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# -*- coding: utf-8 -*- |
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# Copyright 2019 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._chao_dice. |
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Chao's Dice similarity |
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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 ._chao_jaccard import ChaoJaccard |
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__all__ = ['ChaoDice'] |
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class ChaoDice(ChaoJaccard): |
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r"""Chao's Dice similarity. |
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Chao's Dice similarity :cite:`Chao:2004` |
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.. versionadded:: 0.4.1 |
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""" |
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def __init__(self, **kwargs): |
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"""Initialize ChaoDice instance. |
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Parameters |
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---------- |
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**kwargs |
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Arbitrary keyword arguments |
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.. versionadded:: 0.4.1 |
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""" |
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super(ChaoDice, self).__init__(**kwargs) |
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def sim(self, src, tar): |
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"""Return the normalized Chao's Dice similarity of two strings. |
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Parameters |
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---------- |
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src : str |
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Source string for comparison |
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tar : str |
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Target string for comparison |
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Returns |
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------- |
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float |
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Normalized Chao's Dice similarity |
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Examples |
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-------- |
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>>> import random |
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>>> random.seed(0) |
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>>> cmp = ChaoDice() |
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>>> cmp.sim('cat', 'hat') |
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0.36666666666666664 |
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>>> cmp.sim('Niall', 'Neil') |
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0.27868852459016397 |
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>>> cmp.sim('aluminum', 'Catalan') |
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0.0 |
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>>> cmp.sim('ATCG', 'TAGC') |
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0.0 |
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.. versionadded:: 0.4.1 |
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""" |
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return max(0.0, min(1.0, self.sim_score(src, tar))) |
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def sim_score(self, src, tar): |
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"""Return the Chao's Dice similarity of two strings. |
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Parameters |
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---------- |
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src : str |
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Source string for comparison |
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tar : str |
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Target string for comparison |
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Returns |
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------- |
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float |
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Chao's Dice similarity |
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Examples |
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-------- |
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>>> import random |
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>>> random.seed(0) |
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>>> cmp = ChaoDice() |
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>>> cmp.sim_score('cat', 'hat') |
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0.36666666666666664 |
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>>> cmp.sim_score('Niall', 'Neil') |
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0.27868852459016397 |
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>>> cmp.sim_score('aluminum', 'Catalan') |
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0.0 |
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>>> cmp.sim_score('ATCG', 'TAGC') |
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0.0 |
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.. versionadded:: 0.4.1 |
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""" |
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self._tokenize(src, tar) |
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u_hat, v_hat = self._get_estimates(src, tar) |
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num = u_hat * v_hat |
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if num: |
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return 2 * num / (u_hat + v_hat) |
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return 0.0 |
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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
