607 lines
20 KiB
Python
607 lines
20 KiB
Python
# Copyright (c) Facebook, Inc. and its affiliates.
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#
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# This source code is licensed under the MIT license found in the
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# LICENSE file in the root directory of this source tree.
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from argparse import Namespace
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import contextlib
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import copy
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import math
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import numpy as np
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import torch
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import torch.nn as nn
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import torch.nn.functional as F
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from dataclasses import dataclass, field
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from omegaconf import MISSING, II, open_dict
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from typing import Any
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from fairseq import checkpoint_utils, tasks, utils
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from fairseq.dataclass import FairseqDataclass
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from fairseq.dataclass.utils import convert_namespace_to_omegaconf
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from fairseq.tasks import FairseqTask
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from fairseq.models import (
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BaseFairseqModel,
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FairseqEncoder,
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FairseqEncoderDecoderModel,
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FairseqIncrementalDecoder,
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register_model,
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)
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from fairseq.models.wav2vec.wav2vec2 import MASKING_DISTRIBUTION_CHOICES
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from fairseq.modules import LayerNorm, PositionalEmbedding, TransformerDecoderLayer
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@dataclass
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class Wav2Vec2AsrConfig(FairseqDataclass):
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w2v_path: str = field(
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default=MISSING, metadata={"help": "path to wav2vec 2.0 model"}
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)
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no_pretrained_weights: bool = field(
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default=False, metadata={"help": "if true, does not load pretrained weights"}
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)
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dropout_input: float = field(
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default=0.0,
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metadata={"help": "dropout to apply to the input (after feat extr)"},
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)
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final_dropout: float = field(
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default=0.0,
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metadata={"help": "dropout after transformer and before final projection"},
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)
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dropout: float = field(
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default=0.0, metadata={"help": "dropout probability inside wav2vec 2.0 model"}
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)
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attention_dropout: float = field(
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default=0.0,
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metadata={
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"help": "dropout probability for attention weights inside wav2vec 2.0 model"
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},
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)
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activation_dropout: float = field(
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default=0.0,
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metadata={
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"help": "dropout probability after activation in FFN inside wav2vec 2.0 model"
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},
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)
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# masking
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apply_mask: bool = field(
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default=False, metadata={"help": "apply masking during fine-tuning"}
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)
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mask_length: int = field(
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default=10, metadata={"help": "repeat the mask indices multiple times"}
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)
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mask_prob: float = field(
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default=0.5,
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metadata={
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"help": "probability of replacing a token with mask (normalized by length)"
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},
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)
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mask_selection: MASKING_DISTRIBUTION_CHOICES = field(
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default="static", metadata={"help": "how to choose masks"}
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)
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mask_other: float = field(
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default=0,
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metadata={
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"help": "secondary mask argument (used for more complex distributions), "
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"see help in compute_mask_indices"
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},
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)
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no_mask_overlap: bool = field(
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default=False, metadata={"help": "whether to allow masks to overlap"}
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)
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# channel masking
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mask_channel_length: int = field(
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default=10, metadata={"help": "length of the mask for features (channels)"}
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)
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mask_channel_prob: float = field(
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default=0.0, metadata={"help": "probability of replacing a feature with 0"}
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)
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mask_channel_selection: MASKING_DISTRIBUTION_CHOICES = field(
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default="static",
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metadata={"help": "how to choose mask length for channel masking"},
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)
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mask_channel_other: float = field(
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default=0,
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metadata={
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"help": "secondary mask argument (used for more complex distributions), "
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"see help in compute_mask_indicesh"
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},
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)
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no_mask_channel_overlap: bool = field(
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default=False, metadata={"help": "whether to allow channel masks to overlap"}
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)
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freeze_finetune_updates: int = field(
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default=0, metadata={"help": "dont finetune wav2vec for this many updates"}
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)
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feature_grad_mult: float = field(
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default=0.0, metadata={"help": "reset feature grad mult in wav2vec 2.0 to this"}
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)
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layerdrop: float = field(
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default=0.0, metadata={"help": "probability of dropping a layer in wav2vec 2.0"}
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)
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normalize: bool = II("task.normalize")
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data: str = II("task.data")
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# this holds the loaded wav2vec args
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w2v_args: Any = None
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@dataclass
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class Wav2Vec2CtcConfig(Wav2Vec2AsrConfig):
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pass
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@register_model("wav2vec_ctc", dataclass=Wav2Vec2CtcConfig)
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class Wav2VecCtc(BaseFairseqModel):
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def __init__(self, cfg: Wav2Vec2CtcConfig, w2v_encoder: BaseFairseqModel):
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super().__init__()
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self.cfg = cfg
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self.w2v_encoder = w2v_encoder
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def upgrade_state_dict_named(self, state_dict, name):
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super().upgrade_state_dict_named(state_dict, name)
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return state_dict
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@classmethod
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def build_model(cls, cfg: Wav2Vec2CtcConfig, task: FairseqTask):
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"""Build a new model instance."""
