# 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._azzoo.
AZZOO similarity
"""
from ._token_distance import _TokenDistance
__all__ = ['AZZOO']
[docs]class AZZOO(_TokenDistance):
r"""AZZOO similarity.
For two sets X and Y, and alphabet N, and a parameter :math:`\sigma`,
AZZOO similarity :cite:`Cha:2006` is
.. math::
sim_{AZZOO_{\sigma}}(X, Y) =
\sum{s_i}
where :math:`s_i = 1` if :math:`X_i = Y_i = 1`,
:math:`s_i = \sigma` if :math:`X_i = Y_i = 0`,
and :math:`s_i = 0` otherwise.
In :ref:`2x2 confusion table terms <confusion_table>`, where a+b+c+d=n,
this is
.. math::
sim_{AZZOO} = a + \sigma \cdot d
.. versionadded:: 0.4.0
"""
def __init__(
self,
sigma=0.5,
alphabet=None,
tokenizer=None,
intersection_type='crisp',
**kwargs
):
"""Initialize AZZOO instance.
Parameters
----------
sigma : float
Sigma designates the contribution to similarity given by the
0-0 samples in the set.
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(AZZOO, self).__init__(
alphabet=alphabet,
tokenizer=tokenizer,
intersection_type=intersection_type,
**kwargs
)
self.set_params(sigma=sigma)
[docs] def sim_score(self, src, tar):
"""Return the AZZOO 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
AZZOO similarity
Examples
--------
>>> cmp = AZZOO()
>>> cmp.sim_score('cat', 'hat')
391.0
>>> cmp.sim_score('Niall', 'Neil')
389.5
>>> cmp.sim_score('aluminum', 'Catalan')
385.5
>>> cmp.sim_score('ATCG', 'TAGC')
387.0
.. versionadded:: 0.4.0
"""
self._tokenize(src, tar)
a = self._intersection_card()
d = self._total_complement_card()
return a + self.params['sigma'] * d
[docs] def sim(self, src, tar):
"""Return the AZZOO 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
AZZOO similarity
Examples
--------
>>> cmp = AZZOO()
>>> cmp.sim('cat', 'hat')
0.9923857868020305
>>> cmp.sim('Niall', 'Neil')
0.9860759493670886
>>> cmp.sim('aluminum', 'Catalan')
0.9710327455919395
>>> cmp.sim('ATCG', 'TAGC')
0.9809885931558935
.. versionadded:: 0.4.0
"""
den = max(self.sim_score(src, src), self.sim_score(tar, tar))
if den == 0.0:
return 1.0
return self.sim_score(src, tar) / den
if __name__ == '__main__':
import doctest
doctest.testmod()