# Source code for abydos.distance._baulieu_vi

# Copyright 2019-2020 by Christopher C. Little.
# This file is part of Abydos.
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"""abydos.distance._baulieu_vi.

Baulieu VI distance
"""

from ._token_distance import _TokenDistance

__all__ = ['BaulieuVI']

[docs]class BaulieuVI(_TokenDistance): r"""Baulieu VI distance. For two sets X and Y and a population N, Baulieu VI distance :cite:Baulieu:1997 is .. math:: dist_{BaulieuVI}(X, Y) = \frac{|X \setminus Y| + |Y \setminus X|} {|X \cap Y| + |X \setminus Y| + |Y \setminus X| + 1} This is Baulieu's 24th dissimilarity coefficient. This coefficient fails Baulieu's (P3) property, that :math:D(a,b,c,d) = 1 for some (a,b,c,d). Rather, :math:D(a,b,c,d) < 1, but :math:\lim_{b \to \infty, c \to \infty} D(a,b,c,d) = 0 for :math:a = 0. In :ref:2x2 confusion table terms <confusion_table>, where a+b+c+d=n, this is .. math:: dist_{BaulieuVI} = \frac{b+c}{a+b+c+1} .. versionadded:: 0.4.0 """ def __init__( self, alphabet=None, tokenizer=None, intersection_type='crisp', **kwargs ): """Initialize BaulieuVI 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(BaulieuVI, self).__init__( alphabet=alphabet, tokenizer=tokenizer, intersection_type=intersection_type, **kwargs )
[docs] def dist(self, src, tar): """Return the Baulieu VI distance 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 Baulieu VI distance Examples -------- >>> cmp = BaulieuVI() >>> cmp.dist('cat', 'hat') 0.5714285714285714 >>> cmp.dist('Niall', 'Neil') 0.7 >>> cmp.dist('aluminum', 'Catalan') 0.8823529411764706 >>> cmp.dist('ATCG', 'TAGC') 0.9090909090909091 .. versionadded:: 0.4.0 """ self._tokenize(src, tar) a = self._intersection_card() b = self._src_only_card() c = self._tar_only_card() return (b + c) / (a + b + c + 1)
if __name__ == '__main__': import doctest doctest.testmod()