# Copyright 2014-2020 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._mra.
The Match Rating Algorithm's distance measure
"""
from deprecation import deprecated
from ._distance import _Distance
from .. import __version__
from ..phonetic import mra
__all__ = ['MRA', 'dist_mra', 'mra_compare', 'sim_mra']
[docs]class MRA(_Distance):
"""Match Rating Algorithm comparison rating.
The Western Airlines Surname Match Rating Algorithm comparison rating, as
presented on page 18 of :cite:`Moore:1977`.
.. versionadded:: 0.3.6
"""
[docs] def dist_abs(self, src, tar):
"""Return the MRA comparison rating of two strings.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
int
MRA comparison rating
Examples
--------
>>> cmp = MRA()
>>> cmp.dist_abs('cat', 'hat')
5
>>> cmp.dist_abs('Niall', 'Neil')
6
>>> cmp.dist_abs('aluminum', 'Catalan')
0
>>> cmp.dist_abs('ATCG', 'TAGC')
5
.. versionadded:: 0.1.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
if src == tar:
return 6
if src == '' or tar == '':
return 0
src = list(mra(src))
tar = list(mra(tar))
if abs(len(src) - len(tar)) > 2:
return 0
length_sum = len(src) + len(tar)
if length_sum < 5:
min_rating = 5
elif length_sum < 8:
min_rating = 4
elif length_sum < 12:
min_rating = 3
else:
min_rating = 2
for _ in range(2):
new_src = []
new_tar = []
minlen = min(len(src), len(tar))
for i in range(minlen):
if src[i] != tar[i]:
new_src.append(src[i])
new_tar.append(tar[i])
src = new_src + src[minlen:]
tar = new_tar + tar[minlen:]
src.reverse()
tar.reverse()
similarity = 6 - max(len(src), len(tar))
if similarity >= min_rating:
return similarity
return 0
[docs] def sim(self, src, tar):
"""Return the normalized MRA similarity of two strings.
This is the MRA normalized to :math:`[0, 1]`, given that MRA itself is
constrained to the range :math:`[0, 6]`.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
float
Normalized MRA similarity
Examples
--------
>>> cmp = MRA()
>>> cmp.sim('cat', 'hat')
0.8333333333333334
>>> cmp.sim('Niall', 'Neil')
1.0
>>> cmp.sim('aluminum', 'Catalan')
0.0
>>> cmp.sim('ATCG', 'TAGC')
0.8333333333333334
.. versionadded:: 0.1.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
return mra_compare(src, tar) / 6
[docs]@deprecated(
deprecated_in='0.4.0',
removed_in='0.6.0',
current_version=__version__,
details='Use the MRA.dist_abs method instead.',
)
def mra_compare(src, tar):
"""Return the MRA comparison rating of two strings.
This is a wrapper for :py:meth:`MRA.dist_abs`.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
int
MRA comparison rating
Examples
--------
>>> mra_compare('cat', 'hat')
5
>>> mra_compare('Niall', 'Neil')
6
>>> mra_compare('aluminum', 'Catalan')
0
>>> mra_compare('ATCG', 'TAGC')
5
.. versionadded:: 0.1.0
"""
return MRA().dist_abs(src, tar)
[docs]@deprecated(
deprecated_in='0.4.0',
removed_in='0.6.0',
current_version=__version__,
details='Use the MRA.sim method instead.',
)
def sim_mra(src, tar):
"""Return the normalized MRA similarity of two strings.
This is a wrapper for :py:meth:`MRA.sim`.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
float
Normalized MRA similarity
Examples
--------
>>> sim_mra('cat', 'hat')
0.8333333333333334
>>> sim_mra('Niall', 'Neil')
1.0
>>> sim_mra('aluminum', 'Catalan')
0.0
>>> sim_mra('ATCG', 'TAGC')
0.8333333333333334
.. versionadded:: 0.1.0
"""
return MRA().sim(src, tar)
[docs]@deprecated(
deprecated_in='0.4.0',
removed_in='0.6.0',
current_version=__version__,
details='Use the MRA.dist method instead.',
)
def dist_mra(src, tar):
"""Return the normalized MRA distance between two strings.
This is a wrapper for :py:meth:`MRA.dist`.
Parameters
----------
src : str
Source string for comparison
tar : str
Target string for comparison
Returns
-------
float
Normalized MRA distance
Examples
--------
>>> dist_mra('cat', 'hat')
0.16666666666666663
>>> dist_mra('Niall', 'Neil')
0.0
>>> dist_mra('aluminum', 'Catalan')
1.0
>>> dist_mra('ATCG', 'TAGC')
0.16666666666666663
.. versionadded:: 0.1.0
"""
return MRA().dist(src, tar)
if __name__ == '__main__':
import doctest
doctest.testmod()