

Project description

Efficient Python implementation of the integer square root function.

PyPI version and link. travis coveralls


Given an arbitrarily large non-negative integer n, finds the largest integer r such that r**2 <= n and (r+1)**2 > n. The running time is linear in the bit length of the integer.

Package Installation and Usage

The package is available on PyPI:

python -m pip install isqrt

The library can be imported in the usual way:

from isqrt import isqrt

Testing and Conventions

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


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

python isqrt/ -v

Style conventions are enforced using Pylint:

pylint isqrt


The initial version of this function was posted on Stack Overflow. A more efficient version was implemented by Alexander Gosselin here. The implementation in this package is adapted almost directly from these previous implementations.


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


Beginning with version 0.10.0, 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.

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Files for isqrt, version 0.10.0
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