chore: import upstream snapshot with attribution

edgelm/examples/speech_recognition/README.md

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+### 2021 Update: We are merging this example into the [S2T framework](../speech_to_text), which supports more generic speech-to-text tasks (e.g. speech translation) and more flexible data processing pipelines. Please stay tuned.
+
+# Speech Recognition
+`examples/speech_recognition` is implementing ASR task in Fairseq, along with needed features, datasets, models and loss functions to train and infer model described in [Transformers with convolutional context for ASR (Abdelrahman Mohamed et al., 2019)](https://arxiv.org/abs/1904.11660).
+
+
+## Additional dependencies
+On top of main fairseq dependencies there are couple more additional requirements.
+
+1) Please follow the instructions to install [torchaudio](https://github.com/pytorch/audio). This is required to compute audio fbank features.
+2) [Sclite](http://www1.icsi.berkeley.edu/Speech/docs/sctk-1.2/sclite.htm#sclite_name_0) is used to measure WER. Sclite can be downloaded and installed from source from sctk package [here](http://www.openslr.org/4/). Training and inference doesn't require Sclite dependency.
+3) [sentencepiece](https://github.com/google/sentencepiece) is required in order to create dataset with word-piece targets.
+
+## Preparing librispeech data
+```
+./examples/speech_recognition/datasets/prepare-librispeech.sh $DIR_TO_SAVE_RAW_DATA $DIR_FOR_PREPROCESSED_DATA
+```
+
+## Training librispeech data
+```
+python train.py $DIR_FOR_PREPROCESSED_DATA --save-dir $MODEL_PATH --max-epoch 80 --task speech_recognition --arch vggtransformer_2 --optimizer adadelta --lr 1.0 --adadelta-eps 1e-8 --adadelta-rho 0.95 --clip-norm 10.0  --max-tokens 5000 --log-format json --log-interval 1 --criterion cross_entropy_acc --user-dir examples/speech_recognition/
+```
+
+## Inference for librispeech
+`$SET` can be `test_clean` or `test_other`
+Any checkpoint in `$MODEL_PATH` can be selected. In this example we are working with `checkpoint_last.pt`
+```
+python examples/speech_recognition/infer.py $DIR_FOR_PREPROCESSED_DATA --task speech_recognition --max-tokens 25000 --nbest 1 --path $MODEL_PATH/checkpoint_last.pt --beam 20 --results-path $RES_DIR --batch-size 40 --gen-subset $SET --user-dir examples/speech_recognition/
+```
+
+## Inference for librispeech
+```
+sclite -r ${RES_DIR}/ref.word-checkpoint_last.pt-${SET}.txt -h ${RES_DIR}/hypo.word-checkpoint_last.pt-${SET}.txt -i rm -o all stdout > $RES_REPORT
+```
+`Sum/Avg` row from first table of the report has WER
+
+## Using flashlight (previously called [wav2letter](https://github.com/facebookresearch/wav2letter)) components
+[flashlight](https://github.com/facebookresearch/flashlight) now has integration with fairseq. Currently this includes:
+
+* AutoSegmentationCriterion (ASG)
+* flashlight-style Conv/GLU model
+* flashlight's beam search decoder
+
+To use these, follow the instructions on [this page](https://github.com/facebookresearch/flashlight/tree/master/bindings/python) to install python bindings.
+
+## Training librispeech data (flashlight style, Conv/GLU + ASG loss)
+Training command:
+```
+python train.py $DIR_FOR_PREPROCESSED_DATA --save-dir $MODEL_PATH --max-epoch 100 --task speech_recognition --arch w2l_conv_glu_enc --batch-size 4 --optimizer sgd --lr 0.3,0.8 --momentum 0.8 --clip-norm 0.2 --max-tokens 50000 --log-format json --log-interval 100 --num-workers 0 --sentence-avg --criterion asg_loss --asg-transitions-init 5 --max-replabel 2 --linseg-updates 8789 --user-dir examples/speech_recognition
+```
+
+Note that ASG loss currently doesn't do well with word-pieces. You should prepare a dataset with character targets by setting `nbpe=31` in `prepare-librispeech.sh`.
+
+## Inference for librispeech (flashlight decoder, n-gram LM)
+Inference command:
+```
+python examples/speech_recognition/infer.py $DIR_FOR_PREPROCESSED_DATA --task speech_recognition --seed 1 --nbest 1 --path $MODEL_PATH/checkpoint_last.pt --gen-subset $SET --results-path $RES_DIR --w2l-decoder kenlm --kenlm-model $KENLM_MODEL_PATH --lexicon $LEXICON_PATH --beam 200 --beam-threshold 15 --lm-weight 1.5 --word-score 1.5 --sil-weight -0.3 --criterion asg_loss --max-replabel 2 --user-dir examples/speech_recognition
+```
+
+`$KENLM_MODEL_PATH` should be a standard n-gram language model file. `$LEXICON_PATH` should be a flashlight-style lexicon (list of known words and their spellings). For ASG inference, a lexicon line should look like this (note the repetition labels):
+```
+doorbell  D O 1 R B E L 1 ▁
+```
+For CTC inference with word-pieces, repetition labels are not used and the lexicon should have most common spellings for each word (one can use sentencepiece's `NBestEncodeAsPieces` for this):
+```
+doorbell  ▁DOOR BE LL
+doorbell  ▁DOOR B E LL
+doorbell  ▁DO OR BE LL
+doorbell  ▁DOOR B EL L
+doorbell  ▁DOOR BE L L
+doorbell  ▁DO OR B E LL
+doorbell  ▁DOOR B E L L
+doorbell  ▁DO OR B EL L
+doorbell  ▁DO O R BE LL
+doorbell  ▁DO OR BE L L
+```
+Lowercase vs. uppercase matters: the *word* should match the case of the n-gram language model (i.e. `$KENLM_MODEL_PATH`), while the *spelling* should match the case of the token dictionary (i.e. `$DIR_FOR_PREPROCESSED_DATA/dict.txt`).
+
+## Inference for librispeech (flashlight decoder, viterbi only)
+Inference command:
+```
+python examples/speech_recognition/infer.py $DIR_FOR_PREPROCESSED_DATA --task speech_recognition --seed 1 --nbest 1 --path $MODEL_PATH/checkpoint_last.pt --gen-subset $SET --results-path $RES_DIR --w2l-decoder viterbi --criterion asg_loss --max-replabel 2 --user-dir examples/speech_recognition
+```

edgelm/examples/speech_recognition/__init__.py

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+from . import criterions, models, tasks  # noqa

edgelm/examples/speech_recognition/criterions/ASG_loss.py

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+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch
+from examples.speech_recognition.data.replabels import pack_replabels
+from fairseq import utils
+from fairseq.criterions import FairseqCriterion, register_criterion
+
+
+@register_criterion("asg_loss")
+class ASGCriterion(FairseqCriterion):
+    @staticmethod
+    def add_args(parser):
+        group = parser.add_argument_group("ASG Loss")
+        group.add_argument(
+            "--asg-transitions-init",
+            help="initial diagonal value of transition matrix",
+            type=float,
+            default=0.0,
+        )
+        group.add_argument(
+            "--max-replabel", help="maximum # of replabels", type=int, default=2
+        )
+        group.add_argument(
+            "--linseg-updates",
+            help="# of training updates to use LinSeg initialization",
+            type=int,
+            default=0,
+        )
+        group.add_argument(
+            "--hide-linseg-messages",
+            help="hide messages about LinSeg initialization",
+            action="store_true",
+        )
+
+    def __init__(
+        self,
+        task,
+        silence_token,
+        asg_transitions_init,
+        max_replabel,
+        linseg_updates,
+        hide_linseg_messages,
+    ):
+        from flashlight.lib.sequence.criterion import ASGLoss, CriterionScaleMode
+
+        super().__init__(task)
+        self.tgt_dict = task.target_dictionary
+        self.eos = self.tgt_dict.eos()
+        self.silence = (
+            self.tgt_dict.index(silence_token)
+            if silence_token in self.tgt_dict
+            else None
+        )
+        self.max_replabel = max_replabel
+
+        num_labels = len(self.tgt_dict)
+        self.asg = ASGLoss(num_labels, scale_mode=CriterionScaleMode.TARGET_SZ_SQRT)
+        self.asg.trans = torch.nn.Parameter(
+            asg_transitions_init * torch.eye(num_labels), requires_grad=True
+        )
+
+        self.linseg_progress = torch.nn.Parameter(
+            torch.tensor([0], dtype=torch.int), requires_grad=False
+        )
+        self.linseg_maximum = linseg_updates
+        self.linseg_message_state = "none" if hide_linseg_messages else "start"
+
+    @classmethod
+    def build_criterion(cls, args, task):
+        return cls(
+            task,
+            args.silence_token,
+            args.asg_transitions_init,
+            args.max_replabel,
+            args.linseg_updates,
+            args.hide_linseg_messages,
+        )
+
+    def linseg_step(self):
+        if not self.training:
+            return False
+        if self.linseg_progress.item() < self.linseg_maximum:
+            if self.linseg_message_state == "start":
+                print("| using LinSeg to initialize ASG")
+                self.linseg_message_state = "finish"
+            self.linseg_progress.add_(1)
+            return True
+        elif self.linseg_message_state == "finish":
+            print("| finished LinSeg initialization")
+            self.linseg_message_state = "none"
+        return False
+
+    def replace_eos_with_silence(self, tgt):
+        if tgt[-1] != self.eos:
+            return tgt
+        elif self.silence is None or (len(tgt) > 1 and tgt[-2] == self.silence):
+            return tgt[:-1]
+        else:
+            return tgt[:-1] + [self.silence]
+
+    def forward(self, model, sample, reduce=True):
+        """Compute the loss for the given sample.
+
+        Returns a tuple with three elements:
+        1) the loss
+        2) the sample size, which is used as the denominator for the gradient
+        3) logging outputs to display while training
+        """
+
+        net_output = model(**sample["net_input"])
+        emissions = net_output["encoder_out"].transpose(0, 1).contiguous()
+        B = emissions.size(0)
+        T = emissions.size(1)
+        device = emissions.device
+
+        target = torch.IntTensor(B, T)
+        target_size = torch.IntTensor(B)
+        using_linseg = self.linseg_step()
+
+        for b in range(B):
+            initial_target_size = sample["target_lengths"][b].item()
+            if initial_target_size == 0:
+                raise ValueError("target size cannot be zero")
+
+            tgt = sample["target"][b, :initial_target_size].tolist()
+            tgt = self.replace_eos_with_silence(tgt)
+            tgt = pack_replabels(tgt, self.tgt_dict, self.max_replabel)
+            tgt = tgt[:T]
+
+            if using_linseg:
+                tgt = [tgt[t * len(tgt) // T] for t in range(T)]
+
+            target[b][: len(tgt)] = torch.IntTensor(tgt)
+            target_size[b] = len(tgt)
+
+        loss = self.asg.forward(emissions, target.to(device), target_size.to(device))
+
+        if reduce:
+            loss = torch.sum(loss)
+
+        sample_size = (
+            sample["target"].size(0) if self.args.sentence_avg else sample["ntokens"]
+        )
+        logging_output = {
+            "loss": utils.item(loss.data) if reduce else loss.data,
+            "ntokens": sample["ntokens"],
+            "nsentences": sample["target"].size(0),
+            "sample_size": sample_size,
+        }
+        return loss, sample_size, logging_output
+
+    @staticmethod
+    def aggregate_logging_outputs(logging_outputs):
+        """Aggregate logging outputs from data parallel training."""
+        loss_sum = sum(log.get("loss", 0) for log in logging_outputs)
+        ntokens = sum(log.get("ntokens", 0) for log in logging_outputs)
+        nsentences = sum(log.get("nsentences", 0) for log in logging_outputs)
+        sample_size = sum(log.get("sample_size", 0) for log in logging_outputs)
+        agg_output = {
+            "loss": loss_sum / nsentences,
+            "ntokens": ntokens,
+            "nsentences": nsentences,
+            "sample_size": sample_size,
+        }
+        return agg_output

edgelm/examples/speech_recognition/criterions/__init__.py

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+import importlib
+import os
+
+
+# ASG loss requires flashlight bindings
+files_to_skip = set()
+try:
+    import flashlight.lib.sequence.criterion
+except ImportError:
+    files_to_skip.add("ASG_loss.py")
+
+for file in sorted(os.listdir(os.path.dirname(__file__))):
+    if file.endswith(".py") and not file.startswith("_") and file not in files_to_skip:
+        criterion_name = file[: file.find(".py")]
+        importlib.import_module(
+            "examples.speech_recognition.criterions." + criterion_name
+        )

edgelm/examples/speech_recognition/criterions/cross_entropy_acc.py

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+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import logging
+import math
+
+import torch
+import torch.nn.functional as F
+from fairseq import utils
+from fairseq.criterions import FairseqCriterion, register_criterion
+
+
+@register_criterion("cross_entropy_acc")
+class CrossEntropyWithAccCriterion(FairseqCriterion):
+    def __init__(self, task, sentence_avg):
+        super().__init__(task)
+        self.sentence_avg = sentence_avg
+
+    def compute_loss(self, model, net_output, target, reduction, log_probs):
+        # N, T -> N * T
+        target = target.view(-1)
+        lprobs = model.get_normalized_probs(net_output, log_probs=log_probs)
+        if not hasattr(lprobs, "batch_first"):
+            logging.warning(
+                "ERROR: we need to know whether "
+                "batch first for the net output; "
+                "you need to set batch_first attribute for the return value of "
+                "model.get_normalized_probs. Now, we assume this is true, but "
+                "in the future, we will raise exception instead. "
+            )
+        batch_first = getattr(lprobs, "batch_first", True)
+        if not batch_first:
+            lprobs = lprobs.transpose(0, 1)
+
+        # N, T, D -> N * T, D
+        lprobs = lprobs.view(-1, lprobs.size(-1))
+        loss = F.nll_loss(
+            lprobs, target, ignore_index=self.padding_idx, reduction=reduction
+        )
+        return lprobs, loss
+
+    def get_logging_output(self, sample, target, lprobs, loss):
+        target = target.view(-1)
+        mask = target != self.padding_idx
+        correct = torch.sum(
+            lprobs.argmax(1).masked_select(mask) == target.masked_select(mask)
+        )
+        total = torch.sum(mask)
+        sample_size = (
+            sample["target"].size(0) if self.sentence_avg else sample["ntokens"]
+        )
+
+        logging_output = {
+            "loss": utils.item(loss.data),  # * sample['ntokens'],
+            "ntokens": sample["ntokens"],
+            "nsentences": sample["target"].size(0),
+            "sample_size": sample_size,
+            "correct": utils.item(correct.data),
+            "total": utils.item(total.data),
+            "nframes": torch.sum(sample["net_input"]["src_lengths"]).item(),
+        }
+
+        return sample_size, logging_output
+
+    def forward(self, model, sample, reduction="sum", log_probs=True):
+        """Computes the cross entropy with accuracy metric for the given sample.
+
+        This is similar to CrossEntropyCriterion in fairseq, but also
+        computes accuracy metrics as part of logging
+
+        Args:
+            logprobs (Torch.tensor) of shape N, T, D i.e.
+                batchsize, timesteps, dimensions
+            targets (Torch.tensor) of shape N, T  i.e batchsize, timesteps
+
+        Returns:
+        tuple: With three elements:
+            1) the loss
+            2) the sample size, which is used as the denominator for the gradient
+            3) logging outputs to display while training
+
+        TODO:
+            * Currently this Criterion will only work with LSTMEncoderModels or
+            FairseqModels which have decoder, or Models which return TorchTensor
+            as net_output.
+            We need to make a change to support all FairseqEncoder models.
+        """
+        net_output = model(**sample["net_input"])
+        target = model.get_targets(sample, net_output)
+        lprobs, loss = self.compute_loss(
+            model, net_output, target, reduction, log_probs
+        )
+        sample_size, logging_output = self.get_logging_output(
+            sample, target, lprobs, loss
+        )
+        return loss, sample_size, logging_output
+
+    @staticmethod
+    def aggregate_logging_outputs(logging_outputs):
+        """Aggregate logging outputs from data parallel training."""
+        correct_sum = sum(log.get("correct", 0) for log in logging_outputs)
+        total_sum = sum(log.get("total", 0) for log in logging_outputs)
+        loss_sum = sum(log.get("loss", 0) for log in logging_outputs)
+        ntokens = sum(log.get("ntokens", 0) for log in logging_outputs)
+        nsentences = sum(log.get("nsentences", 0) for log in logging_outputs)
+        sample_size = sum(log.get("sample_size", 0) for log in logging_outputs)
+        nframes = sum(log.get("nframes", 0) for log in logging_outputs)
+        agg_output = {
+            "loss": loss_sum / sample_size / math.log(2) if sample_size > 0 else 0.0,
+            # if args.sentence_avg, then sample_size is nsentences, then loss
+            # is per-sentence loss; else sample_size is ntokens, the loss
+            # becomes per-output token loss
+            "ntokens": ntokens,
+            "nsentences": nsentences,
+            "nframes": nframes,
+            "sample_size": sample_size,
+            "acc": correct_sum * 100.0 / total_sum if total_sum > 0 else 0.0,
+            "correct": correct_sum,
+            "total": total_sum,
+            # total is the number of validate tokens
+        }
+        if sample_size != ntokens:
+            agg_output["nll_loss"] = loss_sum / ntokens / math.log(2)
+        # loss: per output token loss
+        # nll_loss: per sentence loss
+        return agg_output

edgelm/examples/speech_recognition/data/__init__.py

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+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from .asr_dataset import AsrDataset
+
+
+__all__ = [
+    "AsrDataset",
+]

edgelm/examples/speech_recognition/data/asr_dataset.py

@@ -0,0 +1,122 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import os
+
+import numpy as np
+from fairseq.data import FairseqDataset
+
+from . import data_utils
+from .collaters import Seq2SeqCollater
+
+
+class AsrDataset(FairseqDataset):
+    """
+    A dataset representing speech and corresponding transcription.
+
+    Args:
+        aud_paths: (List[str]): A list of str with paths to audio files.
+        aud_durations_ms (List[int]): A list of int containing the durations of
+            audio files.
+        tgt (List[torch.LongTensor]): A list of LongTensors containing the indices
+            of target transcriptions.
+        tgt_dict (~fairseq.data.Dictionary): target vocabulary.
+        ids (List[str]): A list of utterance IDs.
+        speakers (List[str]): A list of speakers corresponding to utterances.
+        num_mel_bins (int): Number of triangular mel-frequency bins (default: 80)
+        frame_length (float): Frame length in milliseconds (default: 25.0)
+        frame_shift (float): Frame shift in milliseconds (default: 10.0)
+    """
+
+    def __init__(
+        self,
+        aud_paths,
+        aud_durations_ms,
+        tgt,
+        tgt_dict,
+        ids,
+        speakers,
+        num_mel_bins=80,
+        frame_length=25.0,
+        frame_shift=10.0,
+    ):
+        assert frame_length > 0
+        assert frame_shift > 0
+        assert all(x > frame_length for x in aud_durations_ms)
+        self.frame_sizes = [
+            int(1 + (d - frame_length) / frame_shift) for d in aud_durations_ms
+        ]
+
+        assert len(aud_paths) > 0
+        assert len(aud_paths) == len(aud_durations_ms)
+        assert len(aud_paths) == len(tgt)
+        assert len(aud_paths) == len(ids)
+        assert len(aud_paths) == len(speakers)
+        self.aud_paths = aud_paths
+        self.tgt_dict = tgt_dict
+        self.tgt = tgt
+        self.ids = ids
+        self.speakers = speakers
+        self.num_mel_bins = num_mel_bins
+        self.frame_length = frame_length
+        self.frame_shift = frame_shift
+
+        self.s2s_collater = Seq2SeqCollater(
+            0,
+            1,
+            pad_index=self.tgt_dict.pad(),
+            eos_index=self.tgt_dict.eos(),
+            move_eos_to_beginning=True,
+        )
+
+    def __getitem__(self, index):
+        import torchaudio
+        import torchaudio.compliance.kaldi as kaldi
+
+        tgt_item = self.tgt[index] if self.tgt is not None else None
+
+        path = self.aud_paths[index]
+        if not os.path.exists(path):
+            raise FileNotFoundError("Audio file not found: {}".format(path))
+        sound, sample_rate = torchaudio.load_wav(path)
+        output = kaldi.fbank(
+            sound,
+            num_mel_bins=self.num_mel_bins,
+            frame_length=self.frame_length,
+            frame_shift=self.frame_shift,
+        )
+        output_cmvn = data_utils.apply_mv_norm(output)
+
+        return {"id": index, "data": [output_cmvn.detach(), tgt_item]}
+
+    def __len__(self):
+        return len(self.aud_paths)
+
+    def collater(self, samples):
+        """Merge a list of samples to form a mini-batch.
+
+        Args:
+            samples (List[int]): sample indices to collate
+
+        Returns:
+            dict: a mini-batch suitable for forwarding with a Model
+        """
+        return self.s2s_collater.collate(samples)
+
+    def num_tokens(self, index):
+        return self.frame_sizes[index]
+
+    def size(self, index):
+        """Return an example's size as a float or tuple. This value is used when
+        filtering a dataset with ``--max-positions``."""
+        return (
+            self.frame_sizes[index],
+            len(self.tgt[index]) if self.tgt is not None else 0,
+        )
+
+    def ordered_indices(self):
+        """Return an ordered list of indices. Batches will be constructed based
+        on this order."""
+        return np.arange(len(self))