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w2v_encoder = Wav2VecEncoder(cfg, task.target_dictionary)
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return cls(cfg, w2v_encoder)
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def get_normalized_probs(self, net_output, log_probs):
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"""Get normalized probabilities (or log probs) from a net's output."""
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logits = net_output["encoder_out"]
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if log_probs:
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return utils.log_softmax(logits.float(), dim=-1)
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else:
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return utils.softmax(logits.float(), dim=-1)
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def get_logits(self, net_output):
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logits = net_output["encoder_out"]
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padding = net_output["padding_mask"]
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if padding is not None and padding.any():
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padding = padding.T
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logits[padding][...,0] = 0
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logits[padding][...,1:] = float('-inf')
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return logits
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def forward(self, **kwargs):
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x = self.w2v_encoder(**kwargs)
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return x
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@dataclass
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class Wav2Vec2Seq2SeqConfig(Wav2Vec2AsrConfig):
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decoder_embed_dim: int = field(
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default=768, metadata={"help": "decoder embedding dimension"}
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)
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decoder_ffn_embed_dim: int = field(
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default=3072, metadata={"help": "decoder embedding dimension for FFN"}
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)
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decoder_layers: int = field(default=6, metadata={"help": "num of decoder layers"})
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decoder_layerdrop: float = field(
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default=0.0, metadata={"help": "decoder layerdrop chance"}
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)
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decoder_attention_heads: int = field(
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default=4, metadata={"help": "num decoder attention heads"}
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)
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decoder_learned_pos: bool = field(
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default=False,
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metadata={"help": "use learned positional embeddings in the decoder"},
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)
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decoder_normalize_before: bool = field(
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default=False, metadata={"help": "apply layernorm before each decoder block"}
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)
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no_token_positional_embeddings: bool = field(
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default=False,
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metadata={
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"help": "if set, disables positional embeddings (outside self attention)"
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},
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)
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decoder_dropout: float = field(
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default=0.0, metadata={"help": "dropout probability in the decoder"}
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)
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decoder_attention_dropout: float = field(
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default=0.0,
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metadata={
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"help": "dropout probability for attention weights inside the decoder"
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},
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)
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decoder_activation_dropout: float = field(
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default=0.0,
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metadata={
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"help": "dropout probability after activation in FFN inside the decoder"
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},
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)
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max_target_positions: int = field(
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default=2048, metadata={"help": "max target positions"}
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)
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share_decoder_input_output_embed: bool = field(
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default=False, metadata={"help": "share decoder input and output embeddings"}
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)
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autoregressive: bool = II("task.autoregressive")
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@register_model("wav2vec_seq2seq", dataclass=Wav2Vec2Seq2SeqConfig)
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class Wav2Vec2Seq2SeqModel(FairseqEncoderDecoderModel):
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def __init__(self, encoder, decoder):
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super().__init__(encoder, decoder)
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@classmethod
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def build_model(cls, cfg: Wav2Vec2Seq2SeqConfig, task: FairseqTask):
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"""Build a new model instance."""
