chore: import upstream snapshot with attribution
This commit is contained in:
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# 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 .models import linformer_roberta # noqa
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# 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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"""
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Linformer: Self-Attention with Linear Complexity
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"""
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import logging
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from fairseq.models import register_model, register_model_architecture
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from fairseq.models.roberta import RobertaEncoder, RobertaModel
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from ..modules.linformer_sentence_encoder import LinformerSentenceEncoder
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logger = logging.getLogger(__name__)
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@register_model("linformer_roberta")
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class LinformerModel(RobertaModel):
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@staticmethod
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def add_args(parser):
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RobertaModel.add_args(parser)
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# add args for Linformer
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parser.add_argument(
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"--compressed", type=int, help="compressed ratio of sequence length"
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)
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parser.add_argument(
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"--shared-kv-compressed",
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type=int,
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help="share compressed matrix between k and v, in each layer",
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)
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parser.add_argument(
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"--shared-layer-kv-compressed",
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type=int,
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help="share compressed matrix between k and v and across all layers",
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)
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parser.add_argument(
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"--freeze-compress",
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type=int,
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help="freeze the parameters in compressed layer",
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)
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@classmethod
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def build_model(cls, args, task):
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"""Build a new model instance."""
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# make sure all arguments are present
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base_architecture(args)
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if not hasattr(args, "max_positions"):
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args.max_positions = args.tokens_per_sample
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encoder = LinformerEncoder(args, task.source_dictionary)
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return cls(args, encoder)
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class LinformerEncoder(RobertaEncoder):
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"""Linformer encoder."""
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def __init__(self, args, dictionary):
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super().__init__(args, dictionary)
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self.sentence_encoder = LinformerSentenceEncoder(
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padding_idx=dictionary.pad(),
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vocab_size=len(dictionary),
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num_encoder_layers=args.encoder_layers,
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embedding_dim=args.encoder_embed_dim,
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ffn_embedding_dim=args.encoder_ffn_embed_dim,
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num_attention_heads=args.encoder_attention_heads,
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dropout=args.dropout,
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attention_dropout=args.attention_dropout,
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activation_dropout=args.activation_dropout,
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layerdrop=args.encoder_layerdrop,
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max_seq_len=args.max_positions,
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num_segments=0,
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encoder_normalize_before=True,
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apply_bert_init=True,
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activation_fn=args.activation_fn,
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q_noise=args.quant_noise_pq,
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qn_block_size=args.quant_noise_pq_block_size,
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compressed=args.compressed,
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shared_kv_compressed=args.shared_kv_compressed,
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shared_layer_kv_compressed=args.shared_layer_kv_compressed,
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freeze_compress=args.freeze_compress,
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)
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@register_model_architecture("linformer_roberta", "linformer_roberta")
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def base_architecture(args):
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args.encoder_layers = getattr(args, "encoder_layers", 12)
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args.encoder_embed_dim = getattr(args, "encoder_embed_dim", 768)
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args.encoder_ffn_embed_dim = getattr(args, "encoder_ffn_embed_dim", 3072)
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args.encoder_attention_heads = getattr(args, "encoder_attention_heads", 12)
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args.activation_fn = getattr(args, "activation_fn", "gelu")
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args.pooler_activation_fn = getattr(args, "pooler_activation_fn", "tanh")
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args.dropout = getattr(args, "dropout", 0.1)
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args.attention_dropout = getattr(args, "attention_dropout", 0.1)
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args.activation_dropout = getattr(args, "activation_dropout", 0.0)
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args.pooler_dropout = getattr(args, "pooler_dropout", 0.0)
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args.encoder_layers_to_keep = getattr(args, "encoder_layers_to_keep", None)
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args.encoder_layerdrop = getattr(args, "encoder_layerdrop", 0.0)
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args.compressed = getattr(args, "compressed", 4)
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args.shared_kv_compressed = getattr(args, "shared_kv_compressed", 0)
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args.shared_layer_kv_compressed = getattr(args, "shared_layer_kv_compressed", 0)
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args.freeze_compress = getattr(args, "freeze_compress", 0)
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@register_model_architecture("linformer_roberta", "linformer_roberta_base")
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def linformer_roberta_base_architecture(args):
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base_architecture(args)
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@register_model_architecture("linformer_roberta", "linformer_roberta_large")
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def linformer_roberta_large_architecture(args):
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args.encoder_layers = getattr(args, "encoder_layers", 24)
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args.encoder_embed_dim = getattr(args, "encoder_embed_dim", 1024)
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args.encoder_ffn_embed_dim = getattr(args, "encoder_ffn_embed_dim", 4096)
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args.encoder_attention_heads = getattr(args, "encoder_attention_heads", 16)
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args.activation_fn = getattr(args, "activation_fn", "gelu")
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args.pooler_activation_fn = getattr(args, "pooler_activation_fn", "tanh")
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args.dropout = getattr(args, "dropout", 0.1)