edgelm/examples/speech_recognition/data/collaters.py

@@ -0,0 +1,131 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+"""
+    This module contains collection of classes which implement
+    collate functionalities for various tasks.
+
+    Collaters should know what data to expect for each sample
+    and they should pack / collate them into batches
+"""
+
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import numpy as np
+import torch
+from fairseq.data import data_utils as fairseq_data_utils
+
+
+class Seq2SeqCollater(object):
+    """
+    Implements collate function mainly for seq2seq tasks
+    This expects each sample to contain feature (src_tokens) and
+    targets.
+    This collator is also used for aligned training task.
+    """
+
+    def __init__(
+        self,
+        feature_index=0,
+        label_index=1,
+        pad_index=1,
+        eos_index=2,
+        move_eos_to_beginning=True,
+    ):
+        self.feature_index = feature_index
+        self.label_index = label_index
+        self.pad_index = pad_index
+        self.eos_index = eos_index
+        self.move_eos_to_beginning = move_eos_to_beginning
+
+    def _collate_frames(self, frames):
+        """Convert a list of 2d frames into a padded 3d tensor
+        Args:
+            frames (list): list of 2d frames of size L[i]*f_dim. Where L[i] is
+                length of i-th frame and f_dim is static dimension of features
+        Returns:
+            3d tensor of size len(frames)*len_max*f_dim where len_max is max of L[i]
+        """
+        len_max = max(frame.size(0) for frame in frames)
+        f_dim = frames[0].size(1)
+        res = frames[0].new(len(frames), len_max, f_dim).fill_(0.0)
+
+        for i, v in enumerate(frames):
+            res[i, : v.size(0)] = v
+
+        return res
+
+    def collate(self, samples):
+        """
+        utility function to collate samples into batch for speech recognition.
+        """
+        if len(samples) == 0:
+            return {}
+
+        # parse samples into torch tensors
+        parsed_samples = []
+        for s in samples:
+            # skip invalid samples
+            if s["data"][self.feature_index] is None:
+                continue
+            source = s["data"][self.feature_index]
+            if isinstance(source, (np.ndarray, np.generic)):
+                source = torch.from_numpy(source)
+            target = s["data"][self.label_index]
+            if isinstance(target, (np.ndarray, np.generic)):
+                target = torch.from_numpy(target).long()
+            elif isinstance(target, list):
+                target = torch.LongTensor(target)
+
+            parsed_sample = {"id": s["id"], "source": source, "target": target}
+            parsed_samples.append(parsed_sample)
+        samples = parsed_samples
+
+        id = torch.LongTensor([s["id"] for s in samples])
+        frames = self._collate_frames([s["source"] for s in samples])
+        # sort samples by descending number of frames
+        frames_lengths = torch.LongTensor([s["source"].size(0) for s in samples])
+        frames_lengths, sort_order = frames_lengths.sort(descending=True)
+        id = id.index_select(0, sort_order)
+        frames = frames.index_select(0, sort_order)
+
+        target = None
+        target_lengths = None
+        prev_output_tokens = None
+        if samples[0].get("target", None) is not None:
+            ntokens = sum(len(s["target"]) for s in samples)
+            target = fairseq_data_utils.collate_tokens(
+                [s["target"] for s in samples],
+                self.pad_index,
+                self.eos_index,
+                left_pad=False,
+                move_eos_to_beginning=False,
+            )
+            target = target.index_select(0, sort_order)
+            target_lengths = torch.LongTensor(
+                [s["target"].size(0) for s in samples]
+            ).index_select(0, sort_order)
+            prev_output_tokens = fairseq_data_utils.collate_tokens(
+                [s["target"] for s in samples],
+                self.pad_index,
+                self.eos_index,
+                left_pad=False,
+                move_eos_to_beginning=self.move_eos_to_beginning,
+            )
+            prev_output_tokens = prev_output_tokens.index_select(0, sort_order)
+        else:
+            ntokens = sum(len(s["source"]) for s in samples)
+
+        batch = {
+            "id": id,
+            "ntokens": ntokens,
+            "net_input": {"src_tokens": frames, "src_lengths": frames_lengths},
+            "target": target,
+            "target_lengths": target_lengths,
+            "nsentences": len(samples),
+        }
+        if prev_output_tokens is not None:
+            batch["net_input"]["prev_output_tokens"] = prev_output_tokens
+        return batch

edgelm/examples/speech_recognition/data/data_utils.py

@@ -0,0 +1,100 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch
+
+
+def calc_mean_invstddev(feature):
+    if len(feature.size()) != 2:
+        raise ValueError("We expect the input feature to be 2-D tensor")
+    mean = feature.mean(0)
+    var = feature.var(0)
+    # avoid division by ~zero
+    eps = 1e-8
+    if (var < eps).any():
+        return mean, 1.0 / (torch.sqrt(var) + eps)
+    return mean, 1.0 / torch.sqrt(var)
+
+
+def apply_mv_norm(features):
+    # If there is less than 2 spectrograms, the variance cannot be computed (is NaN)
+    # and normalization is not possible, so return the item as it is
+    if features.size(0) < 2:
+        return features
+    mean, invstddev = calc_mean_invstddev(features)
+    res = (features - mean) * invstddev
+    return res
+
+
+def lengths_to_encoder_padding_mask(lengths, batch_first=False):
+    """
+    convert lengths (a 1-D Long/Int tensor) to 2-D binary tensor
+
+    Args:
+        lengths: a (B, )-shaped tensor
+
+    Return:
+        max_length: maximum length of B sequences
+        encoder_padding_mask: a (max_length, B) binary mask, where
+        [t, b] = 0 for t < lengths[b] and 1 otherwise
+
+    TODO:
+        kernelize this function if benchmarking shows this function is slow
+    """
+    max_lengths = torch.max(lengths).item()
+    bsz = lengths.size(0)
+    encoder_padding_mask = torch.arange(
+        max_lengths
+    ).to(  # a (T, ) tensor with [0, ..., T-1]
+        lengths.device
+    ).view(  # move to the right device
+        1, max_lengths
+    ).expand(  # reshape to (1, T)-shaped tensor
+        bsz, -1
+    ) >= lengths.view(  # expand to (B, T)-shaped tensor
+        bsz, 1
+    ).expand(
+        -1, max_lengths
+    )
+    if not batch_first:
+        return encoder_padding_mask.t(), max_lengths
+    else:
+        return encoder_padding_mask, max_lengths
+
+
+def encoder_padding_mask_to_lengths(
+    encoder_padding_mask, max_lengths, batch_size, device
+):
+    """
+    convert encoder_padding_mask (2-D binary tensor) to a 1-D tensor
+
+    Conventionally, encoder output contains a encoder_padding_mask, which is
+    a 2-D mask in a shape (T, B), whose (t, b) element indicate whether
+    encoder_out[t, b] is a valid output (=0) or not (=1). Occasionally, we
+    need to convert this mask tensor to a 1-D tensor in shape (B, ), where
+    [b] denotes the valid length of b-th sequence
+
+    Args:
+        encoder_padding_mask: a (T, B)-shaped binary tensor or None; if None,
+        indicating all are valid
+    Return:
+        seq_lengths: a (B,)-shaped tensor, where its (b, )-th element is the
+        number of valid elements of b-th sequence
+
+        max_lengths: maximum length of all sequence, if encoder_padding_mask is
+        not None, max_lengths must equal to encoder_padding_mask.size(0)
+
+        batch_size: batch size; if encoder_padding_mask is
+        not None, max_lengths must equal to encoder_padding_mask.size(1)
+
+        device: which device to put the result on
+    """
+    if encoder_padding_mask is None:
+        return torch.Tensor([max_lengths] * batch_size).to(torch.int32).to(device)
+
+    assert encoder_padding_mask.size(0) == max_lengths, "max_lengths does not match"
+    assert encoder_padding_mask.size(1) == batch_size, "batch_size does not match"
+
+    return max_lengths - torch.sum(encoder_padding_mask, dim=0)

edgelm/examples/speech_recognition/data/replabels.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Replabel transforms for use with flashlight's ASG criterion.
+"""
+
+
+def replabel_symbol(i):
+    """
+    Replabel symbols used in flashlight, currently just "1", "2", ...
+    This prevents training with numeral tokens, so this might change in the future
+    """
+    return str(i)
+
+
+def pack_replabels(tokens, dictionary, max_reps):
+    """
+    Pack a token sequence so that repeated symbols are replaced by replabels
+    """
+    if len(tokens) == 0 or max_reps <= 0:
+        return tokens
+
+    replabel_value_to_idx = [0] * (max_reps + 1)
+    for i in range(1, max_reps + 1):
+        replabel_value_to_idx[i] = dictionary.index(replabel_symbol(i))
+
+    result = []
+    prev_token = -1
+    num_reps = 0
+    for token in tokens:
+        if token == prev_token and num_reps < max_reps:
+            num_reps += 1
+        else:
+            if num_reps > 0:
+                result.append(replabel_value_to_idx[num_reps])
+                num_reps = 0
+            result.append(token)
+            prev_token = token
+    if num_reps > 0:
+        result.append(replabel_value_to_idx[num_reps])
+    return result
+
+
+def unpack_replabels(tokens, dictionary, max_reps):
+    """
+    Unpack a token sequence so that replabels are replaced by repeated symbols
+    """
+    if len(tokens) == 0 or max_reps <= 0:
+        return tokens
+
+    replabel_idx_to_value = {}
+    for i in range(1, max_reps + 1):
+        replabel_idx_to_value[dictionary.index(replabel_symbol(i))] = i
+
+    result = []
+    prev_token = -1
+    for token in tokens:
+        try:
+            for _ in range(replabel_idx_to_value[token]):
+                result.append(prev_token)
+            prev_token = -1
+        except KeyError:
+            result.append(token)
+            prev_token = token
+    return result

edgelm/examples/speech_recognition/datasets/asr_prep_json.py

@@ -0,0 +1,125 @@
+#!/usr/bin/env python3
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import argparse
+import concurrent.futures
+import json
+import multiprocessing
+import os
+from collections import namedtuple
+from itertools import chain
+
+import sentencepiece as spm
+from fairseq.data import Dictionary
+
+
+MILLISECONDS_TO_SECONDS = 0.001
+
+
+def process_sample(aud_path, lable, utt_id, sp, tgt_dict):
+    import torchaudio
+
+    input = {}
+    output = {}
+    si, ei = torchaudio.info(aud_path)
+    input["length_ms"] = int(
+        si.length / si.channels / si.rate / MILLISECONDS_TO_SECONDS
+    )
+    input["path"] = aud_path
+
+    token = " ".join(sp.EncodeAsPieces(lable))
+    ids = tgt_dict.encode_line(token, append_eos=False)
+    output["text"] = lable
+    output["token"] = token
+    output["tokenid"] = ", ".join(map(str, [t.tolist() for t in ids]))
+    return {utt_id: {"input": input, "output": output}}
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--audio-dirs",
+        nargs="+",
+        default=["-"],
+        required=True,
+        help="input directories with audio files",
+    )
+    parser.add_argument(
+        "--labels",
+        required=True,
+        help="aggregated input labels with format <ID LABEL> per line",
+        type=argparse.FileType("r", encoding="UTF-8"),
+    )
+    parser.add_argument(
+        "--spm-model",
+        required=True,
+        help="sentencepiece model to use for encoding",
+        type=argparse.FileType("r", encoding="UTF-8"),
+    )
+    parser.add_argument(
+        "--dictionary",
+        required=True,
+        help="file to load fairseq dictionary from",
+        type=argparse.FileType("r", encoding="UTF-8"),
+    )
+    parser.add_argument("--audio-format", choices=["flac", "wav"], default="wav")
+    parser.add_argument(
+        "--output",
+        required=True,
+        type=argparse.FileType("w"),
+        help="path to save json output",
+    )
+    args = parser.parse_args()
+
+    sp = spm.SentencePieceProcessor()
+    sp.Load(args.spm_model.name)
+
+    tgt_dict = Dictionary.load(args.dictionary)
+
+    labels = {}
+    for line in args.labels:
+        (utt_id, label) = line.split(" ", 1)
+        labels[utt_id] = label
+    if len(labels) == 0:
+        raise Exception("No labels found in ", args.labels_path)
+
+    Sample = namedtuple("Sample", "aud_path utt_id")
+    samples = []
+    for path, _, files in chain.from_iterable(
+        os.walk(path) for path in args.audio_dirs
+    ):
+        for f in files:
+            if f.endswith(args.audio_format):
+                if len(os.path.splitext(f)) != 2:
+                    raise Exception("Expect <utt_id.extension> file name. Got: ", f)
+                utt_id = os.path.splitext(f)[0]
+                if utt_id not in labels:
+                    continue
+                samples.append(Sample(os.path.join(path, f), utt_id))
+
+    utts = {}
+    num_cpu = multiprocessing.cpu_count()
+    with concurrent.futures.ThreadPoolExecutor(max_workers=num_cpu) as executor:
+        future_to_sample = {
+            executor.submit(
+                process_sample, s.aud_path, labels[s.utt_id], s.utt_id, sp, tgt_dict
+            ): s
+            for s in samples
+        }
+        for future in concurrent.futures.as_completed(future_to_sample):
+            try:
+                data = future.result()
+            except Exception as exc:
+                print("generated an exception: ", exc)
+            else:
+                utts.update(data)
+    json.dump({"utts": utts}, args.output, indent=4)
+
+
+if __name__ == "__main__":
+    main()

edgelm/examples/speech_recognition/datasets/prepare-librispeech.sh

@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+# Prepare librispeech dataset
+
+base_url=www.openslr.org/resources/12
+train_dir=train_960
+
+if [ "$#" -ne 2 ]; then
+  echo "Usage: $0 <download_dir> <out_dir>"
+  echo "e.g.: $0 /tmp/librispeech_raw/ ~/data/librispeech_final"
+  exit 1
+fi
+
+download_dir=${1%/}
+out_dir=${2%/}
+
+fairseq_root=~/fairseq-py/
+mkdir -p ${out_dir}
+cd ${out_dir} || exit
+
+nbpe=5000
+bpemode=unigram
+
+if [ ! -d "$fairseq_root" ]; then
+    echo "$0: Please set correct fairseq_root"
+    exit 1
+fi
+
+echo "Data Download"
+for part in dev-clean test-clean dev-other test-other train-clean-100 train-clean-360 train-other-500; do
+    url=$base_url/$part.tar.gz
+    if ! wget -P $download_dir $url; then
+        echo "$0: wget failed for $url"
+        exit 1
+    fi
+    if ! tar -C $download_dir -xvzf $download_dir/$part.tar.gz; then
+        echo "$0: error un-tarring archive $download_dir/$part.tar.gz"
+        exit 1
+    fi
+done
+
+echo "Merge all train packs into one"
+mkdir -p ${download_dir}/LibriSpeech/${train_dir}/
+for part in train-clean-100 train-clean-360 train-other-500; do
+    mv ${download_dir}/LibriSpeech/${part}/* $download_dir/LibriSpeech/${train_dir}/
+done
+echo "Merge train text"
+find ${download_dir}/LibriSpeech/${train_dir}/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/${train_dir}/text
+
+# Use combined dev-clean and dev-other as validation set
+find ${download_dir}/LibriSpeech/dev-clean/ ${download_dir}/LibriSpeech/dev-other/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/valid_text
+find ${download_dir}/LibriSpeech/test-clean/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/test-clean/text
+find ${download_dir}/LibriSpeech/test-other/ -name '*.txt' -exec cat {} \; >> ${download_dir}/LibriSpeech/test-other/text
+
+
+dict=data/lang_char/${train_dir}_${bpemode}${nbpe}_units.txt
+encoded=data/lang_char/${train_dir}_${bpemode}${nbpe}_encoded.txt
+fairseq_dict=data/lang_char/${train_dir}_${bpemode}${nbpe}_fairseq_dict.txt
+bpemodel=data/lang_char/${train_dir}_${bpemode}${nbpe}
+echo "dictionary: ${dict}"
+echo "Dictionary preparation"
+mkdir -p data/lang_char/
+echo "<unk> 3" > ${dict}
+echo "</s> 2" >> ${dict}
+echo "<pad> 1" >> ${dict}
+cut -f 2- -d" " ${download_dir}/LibriSpeech/${train_dir}/text > data/lang_char/input.txt
+spm_train --input=data/lang_char/input.txt --vocab_size=${nbpe} --model_type=${bpemode} --model_prefix=${bpemodel} --input_sentence_size=100000000 --unk_id=3 --eos_id=2 --pad_id=1 --bos_id=-1 --character_coverage=1
+spm_encode --model=${bpemodel}.model --output_format=piece < data/lang_char/input.txt > ${encoded}
+cat ${encoded} | tr ' ' '\n' | sort | uniq | awk '{print $0 " " NR+3}' >> ${dict}
+cat ${encoded} | tr ' ' '\n' | sort | uniq -c | awk '{print $2 " " $1}' > ${fairseq_dict}
+wc -l ${dict}
+
+echo "Prepare train and test jsons"
+for part in train_960 test-other test-clean; do
+    python ${fairseq_root}/examples/speech_recognition/datasets/asr_prep_json.py --audio-dirs ${download_dir}/LibriSpeech/${part} --labels ${download_dir}/LibriSpeech/${part}/text --spm-model ${bpemodel}.model --audio-format flac --dictionary ${fairseq_dict} --output ${part}.json
+done
+# fairseq expects to find train.json and valid.json during training
+mv train_960.json train.json
+
+echo "Prepare valid json"
+python ${fairseq_root}/examples/speech_recognition/datasets/asr_prep_json.py --audio-dirs ${download_dir}/LibriSpeech/dev-clean ${download_dir}/LibriSpeech/dev-other --labels ${download_dir}/LibriSpeech/valid_text --spm-model ${bpemodel}.model --audio-format flac --dictionary ${fairseq_dict} --output valid.json
+
+cp ${fairseq_dict} ./dict.txt
+cp ${bpemodel}.model ./spm.model

