File size: 7,235 Bytes
7934b29
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
# Copyright (c) 2022, NVIDIA CORPORATION.  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 os
from functools import lru_cache

import pytest
import torch
from omegaconf import DictConfig, OmegaConf

from nemo.collections.asr.metrics.wer import CTCDecoding, CTCDecodingConfig
from nemo.collections.asr.metrics.wer_bpe import CTCBPEDecoding, CTCBPEDecodingConfig
from nemo.collections.asr.parts.mixins import mixins
from nemo.collections.asr.parts.utils.rnnt_utils import Hypothesis


def char_vocabulary():
    return [' ', 'a', 'b', 'c', 'd', 'e', 'f']


@pytest.fixture()
@lru_cache(maxsize=8)
def tmp_tokenizer(test_data_dir):
    cfg = DictConfig({'dir': os.path.join(test_data_dir, "asr", "tokenizers", "an4_wpe_128"), 'type': 'wpe'})

    class _TmpASRBPE(mixins.ASRBPEMixin):
        def register_artifact(self, _, vocab_path):
            return vocab_path

    asrbpe = _TmpASRBPE()
    asrbpe._setup_tokenizer(cfg)
    return asrbpe.tokenizer


def check_char_timestamps(hyp: Hypothesis, decoding: CTCDecoding):
    assert hyp.timestep is not None
    assert isinstance(hyp.timestep, dict)
    assert 'timestep' in hyp.timestep
    assert 'char' in hyp.timestep
    assert 'word' in hyp.timestep

    words = hyp.text.split(decoding.word_seperator)
    words = list(filter(lambda x: x != '', words))
    assert len(hyp.timestep['word']) == len(words)


def check_subword_timestamps(hyp: Hypothesis, decoding: CTCBPEDecoding):
    assert hyp.timestep is not None
    assert isinstance(hyp.timestep, dict)
    assert 'timestep' in hyp.timestep
    assert 'char' in hyp.timestep
    assert 'word' in hyp.timestep

    chars = list(hyp.text)
    chars = list(filter(lambda x: x not in ['', ' ', '#'], chars))
    all_chars = [list(decoding.tokenizer.tokens_to_text(data['char'])) for data in hyp.timestep['char']]
    all_chars = [char for subword in all_chars for char in subword]
    all_chars = list(filter(lambda x: x not in ['', ' ', '#'], all_chars))
    assert len(chars) == len(all_chars)


class TestCTCDecoding:
    @pytest.mark.unit
    def test_constructor(self):
        cfg = CTCDecodingConfig()
        vocab = char_vocabulary()
        decoding = CTCDecoding(decoding_cfg=cfg, vocabulary=vocab)
        assert decoding is not None

    @pytest.mark.unit
    def test_constructor_subword(self, tmp_tokenizer):
        cfg = CTCBPEDecodingConfig()
        decoding = CTCBPEDecoding(decoding_cfg=cfg, tokenizer=tmp_tokenizer)
        assert decoding is not None

    @pytest.mark.unit
    def test_char_decoding_greedy_forward(self,):
        cfg = CTCDecodingConfig(strategy='greedy')
        vocab = char_vocabulary()
        decoding = CTCDecoding(decoding_cfg=cfg, vocabulary=vocab)

        B, T = 4, 20
        V = len(char_vocabulary()) + 1
        input_signal = torch.randn(size=(B, T, V))
        length = torch.randint(low=1, high=T, size=[B])

        with torch.no_grad():
            texts, _ = decoding.ctc_decoder_predictions_tensor(
                input_signal, length, fold_consecutive=True, return_hypotheses=False
            )

            for text in texts:
                assert isinstance(text, str)

    @pytest.mark.unit
    @pytest.mark.parametrize('alignments', [False, True])
    @pytest.mark.parametrize('timestamps', [False, True])
    def test_char_decoding_greedy_forward_hypotheses(self, alignments, timestamps):
        cfg = CTCDecodingConfig(strategy='greedy', preserve_alignments=alignments, compute_timestamps=timestamps)
        vocab = char_vocabulary()
        decoding = CTCDecoding(decoding_cfg=cfg, vocabulary=vocab)

        B, T = 4, 20
        V = len(char_vocabulary()) + 1
        input_signal = torch.randn(size=(B, T, V))
        length = torch.randint(low=1, high=T, size=[B])

        with torch.no_grad():
            hyps, _ = decoding.ctc_decoder_predictions_tensor(
                input_signal, length, fold_consecutive=True, return_hypotheses=True
            )

            for idx, hyp in enumerate(hyps):
                assert isinstance(hyp, Hypothesis)
                assert torch.is_tensor(hyp.y_sequence)
                assert isinstance(hyp.text, str)

                # alignments check
                if alignments:
                    assert hyp.alignments is not None
                    assert isinstance(hyp.alignments, tuple)
                    assert len(hyp.alignments[0]) == length[idx]
                    assert len(hyp.alignments[1]) == length[idx]

                # timestamps check
                if timestamps:
                    check_char_timestamps(hyp, decoding)

    @pytest.mark.unit
    def test_subword_decoding_greedy_forward(self, tmp_tokenizer):
        cfg = CTCBPEDecodingConfig(strategy='greedy')
        decoding = CTCBPEDecoding(decoding_cfg=cfg, tokenizer=tmp_tokenizer)

        B, T = 4, 20
        V = decoding.tokenizer.tokenizer.vocab_size + 1
        input_signal = torch.randn(size=(B, T, V))
        length = torch.randint(low=1, high=T, size=[B])

        with torch.no_grad():
            texts, _ = decoding.ctc_decoder_predictions_tensor(
                input_signal, length, fold_consecutive=True, return_hypotheses=False
            )

            for text in texts:
                assert isinstance(text, str)

    @pytest.mark.unit
    @pytest.mark.parametrize('alignments', [False, True])
    @pytest.mark.parametrize('timestamps', [False, True])
    def test_subword_decoding_greedy_forward_hypotheses(self, tmp_tokenizer, alignments, timestamps):
        cfg = CTCBPEDecodingConfig(strategy='greedy', preserve_alignments=alignments, compute_timestamps=timestamps)
        decoding = CTCBPEDecoding(decoding_cfg=cfg, tokenizer=tmp_tokenizer)

        B, T = 4, 20
        V = decoding.tokenizer.tokenizer.vocab_size + 1
        input_signal = torch.randn(size=(B, T, V))
        length = torch.randint(low=1, high=T, size=[B])

        with torch.no_grad():
            hyps, _ = decoding.ctc_decoder_predictions_tensor(
                input_signal, length, fold_consecutive=True, return_hypotheses=True
            )

            for idx, hyp in enumerate(hyps):
                assert isinstance(hyp, Hypothesis)
                assert torch.is_tensor(hyp.y_sequence)
                assert isinstance(hyp.text, str)

                # alignments check
                if alignments:
                    assert hyp.alignments is not None
                    assert isinstance(hyp.alignments, tuple)
                    assert len(hyp.alignments[0]) == length[idx]
                    assert len(hyp.alignments[1]) == length[idx]

                # timestamps check
                if timestamps:
                    check_subword_timestamps(hyp, decoding)