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args.attention_dropout = getattr(args, "attention_dropout", 0.1)
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args.activation_dropout = getattr(args, "activation_dropout", 0.0)
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args.pooler_dropout = getattr(args, "pooler_dropout", 0.0)
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args.compressed = getattr(args, "compressed", 4)
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args.shared_kv_compressed = getattr(args, "shared_kv_compressed", 0)
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args.shared_layer_kv_compressed = getattr(args, "shared_layer_kv_compressed", 0)
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+169
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# 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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import math
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import torch.nn as nn
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from fairseq.modules import TransformerSentenceEncoder
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from .linformer_sentence_encoder_layer import LinformerSentenceEncoderLayer
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class LinformerSentenceEncoder(TransformerSentenceEncoder):
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"""
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Implementation for a Bi-directional Linformer based Sentence Encoder used
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in BERT/XLM style pre-trained models.
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This first computes the token embedding using the token embedding matrix,
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position embeddings (if specified) and segment embeddings
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(if specified). After applying the specified number of
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LinformerEncoderLayers, it outputs all the internal states of the
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encoder as well as the final representation associated with the first
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token (usually CLS token).
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Input:
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- tokens: B x T matrix representing sentences
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- segment_labels: B x T matrix representing segment label for tokens
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Output:
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- a tuple of the following:
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- a list of internal model states used to compute the
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predictions where each tensor has shape T x B x C
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- sentence representation associated with first input token
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in format B x C.
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"""
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def __init__(
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self,
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padding_idx: int,
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vocab_size: int,
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num_encoder_layers: int = 6,
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embedding_dim: int = 768,
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ffn_embedding_dim: int = 3072,
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num_attention_heads: int = 8,
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dropout: float = 0.1,
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attention_dropout: float = 0.1,
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activation_dropout: float = 0.1,
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layerdrop: float = 0.0,
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max_seq_len: int = 256,
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num_segments: int = 2,
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use_position_embeddings: bool = True,
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offset_positions_by_padding: bool = True,
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encoder_normalize_before: bool = False,
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apply_bert_init: bool = False,
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activation_fn: str = "relu",
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learned_pos_embedding: bool = True,
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embed_scale: float = None,
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freeze_embeddings: bool = False,
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n_trans_layers_to_freeze: int = 0,
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export: bool = False,
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traceable: bool = False,
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q_noise: float = 0.0,
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qn_block_size: int = 8,
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compressed: int = 4,
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shared_kv_compressed: int = 0,
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shared_layer_kv_compressed: int = 0,
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freeze_compress: int = 0,
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) -> None:
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# Initialize linformer parameters
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self.compressed = compressed
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self.shared_kv_compressed = shared_kv_compressed
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self.shared_layer_kv_compressed = shared_layer_kv_compressed
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self.compress_layer = None
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self.freeze_compress = freeze_compress
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super().__init__(
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padding_idx=padding_idx,
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vocab_size=vocab_size,
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num_encoder_layers=num_encoder_layers,
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embedding_dim=embedding_dim,
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ffn_embedding_dim=ffn_embedding_dim,
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num_attention_heads=num_attention_heads,
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dropout=dropout,
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attention_dropout=attention_dropout,
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activation_dropout=activation_dropout,
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layerdrop=layerdrop,
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max_seq_len=max_seq_len,
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num_segments=num_segments,
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use_position_embeddings=use_position_embeddings,
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offset_positions_by_padding=offset_positions_by_padding,
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encoder_normalize_before=encoder_normalize_before,
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apply_bert_init=apply_bert_init,
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activation_fn=activation_fn,
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learned_pos_embedding=learned_pos_embedding,
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embed_scale=embed_scale,
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freeze_embeddings=freeze_embeddings,
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n_trans_layers_to_freeze=n_trans_layers_to_freeze,
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export=export,
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traceable=traceable,
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q_noise=q_noise,
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qn_block_size=qn_block_size,
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)
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def build_transformer_sentence_encoder_layer(
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self,
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embedding_dim,
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ffn_embedding_dim,
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num_attention_heads,
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dropout,
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attention_dropout,
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activation_dropout,
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activation_fn,
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export,
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q_noise,
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qn_block_size,
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):
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if self.shared_layer_kv_compressed == 1:
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compress_layer = nn.Linear(