edgelm/examples/speech_recognition/infer.py

@@ -0,0 +1,436 @@
+#!/usr/bin/env python3 -u
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Run inference for pre-processed data with a trained model.
+"""
+
+import ast
+import logging
+import math
+import os
+import sys
+
+import editdistance
+import numpy as np
+import torch
+from fairseq import checkpoint_utils, options, progress_bar, tasks, utils
+from fairseq.data.data_utils import post_process
+from fairseq.logging.meters import StopwatchMeter, TimeMeter
+
+
+logging.basicConfig()
+logging.root.setLevel(logging.INFO)
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+
+def add_asr_eval_argument(parser):
+    parser.add_argument("--kspmodel", default=None, help="sentence piece model")
+    parser.add_argument(
+        "--wfstlm", default=None, help="wfstlm on dictonary output units"
+    )
+    parser.add_argument(
+        "--rnnt_decoding_type",
+        default="greedy",
+        help="wfstlm on dictonary\
+output units",
+    )
+    try:
+        parser.add_argument(
+            "--lm-weight",
+            "--lm_weight",
+            type=float,
+            default=0.2,
+            help="weight for lm while interpolating with neural score",
+        )
+    except:
+        pass
+    parser.add_argument(
+        "--rnnt_len_penalty", default=-0.5, help="rnnt length penalty on word level"
+    )
+    parser.add_argument(
+        "--w2l-decoder",
+        choices=["viterbi", "kenlm", "fairseqlm"],
+        help="use a w2l decoder",
+    )
+    parser.add_argument("--lexicon", help="lexicon for w2l decoder")
+    parser.add_argument("--unit-lm", action="store_true", help="if using a unit lm")
+    parser.add_argument("--kenlm-model", "--lm-model", help="lm model for w2l decoder")
+    parser.add_argument("--beam-threshold", type=float, default=25.0)
+    parser.add_argument("--beam-size-token", type=float, default=100)
+    parser.add_argument("--word-score", type=float, default=1.0)
+    parser.add_argument("--unk-weight", type=float, default=-math.inf)
+    parser.add_argument("--sil-weight", type=float, default=0.0)
+    parser.add_argument(
+        "--dump-emissions",
+        type=str,
+        default=None,
+        help="if present, dumps emissions into this file and exits",
+    )
+    parser.add_argument(
+        "--dump-features",
+        type=str,
+        default=None,
+        help="if present, dumps features into this file and exits",
+    )
+    parser.add_argument(
+        "--load-emissions",
+        type=str,
+        default=None,
+        help="if present, loads emissions from this file",
+    )
+    return parser
+
+
+def check_args(args):
+    # assert args.path is not None, "--path required for generation!"
+    # assert args.results_path is not None, "--results_path required for generation!"
+    assert (
+        not args.sampling or args.nbest == args.beam
+    ), "--sampling requires --nbest to be equal to --beam"
+    assert (
+        args.replace_unk is None or args.raw_text
+    ), "--replace-unk requires a raw text dataset (--raw-text)"
+
+
+def get_dataset_itr(args, task, models):
+    return task.get_batch_iterator(
+        dataset=task.dataset(args.gen_subset),
+        max_tokens=args.max_tokens,
+        max_sentences=args.batch_size,
+        max_positions=(sys.maxsize, sys.maxsize),
+        ignore_invalid_inputs=args.skip_invalid_size_inputs_valid_test,
+        required_batch_size_multiple=args.required_batch_size_multiple,
+        num_shards=args.num_shards,
+        shard_id=args.shard_id,
+        num_workers=args.num_workers,
+        data_buffer_size=args.data_buffer_size,
+    ).next_epoch_itr(shuffle=False)
+
+
+def process_predictions(
+    args, hypos, sp, tgt_dict, target_tokens, res_files, speaker, id
+):
+    for hypo in hypos[: min(len(hypos), args.nbest)]:
+        hyp_pieces = tgt_dict.string(hypo["tokens"].int().cpu())
+
+        if "words" in hypo:
+            hyp_words = " ".join(hypo["words"])
+        else:
+            hyp_words = post_process(hyp_pieces, args.post_process)
+
+        if res_files is not None:
+            print(
+                "{} ({}-{})".format(hyp_pieces, speaker, id),
+                file=res_files["hypo.units"],
+            )
+            print(
+                "{} ({}-{})".format(hyp_words, speaker, id),
+                file=res_files["hypo.words"],
+            )
+
+        tgt_pieces = tgt_dict.string(target_tokens)
+        tgt_words = post_process(tgt_pieces, args.post_process)
+
+        if res_files is not None:
+            print(
+                "{} ({}-{})".format(tgt_pieces, speaker, id),
+                file=res_files["ref.units"],
+            )
+            print(
+                "{} ({}-{})".format(tgt_words, speaker, id), file=res_files["ref.words"]
+            )
+
+        if not args.quiet:
+            logger.info("HYPO:" + hyp_words)
+            logger.info("TARGET:" + tgt_words)
+            logger.info("___________________")
+
+        hyp_words = hyp_words.split()
+        tgt_words = tgt_words.split()
+        return editdistance.eval(hyp_words, tgt_words), len(tgt_words)
+
+
+def prepare_result_files(args):
+    def get_res_file(file_prefix):
+        if args.num_shards > 1:
+            file_prefix = f"{args.shard_id}_{file_prefix}"
+        path = os.path.join(
+            args.results_path,
+            "{}-{}-{}.txt".format(
+                file_prefix, os.path.basename(args.path), args.gen_subset
+            ),
+        )
+        return open(path, "w", buffering=1)
+
+    if not args.results_path:
+        return None
+
+    return {
+        "hypo.words": get_res_file("hypo.word"),
+        "hypo.units": get_res_file("hypo.units"),
+        "ref.words": get_res_file("ref.word"),
+        "ref.units": get_res_file("ref.units"),
+    }
+
+
+def optimize_models(args, use_cuda, models):
+    """Optimize ensemble for generation"""
+    for model in models:
+        model.make_generation_fast_(
+            beamable_mm_beam_size=None if args.no_beamable_mm else args.beam,
+            need_attn=args.print_alignment,
+        )
+        if args.fp16:
+            model.half()
+        if use_cuda:
+            model.cuda()
+
+
+def apply_half(t):
+    if t.dtype is torch.float32:
+        return t.to(dtype=torch.half)
+    return t
+
+
+class ExistingEmissionsDecoder(object):
+    def __init__(self, decoder, emissions):
+        self.decoder = decoder
+        self.emissions = emissions
+
+    def generate(self, models, sample, **unused):
+        ids = sample["id"].cpu().numpy()
+        try:
+            emissions = np.stack(self.emissions[ids])
+        except:
+            print([x.shape for x in self.emissions[ids]])
+            raise Exception("invalid sizes")
+        emissions = torch.from_numpy(emissions)
+        return self.decoder.decode(emissions)
+
+
+def main(args, task=None, model_state=None):
+    check_args(args)
+
+    use_fp16 = args.fp16
+    if args.max_tokens is None and args.batch_size is None:
+        args.max_tokens = 4000000
+    logger.info(args)
+
+    use_cuda = torch.cuda.is_available() and not args.cpu
+
+    logger.info("| decoding with criterion {}".format(args.criterion))
+
+    task = tasks.setup_task(args)
+
+    # Load ensemble
+    if args.load_emissions:
+        models, criterions = [], []
+        task.load_dataset(args.gen_subset)
+    else:
+        logger.info("| loading model(s) from {}".format(args.path))
+        models, saved_cfg, task = checkpoint_utils.load_model_ensemble_and_task(
+            utils.split_paths(args.path, separator="\\"),
+            arg_overrides=ast.literal_eval(args.model_overrides),
+            task=task,
+            suffix=args.checkpoint_suffix,
+            strict=(args.checkpoint_shard_count == 1),
+            num_shards=args.checkpoint_shard_count,
+            state=model_state,
+        )
+        optimize_models(args, use_cuda, models)
+        task.load_dataset(args.gen_subset, task_cfg=saved_cfg.task)
+
+
+    # Set dictionary
+    tgt_dict = task.target_dictionary
+
+    logger.info(
+        "| {} {} {} examples".format(
+            args.data, args.gen_subset, len(task.dataset(args.gen_subset))
+        )
+    )
+
+    # hack to pass transitions to W2lDecoder
+    if args.criterion == "asg_loss":
+        raise NotImplementedError("asg_loss is currently not supported")
+        # trans = criterions[0].asg.trans.data
+        # args.asg_transitions = torch.flatten(trans).tolist()
+
+    # Load dataset (possibly sharded)
+    itr = get_dataset_itr(args, task, models)
+
+    # Initialize generator
+    gen_timer = StopwatchMeter()
+
+    def build_generator(args):
+        w2l_decoder = getattr(args, "w2l_decoder", None)
+        if w2l_decoder == "viterbi":
+            from examples.speech_recognition.w2l_decoder import W2lViterbiDecoder
+
+            return W2lViterbiDecoder(args, task.target_dictionary)
+        elif w2l_decoder == "kenlm":
+            from examples.speech_recognition.w2l_decoder import W2lKenLMDecoder
+
+            return W2lKenLMDecoder(args, task.target_dictionary)
+        elif w2l_decoder == "fairseqlm":
+            from examples.speech_recognition.w2l_decoder import W2lFairseqLMDecoder
+
+            return W2lFairseqLMDecoder(args, task.target_dictionary)
+        else:
+            print(
+                "only flashlight decoders with (viterbi, kenlm, fairseqlm) options are supported at the moment"
+            )
+
+    # please do not touch this unless you test both generate.py and infer.py with audio_pretraining task
+    generator = build_generator(args)
+
+    if args.load_emissions:
+        generator = ExistingEmissionsDecoder(
+            generator, np.load(args.load_emissions, allow_pickle=True)
+        )
+        logger.info("loaded emissions from " + args.load_emissions)
+
+    num_sentences = 0
+
+    if args.results_path is not None and not os.path.exists(args.results_path):
+        os.makedirs(args.results_path)
+
+    max_source_pos = (
+        utils.resolve_max_positions(
+            task.max_positions(), *[model.max_positions() for model in models]
+        ),
+    )
+
+    if max_source_pos is not None:
+        max_source_pos = max_source_pos[0]
+        if max_source_pos is not None:
+            max_source_pos = max_source_pos[0] - 1
+
+    if args.dump_emissions:
+        emissions = {}
+    if args.dump_features:
+        features = {}
+        models[0].bert.proj = None
+    else:
+        res_files = prepare_result_files(args)
+    errs_t = 0
+    lengths_t = 0
+    with progress_bar.build_progress_bar(args, itr) as t:
+        wps_meter = TimeMeter()
+        for sample in t:
+            sample = utils.move_to_cuda(sample) if use_cuda else sample
+            if use_fp16:
+                sample = utils.apply_to_sample(apply_half, sample)
+            if "net_input" not in sample:
+                continue
+
+            prefix_tokens = None
+            if args.prefix_size > 0:
+                prefix_tokens = sample["target"][:, : args.prefix_size]
+
+            gen_timer.start()
+            if args.dump_emissions:
+                with torch.no_grad():
+                    encoder_out = models[0](**sample["net_input"])
+                    emm = models[0].get_normalized_probs(encoder_out, log_probs=True)
+                    emm = emm.transpose(0, 1).cpu().numpy()
+                    for i, id in enumerate(sample["id"]):
+                        emissions[id.item()] = emm[i]
+                    continue
+            elif args.dump_features:
+                with torch.no_grad():
+                    encoder_out = models[0](**sample["net_input"])
+                    feat = encoder_out["encoder_out"].transpose(0, 1).cpu().numpy()
+                    for i, id in enumerate(sample["id"]):
+                        padding = (
+                            encoder_out["encoder_padding_mask"][i].cpu().numpy()
+                            if encoder_out["encoder_padding_mask"] is not None
+                            else None
+                        )
+                        features[id.item()] = (feat[i], padding)
+                    continue
+            hypos = task.inference_step(generator, models, sample, prefix_tokens)
+            num_generated_tokens = sum(len(h[0]["tokens"]) for h in hypos)
+            gen_timer.stop(num_generated_tokens)
+
+            for i, sample_id in enumerate(sample["id"].tolist()):
+                speaker = None
+                # id = task.dataset(args.gen_subset).ids[int(sample_id)]
+                id = sample_id
+                toks = (
+                    sample["target"][i, :]
+                    if "target_label" not in sample
+                    else sample["target_label"][i, :]
+                )
+                target_tokens = utils.strip_pad(toks, tgt_dict.pad()).int().cpu()
+                # Process top predictions
+                errs, length = process_predictions(
+                    args,
+                    hypos[i],
+                    None,
+                    tgt_dict,
+                    target_tokens,
+                    res_files,
+                    speaker,
+                    id,
+                )
+                errs_t += errs
+                lengths_t += length
+
+            wps_meter.update(num_generated_tokens)
+            t.log({"wps": round(wps_meter.avg)})
+            num_sentences += (
+                sample["nsentences"] if "nsentences" in sample else sample["id"].numel()
+            )
+
+    wer = None
+    if args.dump_emissions:
+        emm_arr = []
+        for i in range(len(emissions)):
+            emm_arr.append(emissions[i])
+        np.save(args.dump_emissions, emm_arr)
+        logger.info(f"saved {len(emissions)} emissions to {args.dump_emissions}")
+    elif args.dump_features:
+        feat_arr = []
+        for i in range(len(features)):
+            feat_arr.append(features[i])
+        np.save(args.dump_features, feat_arr)
+        logger.info(f"saved {len(features)} emissions to {args.dump_features}")
+    else:
+        if lengths_t > 0:
+            wer = errs_t * 100.0 / lengths_t
+            logger.info(f"WER: {wer}")
+
+        logger.info(
+            "| Processed {} sentences ({} tokens) in {:.1f}s ({:.2f}"
+            "sentences/s, {:.2f} tokens/s)".format(
+                num_sentences,
+                gen_timer.n,
+                gen_timer.sum,
+                num_sentences / gen_timer.sum,
+                1.0 / gen_timer.avg,
+            )
+        )
+        logger.info("| Generate {} with beam={}".format(args.gen_subset, args.beam))
+    return task, wer
+
+
+def make_parser():
+    parser = options.get_generation_parser()
+    parser = add_asr_eval_argument(parser)
+    return parser
+
+
+def cli_main():
+    parser = make_parser()
+    args = options.parse_args_and_arch(parser)
+    main(args)
+
+
+if __name__ == "__main__":
+    cli_main()

edgelm/examples/speech_recognition/kaldi/add-self-loop-simple.cc

@@ -0,0 +1,94 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <iostream>
+#include "fstext/fstext-lib.h" // @manual
+#include "util/common-utils.h" // @manual
+
+/*
+ * This program is to modify a FST without self-loop by:
+ *   for each incoming arc with non-eps input symbol, add a self-loop arc
+ *   with that non-eps symbol as input and eps as output.
+ *
+ * This is to make sure the resultant FST can do deduplication for repeated
+ * symbols, which is very common in acoustic model
+ *
+ */
+namespace {
+int32 AddSelfLoopsSimple(fst::StdVectorFst* fst) {
+  typedef fst::MutableArcIterator<fst::StdVectorFst> IterType;
+
+  int32 num_states_before = fst->NumStates();
+  fst::MakePrecedingInputSymbolsSame(false, fst);
+  int32 num_states_after = fst->NumStates();
+  KALDI_LOG << "There are " << num_states_before
+            << " states in the original FST; "
+            << " after MakePrecedingInputSymbolsSame, there are "
+            << num_states_after << " states " << std::endl;
+
+  auto weight_one = fst::StdArc::Weight::One();
+
+  int32 num_arc_added = 0;
+
+  fst::StdArc self_loop_arc;
+  self_loop_arc.weight = weight_one;
+
+  int32 num_states = fst->NumStates();
+  std::vector<std::set<int32>> incoming_non_eps_label_per_state(num_states);
+
+  for (int32 state = 0; state < num_states; state++) {
+    for (IterType aiter(fst, state); !aiter.Done(); aiter.Next()) {
+      fst::StdArc arc(aiter.Value());
+      if (arc.ilabel != 0) {
+        incoming_non_eps_label_per_state[arc.nextstate].insert(arc.ilabel);
+      }
+    }
+  }
+
+  for (int32 state = 0; state < num_states; state++) {
+    if (!incoming_non_eps_label_per_state[state].empty()) {
+      auto& ilabel_set = incoming_non_eps_label_per_state[state];
+      for (auto it = ilabel_set.begin(); it != ilabel_set.end(); it++) {
+        self_loop_arc.ilabel = *it;
+        self_loop_arc.olabel = 0;
+        self_loop_arc.nextstate = state;
+        fst->AddArc(state, self_loop_arc);
+        num_arc_added++;
+      }
+    }
+  }
+  return num_arc_added;
+}
+
+void print_usage() {
+  std::cout << "add-self-loop-simple usage:\n"
+               "\tadd-self-loop-simple <in-fst> <out-fst> \n";
+}
+} // namespace
+
+int main(int argc, char** argv) {
+  if (argc != 3) {
+    print_usage();
+    exit(1);
+  }
+
+  auto input = argv[1];
+  auto output = argv[2];
+
+  auto fst = fst::ReadFstKaldi(input);
+  auto num_states = fst->NumStates();
+  KALDI_LOG << "Loading FST from " << input << " with " << num_states
+            << " states." << std::endl;
+
+  int32 num_arc_added = AddSelfLoopsSimple(fst);
+  KALDI_LOG << "Adding " << num_arc_added << " self-loop arcs " << std::endl;
+
+  fst::WriteFstKaldi(*fst, std::string(output));
+  KALDI_LOG << "Writing FST to " << output << std::endl;
+
+  delete fst;
+}

edgelm/examples/speech_recognition/kaldi/config/kaldi_initializer.yaml

@@ -0,0 +1,8 @@
+# @package _group_
+
+data_dir: ???
+fst_dir: ???
+in_labels: ???
+kaldi_root: ???
+lm_arpa: ???
+blank_symbol: <s>

edgelm/examples/speech_recognition/kaldi/kaldi_decoder.py

@@ -0,0 +1,244 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from concurrent.futures import ThreadPoolExecutor
+import logging
+from omegaconf import MISSING
+import os
+import torch
+from typing import Optional
+import warnings
+
+
+from dataclasses import dataclass
+from fairseq.dataclass import FairseqDataclass
+from .kaldi_initializer import KaldiInitializerConfig, initalize_kaldi
+
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class KaldiDecoderConfig(FairseqDataclass):
+    hlg_graph_path: Optional[str] = None
+    output_dict: str = MISSING
+
+    kaldi_initializer_config: Optional[KaldiInitializerConfig] = None
+
+    acoustic_scale: float = 0.5
+    max_active: int = 10000
+    beam_delta: float = 0.5
+    hash_ratio: float = 2.0
+
+    is_lattice: bool = False
+    lattice_beam: float = 10.0
+    prune_interval: int = 25
+    determinize_lattice: bool = True
+    prune_scale: float = 0.1
+    max_mem: int = 0
+    phone_determinize: bool = True
+    word_determinize: bool = True
+    minimize: bool = True
+
+    num_threads: int = 1
+
+
+class KaldiDecoder(object):
+    def __init__(
+        self,
+        cfg: KaldiDecoderConfig,
+        beam: int,
+        nbest: int = 1,
+    ):
+        try:
+            from kaldi.asr import FasterRecognizer, LatticeFasterRecognizer
+            from kaldi.base import set_verbose_level
+            from kaldi.decoder import (
+                FasterDecoder,
+                FasterDecoderOptions,
+                LatticeFasterDecoder,
+                LatticeFasterDecoderOptions,
+            )
+            from kaldi.lat.functions import DeterminizeLatticePhonePrunedOptions
+            from kaldi.fstext import read_fst_kaldi, SymbolTable
+        except:
+            warnings.warn(
+                "pykaldi is required for this functionality. Please install from https://github.com/pykaldi/pykaldi"
+            )
+
+        # set_verbose_level(2)
+
+        self.acoustic_scale = cfg.acoustic_scale
+        self.nbest = nbest
+
+        if cfg.hlg_graph_path is None:
+            assert (
+                cfg.kaldi_initializer_config is not None
+            ), "Must provide hlg graph path or kaldi initializer config"
+            cfg.hlg_graph_path = initalize_kaldi(cfg.kaldi_initializer_config)
+
+        assert os.path.exists(cfg.hlg_graph_path), cfg.hlg_graph_path
+
+        if cfg.is_lattice:
+            self.dec_cls = LatticeFasterDecoder
+            opt_cls = LatticeFasterDecoderOptions
+            self.rec_cls = LatticeFasterRecognizer
+        else:
+            assert self.nbest == 1, "nbest > 1 requires lattice decoder"
+            self.dec_cls = FasterDecoder
+            opt_cls = FasterDecoderOptions
+            self.rec_cls = FasterRecognizer
+
+        self.decoder_options = opt_cls()
+        self.decoder_options.beam = beam
+        self.decoder_options.max_active = cfg.max_active
+        self.decoder_options.beam_delta = cfg.beam_delta
+        self.decoder_options.hash_ratio = cfg.hash_ratio
+
+        if cfg.is_lattice:
+            self.decoder_options.lattice_beam = cfg.lattice_beam
+            self.decoder_options.prune_interval = cfg.prune_interval
+            self.decoder_options.determinize_lattice = cfg.determinize_lattice
+            self.decoder_options.prune_scale = cfg.prune_scale
+            det_opts = DeterminizeLatticePhonePrunedOptions()
+            det_opts.max_mem = cfg.max_mem
+            det_opts.phone_determinize = cfg.phone_determinize
+            det_opts.word_determinize = cfg.word_determinize
+            det_opts.minimize = cfg.minimize
+            self.decoder_options.det_opts = det_opts
+
+        self.output_symbols = {}
+        with open(cfg.output_dict, "r") as f:
+            for line in f:
+                items = line.rstrip().split()
+                assert len(items) == 2
+                self.output_symbols[int(items[1])] = items[0]
+
+        logger.info(f"Loading FST from {cfg.hlg_graph_path}")
+        self.fst = read_fst_kaldi(cfg.hlg_graph_path)
+        self.symbol_table = SymbolTable.read_text(cfg.output_dict)
+
+        self.executor = ThreadPoolExecutor(max_workers=cfg.num_threads)
+
+    def generate(self, models, sample, **unused):
+        """Generate a batch of inferences."""
+        # model.forward normally channels prev_output_tokens into the decoder
+        # separately, but SequenceGenerator directly calls model.encoder
+        encoder_input = {
+            k: v for k, v in sample["net_input"].items() if k != "prev_output_tokens"
+        }
+        emissions, padding = self.get_emissions(models, encoder_input)
+        return self.decode(emissions, padding)
+
+    def get_emissions(self, models, encoder_input):
+        """Run encoder and normalize emissions"""
+        model = models[0]
+
+        all_encoder_out = [m(**encoder_input) for m in models]
+
+        if len(all_encoder_out) > 1:
+
+            if "encoder_out" in all_encoder_out[0]:
+                encoder_out = {
+                    "encoder_out": sum(e["encoder_out"] for e in all_encoder_out)
+                    / len(all_encoder_out),
+                    "encoder_padding_mask": all_encoder_out[0]["encoder_padding_mask"],
+                }
+                padding = encoder_out["encoder_padding_mask"]
+            else:
+                encoder_out = {
+                    "logits": sum(e["logits"] for e in all_encoder_out)
+                    / len(all_encoder_out),
+                    "padding_mask": all_encoder_out[0]["padding_mask"],
+                }
+                padding = encoder_out["padding_mask"]
+        else:
+            encoder_out = all_encoder_out[0]
+            padding = (
+                encoder_out["padding_mask"]
+                if "padding_mask" in encoder_out
+                else encoder_out["encoder_padding_mask"]
+            )
+
+        if hasattr(model, "get_logits"):
+            emissions = model.get_logits(encoder_out, normalize=True)
+        else:
+            emissions = model.get_normalized_probs(encoder_out, log_probs=True)
+
+        return (
+            emissions.cpu().float().transpose(0, 1),
+            padding.cpu() if padding is not None and padding.any() else None,
+        )
+
+    def decode_one(self, logits, padding):
+        from kaldi.matrix import Matrix
+
+        decoder = self.dec_cls(self.fst, self.decoder_options)
+        asr = self.rec_cls(
+            decoder, self.symbol_table, acoustic_scale=self.acoustic_scale
+        )
+
+        if padding is not None:
+            logits = logits[~padding]
+
+        mat = Matrix(logits.numpy())
+
+        out = asr.decode(mat)
+
+        if self.nbest > 1:
+            from kaldi.fstext import shortestpath
+            from kaldi.fstext.utils import (
+                convert_compact_lattice_to_lattice,
+                convert_lattice_to_std,
+                convert_nbest_to_list,
+                get_linear_symbol_sequence,
+            )
+
+            lat = out["lattice"]
+
+            sp = shortestpath(lat, nshortest=self.nbest)
+
+            sp = convert_compact_lattice_to_lattice(sp)
+            sp = convert_lattice_to_std(sp)
+            seq = convert_nbest_to_list(sp)
+
+            results = []
+            for s in seq:
+                _, o, w = get_linear_symbol_sequence(s)
+                words = list(self.output_symbols[z] for z in o)
+                results.append(
+                    {
+                        "tokens": words,
+                        "words": words,
+                        "score": w.value,
+                        "emissions": logits,
+                    }
+                )
+            return results
+        else:
+            words = out["text"].split()
+            return [
+                {
+                    "tokens": words,
+                    "words": words,
+                    "score": out["likelihood"],
+                    "emissions": logits,
+                }
+            ]
+
+    def decode(self, emissions, padding):
+        if padding is None:
+            padding = [None] * len(emissions)
+
+        ret = list(
+            map(
+                lambda e, p: self.executor.submit(self.decode_one, e, p),
+                emissions,
+                padding,
+            )
+        )
+        return ret