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assert cfg.autoregressive, "Please set task.autoregressive=true for seq2seq asr models"
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src_dict, tgt_dict = task.source_dictionary, task.target_dictionary
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def build_embedding(dictionary, embed_dim):
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num_embeddings = len(dictionary)
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padding_idx = dictionary.pad()
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emb = Embedding(num_embeddings, embed_dim, padding_idx)
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return emb
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decoder_embed_tokens = build_embedding(tgt_dict, cfg.decoder_embed_dim)
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encoder = cls.build_encoder(cfg)
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decoder = cls.build_decoder(cfg, tgt_dict, decoder_embed_tokens)
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return Wav2Vec2Seq2SeqModel(encoder, decoder)
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@classmethod
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def build_encoder(cls, cfg: Wav2Vec2AsrConfig):
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return Wav2VecEncoder(cfg)
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@classmethod
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def build_decoder(cls, cfg: Wav2Vec2Seq2SeqConfig, tgt_dict, embed_tokens):
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return TransformerDecoder(cfg, tgt_dict, embed_tokens)
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def forward(self, **kwargs):
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encoder_out = self.encoder(tbc=False, **kwargs)
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decoder_out = self.decoder(encoder_out=encoder_out, **kwargs)
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return decoder_out
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def upgrade_state_dict_named(self, state_dict, name):
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super().upgrade_state_dict_named(state_dict, name)
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return state_dict
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class Wav2VecEncoder(FairseqEncoder):
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def __init__(self, cfg: Wav2Vec2AsrConfig, tgt_dict=None):
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self.apply_mask = cfg.apply_mask
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arg_overrides = {
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"dropout": cfg.dropout,
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"activation_dropout": cfg.activation_dropout,
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"dropout_input": cfg.dropout_input,
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"attention_dropout": cfg.attention_dropout,
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"mask_length": cfg.mask_length,
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"mask_prob": cfg.mask_prob,
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"mask_selection": cfg.mask_selection,
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"mask_other": cfg.mask_other,
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"no_mask_overlap": cfg.no_mask_overlap,
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"mask_channel_length": cfg.mask_channel_length,
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"mask_channel_prob": cfg.mask_channel_prob,
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"mask_channel_selection": cfg.mask_channel_selection,
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"mask_channel_other": cfg.mask_channel_other,
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"no_mask_channel_overlap": cfg.no_mask_channel_overlap,
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"encoder_layerdrop": cfg.layerdrop,
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"feature_grad_mult": cfg.feature_grad_mult,
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}
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if cfg.w2v_args is None:
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state = checkpoint_utils.load_checkpoint_to_cpu(cfg.w2v_path, arg_overrides)
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w2v_args = state.get("cfg", None)
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if w2v_args is None:
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w2v_args = convert_namespace_to_omegaconf(state["args"])
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cfg.w2v_args = w2v_args
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else:
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state = None
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w2v_args = cfg.w2v_args
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if isinstance(w2v_args, Namespace):
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cfg.w2v_args = w2v_args = convert_namespace_to_omegaconf(w2v_args)
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assert cfg.normalize == w2v_args.task.normalize, (
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"Fine-tuning works best when data normalization is the same. "
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"Please check that --normalize is set or unset for both pre-training and here"
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)
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w2v_args.task.data = cfg.data
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task = tasks.setup_task(w2v_args.task)
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model = task.build_model(w2v_args.model)
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if state is not None and not cfg.no_pretrained_weights:
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model.load_state_dict(state["model"], strict=True)
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model.remove_pretraining_modules()
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super().__init__(task.source_dictionary)
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d = w2v_args.model.encoder_embed_dim
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self.w2v_model = model
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self.final_dropout = nn.Dropout(cfg.final_dropout)
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self.freeze_finetune_updates = cfg.freeze_finetune_updates
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self.num_updates = 0
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if tgt_dict is not None:
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self.proj = Linear(d, len(tgt_dict))
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elif getattr(cfg, "decoder_embed_dim", d) != d:
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self.proj = Linear(d, cfg.decoder_embed_dim)
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else:
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self.proj = None
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def set_num_updates(self, num_updates):
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"""Set the number of parameters updates."""