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self.max_seq_len, self.max_seq_len // self.compressed
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)
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# intialize parameters for compressed layer
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nn.init.xavier_uniform_(compress_layer.weight, gain=1 / math.sqrt(2))
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if self.freeze_compress == 1:
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compress_layer.weight.requires_grad = False
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self.compress_layer = compress_layer
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return LinformerSentenceEncoderLayer(
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embedding_dim=embedding_dim,
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ffn_embedding_dim=ffn_embedding_dim,
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num_attention_heads=num_attention_heads,
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dropout=dropout,
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attention_dropout=attention_dropout,
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activation_dropout=activation_dropout,
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activation_fn=activation_fn,
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export=export,
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q_noise=q_noise,
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qn_block_size=qn_block_size,
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compressed=self.compressed,
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max_seq_len=self.max_seq_len,
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shared_kv_compressed=self.shared_kv_compressed,
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shared_compress_layer=(
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None if self.shared_layer_kv_compressed == 0 else self.compress_layer
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),
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freeze_compress=self.freeze_compress,
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)
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def upgrade_state_dict_named(self, state_dict, name):
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prefix = name + "." if name != "" else ""
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items_to_add = {}
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keys_to_remove = []
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# update key name for shared layer in new version of code
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for k in state_dict.keys():
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if k.startswith(prefix + "compress_layer"):
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if self.shared_layer_kv_compressed:
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for layer_idx in range(len(self.layers)):
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new_k = prefix + "layers.{0}.shared_compress_layer.{1}".format(
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layer_idx,
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k[len(prefix + "compress_layer.") :],
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)
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items_to_add[new_k] = state_dict[k]
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for k in keys_to_remove:
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del state_dict[k]
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for key, value in items_to_add.items():
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state_dict[key] = value
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+84
@@ -0,0 +1,84 @@
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# 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 typing import Callable
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from fairseq.modules import TransformerSentenceEncoderLayer
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from .multihead_linear_attention import MultiheadLinearAttention
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class LinformerSentenceEncoderLayer(TransformerSentenceEncoderLayer):
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"""
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Implements a Linformer Encoder Layer used in BERT/XLM style pre-trained
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models.
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"""
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def __init__(
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self,
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embedding_dim: int = 768,
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ffn_embedding_dim: int = 3072,
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num_attention_heads: int = 8,
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dropout: float = 0.1,
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attention_dropout: float = 0.1,
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activation_dropout: float = 0.1,
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activation_fn: str = "relu",
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export: bool = False,
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q_noise: float = 0.0,
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qn_block_size: int = 8,
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init_fn: Callable = None,
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compressed: int = 1,
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max_seq_len: int = 256,
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shared_kv_compressed: int = 0,
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shared_compress_layer: any = None,
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freeze_compress: int = 0,
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) -> None:
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# Initialize linformer parameters
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self.compressed = compressed
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self.max_seq_len = max_seq_len
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self.shared_kv_compressed = shared_kv_compressed
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self.freeze_compress = freeze_compress
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def init_fn():
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# This needs to be set after nn.Module.__init__ is called
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self.shared_compress_layer = shared_compress_layer
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super().__init__(
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embedding_dim=embedding_dim,
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ffn_embedding_dim=ffn_embedding_dim,
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num_attention_heads=num_attention_heads,
|
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dropout=dropout,
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attention_dropout=attention_dropout,
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activation_dropout=activation_dropout,
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activation_fn=activation_fn,
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export=export,
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q_noise=q_noise,
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qn_block_size=qn_block_size,
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init_fn=init_fn,
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)
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def build_self_attention(
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self,
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embed_dim,
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num_attention_heads,
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dropout,
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self_attention,
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q_noise,
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qn_block_size,
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):
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return MultiheadLinearAttention(
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embed_dim,
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num_attention_heads,
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dropout=dropout,
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self_attention=True,
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q_noise=q_noise,
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qn_block_size=qn_block_size,
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compressed=self.compressed,
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max_seq_len=self.max_seq_len,
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shared_kv_compressed=self.shared_kv_compressed,
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shared_compress_layer=self.shared_compress_layer,
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freeze_compress=self.freeze_compress,
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)
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+481
@@ -0,0 +1,481 @@
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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.