edgelm/examples/speech_recognition/kaldi/kaldi_initializer.py

@@ -0,0 +1,698 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from dataclasses import dataclass
+import hydra
+from hydra.core.config_store import ConfigStore
+import logging
+from omegaconf import MISSING, OmegaConf
+import os
+import os.path as osp
+from pathlib import Path
+import subprocess
+from typing import Optional
+
+from fairseq.data.dictionary import Dictionary
+from fairseq.dataclass import FairseqDataclass
+
+script_dir = Path(__file__).resolve().parent
+config_path = script_dir / "config"
+
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class KaldiInitializerConfig(FairseqDataclass):
+    data_dir: str = MISSING
+    fst_dir: Optional[str] = None
+    in_labels: str = MISSING
+    out_labels: Optional[str] = None
+    wav2letter_lexicon: Optional[str] = None
+    lm_arpa: str = MISSING
+    kaldi_root: str = MISSING
+    blank_symbol: str = "<s>"
+    silence_symbol: Optional[str] = None
+
+
+def create_units(fst_dir: Path, in_labels: str, vocab: Dictionary) -> Path:
+    in_units_file = fst_dir / f"kaldi_dict.{in_labels}.txt"
+    if not in_units_file.exists():
+
+        logger.info(f"Creating {in_units_file}")
+
+        with open(in_units_file, "w") as f:
+            print("<eps> 0", file=f)
+            i = 1
+            for symb in vocab.symbols[vocab.nspecial :]:
+                if not symb.startswith("madeupword"):
+                    print(f"{symb} {i}", file=f)
+                    i += 1
+    return in_units_file
+
+
+def create_lexicon(
+    cfg: KaldiInitializerConfig,
+    fst_dir: Path,
+    unique_label: str,
+    in_units_file: Path,
+    out_words_file: Path,
+) -> (Path, Path):
+
+    disambig_in_units_file = fst_dir / f"kaldi_dict.{cfg.in_labels}_disambig.txt"
+    lexicon_file = fst_dir / f"kaldi_lexicon.{unique_label}.txt"
+    disambig_lexicon_file = fst_dir / f"kaldi_lexicon.{unique_label}_disambig.txt"
+    if (
+        not lexicon_file.exists()
+        or not disambig_lexicon_file.exists()
+        or not disambig_in_units_file.exists()
+    ):
+        logger.info(f"Creating {lexicon_file} (in units file: {in_units_file})")
+
+        assert cfg.wav2letter_lexicon is not None or cfg.in_labels == cfg.out_labels
+
+        if cfg.wav2letter_lexicon is not None:
+            lm_words = set()
+            with open(out_words_file, "r") as lm_dict_f:
+                for line in lm_dict_f:
+                    lm_words.add(line.split()[0])
+
+            num_skipped = 0
+            total = 0
+            with open(cfg.wav2letter_lexicon, "r") as w2l_lex_f, open(
+                lexicon_file, "w"
+            ) as out_f:
+                for line in w2l_lex_f:
+                    items = line.rstrip().split("\t")
+                    assert len(items) == 2, items
+                    if items[0] in lm_words:
+                        print(items[0], items[1], file=out_f)
+                    else:
+                        num_skipped += 1
+                        logger.debug(
+                            f"Skipping word {items[0]} as it was not found in LM"
+                        )
+                    total += 1
+            if num_skipped > 0:
+                logger.warning(
+                    f"Skipped {num_skipped} out of {total} words as they were not found in LM"
+                )
+        else:
+            with open(in_units_file, "r") as in_f, open(lexicon_file, "w") as out_f:
+                for line in in_f:
+                    symb = line.split()[0]
+                    if symb != "<eps>" and symb != "<ctc_blank>" and symb != "<SIL>":
+                        print(symb, symb, file=out_f)
+
+        lex_disambig_path = (
+            Path(cfg.kaldi_root) / "egs/wsj/s5/utils/add_lex_disambig.pl"
+        )
+        res = subprocess.run(
+            [lex_disambig_path, lexicon_file, disambig_lexicon_file],
+            check=True,
+            capture_output=True,
+        )
+        ndisambig = int(res.stdout)
+        disamib_path = Path(cfg.kaldi_root) / "egs/wsj/s5/utils/add_disambig.pl"
+        res = subprocess.run(
+            [disamib_path, "--include-zero", in_units_file, str(ndisambig)],
+            check=True,
+            capture_output=True,
+        )
+        with open(disambig_in_units_file, "wb") as f:
+            f.write(res.stdout)
+
+    return disambig_lexicon_file, disambig_in_units_file
+
+
+def create_G(
+    kaldi_root: Path, fst_dir: Path, lm_arpa: Path, arpa_base: str
+) -> (Path, Path):
+
+    out_words_file = fst_dir / f"kaldi_dict.{arpa_base}.txt"
+    grammar_graph = fst_dir / f"G_{arpa_base}.fst"
+    if not grammar_graph.exists() or not out_words_file.exists():
+        logger.info(f"Creating {grammar_graph}")
+        arpa2fst = kaldi_root / "src/lmbin/arpa2fst"
+        subprocess.run(
+            [
+                arpa2fst,
+                "--disambig-symbol=#0",
+                f"--write-symbol-table={out_words_file}",
+                lm_arpa,
+                grammar_graph,
+            ],
+            check=True,
+        )
+    return grammar_graph, out_words_file
+
+
+def create_L(
+    kaldi_root: Path,
+    fst_dir: Path,
+    unique_label: str,
+    lexicon_file: Path,
+    in_units_file: Path,
+    out_words_file: Path,
+) -> Path:
+    lexicon_graph = fst_dir / f"L.{unique_label}.fst"
+
+    if not lexicon_graph.exists():
+        logger.info(f"Creating {lexicon_graph} (in units: {in_units_file})")
+        make_lex = kaldi_root / "egs/wsj/s5/utils/make_lexicon_fst.pl"
+        fstcompile = kaldi_root / "tools/openfst-1.6.7/bin/fstcompile"
+        fstaddselfloops = kaldi_root / "src/fstbin/fstaddselfloops"
+        fstarcsort = kaldi_root / "tools/openfst-1.6.7/bin/fstarcsort"
+
+        def write_disambig_symbol(file):
+            with open(file, "r") as f:
+                for line in f:
+                    items = line.rstrip().split()
+                    if items[0] == "#0":
+                        out_path = str(file) + "_disamig"
+                        with open(out_path, "w") as out_f:
+                            print(items[1], file=out_f)
+                            return out_path
+
+            return None
+
+        in_disambig_sym = write_disambig_symbol(in_units_file)
+        assert in_disambig_sym is not None
+        out_disambig_sym = write_disambig_symbol(out_words_file)
+        assert out_disambig_sym is not None
+
+        try:
+            with open(lexicon_graph, "wb") as out_f:
+                res = subprocess.run(
+                    [make_lex, lexicon_file], capture_output=True, check=True
+                )
+                assert len(res.stderr) == 0, res.stderr.decode("utf-8")
+                res = subprocess.run(
+                    [
+                        fstcompile,
+                        f"--isymbols={in_units_file}",
+                        f"--osymbols={out_words_file}",
+                        "--keep_isymbols=false",
+                        "--keep_osymbols=false",
+                    ],
+                    input=res.stdout,
+                    capture_output=True,
+                )
+                assert len(res.stderr) == 0, res.stderr.decode("utf-8")
+                res = subprocess.run(
+                    [fstaddselfloops, in_disambig_sym, out_disambig_sym],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstarcsort, "--sort_type=olabel"],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                out_f.write(res.stdout)
+        except subprocess.CalledProcessError as e:
+            logger.error(f"cmd: {e.cmd}, err: {e.stderr.decode('utf-8')}")
+            os.remove(lexicon_graph)
+            raise
+        except AssertionError:
+            os.remove(lexicon_graph)
+            raise
+
+    return lexicon_graph
+
+
+def create_LG(
+    kaldi_root: Path,
+    fst_dir: Path,
+    unique_label: str,
+    lexicon_graph: Path,
+    grammar_graph: Path,
+) -> Path:
+    lg_graph = fst_dir / f"LG.{unique_label}.fst"
+
+    if not lg_graph.exists():
+        logger.info(f"Creating {lg_graph}")
+
+        fsttablecompose = kaldi_root / "src/fstbin/fsttablecompose"
+        fstdeterminizestar = kaldi_root / "src/fstbin/fstdeterminizestar"
+        fstminimizeencoded = kaldi_root / "src/fstbin/fstminimizeencoded"
+        fstpushspecial = kaldi_root / "src/fstbin/fstpushspecial"
+        fstarcsort = kaldi_root / "tools/openfst-1.6.7/bin/fstarcsort"
+
+        try:
+            with open(lg_graph, "wb") as out_f:
+                res = subprocess.run(
+                    [fsttablecompose, lexicon_graph, grammar_graph],
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [
+                        fstdeterminizestar,
+                        "--use-log=true",
+                    ],
+                    input=res.stdout,
+                    capture_output=True,
+                )
+                res = subprocess.run(
+                    [fstminimizeencoded],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstpushspecial],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstarcsort, "--sort_type=ilabel"],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                out_f.write(res.stdout)
+        except subprocess.CalledProcessError as e:
+            logger.error(f"cmd: {e.cmd}, err: {e.stderr.decode('utf-8')}")
+            os.remove(lg_graph)
+            raise
+
+    return lg_graph
+
+
+def create_H(
+    kaldi_root: Path,
+    fst_dir: Path,
+    disambig_out_units_file: Path,
+    in_labels: str,
+    vocab: Dictionary,
+    blk_sym: str,
+    silence_symbol: Optional[str],
+) -> (Path, Path, Path):
+    h_graph = (
+        fst_dir / f"H.{in_labels}{'_' + silence_symbol if silence_symbol else ''}.fst"
+    )
+    h_out_units_file = fst_dir / f"kaldi_dict.h_out.{in_labels}.txt"
+    disambig_in_units_file_int = Path(str(h_graph) + "isym_disambig.int")
+    disambig_out_units_file_int = Path(str(disambig_out_units_file) + ".int")
+    if (
+        not h_graph.exists()
+        or not h_out_units_file.exists()
+        or not disambig_in_units_file_int.exists()
+    ):
+        logger.info(f"Creating {h_graph}")
+        eps_sym = "<eps>"
+
+        num_disambig = 0
+        osymbols = []
+
+        with open(disambig_out_units_file, "r") as f, open(
+            disambig_out_units_file_int, "w"
+        ) as out_f:
+            for line in f:
+                symb, id = line.rstrip().split()
+                if line.startswith("#"):
+                    num_disambig += 1
+                    print(id, file=out_f)
+                else:
+                    if len(osymbols) == 0:
+                        assert symb == eps_sym, symb
+                    osymbols.append((symb, id))
+
+        i_idx = 0
+        isymbols = [(eps_sym, 0)]
+
+        imap = {}
+
+        for i, s in enumerate(vocab.symbols):
+            i_idx += 1
+            isymbols.append((s, i_idx))
+            imap[s] = i_idx
+
+        fst_str = []
+
+        node_idx = 0
+        root_node = node_idx
+
+        special_symbols = [blk_sym]
+        if silence_symbol is not None:
+            special_symbols.append(silence_symbol)
+
+        for ss in special_symbols:
+            fst_str.append("{} {} {} {}".format(root_node, root_node, ss, eps_sym))
+
+        for symbol, _ in osymbols:
+            if symbol == eps_sym or symbol.startswith("#"):
+                continue
+
+            node_idx += 1
+            # 1. from root to emitting state
+            fst_str.append("{} {} {} {}".format(root_node, node_idx, symbol, symbol))
+            # 2. from emitting state back to root
+            fst_str.append("{} {} {} {}".format(node_idx, root_node, eps_sym, eps_sym))
+            # 3. from emitting state to optional blank state
+            pre_node = node_idx
+            node_idx += 1
+            for ss in special_symbols:
+                fst_str.append("{} {} {} {}".format(pre_node, node_idx, ss, eps_sym))
+            # 4. from blank state back to root
+            fst_str.append("{} {} {} {}".format(node_idx, root_node, eps_sym, eps_sym))
+
+        fst_str.append("{}".format(root_node))
+
+        fst_str = "\n".join(fst_str)
+        h_str = str(h_graph)
+        isym_file = h_str + ".isym"
+
+        with open(isym_file, "w") as f:
+            for sym, id in isymbols:
+                f.write("{} {}\n".format(sym, id))
+
+        with open(h_out_units_file, "w") as f:
+            for sym, id in osymbols:
+                f.write("{} {}\n".format(sym, id))
+
+        with open(disambig_in_units_file_int, "w") as f:
+            disam_sym_id = len(isymbols)
+            for _ in range(num_disambig):
+                f.write("{}\n".format(disam_sym_id))
+                disam_sym_id += 1
+
+        fstcompile = kaldi_root / "tools/openfst-1.6.7/bin/fstcompile"
+        fstaddselfloops = kaldi_root / "src/fstbin/fstaddselfloops"
+        fstarcsort = kaldi_root / "tools/openfst-1.6.7/bin/fstarcsort"
+
+        try:
+            with open(h_graph, "wb") as out_f:
+                res = subprocess.run(
+                    [
+                        fstcompile,
+                        f"--isymbols={isym_file}",
+                        f"--osymbols={h_out_units_file}",
+                        "--keep_isymbols=false",
+                        "--keep_osymbols=false",
+                    ],
+                    input=str.encode(fst_str),
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [
+                        fstaddselfloops,
+                        disambig_in_units_file_int,
+                        disambig_out_units_file_int,
+                    ],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstarcsort, "--sort_type=olabel"],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                out_f.write(res.stdout)
+        except subprocess.CalledProcessError as e:
+            logger.error(f"cmd: {e.cmd}, err: {e.stderr.decode('utf-8')}")
+            os.remove(h_graph)
+            raise
+    return h_graph, h_out_units_file, disambig_in_units_file_int
+
+
+def create_HLGa(
+    kaldi_root: Path,
+    fst_dir: Path,
+    unique_label: str,
+    h_graph: Path,
+    lg_graph: Path,
+    disambig_in_words_file_int: Path,
+) -> Path:
+    hlga_graph = fst_dir / f"HLGa.{unique_label}.fst"
+
+    if not hlga_graph.exists():
+        logger.info(f"Creating {hlga_graph}")
+
+        fsttablecompose = kaldi_root / "src/fstbin/fsttablecompose"
+        fstdeterminizestar = kaldi_root / "src/fstbin/fstdeterminizestar"
+        fstrmsymbols = kaldi_root / "src/fstbin/fstrmsymbols"
+        fstrmepslocal = kaldi_root / "src/fstbin/fstrmepslocal"
+        fstminimizeencoded = kaldi_root / "src/fstbin/fstminimizeencoded"
+
+        try:
+            with open(hlga_graph, "wb") as out_f:
+                res = subprocess.run(
+                    [
+                        fsttablecompose,
+                        h_graph,
+                        lg_graph,
+                    ],
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstdeterminizestar, "--use-log=true"],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstrmsymbols, disambig_in_words_file_int],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstrmepslocal],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstminimizeencoded],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                out_f.write(res.stdout)
+        except subprocess.CalledProcessError as e:
+            logger.error(f"cmd: {e.cmd}, err: {e.stderr.decode('utf-8')}")
+            os.remove(hlga_graph)
+            raise
+
+    return hlga_graph
+
+
+def create_HLa(
+    kaldi_root: Path,
+    fst_dir: Path,
+    unique_label: str,
+    h_graph: Path,
+    l_graph: Path,
+    disambig_in_words_file_int: Path,
+) -> Path:
+    hla_graph = fst_dir / f"HLa.{unique_label}.fst"
+
+    if not hla_graph.exists():
+        logger.info(f"Creating {hla_graph}")
+
+        fsttablecompose = kaldi_root / "src/fstbin/fsttablecompose"
+        fstdeterminizestar = kaldi_root / "src/fstbin/fstdeterminizestar"
+        fstrmsymbols = kaldi_root / "src/fstbin/fstrmsymbols"
+        fstrmepslocal = kaldi_root / "src/fstbin/fstrmepslocal"
+        fstminimizeencoded = kaldi_root / "src/fstbin/fstminimizeencoded"
+
+        try:
+            with open(hla_graph, "wb") as out_f:
+                res = subprocess.run(
+                    [
+                        fsttablecompose,
+                        h_graph,
+                        l_graph,
+                    ],
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstdeterminizestar, "--use-log=true"],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstrmsymbols, disambig_in_words_file_int],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstrmepslocal],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                res = subprocess.run(
+                    [fstminimizeencoded],
+                    input=res.stdout,
+                    capture_output=True,
+                    check=True,
+                )
+                out_f.write(res.stdout)
+        except subprocess.CalledProcessError as e:
+            logger.error(f"cmd: {e.cmd}, err: {e.stderr.decode('utf-8')}")
+            os.remove(hla_graph)
+            raise
+
+    return hla_graph
+
+
+def create_HLG(
+    kaldi_root: Path,
+    fst_dir: Path,
+    unique_label: str,
+    hlga_graph: Path,
+    prefix: str = "HLG",
+) -> Path:
+    hlg_graph = fst_dir / f"{prefix}.{unique_label}.fst"
+
+    if not hlg_graph.exists():
+        logger.info(f"Creating {hlg_graph}")
+
+        add_self_loop = script_dir / "add-self-loop-simple"
+        kaldi_src = kaldi_root / "src"
+        kaldi_lib = kaldi_src / "lib"
+
+        try:
+            if not add_self_loop.exists():
+                fst_include = kaldi_root / "tools/openfst-1.6.7/include"
+                add_self_loop_src = script_dir / "add-self-loop-simple.cc"
+
+                subprocess.run(
+                    [
+                        "c++",
+                        f"-I{kaldi_src}",
+                        f"-I{fst_include}",
+                        f"-L{kaldi_lib}",
+                        add_self_loop_src,
+                        "-lkaldi-base",
+                        "-lkaldi-fstext",
+                        "-o",
+                        add_self_loop,
+                    ],
+                    check=True,
+                )
+
+            my_env = os.environ.copy()
+            my_env["LD_LIBRARY_PATH"] = f"{kaldi_lib}:{my_env['LD_LIBRARY_PATH']}"
+
+            subprocess.run(
+                [
+                    add_self_loop,
+                    hlga_graph,
+                    hlg_graph,
+                ],
+                check=True,
+                capture_output=True,
+                env=my_env,
+            )
+        except subprocess.CalledProcessError as e:
+            logger.error(f"cmd: {e.cmd}, err: {e.stderr.decode('utf-8')}")
+            raise
+
+    return hlg_graph
+
+
+def initalize_kaldi(cfg: KaldiInitializerConfig) -> Path:
+    if cfg.fst_dir is None:
+        cfg.fst_dir = osp.join(cfg.data_dir, "kaldi")
+    if cfg.out_labels is None:
+        cfg.out_labels = cfg.in_labels
+
+    kaldi_root = Path(cfg.kaldi_root)
+    data_dir = Path(cfg.data_dir)
+    fst_dir = Path(cfg.fst_dir)
+    fst_dir.mkdir(parents=True, exist_ok=True)
+
+    arpa_base = osp.splitext(osp.basename(cfg.lm_arpa))[0]
+    unique_label = f"{cfg.in_labels}.{arpa_base}"
+
+    with open(data_dir / f"dict.{cfg.in_labels}.txt", "r") as f:
+        vocab = Dictionary.load(f)
+
+    in_units_file = create_units(fst_dir, cfg.in_labels, vocab)
+
+    grammar_graph, out_words_file = create_G(
+        kaldi_root, fst_dir, Path(cfg.lm_arpa), arpa_base
+    )
+
+    disambig_lexicon_file, disambig_L_in_units_file = create_lexicon(
+        cfg, fst_dir, unique_label, in_units_file, out_words_file
+    )
+
+    h_graph, h_out_units_file, disambig_in_units_file_int = create_H(
+        kaldi_root,
+        fst_dir,
+        disambig_L_in_units_file,
+        cfg.in_labels,
+        vocab,
+        cfg.blank_symbol,
+        cfg.silence_symbol,
+    )
+    lexicon_graph = create_L(
+        kaldi_root,
+        fst_dir,
+        unique_label,
+        disambig_lexicon_file,
+        disambig_L_in_units_file,
+        out_words_file,
+    )
+    lg_graph = create_LG(
+        kaldi_root, fst_dir, unique_label, lexicon_graph, grammar_graph
+    )
+    hlga_graph = create_HLGa(
+        kaldi_root, fst_dir, unique_label, h_graph, lg_graph, disambig_in_units_file_int
+    )
+    hlg_graph = create_HLG(kaldi_root, fst_dir, unique_label, hlga_graph)
+
+    # for debugging
+    # hla_graph = create_HLa(kaldi_root, fst_dir, unique_label, h_graph, lexicon_graph, disambig_in_units_file_int)
+    # hl_graph = create_HLG(kaldi_root, fst_dir, unique_label, hla_graph, prefix="HL_looped")
+    # create_HLG(kaldi_root, fst_dir, "phnc", h_graph, prefix="H_looped")
+
+    return hlg_graph
+
+
+@hydra.main(config_path=config_path, config_name="kaldi_initializer")
+def cli_main(cfg: KaldiInitializerConfig) -> None:
+    container = OmegaConf.to_container(cfg, resolve=True, enum_to_str=True)
+    cfg = OmegaConf.create(container)
+    OmegaConf.set_struct(cfg, True)
+    initalize_kaldi(cfg)
+
+
+if __name__ == "__main__":
+
+    logging.root.setLevel(logging.INFO)
+    logging.basicConfig(level=logging.INFO)
+
+    try:
+        from hydra._internal.utils import (
+            get_args,
+        )  # pylint: disable=import-outside-toplevel
+
+        cfg_name = get_args().config_name or "kaldi_initializer"
+    except ImportError:
+        logger.warning("Failed to get config name from hydra args")
+        cfg_name = "kaldi_initializer"
+
+    cs = ConfigStore.instance()
+    cs.store(name=cfg_name, node=KaldiInitializerConfig)
+
+    cli_main()

