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# -*- coding: utf-8 -*- |
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# Copyright 2018 by Christopher C. Little. |
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# This file is part of Abydos. |
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# |
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# Abydos is free software: you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation, either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# Abydos is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with Abydos. If not, see <http://www.gnu.org/licenses/>. |
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"""abydos.distance._chebyshev. |
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Chebyshev distance |
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""" |
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from __future__ import ( |
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absolute_import, |
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division, |
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print_function, |
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unicode_literals, |
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) |
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from ._minkowski import Minkowski |
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__all__ = ['Chebyshev', 'chebyshev'] |
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class Chebyshev(Minkowski): |
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r"""Chebyshev distance. |
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Euclidean distance is the chessboard distance, |
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equivalent to Minkowski distance in :math:`L^\infty-space`. |
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""" |
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def dist_abs(self, src, tar, qval=2, alphabet=None): |
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r"""Return the Chebyshev distance between two strings. |
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Args: |
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src (str): Source string (or QGrams/Counter objects) for comparison |
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tar (str): Target string (or QGrams/Counter objects) for comparison |
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qval (int): The length of each q-gram; 0 for non-q-gram version |
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alphabet (collection or int): The values or size of the alphabet |
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Returns: |
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float: The Chebyshev distance |
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Examples: |
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>>> cmp = Chebyshev() |
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>>> cmp.dist_abs('cat', 'hat') |
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1.0 |
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>>> cmp.dist_abs('Niall', 'Neil') |
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1.0 |
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>>> cmp.dist_abs('Colin', 'Cuilen') |
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1.0 |
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>>> cmp.dist_abs('ATCG', 'TAGC') |
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1.0 |
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>>> cmp.dist_abs('ATCG', 'TAGC', qval=1) |
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0.0 |
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>>> cmp.dist_abs('ATCGATTCGGAATTTC', 'TAGCATAATCGCCG', qval=1) |
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3.0 |
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""" |
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return super(self.__class__, self).dist_abs( |
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src, tar, qval, float('inf'), False, alphabet |
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) |
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def sim(self, *args, **kwargs): |
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"""Raise exception when called. |
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Args: |
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*args: Variable length argument list |
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**kwargs: Arbitrary keyword arguments |
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Raises: |
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Exception: Method disabled for Chebyshev distance |
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""" |
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raise Exception('Method disabled for Chebyshev distance.') |
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def dist(self, *args, **kwargs): |
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"""Raise exception when called. |
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Args: |
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*args: Variable length argument list |
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**kwargs: Arbitrary keyword arguments |
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Raises: |
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Exception: Method disabled for Chebyshev distance |
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""" |
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raise Exception('Method disabled for Chebyshev distance.') |
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def chebyshev(src, tar, qval=2, alphabet=None): |
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r"""Return the Chebyshev distance between two strings. |
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This is a wrapper for the :py:meth:`Chebyshev.dist_abs`. |
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Args: |
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src (str): Source string (or QGrams/Counter objects) for comparison |
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tar (str): Target string (or QGrams/Counter objects) for comparison |
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qval (int): The length of each q-gram; 0 for non-q-gram version |
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alphabet (collection or int): The values or size of the alphabet |
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Returns: |
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float: The Chebyshev distance |
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Examples: |
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>>> chebyshev('cat', 'hat') |
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1.0 |
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>>> chebyshev('Niall', 'Neil') |
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1.0 |
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>>> chebyshev('Colin', 'Cuilen') |
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1.0 |
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>>> chebyshev('ATCG', 'TAGC') |
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1.0 |
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>>> chebyshev('ATCG', 'TAGC', qval=1) |
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0.0 |
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>>> chebyshev('ATCGATTCGGAATTTC', 'TAGCATAATCGCCG', qval=1) |
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3.0 |
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""" |
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return Chebyshev().dist_abs(src, tar, qval, alphabet) |
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if __name__ == '__main__': |
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import doctest |
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doctest.testmod() |
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chrislit /
abydos
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