|
||||
|
||||
import math
|
||||
from typing import Dict, Optional, Tuple
|
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|
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import torch
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import torch.nn.functional as F
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from fairseq import utils
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from fairseq.incremental_decoding_utils import with_incremental_state
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from fairseq.modules.quant_noise import quant_noise
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from torch import Tensor, nn
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from torch.nn import Parameter
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||||
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@with_incremental_state
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class MultiheadLinearAttention(nn.Module):
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"""Multi-headed linformer attention.
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Projects the key and values down to the compressed dimension, before computing self-attention.
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|
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See "Linformer: Self-Attention with Linear Complexity" for more details.
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"""
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||||
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def __init__(
|
||||
self,
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||||
embed_dim,
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num_heads,
|
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kdim=None,
|
||||
vdim=None,
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||||
dropout=0.0,
|
||||
bias=True,
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||||
add_bias_kv=False,
|
||||
add_zero_attn=False,
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||||
self_attention=False,
|
||||
encoder_decoder_attention=False,
|
||||
q_noise=0.0,
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||||
qn_block_size=8,
|
||||
compressed=1,
|
||||
max_seq_len=256,
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||||
shared_kv_compressed=0,
|
||||
shared_compress_layer=None,
|
||||
freeze_compress=0,
|
||||
):
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||||
super().__init__()
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||||
self.embed_dim = embed_dim
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||||
self.kdim = kdim if kdim is not None else embed_dim
|
||||
self.vdim = vdim if vdim is not None else embed_dim
|
||||
self.qkv_same_dim = self.kdim == embed_dim and self.vdim == embed_dim
|
||||
|
||||
self.num_heads = num_heads
|
||||
self.dropout = dropout
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||||
self.head_dim = embed_dim // num_heads
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||||
assert (
|
||||
self.head_dim * num_heads == self.embed_dim
|
||||
), "embed_dim must be divisible by num_heads"
|
||||
self.scaling = self.head_dim ** -0.5
|
||||
|
||||
self.self_attention = self_attention
|
||||
self.encoder_decoder_attention = encoder_decoder_attention
|
||||
|
||||
assert not self.self_attention or self.qkv_same_dim, (
|
||||
"Self-attention requires query, key and " "value to be of the same size"
|
||||
)
|
||||
|
||||
self.k_proj = quant_noise(
|
||||
nn.Linear(self.kdim, embed_dim, bias=bias), q_noise, qn_block_size
|
||||
)
|
||||
self.v_proj = quant_noise(
|
||||
nn.Linear(self.vdim, embed_dim, bias=bias), q_noise, qn_block_size
|
||||
)
|
||||
self.q_proj = quant_noise(
|
||||
nn.Linear(embed_dim, embed_dim, bias=bias), q_noise, qn_block_size