edgelm/examples/speech_recognition/models/__init__.py

@@ -0,0 +1,8 @@
+import importlib
+import os
+
+
+for file in sorted(os.listdir(os.path.dirname(__file__))):
+    if file.endswith(".py") and not file.startswith("_"):
+        model_name = file[: file.find(".py")]
+        importlib.import_module("examples.speech_recognition.models." + model_name)

edgelm/examples/speech_recognition/models/w2l_conv_glu_enc.py

@@ -0,0 +1,177 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import math
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from fairseq.models import (
+    FairseqEncoder,
+    FairseqEncoderModel,
+    register_model,
+    register_model_architecture,
+)
+from fairseq.modules.fairseq_dropout import FairseqDropout
+
+
+default_conv_enc_config = """[
+    (400, 13, 170, 0.2),
+    (440, 14, 0, 0.214),
+    (484, 15, 0, 0.22898),
+    (532, 16, 0, 0.2450086),
+    (584, 17, 0, 0.262159202),
+    (642, 18, 0, 0.28051034614),
+    (706, 19, 0, 0.30014607037),
+    (776, 20, 0, 0.321156295296),
+    (852, 21, 0, 0.343637235966),
+    (936, 22, 0, 0.367691842484),
+    (1028, 23, 0, 0.393430271458),
+    (1130, 24, 0, 0.42097039046),
+    (1242, 25, 0, 0.450438317792),
+    (1366, 26, 0, 0.481969000038),
+    (1502, 27, 0, 0.51570683004),
+    (1652, 28, 0, 0.551806308143),
+    (1816, 29, 0, 0.590432749713),
+]"""
+
+
+@register_model("asr_w2l_conv_glu_encoder")
+class W2lConvGluEncoderModel(FairseqEncoderModel):
+    def __init__(self, encoder):
+        super().__init__(encoder)
+
+    @staticmethod
+    def add_args(parser):
+        """Add model-specific arguments to the parser."""
+        parser.add_argument(
+            "--input-feat-per-channel",
+            type=int,
+            metavar="N",
+            help="encoder input dimension per input channel",
+        )
+        parser.add_argument(
+            "--in-channels",
+            type=int,
+            metavar="N",
+            help="number of encoder input channels",
+        )
+        parser.add_argument(
+            "--conv-enc-config",
+            type=str,
+            metavar="EXPR",
+            help="""
+    an array of tuples each containing the configuration of one conv layer
+    [(out_channels, kernel_size, padding, dropout), ...]
+            """,
+        )
+
+    @classmethod
+    def build_model(cls, args, task):
+        """Build a new model instance."""
+        conv_enc_config = getattr(args, "conv_enc_config", default_conv_enc_config)
+        encoder = W2lConvGluEncoder(
+            vocab_size=len(task.target_dictionary),
+            input_feat_per_channel=args.input_feat_per_channel,
+            in_channels=args.in_channels,
+            conv_enc_config=eval(conv_enc_config),
+        )
+        return cls(encoder)
+
+    def get_normalized_probs(self, net_output, log_probs, sample=None):
+        lprobs = super().get_normalized_probs(net_output, log_probs, sample)
+        lprobs.batch_first = False
+        return lprobs
+
+
+class W2lConvGluEncoder(FairseqEncoder):
+    def __init__(
+        self, vocab_size, input_feat_per_channel, in_channels, conv_enc_config
+    ):
+        super().__init__(None)
+
+        self.input_dim = input_feat_per_channel
+        if in_channels != 1:
+            raise ValueError("only 1 input channel is currently supported")
+
+        self.conv_layers = nn.ModuleList()
+        self.linear_layers = nn.ModuleList()
+        self.dropouts = []
+        cur_channels = input_feat_per_channel
+
+        for out_channels, kernel_size, padding, dropout in conv_enc_config:
+            layer = nn.Conv1d(cur_channels, out_channels, kernel_size, padding=padding)
+            layer.weight.data.mul_(math.sqrt(3))  # match wav2letter init
+            self.conv_layers.append(nn.utils.weight_norm(layer))
+            self.dropouts.append(
+                FairseqDropout(dropout, module_name=self.__class__.__name__)
+            )
+            if out_channels % 2 != 0:
+                raise ValueError("odd # of out_channels is incompatible with GLU")
+            cur_channels = out_channels // 2  # halved by GLU
+
+        for out_channels in [2 * cur_channels, vocab_size]:
+            layer = nn.Linear(cur_channels, out_channels)
+            layer.weight.data.mul_(math.sqrt(3))
+            self.linear_layers.append(nn.utils.weight_norm(layer))
+            cur_channels = out_channels // 2
+
+    def forward(self, src_tokens, src_lengths, **kwargs):
+
+        """
+        src_tokens: padded tensor (B, T, C * feat)
+        src_lengths: tensor of original lengths of input utterances (B,)
+        """
+        B, T, _ = src_tokens.size()
+        x = src_tokens.transpose(1, 2).contiguous()  # (B, feat, T) assuming C == 1
+
+        for layer_idx in range(len(self.conv_layers)):
+            x = self.conv_layers[layer_idx](x)
+            x = F.glu(x, dim=1)
+            x = self.dropouts[layer_idx](x)
+
+        x = x.transpose(1, 2).contiguous()  # (B, T, 908)
+        x = self.linear_layers[0](x)
+        x = F.glu(x, dim=2)
+        x = self.dropouts[-1](x)
+        x = self.linear_layers[1](x)
+
+        assert x.size(0) == B
+        assert x.size(1) == T
+
+        encoder_out = x.transpose(0, 1)  # (T, B, vocab_size)
+
+        # need to debug this -- find a simpler/elegant way in pytorch APIs
+        encoder_padding_mask = (
+            torch.arange(T).view(1, T).expand(B, -1).to(x.device)
+            >= src_lengths.view(B, 1).expand(-1, T)
+        ).t()  # (B x T) -> (T x B)
+
+        return {
+            "encoder_out": encoder_out,  # (T, B, vocab_size)
+            "encoder_padding_mask": encoder_padding_mask,  # (T, B)
+        }
+
+    def reorder_encoder_out(self, encoder_out, new_order):
+        encoder_out["encoder_out"] = encoder_out["encoder_out"].index_select(
+            1, new_order
+        )
+        encoder_out["encoder_padding_mask"] = encoder_out[
+            "encoder_padding_mask"
+        ].index_select(1, new_order)
+        return encoder_out
+
+    def max_positions(self):
+        """Maximum input length supported by the encoder."""
+        return (1e6, 1e6)  # an arbitrary large number
+
+
+@register_model_architecture("asr_w2l_conv_glu_encoder", "w2l_conv_glu_enc")
+def w2l_conv_glu_enc(args):
+    args.input_feat_per_channel = getattr(args, "input_feat_per_channel", 80)
+    args.in_channels = getattr(args, "in_channels", 1)
+    args.conv_enc_config = getattr(args, "conv_enc_config", default_conv_enc_config)

edgelm/examples/speech_recognition/new/README.md

@@ -0,0 +1,43 @@
+# Flashlight Decoder
+
+This script runs decoding for pre-trained speech recognition models.
+
+## Usage
+
+Assuming a few variables:
+
+```bash
+checkpoint=<path-to-checkpoint>
+data=<path-to-data-directory>
+lm_model=<path-to-language-model>
+lexicon=<path-to-lexicon>
+```
+
+Example usage for decoding a fine-tuned Wav2Vec model:
+
+```bash
+python $FAIRSEQ_ROOT/examples/speech_recognition/new/infer.py --multirun \
+    task=audio_pretraining \
+    task.data=$data \
+    task.labels=ltr \
+    common_eval.path=$checkpoint \
+    decoding.type=kenlm \
+    decoding.lexicon=$lexicon \
+    decoding.lmpath=$lm_model \
+    dataset.gen_subset=dev_clean,dev_other,test_clean,test_other
+```
+
+Example usage for using Ax to sweep WER parameters (requires `pip install hydra-ax-sweeper`):
+
+```bash
+python $FAIRSEQ_ROOT/examples/speech_recognition/new/infer.py --multirun \
+    hydra/sweeper=ax \
+    task=audio_pretraining \
+    task.data=$data \
+    task.labels=ltr \
+    common_eval.path=$checkpoint \
+    decoding.type=kenlm \
+    decoding.lexicon=$lexicon \
+    decoding.lmpath=$lm_model \
+    dataset.gen_subset=dev_other
+```

edgelm/examples/speech_recognition/new/conf/hydra/sweeper/ax.yaml

@@ -0,0 +1,26 @@
+# @package hydra.sweeper
+_target_: hydra_plugins.hydra_ax_sweeper.ax_sweeper.AxSweeper
+max_batch_size: null
+ax_config:
+  max_trials: 128
+  early_stop:
+    minimize: true
+    max_epochs_without_improvement: 32
+    epsilon: 1.0e-05
+  experiment:
+    name: ${dataset.gen_subset}
+    objective_name: wer
+    minimize: true
+    parameter_constraints: null
+    outcome_constraints: null
+    status_quo: null
+  client:
+    verbose_logging: false
+    random_seed: null
+  params:
+    decoding.lmweight:
+      type: range
+      bounds: [0.0, 5.0]
+    decoding.wordscore:
+      type: range
+      bounds: [-5.0, 5.0]

edgelm/examples/speech_recognition/new/conf/infer.yaml

@@ -0,0 +1,25 @@
+# @package _group_
+
+defaults:
+    - task: null
+    - model: null
+
+hydra:
+  run:
+    dir: ${common_eval.results_path}/${dataset.gen_subset}
+  sweep:
+    dir: ${common_eval.results_path}
+    subdir: ${dataset.gen_subset}
+common_eval:
+  results_path: null
+  path: null
+  post_process: letter
+  quiet: true
+dataset:
+  max_tokens: 1000000
+  gen_subset: test
+distributed_training:
+  distributed_world_size: 1
+decoding:
+  beam: 5
+  type: viterbi

edgelm/examples/speech_recognition/new/decoders/base_decoder.py

@@ -0,0 +1,62 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import itertools as it
+from typing import Any, Dict, List
+
+import torch
+from fairseq.data.dictionary import Dictionary
+from fairseq.models.fairseq_model import FairseqModel
+
+
+class BaseDecoder:
+    def __init__(self, tgt_dict: Dictionary) -> None:
+        self.tgt_dict = tgt_dict
+        self.vocab_size = len(tgt_dict)
+
+        self.blank = (
+            tgt_dict.index("<ctc_blank>")
+            if "<ctc_blank>" in tgt_dict.indices
+            else tgt_dict.bos()
+        )
+        if "<sep>" in tgt_dict.indices:
+            self.silence = tgt_dict.index("<sep>")
+        elif "|" in tgt_dict.indices:
+            self.silence = tgt_dict.index("|")
+        else:
+            self.silence = tgt_dict.eos()
+
+    def generate(
+        self, models: List[FairseqModel], sample: Dict[str, Any], **unused
+    ) -> List[List[Dict[str, torch.LongTensor]]]:
+        encoder_input = {
+            k: v for k, v in sample["net_input"].items() if k != "prev_output_tokens"
+        }
+        emissions = self.get_emissions(models, encoder_input)
+        return self.decode(emissions)
+
+    def get_emissions(
+        self,
+        models: List[FairseqModel],
+        encoder_input: Dict[str, Any],
+    ) -> torch.FloatTensor:
+        model = models[0]
+        encoder_out = model(**encoder_input)
+        if hasattr(model, "get_logits"):
+            emissions = model.get_logits(encoder_out)
+        else:
+            emissions = model.get_normalized_probs(encoder_out, log_probs=True)
+        return emissions.transpose(0, 1).float().cpu().contiguous()
+
+    def get_tokens(self, idxs: torch.IntTensor) -> torch.LongTensor:
+        idxs = (g[0] for g in it.groupby(idxs))
+        idxs = filter(lambda x: x != self.blank, idxs)
+        return torch.LongTensor(list(idxs))
+
+    def decode(
+        self,
+        emissions: torch.FloatTensor,
+    ) -> List[List[Dict[str, torch.LongTensor]]]:
+        raise NotImplementedError

edgelm/examples/speech_recognition/new/decoders/decoder.py

@@ -0,0 +1,32 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from typing import Union
+
+from fairseq.data.dictionary import Dictionary
+
+from .decoder_config import DecoderConfig, FlashlightDecoderConfig
+from .base_decoder import BaseDecoder
+
+
+def Decoder(
+    cfg: Union[DecoderConfig, FlashlightDecoderConfig], tgt_dict: Dictionary
+) -> BaseDecoder:
+
+    if cfg.type == "viterbi":
+        from .viterbi_decoder import ViterbiDecoder
+
+        return ViterbiDecoder(tgt_dict)
+    if cfg.type == "kenlm":
+        from .flashlight_decoder import KenLMDecoder
+
+        return KenLMDecoder(cfg, tgt_dict)
+    if cfg.type == "fairseqlm":
+        from .flashlight_decoder import FairseqLMDecoder
+
+        return FairseqLMDecoder(cfg, tgt_dict)
+    raise NotImplementedError(f"Invalid decoder name: {cfg.name}")

edgelm/examples/speech_recognition/new/decoders/decoder_config.py

@@ -0,0 +1,70 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import math
+from dataclasses import dataclass, field
+from typing import Optional
+
+from fairseq.dataclass.configs import FairseqDataclass
+from fairseq.dataclass.constants import ChoiceEnum
+from omegaconf import MISSING
+
+
+DECODER_CHOICES = ChoiceEnum(["viterbi", "kenlm", "fairseqlm"])
+
+
+@dataclass
+class DecoderConfig(FairseqDataclass):
+    type: DECODER_CHOICES = field(
+        default="viterbi",
+        metadata={"help": "The type of decoder to use"},
+    )
+
+
+@dataclass
+class FlashlightDecoderConfig(FairseqDataclass):
+    nbest: int = field(
+        default=1,
+        metadata={"help": "Number of decodings to return"},
+    )
+    unitlm: bool = field(
+        default=False,
+        metadata={"help": "If set, use unit language model"},
+    )
+    lmpath: str = field(
+        default=MISSING,
+        metadata={"help": "Language model for KenLM decoder"},
+    )
+    lexicon: Optional[str] = field(
+        default=None,
+        metadata={"help": "Lexicon for Flashlight decoder"},
+    )
+    beam: int = field(
+        default=50,
+        metadata={"help": "Number of beams to use for decoding"},
+    )
+    beamthreshold: float = field(
+        default=50.0,
+        metadata={"help": "Threshold for beam search decoding"},
+    )
+    beamsizetoken: Optional[int] = field(
+        default=None, metadata={"help": "Beam size to use"}
+    )
+    wordscore: float = field(
+        default=-1,
+        metadata={"help": "Word score for KenLM decoder"},
+    )
+    unkweight: float = field(
+        default=-math.inf,
+        metadata={"help": "Unknown weight for KenLM decoder"},
+    )
+    silweight: float = field(
+        default=0,
+        metadata={"help": "Silence weight for KenLM decoder"},
+    )
+    lmweight: float = field(
+        default=2,
+        metadata={"help": "Weight for LM while interpolating score"},
+    )

