# Copyright 2019-2020 by Christopher C. Little. # This file is part of Abydos. # # Abydos is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # Abydos is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with Abydos. If not, see <http://www.gnu.org/licenses/>. """abydos.distance._consonni_todeschini_i. Consonni & Todeschini I similarity """ from math import log1p from typing import Any, Counter as TCounter, Optional, Sequence, Set, Union from ._token_distance import _TokenDistance from ..tokenizer import _Tokenizer __all__ = ['ConsonniTodeschiniI'] class ConsonniTodeschiniI(_TokenDistance): r"""Consonni & Todeschini I similarity. For two sets X and Y and a population N, Consonni & Todeschini I similarity :cite:`Consonni:2012` is .. math:: sim_{ConsonniTodeschiniI}(X, Y) = \frac{log(1+|X \cap Y|+|(N \setminus X) \setminus Y|)} {log(1+|N|)} In :ref:`2x2 confusion table terms <confusion_table>`, where a+b+c+d=n, this is .. math:: sim_{ConsonniTodeschiniI} = \frac{log(1+a+d)}{log(1+n)} .. versionadded:: 0.4.0 """ def __init__( self, alphabet: Optional[ Union[TCounter[str], Sequence[str], Set[str], int] ] = None, tokenizer: Optional[_Tokenizer] = None, intersection_type: str = 'crisp', **kwargs: Any ) -> None: """Initialize ConsonniTodeschiniI instance. Parameters ---------- alphabet : Counter, collection, int, or None This represents the alphabet of possible tokens. See :ref:`alphabet <alphabet>` description in :py:class:`_TokenDistance` for details. tokenizer : _Tokenizer A tokenizer instance from the :py:mod:`abydos.tokenizer` package intersection_type : str Specifies the intersection type, and set type as a result: See :ref:`intersection_type <intersection_type>` description in :py:class:`_TokenDistance` for details. **kwargs Arbitrary keyword arguments Other Parameters ---------------- qval : int The length of each q-gram. Using this parameter and tokenizer=None will cause the instance to use the QGram tokenizer with this q value. metric : _Distance A string distance measure class for use in the ``soft`` and ``fuzzy`` variants. threshold : float A threshold value, similarities above which are counted as members of the intersection for the ``fuzzy`` variant. .. versionadded:: 0.4.0 """ super(ConsonniTodeschiniI, self).__init__( alphabet=alphabet, tokenizer=tokenizer, intersection_type=intersection_type, **kwargs ) def sim(self, src: str, tar: str) -> float: """Return the Consonni & Todeschini I similarity of two strings. Parameters ---------- src : str Source string (or QGrams/Counter objects) for comparison tar : str Target string (or QGrams/Counter objects) for comparison Returns ------- float Consonni & Todeschini I similarity Examples -------- >>> cmp = ConsonniTodeschiniI() >>> cmp.sim('cat', 'hat') 0.9992336018090547 >>> cmp.sim('Niall', 'Neil') 0.998656222829757 >>> cmp.sim('aluminum', 'Catalan') 0.9971098629456009 >>> cmp.sim('ATCG', 'TAGC') 0.9980766131469967 .. versionadded:: 0.4.0 """ if src == tar: return 1.0 self._tokenize(src, tar) a = self._intersection_card() d = self._total_complement_card() n = self._population_unique_card() return log1p(a + d) / log1p(n) if __name__ == '__main__': import doctest doctest.testmod()