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super().set_num_updates(num_updates)
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self.num_updates = num_updates
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def forward(self, source, padding_mask, tbc=True, **kwargs):
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w2v_args = {
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"source": source,
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"padding_mask": padding_mask,
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"mask": self.apply_mask and self.training,
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}
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ft = self.freeze_finetune_updates <= self.num_updates
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with torch.no_grad() if not ft else contextlib.ExitStack():
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x, padding_mask = self.w2v_model.extract_features(**w2v_args)
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if tbc:
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# B x T x C -> T x B x C
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x = x.transpose(0, 1)
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x = self.final_dropout(x)
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if self.proj:
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x = self.proj(x)
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return {
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"encoder_out": x, # T x B x C
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"encoder_padding_mask": padding_mask.transpose(0, 1), # T x B
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"padding_mask": padding_mask,
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}
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def reorder_encoder_out(self, encoder_out, new_order):
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if encoder_out["encoder_out"] is not None:
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encoder_out["encoder_out"] = encoder_out["encoder_out"].index_select(
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1, new_order
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)
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if encoder_out["encoder_padding_mask"] is not None:
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encoder_out["encoder_padding_mask"] = encoder_out[
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"encoder_padding_mask"
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].index_select(0, new_order)
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return encoder_out
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def max_positions(self):
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"""Maximum input length supported by the encoder."""
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return None
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def upgrade_state_dict_named(self, state_dict, name):
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return state_dict
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class TransformerDecoder(FairseqIncrementalDecoder):
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"""
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Transformer decoder consisting of *args.decoder_layers* layers. Each layer
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is a :class:`TransformerDecoderLayer`.
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Args:
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args (argparse.Namespace): parsed command-line arguments
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dictionary (~fairseq.data.Dictionary): decoding dictionary
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embed_tokens (torch.nn.Embedding): output embedding
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no_encoder_attn (bool, optional): whether to attend to encoder outputs
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(default: False).
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"""
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def __init__(
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self,
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cfg: Wav2Vec2Seq2SeqConfig,
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dictionary,
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embed_tokens,
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no_encoder_attn=False,
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):
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super().__init__(dictionary)
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self.dropout = cfg.decoder_dropout
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self.share_input_output_embed = cfg.share_decoder_input_output_embed
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input_embed_dim = embed_tokens.embedding_dim
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embed_dim = cfg.decoder_embed_dim
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self.output_embed_dim = cfg.decoder_embed_dim
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self.layerdrop = cfg.decoder_layerdrop
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padding_idx = embed_tokens.padding_idx
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self.max_target_positions = cfg.max_target_positions
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self.embed_tokens = embed_tokens
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self.embed_scale = math.sqrt(embed_dim) # todo: try with input_embed_dim
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self.project_in_dim = (
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Linear(input_embed_dim, embed_dim, bias=False)
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if embed_dim != input_embed_dim
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else None
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)
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self.embed_positions = (
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PositionalEmbedding(
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cfg.max_target_positions,
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embed_dim,
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padding_idx,
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learned=cfg.decoder_learned_pos,
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)
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if not cfg.no_token_positional_embeddings
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else None
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)
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# TODO: update this when transformer gets converted to dataclass configs
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transformer_cfg = copy.deepcopy(cfg)
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with open_dict(transformer_cfg):
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transformer_cfg.dropout = transformer_cfg.decoder_dropout
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transformer_cfg.attention_dropout = (
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transformer_cfg.decoder_attention_dropout
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)
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transformer_cfg.activation_dropout = (
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transformer_cfg.decoder_activation_dropout
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)
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self.layers = nn.ModuleList([])
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self.layers.extend(
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[
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TransformerDecoderLayer(transformer_cfg, no_encoder_attn)
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for _ in range(transformer_cfg.decoder_layers)
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]
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)
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if not self.share_input_output_embed:
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self.embed_out = nn.Parameter(
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torch.Tensor(len(dictionary), self.output_embed_dim)
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)
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nn.init.normal_(self.embed_out, mean=0, std=self.output_embed_dim ** -0.5)
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if transformer_cfg.decoder_normalize_before:
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self.layer_norm = LayerNorm(embed_dim)
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else:
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self.layer_norm = None
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def forward(
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self, prev_output_tokens, encoder_out=None, incremental_state=None, **unused
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):
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"""
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Args:
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prev_output_tokens (LongTensor): previous decoder outputs of shape
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`(batch, tgt_len)`, for teacher forcing
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encoder_out (Tensor, optional): output from the encoder, used for
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encoder-side attention
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incremental_state (dict): dictionary used for storing state during
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:ref:`Incremental decoding`
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Returns:
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tuple:
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- the decoder's output of shape `(batch, tgt_len, vocab)`
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- a dictionary with any model-specific outputs
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"""
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prev_output_tokens = prev_output_tokens.long()
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x, extra = self.extract_features(
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prev_output_tokens, encoder_out, incremental_state
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)
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x = self.output_layer(x)
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return x, extra
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def extract_features(
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self, prev_output_tokens, encoder_out=None, incremental_state=None, **unused
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):
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"""
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Similar to *forward* but only return features.