edgelm/examples/speech_recognition/new/decoders/flashlight_decoder.py

@@ -0,0 +1,431 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import gc
+import os.path as osp
+import warnings
+from collections import deque, namedtuple
+from typing import Any, Dict, Tuple
+
+import numpy as np
+import torch
+from fairseq import tasks
+from fairseq.data.dictionary import Dictionary
+from fairseq.dataclass.utils import convert_namespace_to_omegaconf
+from fairseq.models.fairseq_model import FairseqModel
+from fairseq.utils import apply_to_sample
+from omegaconf import open_dict, OmegaConf
+
+from typing import List
+
+from .decoder_config import FlashlightDecoderConfig
+from .base_decoder import BaseDecoder
+
+try:
+    from flashlight.lib.text.decoder import (
+        LM,
+        CriterionType,
+        DecodeResult,
+        KenLM,
+        LexiconDecoder,
+        LexiconDecoderOptions,
+        LexiconFreeDecoder,
+        LexiconFreeDecoderOptions,
+        LMState,
+        SmearingMode,
+        Trie,
+    )
+    from flashlight.lib.text.dictionary import create_word_dict, load_words
+except ImportError:
+    warnings.warn(
+        "flashlight python bindings are required to use this functionality. "
+        "Please install from "
+        "https://github.com/facebookresearch/flashlight/tree/master/bindings/python"
+    )
+    LM = object
+    LMState = object
+
+
+class KenLMDecoder(BaseDecoder):
+    def __init__(self, cfg: FlashlightDecoderConfig, tgt_dict: Dictionary) -> None:
+        super().__init__(tgt_dict)
+
+        self.nbest = cfg.nbest
+        self.unitlm = cfg.unitlm
+
+        if cfg.lexicon:
+            self.lexicon = load_words(cfg.lexicon)
+            self.word_dict = create_word_dict(self.lexicon)
+            self.unk_word = self.word_dict.get_index("<unk>")
+
+            self.lm = KenLM(cfg.lmpath, self.word_dict)
+            self.trie = Trie(self.vocab_size, self.silence)
+
+            start_state = self.lm.start(False)
+            for word, spellings in self.lexicon.items():
+                word_idx = self.word_dict.get_index(word)
+                _, score = self.lm.score(start_state, word_idx)
+                for spelling in spellings:
+                    spelling_idxs = [tgt_dict.index(token) for token in spelling]
+                    assert (
+                        tgt_dict.unk() not in spelling_idxs
+                    ), f"{word} {spelling} {spelling_idxs}"
+                    self.trie.insert(spelling_idxs, word_idx, score)
+            self.trie.smear(SmearingMode.MAX)
+
+            self.decoder_opts = LexiconDecoderOptions(
+                beam_size=cfg.beam,
+                beam_size_token=cfg.beamsizetoken or len(tgt_dict),
+                beam_threshold=cfg.beamthreshold,
+                lm_weight=cfg.lmweight,
+                word_score=cfg.wordscore,
+                unk_score=cfg.unkweight,
+                sil_score=cfg.silweight,
+                log_add=False,
+                criterion_type=CriterionType.CTC,
+            )
+
+            self.decoder = LexiconDecoder(
+                self.decoder_opts,
+                self.trie,
+                self.lm,
+                self.silence,
+                self.blank,
+                self.unk_word,
+                [],
+                self.unitlm,
+            )
+        else:
+            assert self.unitlm, "Lexicon-free decoding requires unit LM"
+
+            d = {w: [[w]] for w in tgt_dict.symbols}
+            self.word_dict = create_word_dict(d)
+            self.lm = KenLM(cfg.lmpath, self.word_dict)
+            self.decoder_opts = LexiconFreeDecoderOptions(
+                beam_size=cfg.beam,
+                beam_size_token=cfg.beamsizetoken or len(tgt_dict),
+                beam_threshold=cfg.beamthreshold,
+                lm_weight=cfg.lmweight,
+                sil_score=cfg.silweight,
+                log_add=False,
+                criterion_type=CriterionType.CTC,
+            )
+            self.decoder = LexiconFreeDecoder(
+                self.decoder_opts, self.lm, self.silence, self.blank, []
+            )
+
+    def get_timesteps(self, token_idxs: List[int]) -> List[int]:
+        """Returns frame numbers corresponding to every non-blank token.
+
+        Parameters
+        ----------
+        token_idxs : List[int]
+            IDs of decoded tokens.
+
+        Returns
+        -------
+        List[int]
+            Frame numbers corresponding to every non-blank token.
+        """
+        timesteps = []
+        for i, token_idx in enumerate(token_idxs):
+            if token_idx == self.blank:
+                continue
+            if i == 0 or token_idx != token_idxs[i-1]:
+                timesteps.append(i)
+        return timesteps
+
+    def decode(
+        self,
+        emissions: torch.FloatTensor,
+    ) -> List[List[Dict[str, torch.LongTensor]]]:
+        B, T, N = emissions.size()
+        hypos = []
+        for b in range(B):
+            emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
+            results = self.decoder.decode(emissions_ptr, T, N)
+
+            nbest_results = results[: self.nbest]
+            hypos.append(
+                [
+                    {
+                        "tokens": self.get_tokens(result.tokens),
+                        "score": result.score,
+                        "timesteps": self.get_timesteps(result.tokens),
+                        "words": [
+                            self.word_dict.get_entry(x) for x in result.words if x >= 0
+                        ],
+                    }
+                    for result in nbest_results
+                ]
+            )
+        return hypos
+
+
+FairseqLMState = namedtuple(
+    "FairseqLMState",
+    [
+        "prefix",
+        "incremental_state",
+        "probs",
+    ],
+)
+
+
+class FairseqLM(LM):
+    def __init__(self, dictionary: Dictionary, model: FairseqModel) -> None:
+        super().__init__()
+
+        self.dictionary = dictionary
+        self.model = model
+        self.unk = self.dictionary.unk()
+
+        self.save_incremental = False  # this currently does not work properly
+        self.max_cache = 20_000
+
+        if torch.cuda.is_available():
+            model.cuda()
+        model.eval()
+        model.make_generation_fast_()
+
+        self.states = {}
+        self.stateq = deque()
+
+    def start(self, start_with_nothing: bool) -> LMState:
+        state = LMState()
+        prefix = torch.LongTensor([[self.dictionary.eos()]])
+        incremental_state = {} if self.save_incremental else None
+        with torch.no_grad():
+            res = self.model(prefix.cuda(), incremental_state=incremental_state)
+            probs = self.model.get_normalized_probs(res, log_probs=True, sample=None)
+
+        if incremental_state is not None:
+            incremental_state = apply_to_sample(lambda x: x.cpu(), incremental_state)
+        self.states[state] = FairseqLMState(
+            prefix.numpy(), incremental_state, probs[0, -1].cpu().numpy()
+        )
+        self.stateq.append(state)
+
+        return state
+
+    def score(
+        self,
+        state: LMState,
+        token_index: int,
+        no_cache: bool = False,
+    ) -> Tuple[LMState, int]:
+        """
+        Evaluate language model based on the current lm state and new word
+        Parameters:
+        -----------
+        state: current lm state
+        token_index: index of the word
+                     (can be lexicon index then you should store inside LM the
+                      mapping between indices of lexicon and lm, or lm index of a word)
+        Returns:
+        --------
+        (LMState, float): pair of (new state, score for the current word)
+        """
+        curr_state = self.states[state]
+
+        def trim_cache(targ_size: int) -> None:
+            while len(self.stateq) > targ_size:
+                rem_k = self.stateq.popleft()
+                rem_st = self.states[rem_k]
+                rem_st = FairseqLMState(rem_st.prefix, None, None)
+                self.states[rem_k] = rem_st
+
+        if curr_state.probs is None:
+            new_incremental_state = (
+                curr_state.incremental_state.copy()
+                if curr_state.incremental_state is not None
+                else None
+            )
+            with torch.no_grad():
+                if new_incremental_state is not None:
+                    new_incremental_state = apply_to_sample(
+                        lambda x: x.cuda(), new_incremental_state
+                    )
+                elif self.save_incremental:
+                    new_incremental_state = {}
+
+                res = self.model(
+                    torch.from_numpy(curr_state.prefix).cuda(),
+                    incremental_state=new_incremental_state,
+                )
+                probs = self.model.get_normalized_probs(
+                    res, log_probs=True, sample=None
+                )
+
+                if new_incremental_state is not None:
+                    new_incremental_state = apply_to_sample(
+                        lambda x: x.cpu(), new_incremental_state
+                    )
+
+                curr_state = FairseqLMState(
+                    curr_state.prefix, new_incremental_state, probs[0, -1].cpu().numpy()
+                )
+
+            if not no_cache:
+                self.states[state] = curr_state
+                self.stateq.append(state)
+
+        score = curr_state.probs[token_index].item()
+
+        trim_cache(self.max_cache)
+
+        outstate = state.child(token_index)
+        if outstate not in self.states and not no_cache:
+            prefix = np.concatenate(
+                [curr_state.prefix, torch.LongTensor([[token_index]])], -1
+            )
+            incr_state = curr_state.incremental_state
+
+            self.states[outstate] = FairseqLMState(prefix, incr_state, None)
+
+        if token_index == self.unk:
+            score = float("-inf")
+
+        return outstate, score
+
+    def finish(self, state: LMState) -> Tuple[LMState, int]:
+        """
+        Evaluate eos for language model based on the current lm state
+        Returns:
+        --------
+        (LMState, float): pair of (new state, score for the current word)
+        """
+        return self.score(state, self.dictionary.eos())
+
+    def empty_cache(self) -> None:
+        self.states = {}
+        self.stateq = deque()
+        gc.collect()
+
+
+class FairseqLMDecoder(BaseDecoder):
+    def __init__(self, cfg: FlashlightDecoderConfig, tgt_dict: Dictionary) -> None:
+        super().__init__(tgt_dict)
+
+        self.nbest = cfg.nbest
+        self.unitlm = cfg.unitlm
+
+        self.lexicon = load_words(cfg.lexicon) if cfg.lexicon else None
+        self.idx_to_wrd = {}
+
+        checkpoint = torch.load(cfg.lmpath, map_location="cpu")
+
+        if "cfg" in checkpoint and checkpoint["cfg"] is not None:
+            lm_args = checkpoint["cfg"]
+        else:
+            lm_args = convert_namespace_to_omegaconf(checkpoint["args"])
+
+        if not OmegaConf.is_dict(lm_args):
+            lm_args = OmegaConf.create(lm_args)
+
+        with open_dict(lm_args.task):
+            lm_args.task.data = osp.dirname(cfg.lmpath)
+
+        task = tasks.setup_task(lm_args.task)
+        model = task.build_model(lm_args.model)
+        model.load_state_dict(checkpoint["model"], strict=False)
+
+        self.trie = Trie(self.vocab_size, self.silence)
+
+        self.word_dict = task.dictionary
+        self.unk_word = self.word_dict.unk()
+        self.lm = FairseqLM(self.word_dict, model)
+
+        if self.lexicon:
+            start_state = self.lm.start(False)
+            for i, (word, spellings) in enumerate(self.lexicon.items()):
+                if self.unitlm:
+                    word_idx = i
+                    self.idx_to_wrd[i] = word
+                    score = 0
+                else:
+                    word_idx = self.word_dict.index(word)
+                    _, score = self.lm.score(start_state, word_idx, no_cache=True)
+
+                for spelling in spellings:
+                    spelling_idxs = [tgt_dict.index(token) for token in spelling]
+                    assert (
+                        tgt_dict.unk() not in spelling_idxs
+                    ), f"{spelling} {spelling_idxs}"
+                    self.trie.insert(spelling_idxs, word_idx, score)
+            self.trie.smear(SmearingMode.MAX)
+
+            self.decoder_opts = LexiconDecoderOptions(
+                beam_size=cfg.beam,
+                beam_size_token=cfg.beamsizetoken or len(tgt_dict),
+                beam_threshold=cfg.beamthreshold,
+                lm_weight=cfg.lmweight,
+                word_score=cfg.wordscore,
+                unk_score=cfg.unkweight,
+                sil_score=cfg.silweight,
+                log_add=False,
+                criterion_type=CriterionType.CTC,
+            )
+
+            self.decoder = LexiconDecoder(
+                self.decoder_opts,
+                self.trie,
+                self.lm,
+                self.silence,
+                self.blank,
+                self.unk_word,
+                [],
+                self.unitlm,
+            )
+        else:
+            assert self.unitlm, "Lexicon-free decoding requires unit LM"
+
+            d = {w: [[w]] for w in tgt_dict.symbols}
+            self.word_dict = create_word_dict(d)
+            self.lm = KenLM(cfg.lmpath, self.word_dict)
+            self.decoder_opts = LexiconFreeDecoderOptions(
+                beam_size=cfg.beam,
+                beam_size_token=cfg.beamsizetoken or len(tgt_dict),
+                beam_threshold=cfg.beamthreshold,
+                lm_weight=cfg.lmweight,
+                sil_score=cfg.silweight,
+                log_add=False,
+                criterion_type=CriterionType.CTC,
+            )
+            self.decoder = LexiconFreeDecoder(
+                self.decoder_opts, self.lm, self.silence, self.blank, []
+            )
+
+    def decode(
+        self,
+        emissions: torch.FloatTensor,
+    ) -> List[List[Dict[str, torch.LongTensor]]]:
+        B, T, N = emissions.size()
+        hypos = []
+
+        def make_hypo(result: DecodeResult) -> Dict[str, Any]:
+            hypo = {
+                "tokens": self.get_tokens(result.tokens),
+                "score": result.score,
+            }
+            if self.lexicon:
+                hypo["words"] = [
+                    self.idx_to_wrd[x] if self.unitlm else self.word_dict[x]
+                    for x in result.words
+                    if x >= 0
+                ]
+            return hypo
+
+        for b in range(B):
+            emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
+            results = self.decoder.decode(emissions_ptr, T, N)
+
+            nbest_results = results[: self.nbest]
+            hypos.append([make_hypo(result) for result in nbest_results])
+            self.lm.empty_cache()
+
+        return hypos

edgelm/examples/speech_recognition/new/decoders/viterbi_decoder.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import torch
+
+from typing import List, Dict
+
+from .base_decoder import BaseDecoder
+
+
+class ViterbiDecoder(BaseDecoder):
+    def decode(
+        self,
+        emissions: torch.FloatTensor,
+    ) -> List[List[Dict[str, torch.LongTensor]]]:
+        def get_pred(e):
+            toks = e.argmax(dim=-1).unique_consecutive()
+            return toks[toks != self.blank]
+
+        return [[{"tokens": get_pred(x), "score": 0}] for x in emissions]

edgelm/examples/speech_recognition/new/infer.py

@@ -0,0 +1,471 @@
+#!/usr/bin/env python -u
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import ast
+import hashlib
+import logging
+import os
+import shutil
+import sys
+from dataclasses import dataclass, field, is_dataclass
+from pathlib import Path
+from typing import Any, Dict, List, Optional, Tuple, Union
+
+import editdistance
+import torch
+import torch.distributed as dist
+from examples.speech_recognition.new.decoders.decoder_config import (
+    DecoderConfig,
+    FlashlightDecoderConfig,
+)
+from examples.speech_recognition.new.decoders.decoder import Decoder
+from fairseq import checkpoint_utils, distributed_utils, progress_bar, tasks, utils
+from fairseq.data.data_utils import post_process
+from fairseq.dataclass.configs import (
+    CheckpointConfig,
+    CommonConfig,
+    CommonEvalConfig,
+    DatasetConfig,
+    DistributedTrainingConfig,
+    FairseqDataclass,
+)
+from fairseq.logging.meters import StopwatchMeter, TimeMeter
+from fairseq.logging.progress_bar import BaseProgressBar
+from fairseq.models.fairseq_model import FairseqModel
+from omegaconf import OmegaConf
+
+import hydra
+from hydra.core.config_store import ConfigStore
+
+logging.root.setLevel(logging.INFO)
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+
+config_path = Path(__file__).resolve().parent / "conf"
+
+
+@dataclass
+class DecodingConfig(DecoderConfig, FlashlightDecoderConfig):
+    unique_wer_file: bool = field(
+        default=False,
+        metadata={"help": "If set, use a unique file for storing WER"},
+    )
+    results_path: Optional[str] = field(
+        default=None,
+        metadata={
+            "help": "If set, write hypothesis and reference sentences into this directory"
+        },
+    )
+
+
+@dataclass
+class InferConfig(FairseqDataclass):
+    task: Any = None
+    decoding: DecodingConfig = DecodingConfig()
+    common: CommonConfig = CommonConfig()
+    common_eval: CommonEvalConfig = CommonEvalConfig()
+    checkpoint: CheckpointConfig = CheckpointConfig()
+    distributed_training: DistributedTrainingConfig = DistributedTrainingConfig()
+    dataset: DatasetConfig = DatasetConfig()
+    is_ax: bool = field(
+        default=False,
+        metadata={
+            "help": "if true, assumes we are using ax for tuning and returns a tuple for ax to consume"
+        },
+    )
+
+
+def reset_logging():
+    root = logging.getLogger()
+    for handler in root.handlers:
+        root.removeHandler(handler)
+    root.setLevel(os.environ.get("LOGLEVEL", "INFO").upper())
+    handler = logging.StreamHandler(sys.stdout)
+    handler.setFormatter(
+        logging.Formatter(
+            fmt="%(asctime)s | %(levelname)s | %(name)s | %(message)s",
+            datefmt="%Y-%m-%d %H:%M:%S",
+        )
+    )
+    root.addHandler(handler)
+
+
+class InferenceProcessor:
+    cfg: InferConfig
+
+    def __init__(self, cfg: InferConfig) -> None:
+        self.cfg = cfg
+        self.task = tasks.setup_task(cfg.task)
+
+        models, saved_cfg = self.load_model_ensemble()
+        self.models = models
+        self.saved_cfg = saved_cfg
+        self.tgt_dict = self.task.target_dictionary
+
+        self.task.load_dataset(
+            self.cfg.dataset.gen_subset,
+            task_cfg=saved_cfg.task,
+        )
+        self.generator = Decoder(cfg.decoding, self.tgt_dict)
+        self.gen_timer = StopwatchMeter()
+        self.wps_meter = TimeMeter()
+        self.num_sentences = 0
+        self.total_errors = 0
+        self.total_length = 0
+
+        self.hypo_words_file = None
+        self.hypo_units_file = None
+        self.ref_words_file = None
+        self.ref_units_file = None
+
+        self.progress_bar = self.build_progress_bar()
+
+    def __enter__(self) -> "InferenceProcessor":
+        if self.cfg.decoding.results_path is not None:
+            self.hypo_words_file = self.get_res_file("hypo.word")
+            self.hypo_units_file = self.get_res_file("hypo.units")
+            self.ref_words_file = self.get_res_file("ref.word")
+            self.ref_units_file = self.get_res_file("ref.units")
+        return self
+
+    def __exit__(self, *exc) -> bool:
+        if self.cfg.decoding.results_path is not None:
+            self.hypo_words_file.close()
+            self.hypo_units_file.close()
+            self.ref_words_file.close()
+            self.ref_units_file.close()
+        return False
+
+    def __iter__(self) -> Any:
+        for sample in self.progress_bar:
+            if not self.cfg.common.cpu:
+                sample = utils.move_to_cuda(sample)
+
+            # Happens on the last batch.
+            if "net_input" not in sample:
+                continue
+            yield sample
+
+    def log(self, *args, **kwargs):
+        self.progress_bar.log(*args, **kwargs)
+
+    def print(self, *args, **kwargs):
+        self.progress_bar.print(*args, **kwargs)
+
+    def get_res_file(self, fname: str) -> None:
+        fname = os.path.join(self.cfg.decoding.results_path, fname)
+        if self.data_parallel_world_size > 1:
+            fname = f"{fname}.{self.data_parallel_rank}"
+        return open(fname, "w", buffering=1)
+
+    def merge_shards(self) -> None:
+        """Merges all shard files into shard 0, then removes shard suffix."""
+
+        shard_id = self.data_parallel_rank
+        num_shards = self.data_parallel_world_size
+
+        if self.data_parallel_world_size > 1:
+
+            def merge_shards_with_root(fname: str) -> None:
+                fname = os.path.join(self.cfg.decoding.results_path, fname)
+                logger.info("Merging %s on shard %d", fname, shard_id)
+                base_fpath = Path(f"{fname}.0")
+                with open(base_fpath, "a") as out_file:
+                    for s in range(1, num_shards):
+                        shard_fpath = Path(f"{fname}.{s}")
+                        with open(shard_fpath, "r") as in_file:
+                            for line in in_file:
+                                out_file.write(line)
+                        shard_fpath.unlink()
+                shutil.move(f"{fname}.0", fname)
+
+            dist.barrier()  # ensure all shards finished writing
+            if shard_id == (0 % num_shards):
+                merge_shards_with_root("hypo.word")
+            if shard_id == (1 % num_shards):
+                merge_shards_with_root("hypo.units")
+            if shard_id == (2 % num_shards):
+                merge_shards_with_root("ref.word")
+            if shard_id == (3 % num_shards):
+                merge_shards_with_root("ref.units")
+            dist.barrier()
+
+    def optimize_model(self, model: FairseqModel) -> None:
+        model.make_generation_fast_()
+        if self.cfg.common.fp16:
+            model.half()
+        if not self.cfg.common.cpu:
+            model.cuda()
+
+    def load_model_ensemble(self) -> Tuple[List[FairseqModel], FairseqDataclass]:
+        arg_overrides = ast.literal_eval(self.cfg.common_eval.model_overrides)
+        models, saved_cfg = checkpoint_utils.load_model_ensemble(
+            utils.split_paths(self.cfg.common_eval.path, separator="\\"),
+            arg_overrides=arg_overrides,
+            task=self.task,
+            suffix=self.cfg.checkpoint.checkpoint_suffix,
+            strict=(self.cfg.checkpoint.checkpoint_shard_count == 1),
+            num_shards=self.cfg.checkpoint.checkpoint_shard_count,
+        )
+        for model in models:
+            self.optimize_model(model)
+        return models, saved_cfg
+
+    def get_dataset_itr(self, disable_iterator_cache: bool = False) -> None:
+        return self.task.get_batch_iterator(
+            dataset=self.task.dataset(self.cfg.dataset.gen_subset),
+            max_tokens=self.cfg.dataset.max_tokens,
+            max_sentences=self.cfg.dataset.batch_size,
+            max_positions=(sys.maxsize, sys.maxsize),
+            ignore_invalid_inputs=self.cfg.dataset.skip_invalid_size_inputs_valid_test,
+            required_batch_size_multiple=self.cfg.dataset.required_batch_size_multiple,
+            seed=self.cfg.common.seed,
+            num_shards=self.data_parallel_world_size,
+            shard_id=self.data_parallel_rank,
+            num_workers=self.cfg.dataset.num_workers,
+            data_buffer_size=self.cfg.dataset.data_buffer_size,
+            disable_iterator_cache=disable_iterator_cache,
+        ).next_epoch_itr(shuffle=False)
+
+    def build_progress_bar(
+        self,
+        epoch: Optional[int] = None,
+        prefix: Optional[str] = None,
+        default_log_format: str = "tqdm",
+    ) -> BaseProgressBar:
+        return progress_bar.progress_bar(
+            iterator=self.get_dataset_itr(),
+            log_format=self.cfg.common.log_format,
+            log_interval=self.cfg.common.log_interval,
+            epoch=epoch,
+            prefix=prefix,
+            tensorboard_logdir=self.cfg.common.tensorboard_logdir,
+            default_log_format=default_log_format,
+        )
+
+    @property
+    def data_parallel_world_size(self):
+        if self.cfg.distributed_training.distributed_world_size == 1:
+            return 1
+        return distributed_utils.get_data_parallel_world_size()
+
+    @property
+    def data_parallel_rank(self):
+        if self.cfg.distributed_training.distributed_world_size == 1:
+            return 0
+        return distributed_utils.get_data_parallel_rank()
+
+    def process_sentence(
+        self,
+        sample: Dict[str, Any],
+        hypo: Dict[str, Any],
+        sid: int,
+        batch_id: int,
+    ) -> Tuple[int, int]:
+        speaker = None  # Speaker can't be parsed from dataset.
+
+        if "target_label" in sample:
+            toks = sample["target_label"]
+        else:
+            toks = sample["target"]
+        toks = toks[batch_id, :]
+
+        # Processes hypothesis.
+        hyp_pieces = self.tgt_dict.string(hypo["tokens"].int().cpu())
+        if "words" in hypo:
+            hyp_words = " ".join(hypo["words"])
+        else:
+            hyp_words = post_process(hyp_pieces, self.cfg.common_eval.post_process)
+
+        # Processes target.
+        target_tokens = utils.strip_pad(toks, self.tgt_dict.pad())
+        tgt_pieces = self.tgt_dict.string(target_tokens.int().cpu())
+        tgt_words = post_process(tgt_pieces, self.cfg.common_eval.post_process)
+
+        if self.cfg.decoding.results_path is not None:
+            print(f"{hyp_pieces} ({speaker}-{sid})", file=self.hypo_units_file)
+            print(f"{hyp_words} ({speaker}-{sid})", file=self.hypo_words_file)
+            print(f"{tgt_pieces} ({speaker}-{sid})", file=self.ref_units_file)
+            print(f"{tgt_words} ({speaker}-{sid})", file=self.ref_words_file)
+
+        if not self.cfg.common_eval.quiet:
+            logger.info(f"HYPO: {hyp_words}")
+            logger.info(f"REF: {tgt_words}")
+            logger.info("---------------------")
+
+        hyp_words, tgt_words = hyp_words.split(), tgt_words.split()
+
+        return editdistance.eval(hyp_words, tgt_words), len(tgt_words)
+
+    def process_sample(self, sample: Dict[str, Any]) -> None:
+        self.gen_timer.start()
+        hypos = self.task.inference_step(
+            generator=self.generator,
+            models=self.models,
+            sample=sample,
+        )
+        num_generated_tokens = sum(len(h[0]["tokens"]) for h in hypos)
+        self.gen_timer.stop(num_generated_tokens)
+        self.wps_meter.update(num_generated_tokens)
+
+        for batch_id, sample_id in enumerate(sample["id"].tolist()):
+            errs, length = self.process_sentence(
+                sample=sample,
+                sid=sample_id,
+                batch_id=batch_id,
+                hypo=hypos[batch_id][0],
+            )
+            self.total_errors += errs
+            self.total_length += length
+
+        self.log({"wps": round(self.wps_meter.avg)})
+        if "nsentences" in sample:
+            self.num_sentences += sample["nsentences"]
+        else:
+            self.num_sentences += sample["id"].numel()
+
+    def log_generation_time(self) -> None:
+        logger.info(
+            "Processed %d sentences (%d tokens) in %.1fs %.2f "
+            "sentences per second, %.2f tokens per second)",
+            self.num_sentences,
+            self.gen_timer.n,
+            self.gen_timer.sum,
+            self.num_sentences / self.gen_timer.sum,
+            1.0 / self.gen_timer.avg,
+        )
+
+
+def parse_wer(wer_file: Path) -> float:
+    with open(wer_file, "r") as f:
+        return float(f.readline().strip().split(" ")[1])
+
+
+def get_wer_file(cfg: InferConfig) -> Path:
+    """Hashes the decoding parameters to a unique file ID."""
+    base_path = "wer"
+    if cfg.decoding.results_path is not None:
+        base_path = os.path.join(cfg.decoding.results_path, base_path)
+
+    if cfg.decoding.unique_wer_file:
+        yaml_str = OmegaConf.to_yaml(cfg.decoding)
+        fid = int(hashlib.md5(yaml_str.encode("utf-8")).hexdigest(), 16)
+        return Path(f"{base_path}.{fid % 1000000}")
+    else:
+        return Path(base_path)
+
+
+def main(cfg: InferConfig) -> float:
+    """Entry point for main processing logic.
+
+    Args:
+        cfg: The inferance configuration to use.
+        wer: Optional shared memory pointer for returning the WER. If not None,
+            the final WER value will be written here instead of being returned.
+
+    Returns:
+        The final WER if `wer` is None, otherwise None.
+    """
+
+    yaml_str, wer_file = OmegaConf.to_yaml(cfg.decoding), get_wer_file(cfg)
+
+    # Validates the provided configuration.
+    if cfg.dataset.max_tokens is None and cfg.dataset.batch_size is None:
+        cfg.dataset.max_tokens = 4000000
+    if not cfg.common.cpu and not torch.cuda.is_available():
+        raise ValueError("CUDA not found; set `cpu=True` to run without CUDA")
+
+    with InferenceProcessor(cfg) as processor:
+        for sample in processor:
+            processor.process_sample(sample)
+
+        processor.log_generation_time()
+
+        if cfg.decoding.results_path is not None:
+            processor.merge_shards()
+
+        errs_t, leng_t = processor.total_errors, processor.total_length
+
+        if cfg.common.cpu:
+            logger.warning("Merging WER requires CUDA.")
+        elif processor.data_parallel_world_size > 1:
+            stats = torch.LongTensor([errs_t, leng_t]).cuda()
+            dist.all_reduce(stats, op=dist.ReduceOp.SUM)
+            errs_t, leng_t = stats[0].item(), stats[1].item()
+
+        wer = errs_t * 100.0 / leng_t
+
+        if distributed_utils.is_master(cfg.distributed_training):
+            with open(wer_file, "w") as f:
+                f.write(
+                    (
+                        f"WER: {wer}\n"
+                        f"err / num_ref_words = {errs_t} / {leng_t}\n\n"
+                        f"{yaml_str}"
+                    )
+                )
+
+        return wer
+
+
+@hydra.main(config_path=config_path, config_name="infer")
+def hydra_main(cfg: InferConfig) -> Union[float, Tuple[float, Optional[float]]]:
+    container = OmegaConf.to_container(cfg, resolve=True, enum_to_str=True)
+    cfg = OmegaConf.create(container)
+    OmegaConf.set_struct(cfg, True)
+
+    if cfg.common.reset_logging:
+        reset_logging()
+
+    # logger.info("Config:\n%s", OmegaConf.to_yaml(cfg))
+    wer = float("inf")
+
+    try:
+        if cfg.common.profile:
+            with torch.cuda.profiler.profile():
+                with torch.autograd.profiler.emit_nvtx():
+                    distributed_utils.call_main(cfg, main)
+        else:
+            distributed_utils.call_main(cfg, main)
+
+        wer = parse_wer(get_wer_file(cfg))
+    except BaseException as e:  # pylint: disable=broad-except
+        if not cfg.common.suppress_crashes:
+            raise
+        else:
+            logger.error("Crashed! %s", str(e))
+
+    logger.info("Word error rate: %.4f", wer)
+    if cfg.is_ax:
+        return wer, None
+
+    return wer
+
+
+def cli_main() -> None:
+    try:
+        from hydra._internal.utils import (
+            get_args,
+        )  # pylint: disable=import-outside-toplevel
+
+        cfg_name = get_args().config_name or "infer"
+    except ImportError:
+        logger.warning("Failed to get config name from hydra args")
+        cfg_name = "infer"
+
+    cs = ConfigStore.instance()
+    cs.store(name=cfg_name, node=InferConfig)
+
+    for k in InferConfig.__dataclass_fields__:
+        if is_dataclass(InferConfig.__dataclass_fields__[k].type):
+            v = InferConfig.__dataclass_fields__[k].default
+            cs.store(name=k, node=v)
+
+    hydra_main()  # pylint: disable=no-value-for-parameter
+
+
+if __name__ == "__main__":
+    cli_main()

