# Copyright 2018-2020 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.fingerprint._occurrence_halved.
Cisłak & Grabowski's occurrence halved fingerprint
"""
from deprecation import deprecated
from ._fingerprint import MOST_COMMON_LETTERS_CG, _Fingerprint
from .. import __version__
__all__ = ['OccurrenceHalved', 'occurrence_halved_fingerprint']
[docs]class OccurrenceHalved(_Fingerprint):
"""Occurrence Halved Fingerprint.
Based on the occurrence halved fingerprint from :cite:`Cislak:2017`.
.. versionadded:: 0.3.6
"""
def __init__(self, n_bits=16, most_common=MOST_COMMON_LETTERS_CG):
"""Initialize Count instance.
Parameters
----------
n_bits : int
Number of bits in the fingerprint returned
most_common : list
The most common tokens in the target language, ordered by frequency
.. versionadded:: 0.4.0
"""
super(_Fingerprint, self).__init__()
self._n_bits = n_bits
self._most_common = most_common
[docs] def fingerprint(self, word):
"""Return the occurrence halved fingerprint.
Based on the occurrence halved fingerprint from :cite:`Cislak:2017`.
Parameters
----------
word : str
The word to fingerprint
n_bits : int
Number of bits in the fingerprint returned
most_common : list
The most common tokens in the target language, ordered by frequency
Returns
-------
int
The occurrence halved fingerprint
Examples
--------
>>> ohf = OccurrenceHalved()
>>> bin(ohf.fingerprint('hat'))
'0b1010000000010'
>>> bin(ohf.fingerprint('niall'))
'0b10010100000'
>>> bin(ohf.fingerprint('colin'))
'0b1001010000'
>>> bin(ohf.fingerprint('atcg'))
'0b10100000000000'
>>> bin(ohf.fingerprint('entreatment'))
'0b1111010000110000'
.. versionadded:: 0.3.0
.. versionchanged:: 0.3.6
Encapsulated in class
"""
n_bits = self._n_bits
if n_bits % 2:
n_bits += 1
w_len = len(word) // 2
w_1 = set(word[:w_len])
w_2 = set(word[w_len:])
fingerprint = 0
for letter in self._most_common:
if n_bits:
fingerprint <<= 1
if letter in w_1:
fingerprint += 1
fingerprint <<= 1
if letter in w_2:
fingerprint += 1
n_bits -= 2
else:
break
if n_bits > 0:
fingerprint <<= n_bits
return fingerprint
[docs]@deprecated(
deprecated_in='0.4.0',
removed_in='0.6.0',
current_version=__version__,
details='Use the OccurrenceHalved.fingerprint method instead.',
)
def occurrence_halved_fingerprint(
word, n_bits=16, most_common=MOST_COMMON_LETTERS_CG
):
"""Return the occurrence halved fingerprint.
This is a wrapper for :py:meth:`OccurrenceHalved.fingerprint`.
Parameters
----------
word : str
The word to fingerprint
n_bits : int
Number of bits in the fingerprint returned
most_common : list
The most common tokens in the target language, ordered by frequency
Returns
-------
int
The occurrence halved fingerprint
Examples
--------
>>> bin(occurrence_halved_fingerprint('hat'))
'0b1010000000010'
>>> bin(occurrence_halved_fingerprint('niall'))
'0b10010100000'
>>> bin(occurrence_halved_fingerprint('colin'))
'0b1001010000'
>>> bin(occurrence_halved_fingerprint('atcg'))
'0b10100000000000'
>>> bin(occurrence_halved_fingerprint('entreatment'))
'0b1111010000110000'
.. versionadded:: 0.3.0
"""
return OccurrenceHalved(n_bits, most_common).fingerprint(word)
if __name__ == '__main__':
import doctest
doctest.testmod()