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Paddle/python/paddle/fluid/tests/unittests/test_edit_distance_op.py

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3.6 KiB

# Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import unittest
import numpy as np
from op_test import OpTest
def Levenshtein(hyp, ref):
""" Compute the Levenshtein distance between two strings.
:param hyp: hypothesis string in index
:type hyp: list
:param ref: reference string in index
:type ref: list
"""
m = len(hyp)
n = len(ref)
if m == 0:
return n
if n == 0:
return m
dist = np.zeros((m + 1, n + 1)).astype("float32")
for i in range(0, m + 1):
dist[i][0] = i
for j in range(0, n + 1):
dist[0][j] = j
for i in range(1, m + 1):
for j in range(1, n + 1):
cost = 0 if hyp[i - 1] == ref[j - 1] else 1
deletion = dist[i - 1][j] + 1
insertion = dist[i][j - 1] + 1
substitution = dist[i - 1][j - 1] + cost
dist[i][j] = min(deletion, insertion, substitution)
return dist[m][n]
class TestEditDistanceOp(OpTest):
def setUp(self):
self.op_type = "edit_distance"
normalized = False
x1 = np.array([[0, 12, 3, 5, 8, 2]]).astype("int64")
x2 = np.array([[0, 12, 4, 7, 8]]).astype("int64")
x1 = np.transpose(x1)
x2 = np.transpose(x2)
x1_lod = [0, 1, 5]
x2_lod = [0, 3, 4]
num_strs = len(x1_lod) - 1
distance = np.zeros((num_strs, 1)).astype("float32")
sequence_num = np.array(2).astype("int64")
for i in range(0, num_strs):
distance[i] = Levenshtein(
hyp=x1[x1_lod[i]:x1_lod[i + 1]],
ref=x2[x2_lod[i]:x2_lod[i + 1]])
if normalized is True:
len_ref = x2_lod[i + 1] - x2_lod[i]
distance[i] = distance[i] / len_ref
self.attrs = {'normalized': normalized}
self.inputs = {'Hyps': (x1, [x1_lod]), 'Refs': (x2, [x2_lod])}
self.outputs = {'Out': distance, 'SequenceNum': sequence_num}
def test_check_output(self):
self.check_output()
class TestEditDistanceOpNormalized(OpTest):
def setUp(self):
self.op_type = "edit_distance"
normalized = True
x1 = np.array([[0, 10, 3, 6, 5, 8, 2]]).astype("int64")
x2 = np.array([[0, 10, 4, 6, 7, 8]]).astype("int64")
x1 = np.transpose(x1)
x2 = np.transpose(x2)
x1_lod = [0, 1, 3, 6]
x2_lod = [0, 2, 3, 5]
num_strs = len(x1_lod) - 1
distance = np.zeros((num_strs, 1)).astype("float32")
sequence_num = np.array(3).astype("int64")
for i in range(0, num_strs):
distance[i] = Levenshtein(
hyp=x1[x1_lod[i]:x1_lod[i + 1]],
ref=x2[x2_lod[i]:x2_lod[i + 1]])
if normalized is True:
len_ref = x2_lod[i + 1] - x2_lod[i]
distance[i] = distance[i] / len_ref
self.attrs = {'normalized': normalized}
self.inputs = {'Hyps': (x1, [x1_lod]), 'Refs': (x2, [x2_lod])}
self.outputs = {'Out': distance, 'SequenceNum': sequence_num}
def test_check_output(self):
self.check_output()
if __name__ == '__main__':
unittest.main()