edgelm/examples/speech_recognition/tasks/__init__.py

@@ -0,0 +1,8 @@
+import importlib
+import os
+
+
+for file in sorted(os.listdir(os.path.dirname(__file__))):
+    if file.endswith(".py") and not file.startswith("_"):
+        task_name = file[: file.find(".py")]
+        importlib.import_module("examples.speech_recognition.tasks." + task_name)

edgelm/examples/speech_recognition/tasks/speech_recognition.py

@@ -0,0 +1,157 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+import json
+import os
+import re
+import sys
+
+import torch
+from examples.speech_recognition.data import AsrDataset
+from examples.speech_recognition.data.replabels import replabel_symbol
+from fairseq.data import Dictionary
+from fairseq.tasks import LegacyFairseqTask, register_task
+
+
+def get_asr_dataset_from_json(data_json_path, tgt_dict):
+    """
+    Parse data json and create dataset.
+    See scripts/asr_prep_json.py which pack json from raw files
+
+    Json example:
+    {
+    "utts": {
+        "4771-29403-0025": {
+            "input": {
+                "length_ms": 170,
+                "path": "/tmp/file1.flac"
+            },
+            "output": {
+                "text": "HELLO \n",
+                "token": "HE LLO",
+                "tokenid": "4815, 861"
+            }
+        },
+        "1564-142299-0096": {
+            ...
+        }
+    }
+    """
+    if not os.path.isfile(data_json_path):
+        raise FileNotFoundError("Dataset not found: {}".format(data_json_path))
+    with open(data_json_path, "rb") as f:
+        data_samples = json.load(f)["utts"]
+        assert len(data_samples) != 0
+        sorted_samples = sorted(
+            data_samples.items(),
+            key=lambda sample: int(sample[1]["input"]["length_ms"]),
+            reverse=True,
+        )
+        aud_paths = [s[1]["input"]["path"] for s in sorted_samples]
+        ids = [s[0] for s in sorted_samples]
+        speakers = []
+        for s in sorted_samples:
+            m = re.search("(.+?)-(.+?)-(.+?)", s[0])
+            speakers.append(m.group(1) + "_" + m.group(2))
+        frame_sizes = [s[1]["input"]["length_ms"] for s in sorted_samples]
+        tgt = [
+            [int(i) for i in s[1]["output"]["tokenid"].split(", ")]
+            for s in sorted_samples
+        ]
+        # append eos
+        tgt = [[*t, tgt_dict.eos()] for t in tgt]
+        return AsrDataset(aud_paths, frame_sizes, tgt, tgt_dict, ids, speakers)
+
+
+@register_task("speech_recognition")
+class SpeechRecognitionTask(LegacyFairseqTask):
+    """
+    Task for training speech recognition model.
+    """
+
+    @staticmethod
+    def add_args(parser):
+        """Add task-specific arguments to the parser."""
+        parser.add_argument("data", help="path to data directory")
+        parser.add_argument(
+            "--silence-token", default="\u2581", help="token for silence (used by w2l)"
+        )
+        parser.add_argument(
+            "--max-source-positions",
+            default=sys.maxsize,
+            type=int,
+            metavar="N",
+            help="max number of frames in the source sequence",
+        )
+        parser.add_argument(
+            "--max-target-positions",
+            default=1024,
+            type=int,
+            metavar="N",
+            help="max number of tokens in the target sequence",
+        )
+
+    def __init__(self, args, tgt_dict):
+        super().__init__(args)
+        self.tgt_dict = tgt_dict
+
+    @classmethod
+    def setup_task(cls, args, **kwargs):
+        """Setup the task (e.g., load dictionaries)."""
+        dict_path = os.path.join(args.data, "dict.txt")
+        if not os.path.isfile(dict_path):
+            raise FileNotFoundError("Dict not found: {}".format(dict_path))
+        tgt_dict = Dictionary.load(dict_path)
+
+        if args.criterion == "ctc_loss":
+            tgt_dict.add_symbol("<ctc_blank>")
+        elif args.criterion == "asg_loss":
+            for i in range(1, args.max_replabel + 1):
+                tgt_dict.add_symbol(replabel_symbol(i))
+
+        print("| dictionary: {} types".format(len(tgt_dict)))
+        return cls(args, tgt_dict)
+
+    def load_dataset(self, split, combine=False, **kwargs):
+        """Load a given dataset split.
+
+        Args:
+            split (str): name of the split (e.g., train, valid, test)
+        """
+        data_json_path = os.path.join(self.args.data, "{}.json".format(split))
+        self.datasets[split] = get_asr_dataset_from_json(data_json_path, self.tgt_dict)
+
+    def build_generator(self, models, args, **unused):
+        w2l_decoder = getattr(args, "w2l_decoder", None)
+        if w2l_decoder == "viterbi":
+            from examples.speech_recognition.w2l_decoder import W2lViterbiDecoder
+
+            return W2lViterbiDecoder(args, self.target_dictionary)
+        elif w2l_decoder == "kenlm":
+            from examples.speech_recognition.w2l_decoder import W2lKenLMDecoder
+
+            return W2lKenLMDecoder(args, self.target_dictionary)
+        elif w2l_decoder == "fairseqlm":
+            from examples.speech_recognition.w2l_decoder import W2lFairseqLMDecoder
+
+            return W2lFairseqLMDecoder(args, self.target_dictionary)
+        else:
+            return super().build_generator(models, args)
+
+    @property
+    def target_dictionary(self):
+        """Return the :class:`~fairseq.data.Dictionary` for the language
+        model."""
+        return self.tgt_dict
+
+    @property
+    def source_dictionary(self):
+        """Return the source :class:`~fairseq.data.Dictionary` (if applicable
+        for this task)."""
+        return None
+
+    def max_positions(self):
+        """Return the max speech and sentence length allowed by the task."""
+        return (self.args.max_source_positions, self.args.max_target_positions)

edgelm/examples/speech_recognition/utils/wer_utils.py

@@ -0,0 +1,381 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+import re
+from collections import deque
+from enum import Enum
+
+import numpy as np
+
+
+"""
+    Utility modules for computation of Word Error Rate,
+    Alignments, as well as more granular metrics like
+    deletion, insersion and substitutions.
+"""
+
+
+class Code(Enum):
+    match = 1
+    substitution = 2
+    insertion = 3
+    deletion = 4
+
+
+class Token(object):
+    def __init__(self, lbl="", st=np.nan, en=np.nan):
+        if np.isnan(st):
+            self.label, self.start, self.end = "", 0.0, 0.0
+        else:
+            self.label, self.start, self.end = lbl, st, en
+
+
+class AlignmentResult(object):
+    def __init__(self, refs, hyps, codes, score):
+        self.refs = refs  # std::deque<int>
+        self.hyps = hyps  # std::deque<int>
+        self.codes = codes  # std::deque<Code>
+        self.score = score  # float
+
+
+def coordinate_to_offset(row, col, ncols):
+    return int(row * ncols + col)
+
+
+def offset_to_row(offset, ncols):
+    return int(offset / ncols)
+
+
+def offset_to_col(offset, ncols):
+    return int(offset % ncols)
+
+
+def trimWhitespace(str):
+    return re.sub(" +", " ", re.sub(" *$", "", re.sub("^ *", "", str)))
+
+
+def str2toks(str):
+    pieces = trimWhitespace(str).split(" ")
+    toks = []
+    for p in pieces:
+        toks.append(Token(p, 0.0, 0.0))
+    return toks
+
+
+class EditDistance(object):
+    def __init__(self, time_mediated):
+        self.time_mediated_ = time_mediated
+        self.scores_ = np.nan  # Eigen::Matrix<float, Eigen::Dynamic, Eigen::Dynamic>
+        self.backtraces_ = (
+            np.nan
+        )  # Eigen::Matrix<size_t, Eigen::Dynamic, Eigen::Dynamic> backtraces_;
+        self.confusion_pairs_ = {}
+
+    def cost(self, ref, hyp, code):
+        if self.time_mediated_:
+            if code == Code.match:
+                return abs(ref.start - hyp.start) + abs(ref.end - hyp.end)
+            elif code == Code.insertion:
+                return hyp.end - hyp.start
+            elif code == Code.deletion:
+                return ref.end - ref.start
+            else:  # substitution
+                return abs(ref.start - hyp.start) + abs(ref.end - hyp.end) + 0.1
+        else:
+            if code == Code.match:
+                return 0
+            elif code == Code.insertion or code == Code.deletion:
+                return 3
+            else:  # substitution
+                return 4
+
+    def get_result(self, refs, hyps):
+        res = AlignmentResult(refs=deque(), hyps=deque(), codes=deque(), score=np.nan)
+
+        num_rows, num_cols = self.scores_.shape
+        res.score = self.scores_[num_rows - 1, num_cols - 1]
+
+        curr_offset = coordinate_to_offset(num_rows - 1, num_cols - 1, num_cols)
+
+        while curr_offset != 0:
+            curr_row = offset_to_row(curr_offset, num_cols)
+            curr_col = offset_to_col(curr_offset, num_cols)
+
+            prev_offset = self.backtraces_[curr_row, curr_col]
+
+            prev_row = offset_to_row(prev_offset, num_cols)
+            prev_col = offset_to_col(prev_offset, num_cols)
+
+            res.refs.appendleft(curr_row - 1)  # Note: this was .push_front() in C++
+            res.hyps.appendleft(curr_col - 1)
+            if curr_row - 1 == prev_row and curr_col == prev_col:
+                res.codes.appendleft(Code.deletion)
+            elif curr_row == prev_row and curr_col - 1 == prev_col:
+                res.codes.appendleft(Code.insertion)
+            else:
+                # assert(curr_row - 1 == prev_row and curr_col - 1 == prev_col)
+                ref_str = refs[res.refs[0]].label
+                hyp_str = hyps[res.hyps[0]].label
+
+                if ref_str == hyp_str:
+                    res.codes.appendleft(Code.match)
+                else:
+                    res.codes.appendleft(Code.substitution)
+
+                    confusion_pair = "%s -> %s" % (ref_str, hyp_str)
+                    if confusion_pair not in self.confusion_pairs_:
+                        self.confusion_pairs_[confusion_pair] = 1
+                    else:
+                        self.confusion_pairs_[confusion_pair] += 1
+
+            curr_offset = prev_offset
+
+        return res
+
+    def align(self, refs, hyps):
+        if len(refs) == 0 and len(hyps) == 0:
+            return np.nan
+
+        # NOTE: we're not resetting the values in these matrices because every value
+        # will be overridden in the loop below. If this assumption doesn't hold,
+        # be sure to set all entries in self.scores_ and self.backtraces_ to 0.
+        self.scores_ = np.zeros((len(refs) + 1, len(hyps) + 1))
+        self.backtraces_ = np.zeros((len(refs) + 1, len(hyps) + 1))
+
+        num_rows, num_cols = self.scores_.shape
+
+        for i in range(num_rows):
+            for j in range(num_cols):
+                if i == 0 and j == 0:
+                    self.scores_[i, j] = 0.0
+                    self.backtraces_[i, j] = 0
+                    continue
+
+                if i == 0:
+                    self.scores_[i, j] = self.scores_[i, j - 1] + self.cost(
+                        None, hyps[j - 1], Code.insertion
+                    )
+                    self.backtraces_[i, j] = coordinate_to_offset(i, j - 1, num_cols)
+                    continue
+
+                if j == 0:
+                    self.scores_[i, j] = self.scores_[i - 1, j] + self.cost(
+                        refs[i - 1], None, Code.deletion
+                    )
+                    self.backtraces_[i, j] = coordinate_to_offset(i - 1, j, num_cols)
+                    continue
+
+                # Below here both i and j are greater than 0
+                ref = refs[i - 1]
+                hyp = hyps[j - 1]
+                best_score = self.scores_[i - 1, j - 1] + (
+                    self.cost(ref, hyp, Code.match)
+                    if (ref.label == hyp.label)
+                    else self.cost(ref, hyp, Code.substitution)
+                )
+
+                prev_row = i - 1
+                prev_col = j - 1
+                ins = self.scores_[i, j - 1] + self.cost(None, hyp, Code.insertion)
+                if ins < best_score:
+                    best_score = ins
+                    prev_row = i
+                    prev_col = j - 1
+
+                delt = self.scores_[i - 1, j] + self.cost(ref, None, Code.deletion)
+                if delt < best_score:
+                    best_score = delt
+                    prev_row = i - 1
+                    prev_col = j
+
+                self.scores_[i, j] = best_score
+                self.backtraces_[i, j] = coordinate_to_offset(
+                    prev_row, prev_col, num_cols
+                )
+
+        return self.get_result(refs, hyps)
+
+
+class WERTransformer(object):
+    def __init__(self, hyp_str, ref_str, verbose=True):
+        self.ed_ = EditDistance(False)
+        self.id2oracle_errs_ = {}
+        self.utts_ = 0
+        self.words_ = 0
+        self.insertions_ = 0
+        self.deletions_ = 0
+        self.substitutions_ = 0
+
+        self.process(["dummy_str", hyp_str, ref_str])
+
+        if verbose:
+            print("'%s' vs '%s'" % (hyp_str, ref_str))
+            self.report_result()
+
+    def process(self, input):  # std::vector<std::string>&& input
+        if len(input) < 3:
+            print(
+                "Input must be of the form <id> ... <hypo> <ref> , got ",
+                len(input),
+                " inputs:",
+            )
+            return None
+
+        # Align
+        # std::vector<Token> hyps;
+        # std::vector<Token> refs;
+
+        hyps = str2toks(input[-2])
+        refs = str2toks(input[-1])
+
+        alignment = self.ed_.align(refs, hyps)
+        if alignment is None:
+            print("Alignment is null")
+            return np.nan
+
+        # Tally errors
+        ins = 0
+        dels = 0
+        subs = 0
+        for code in alignment.codes:
+            if code == Code.substitution:
+                subs += 1
+            elif code == Code.insertion:
+                ins += 1
+            elif code == Code.deletion:
+                dels += 1
+
+        # Output
+        row = input
+        row.append(str(len(refs)))
+        row.append(str(ins))
+        row.append(str(dels))
+        row.append(str(subs))
+        # print(row)
+
+        # Accumulate
+        kIdIndex = 0
+        kNBestSep = "/"
+
+        pieces = input[kIdIndex].split(kNBestSep)
+
+        if len(pieces) == 0:
+            print(
+                "Error splitting ",
+                input[kIdIndex],
+                " on '",
+                kNBestSep,
+                "', got empty list",
+            )
+            return np.nan
+
+        id = pieces[0]
+        if id not in self.id2oracle_errs_:
+            self.utts_ += 1
+            self.words_ += len(refs)
+            self.insertions_ += ins
+            self.deletions_ += dels
+            self.substitutions_ += subs
+            self.id2oracle_errs_[id] = [ins, dels, subs]
+        else:
+            curr_err = ins + dels + subs
+            prev_err = np.sum(self.id2oracle_errs_[id])
+            if curr_err < prev_err:
+                self.id2oracle_errs_[id] = [ins, dels, subs]
+
+        return 0
+
+    def report_result(self):
+        # print("----------  Summary ---------------")
+        if self.words_ == 0:
+            print("No words counted")
+            return
+
+        # 1-best
+        best_wer = (
+            100.0
+            * (self.insertions_ + self.deletions_ + self.substitutions_)
+            / self.words_
+        )
+
+        print(
+            "\tWER = %0.2f%% (%i utts, %i words, %0.2f%% ins, "
+            "%0.2f%% dels, %0.2f%% subs)"
+            % (
+                best_wer,
+                self.utts_,
+                self.words_,
+                100.0 * self.insertions_ / self.words_,
+                100.0 * self.deletions_ / self.words_,
+                100.0 * self.substitutions_ / self.words_,
+            )
+        )
+
+    def wer(self):
+        if self.words_ == 0:
+            wer = np.nan
+        else:
+            wer = (
+                100.0
+                * (self.insertions_ + self.deletions_ + self.substitutions_)
+                / self.words_
+            )
+        return wer
+
+    def stats(self):
+        if self.words_ == 0:
+            stats = {}
+        else:
+            wer = (
+                100.0
+                * (self.insertions_ + self.deletions_ + self.substitutions_)
+                / self.words_
+            )
+            stats = dict(
+                {
+                    "wer": wer,
+                    "utts": self.utts_,
+                    "numwords": self.words_,
+                    "ins": self.insertions_,
+                    "dels": self.deletions_,
+                    "subs": self.substitutions_,
+                    "confusion_pairs": self.ed_.confusion_pairs_,
+                }
+            )
+        return stats
+
+
+def calc_wer(hyp_str, ref_str):
+    t = WERTransformer(hyp_str, ref_str, verbose=0)
+    return t.wer()
+
+
+def calc_wer_stats(hyp_str, ref_str):
+    t = WERTransformer(hyp_str, ref_str, verbose=0)
+    return t.stats()
+
+
+def get_wer_alignment_codes(hyp_str, ref_str):
+    """
+    INPUT: hypothesis string, reference string
+    OUTPUT: List of alignment codes (intermediate results from WER computation)
+    """
+    t = WERTransformer(hyp_str, ref_str, verbose=0)
+    return t.ed_.align(str2toks(ref_str), str2toks(hyp_str)).codes
+
+
+def merge_counts(x, y):
+    # Merge two hashes which have 'counts' as their values
+    # This can be used for example to merge confusion pair counts
+    #   conf_pairs = merge_counts(conf_pairs, stats['confusion_pairs'])
+    for k, v in y.items():
+        if k not in x:
+            x[k] = 0
+        x[k] += v
+    return x