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Returns:
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tuple:
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- the decoder's features of shape `(batch, tgt_len, embed_dim)`
|
|
- a dictionary with any model-specific outputs
|
|
"""
|
|
|
|
# embed positions
|
|
positions = (
|
|
self.embed_positions(
|
|
prev_output_tokens, incremental_state=incremental_state
|
|
)
|
|
if self.embed_positions is not None
|
|
else None
|
|
)
|
|
|
|
if incremental_state is not None:
|
|
prev_output_tokens = prev_output_tokens[:, -1:]
|
|
if positions is not None:
|
|
positions = positions[:, -1:]
|
|
|
|
# embed tokens and positions
|
|
x = self.embed_scale * self.embed_tokens(prev_output_tokens)
|
|
|
|
if self.project_in_dim is not None:
|
|
x = self.project_in_dim(x)
|
|
|
|
if positions is not None:
|
|
x += positions
|
|
x = F.dropout(x, p=self.dropout, training=self.training)
|
|
|
|
# B x T x C -> T x B x C
|
|
x = x.transpose(0, 1)
|
|
attn = None
|
|
|
|
inner_states = [x]
|
|
|
|
# decoder layers
|
|
for layer in self.layers:
|
|
dropout_probability = np.random.random()
|
|
if not self.training or (dropout_probability > self.layerdrop):
|
|
x, attn, _ = layer(
|
|
x,
|
|
encoder_out["encoder_out"] if encoder_out is not None else None,
|
|
encoder_out["padding_mask"]
|
|
if encoder_out is not None
|
|
else None,
|
|
incremental_state,
|
|
self_attn_mask=self.buffered_future_mask(x)
|
|
if incremental_state is None
|
|
else None,
|
|
)
|
|
inner_states.append(x)
|
|
|
|
if self.layer_norm:
|
|
x = self.layer_norm(x)
|
|
|
|
# T x B x C -> B x T x C
|
|
x = x.transpose(0, 1)
|
|
|
|
return x, {"attn": attn, "inner_states": inner_states}
|
|
|
|
def output_layer(self, features, **kwargs):
|
|
"""Project features to the vocabulary size."""
|
|
# project back to size of vocabulary
|
|
if self.share_input_output_embed:
|
|
return F.linear(features, self.embed_tokens.weight)
|
|
else:
|
|
return F.linear(features, self.embed_out)
|
|
|
|
def max_positions(self):
|
|
"""Maximum output length supported by the decoder."""
|
|
if self.embed_positions is None:
|
|
return self.max_target_positions
|
|
return min(self.max_target_positions, self.embed_positions.max_positions)
|
|
|
|
def buffered_future_mask(self, tensor):
|
|
dim = tensor.size(0)
|
|
if (
|
|
not hasattr(self, "_future_mask")
|
|
or self._future_mask is None
|
|
or self._future_mask.device != tensor.device
|
|
or self._future_mask.size(0) < dim
|
|
):
|
|
self._future_mask = torch.triu(
|
|
utils.fill_with_neg_inf(tensor.new(dim, dim)), 1
|
|
)
|
|
return self._future_mask[:dim, :dim]
|
|
|
|
def upgrade_state_dict_named(self, state_dict, name):
|
|
return state_dict
|
|
|
|
|
|
def Embedding(num_embeddings, embedding_dim, padding_idx):
|
|
m = nn.Embedding(num_embeddings, embedding_dim, padding_idx=padding_idx)
|
|
nn.init.normal_(m.weight, mean=0, std=embedding_dim ** -0.5)
|
|
nn.init.constant_(m.weight[padding_idx], 0)
|
|
return m
|
|
|
|
|
|
def Linear(in_features, out_features, bias=True):
|
|
m = nn.Linear(in_features, out_features, bias)
|
|
nn.init.xavier_uniform_(m.weight)
|
|
if bias:
|
|
nn.init.constant_(m.bias, 0.0)
|
|
return m
|