edgelm/examples/speech_recognition/w2l_decoder.py

@@ -0,0 +1,486 @@
+#!/usr/bin/env python3
+
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
+"""
+Flashlight decoders.
+"""
+
+import gc
+import itertools as it
+import os.path as osp
+from typing import List
+import warnings
+from collections import deque, namedtuple
+
+import numpy as np
+import torch
+from examples.speech_recognition.data.replabels import unpack_replabels
+from fairseq import tasks
+from fairseq.utils import apply_to_sample
+from omegaconf import open_dict
+from fairseq.dataclass.utils import convert_namespace_to_omegaconf
+
+
+try:
+    from flashlight.lib.text.dictionary import create_word_dict, load_words
+    from flashlight.lib.sequence.criterion import CpuViterbiPath, get_data_ptr_as_bytes
+    from flashlight.lib.text.decoder import (
+        CriterionType,
+        LexiconDecoderOptions,
+        KenLM,
+        LM,
+        LMState,
+        SmearingMode,
+        Trie,
+        LexiconDecoder,
+    )
+except:
+    warnings.warn(
+        "flashlight python bindings are required to use this functionality. Please install from https://github.com/facebookresearch/flashlight/tree/master/bindings/python"
+    )
+    LM = object
+    LMState = object
+
+
+class W2lDecoder(object):
+    def __init__(self, args, tgt_dict):
+        self.tgt_dict = tgt_dict
+        self.vocab_size = len(tgt_dict)
+        self.nbest = args.nbest
+
+        # criterion-specific init
+        self.criterion_type = CriterionType.CTC
+        self.blank = (
+            tgt_dict.index("<ctc_blank>")
+            if "<ctc_blank>" in tgt_dict.indices
+            else tgt_dict.bos()
+        )
+        if "<sep>" in tgt_dict.indices:
+            self.silence = tgt_dict.index("<sep>")
+        elif "|" in tgt_dict.indices:
+            self.silence = tgt_dict.index("|")
+        else:
+            self.silence = tgt_dict.eos()
+        self.asg_transitions = None
+
+    def generate(self, models, sample, **unused):
+        """Generate a batch of inferences."""
+        # model.forward normally channels prev_output_tokens into the decoder
+        # separately, but SequenceGenerator directly calls model.encoder
+        encoder_input = {
+            k: v for k, v in sample["net_input"].items() if k != "prev_output_tokens"
+        }
+        emissions = self.get_emissions(models, encoder_input)
+        return self.decode(emissions)
+
+    def get_emissions(self, models, encoder_input):
+        """Run encoder and normalize emissions"""
+        model = models[0]
+        encoder_out = model(**encoder_input)
+        if hasattr(model, "get_logits"):
+            emissions = model.get_logits(encoder_out) # no need to normalize emissions
+        else:
+            emissions = model.get_normalized_probs(encoder_out, log_probs=True)
+        return emissions.transpose(0, 1).float().cpu().contiguous()
+
+    def get_tokens(self, idxs):
+        """Normalize tokens by handling CTC blank, ASG replabels, etc."""
+        idxs = (g[0] for g in it.groupby(idxs))
+        idxs = filter(lambda x: x != self.blank, idxs)
+        return torch.LongTensor(list(idxs))
+
+
+class W2lViterbiDecoder(W2lDecoder):
+    def __init__(self, args, tgt_dict):
+        super().__init__(args, tgt_dict)
+
+    def decode(self, emissions):
+        B, T, N = emissions.size()
+        hypos = []
+        if self.asg_transitions is None:
+            transitions = torch.FloatTensor(N, N).zero_()
+        else:
+            transitions = torch.FloatTensor(self.asg_transitions).view(N, N)
+        viterbi_path = torch.IntTensor(B, T)
+        workspace = torch.ByteTensor(CpuViterbiPath.get_workspace_size(B, T, N))
+        CpuViterbiPath.compute(
+            B,
+            T,
+            N,
+            get_data_ptr_as_bytes(emissions),
+            get_data_ptr_as_bytes(transitions),
+            get_data_ptr_as_bytes(viterbi_path),
+            get_data_ptr_as_bytes(workspace),
+        )
+        return [
+            [{"tokens": self.get_tokens(viterbi_path[b].tolist()), "score": 0}]
+            for b in range(B)
+        ]
+
+
+class W2lKenLMDecoder(W2lDecoder):
+    def __init__(self, args, tgt_dict):
+        super().__init__(args, tgt_dict)
+
+        self.unit_lm = getattr(args, "unit_lm", False)
+
+        if args.lexicon:
+            self.lexicon = load_words(args.lexicon)
+            self.word_dict = create_word_dict(self.lexicon)
+            self.unk_word = self.word_dict.get_index("<unk>")
+
+            self.lm = KenLM(args.kenlm_model, self.word_dict)
+            self.trie = Trie(self.vocab_size, self.silence)
+
+            start_state = self.lm.start(False)
+            for i, (word, spellings) in enumerate(self.lexicon.items()):
+                word_idx = self.word_dict.get_index(word)
+                _, score = self.lm.score(start_state, word_idx)
+                for spelling in spellings:
+                    spelling_idxs = [tgt_dict.index(token) for token in spelling]
+                    assert (
+                        tgt_dict.unk() not in spelling_idxs
+                    ), f"{spelling} {spelling_idxs}"
+                    self.trie.insert(spelling_idxs, word_idx, score)
+            self.trie.smear(SmearingMode.MAX)
+
+            self.decoder_opts = LexiconDecoderOptions(
+                beam_size=args.beam,
+                beam_size_token=int(getattr(args, "beam_size_token", len(tgt_dict))),
+                beam_threshold=args.beam_threshold,
+                lm_weight=args.lm_weight,
+                word_score=args.word_score,
+                unk_score=args.unk_weight,
+                sil_score=args.sil_weight,
+                log_add=False,
+                criterion_type=self.criterion_type,
+            )
+
+            if self.asg_transitions is None:
+                N = 768
+                # self.asg_transitions = torch.FloatTensor(N, N).zero_()
+                self.asg_transitions = []
+
+            self.decoder = LexiconDecoder(
+                self.decoder_opts,
+                self.trie,
+                self.lm,
+                self.silence,
+                self.blank,
+                self.unk_word,
+                self.asg_transitions,
+                self.unit_lm,
+            )
+        else:
+            assert args.unit_lm, "lexicon free decoding can only be done with a unit language model"
+            from flashlight.lib.text.decoder import LexiconFreeDecoder, LexiconFreeDecoderOptions
+
+            d = {w: [[w]] for w in tgt_dict.symbols}
+            self.word_dict = create_word_dict(d)
+            self.lm = KenLM(args.kenlm_model, self.word_dict)
+            self.decoder_opts = LexiconFreeDecoderOptions(
+                beam_size=args.beam,
+                beam_size_token=int(getattr(args, "beam_size_token", len(tgt_dict))),
+                beam_threshold=args.beam_threshold,
+                lm_weight=args.lm_weight,
+                sil_score=args.sil_weight,
+                log_add=False,
+                criterion_type=self.criterion_type,
+            )
+            self.decoder = LexiconFreeDecoder(
+                self.decoder_opts, self.lm, self.silence, self.blank, []
+            )
+
+    def get_timesteps(self, token_idxs: List[int]) -> List[int]:
+        """Returns frame numbers corresponding to every non-blank token.
+
+        Parameters
+        ----------
+        token_idxs : List[int]
+            IDs of decoded tokens.
+
+        Returns
+        -------
+        List[int]
+            Frame numbers corresponding to every non-blank token.
+        """
+        timesteps = []
+        for i, token_idx in enumerate(token_idxs):
+            if token_idx == self.blank:
+                continue
+            if i == 0 or token_idx != token_idxs[i-1]:
+                timesteps.append(i)
+        return timesteps
+
+    def decode(self, emissions):
+        B, T, N = emissions.size()
+        hypos = []
+        for b in range(B):
+            emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
+            results = self.decoder.decode(emissions_ptr, T, N)
+
+            nbest_results = results[: self.nbest]
+            hypos.append(
+                [
+                    {
+                        "tokens": self.get_tokens(result.tokens),
+                        "score": result.score,
+                        "timesteps": self.get_timesteps(result.tokens),
+                        "words": [
+                            self.word_dict.get_entry(x) for x in result.words if x >= 0
+                        ],
+                    }
+                    for result in nbest_results
+                ]
+            )
+        return hypos
+
+
+FairseqLMState = namedtuple("FairseqLMState", ["prefix", "incremental_state", "probs"])
+
+
+class FairseqLM(LM):
+    def __init__(self, dictionary, model):
+        LM.__init__(self)
+        self.dictionary = dictionary
+        self.model = model
+        self.unk = self.dictionary.unk()
+
+        self.save_incremental = False  # this currently does not work properly
+        self.max_cache = 20_000
+
+        model.cuda()
+        model.eval()
+        model.make_generation_fast_()
+
+        self.states = {}
+        self.stateq = deque()
+
+    def start(self, start_with_nothing):
+        state = LMState()
+        prefix = torch.LongTensor([[self.dictionary.eos()]])
+        incremental_state = {} if self.save_incremental else None
+        with torch.no_grad():
+            res = self.model(prefix.cuda(), incremental_state=incremental_state)
+            probs = self.model.get_normalized_probs(res, log_probs=True, sample=None)
+
+        if incremental_state is not None:
+            incremental_state = apply_to_sample(lambda x: x.cpu(), incremental_state)
+        self.states[state] = FairseqLMState(
+            prefix.numpy(), incremental_state, probs[0, -1].cpu().numpy()
+        )
+        self.stateq.append(state)
+
+        return state
+
+    def score(self, state: LMState, token_index: int, no_cache: bool = False):
+        """
+        Evaluate language model based on the current lm state and new word
+        Parameters:
+        -----------
+        state: current lm state
+        token_index: index of the word
+                     (can be lexicon index then you should store inside LM the
+                      mapping between indices of lexicon and lm, or lm index of a word)
+
+        Returns:
+        --------
+        (LMState, float): pair of (new state, score for the current word)
+        """
+        curr_state = self.states[state]
+
+        def trim_cache(targ_size):
+            while len(self.stateq) > targ_size:
+                rem_k = self.stateq.popleft()
+                rem_st = self.states[rem_k]
+                rem_st = FairseqLMState(rem_st.prefix, None, None)
+                self.states[rem_k] = rem_st
+
+        if curr_state.probs is None:
+            new_incremental_state = (
+                curr_state.incremental_state.copy()
+                if curr_state.incremental_state is not None
+                else None
+            )
+            with torch.no_grad():
+                if new_incremental_state is not None:
+                    new_incremental_state = apply_to_sample(
+                        lambda x: x.cuda(), new_incremental_state
+                    )
+                elif self.save_incremental:
+                    new_incremental_state = {}
+
+                res = self.model(
+                    torch.from_numpy(curr_state.prefix).cuda(),
+                    incremental_state=new_incremental_state,
+                )
+                probs = self.model.get_normalized_probs(
+                    res, log_probs=True, sample=None
+                )
+
+                if new_incremental_state is not None:
+                    new_incremental_state = apply_to_sample(
+                        lambda x: x.cpu(), new_incremental_state
+                    )
+
+                curr_state = FairseqLMState(
+                    curr_state.prefix, new_incremental_state, probs[0, -1].cpu().numpy()
+                )
+
+            if not no_cache:
+                self.states[state] = curr_state
+                self.stateq.append(state)
+
+        score = curr_state.probs[token_index].item()
+
+        trim_cache(self.max_cache)
+
+        outstate = state.child(token_index)
+        if outstate not in self.states and not no_cache:
+            prefix = np.concatenate(
+                [curr_state.prefix, torch.LongTensor([[token_index]])], -1
+            )
+            incr_state = curr_state.incremental_state
+
+            self.states[outstate] = FairseqLMState(prefix, incr_state, None)
+
+        if token_index == self.unk:
+            score = float("-inf")
+
+        return outstate, score
+
+    def finish(self, state: LMState):
+        """
+        Evaluate eos for language model based on the current lm state
+
+        Returns:
+        --------
+        (LMState, float): pair of (new state, score for the current word)
+        """
+        return self.score(state, self.dictionary.eos())
+
+    def empty_cache(self):
+        self.states = {}
+        self.stateq = deque()
+        gc.collect()
+
+
+class W2lFairseqLMDecoder(W2lDecoder):
+    def __init__(self, args, tgt_dict):
+        super().__init__(args, tgt_dict)
+
+        self.unit_lm = getattr(args, "unit_lm", False)
+
+        self.lexicon = load_words(args.lexicon) if args.lexicon else None
+        self.idx_to_wrd = {}
+
+        checkpoint = torch.load(args.kenlm_model, map_location="cpu")
+
+        if "cfg" in checkpoint and checkpoint["cfg"] is not None:
+            lm_args = checkpoint["cfg"]
+        else:
+            lm_args = convert_namespace_to_omegaconf(checkpoint["args"])
+
+        with open_dict(lm_args.task):
+            lm_args.task.data = osp.dirname(args.kenlm_model)
+
+        task = tasks.setup_task(lm_args.task)
+        model = task.build_model(lm_args.model)
+        model.load_state_dict(checkpoint["model"], strict=False)
+
+        self.trie = Trie(self.vocab_size, self.silence)
+
+        self.word_dict = task.dictionary
+        self.unk_word = self.word_dict.unk()
+        self.lm = FairseqLM(self.word_dict, model)
+
+        if self.lexicon:
+            start_state = self.lm.start(False)
+            for i, (word, spellings) in enumerate(self.lexicon.items()):
+                if self.unit_lm:
+                    word_idx = i
+                    self.idx_to_wrd[i] = word
+                    score = 0
+                else:
+                    word_idx = self.word_dict.index(word)
+                    _, score = self.lm.score(start_state, word_idx, no_cache=True)
+
+                for spelling in spellings:
+                    spelling_idxs = [tgt_dict.index(token) for token in spelling]
+                    assert (
+                        tgt_dict.unk() not in spelling_idxs
+                    ), f"{spelling} {spelling_idxs}"
+                    self.trie.insert(spelling_idxs, word_idx, score)
+            self.trie.smear(SmearingMode.MAX)
+
+            self.decoder_opts = LexiconDecoderOptions(
+                beam_size=args.beam,
+                beam_size_token=int(getattr(args, "beam_size_token", len(tgt_dict))),
+                beam_threshold=args.beam_threshold,
+                lm_weight=args.lm_weight,
+                word_score=args.word_score,
+                unk_score=args.unk_weight,
+                sil_score=args.sil_weight,
+                log_add=False,
+                criterion_type=self.criterion_type,
+            )
+
+            self.decoder = LexiconDecoder(
+                self.decoder_opts,
+                self.trie,
+                self.lm,
+                self.silence,
+                self.blank,
+                self.unk_word,
+                [],
+                self.unit_lm,
+            )
+        else:
+            assert args.unit_lm, "lexicon free decoding can only be done with a unit language model"
+            from flashlight.lib.text.decoder import LexiconFreeDecoder, LexiconFreeDecoderOptions
+
+            d = {w: [[w]] for w in tgt_dict.symbols}
+            self.word_dict = create_word_dict(d)
+            self.lm = KenLM(args.kenlm_model, self.word_dict)
+            self.decoder_opts = LexiconFreeDecoderOptions(
+                beam_size=args.beam,
+                beam_size_token=int(getattr(args, "beam_size_token", len(tgt_dict))),
+                beam_threshold=args.beam_threshold,
+                lm_weight=args.lm_weight,
+                sil_score=args.sil_weight,
+                log_add=False,
+                criterion_type=self.criterion_type,
+            )
+            self.decoder = LexiconFreeDecoder(
+                self.decoder_opts, self.lm, self.silence, self.blank, []
+            )
+
+    def decode(self, emissions):
+        B, T, N = emissions.size()
+        hypos = []
+
+        def idx_to_word(idx):
+            if self.unit_lm:
+                return self.idx_to_wrd[idx]
+            else:
+                return self.word_dict[idx]
+
+        def make_hypo(result):
+            hypo = {"tokens": self.get_tokens(result.tokens), "score": result.score}
+            if self.lexicon:
+                hypo["words"] = [idx_to_word(x) for x in result.words if x >= 0]
+            return hypo
+
+        for b in range(B):
+            emissions_ptr = emissions.data_ptr() + 4 * b * emissions.stride(0)
+            results = self.decoder.decode(emissions_ptr, T, N)
+
+            nbest_results = results[: self.nbest]
+            hypos.append([make_hypo(result) for result in nbest_results])
+            self.lm.empty_cache()
+
+        return hypos