|
||||
)
|
||||
|
||||
# used for compress sequence to subsequence
|
||||
if shared_compress_layer is None:
|
||||
self.compress_seq_len = max_seq_len // compressed
|
||||
self.compress_k = nn.Linear(max_seq_len, self.compress_seq_len, bias=False)
|
||||
if shared_kv_compressed == 0:
|
||||
self.compress_v = nn.Linear(
|
||||
max_seq_len, self.compress_seq_len, bias=False
|
||||
)
|
||||
self.layerwise_sharing = False
|
||||
else:
|
||||
self.compress_k = shared_compress_layer
|
||||
if shared_kv_compressed == 0:
|
||||
self.compress_v = shared_compress_layer
|
||||
self.layerwise_sharing = True
|
||||
self.shared_kv_compressed = shared_kv_compressed
|
||||
|
||||
self.out_proj = quant_noise(
|
||||
nn.Linear(embed_dim, embed_dim, bias=bias), q_noise, qn_block_size
|
||||
)
|
||||
|
||||
if add_bias_kv:
|
||||
self.bias_k = Parameter(torch.Tensor(1, 1, embed_dim))
|
||||
self.bias_v = Parameter(torch.Tensor(1, 1, embed_dim))
|
||||
else:
|
||||
self.bias_k = self.bias_v = None
|
||||
|
||||
self.add_zero_attn = add_zero_attn
|
||||
|
||||
self.reset_parameters()
|
||||
|
||||
if freeze_compress == 1:
|
||||
self.compress_k.weight.requires_grad = False
|
||||
if shared_kv_compressed == 0:
|
||||
self.compress_v.weight.requires_grad = False
|
||||
|
||||
self.onnx_trace = False
|
||||
|
||||
def prepare_for_onnx_export_(self):
|
||||
self.onnx_trace = True
|
||||
|
||||
def reset_parameters(self):
|
||||
if self.qkv_same_dim:
|
||||
# Empirically observed the convergence to be much better with
|
||||
# the scaled initialization
|
||||
nn.init.xavier_uniform_(self.k_proj.weight, gain=1 / math.sqrt(2))
|
||||
nn.init.xavier_uniform_(self.v_proj.weight, gain=1 / math.sqrt(2))
|
||||
nn.init.xavier_uniform_(self.q_proj.weight, gain=1 / math.sqrt(2))
|
||||
if (
|
||||
not self.layerwise_sharing
|
||||
): # otherwise, we already initialize the parameters
|
||||
nn.init.xavier_uniform_(self.compress_k.weight, gain=1 / math.sqrt(2))
|
||||
if self.shared_kv_compressed == 0:
|
||||
nn.init.xavier_uniform_(
|
||||
self.compress_v.weight, gain=1 / math.sqrt(2)
|
||||
)
|
||||
else:
|
||||
nn.init.xavier_uniform_(self.k_proj.weight)
|
||||
nn.init.xavier_uniform_(self.v_proj.weight)
|
||||
nn.init.xavier_uniform_(self.q_proj.weight)
|
||||
if (
|
||||
not self.layerwise_sharing
|
||||
): # otherwise, we already initialize the parameters
|
||||
nn.init.xavier_uniform_(self.compress_k.weight)
|
||||
if self.shared_kv_compressed == 0:
|
||||
nn.init.xavier_uniform_(self.compress_v.weight)
|
||||
|
||||
nn.init.xavier_uniform_(self.out_proj.weight)
|
||||
if self.out_proj.bias is not None:
|
||||
nn.init.constant_(self.out_proj.bias, 0.0)
|
||||
if self.bias_k is not None:
|
||||
nn.init.xavier_normal_(self.bias_k)
|
||||
if self.bias_v is not None:
|
||||
nn.init.xavier_normal_(self.bias_v)
|
||||
|
||||
def forward(
|
||||
self,
|
||||
query,
|
||||
key: Optional[Tensor],
|
||||
value: Optional[Tensor],
|
||||
key_padding_mask: Optional[Tensor] = None,
|
||||
incremental_state: Optional[Dict[str, Dict[str, Optional[Tensor]]]] = None,
|
||||
need_weights: bool = True,
|
||||
static_kv: bool = False,
|
||||
attn_mask: Optional[Tensor] = None,
|
||||
before_softmax: bool = False,
|
||||
need_head_weights: bool = False,
|
||||
) -> Tuple[Tensor, Optional[Tensor]]:
|
||||
"""Input shape: Time x Batch x Channel
|
||||
|
||||
Args:
|
||||
key_padding_mask (ByteTensor, optional): mask to exclude
|
||||
keys that are pads, of shape `(batch, src_len)`, where
|
||||
padding elements are indicated by 1s.
|
||||
need_weights (bool, optional): return the attention weights,
|
||||
averaged over heads (default: False).
|
||||
attn_mask (ByteTensor, optional): typically used to
|
||||
implement causal attention, where the mask prevents the
|
||||
attention from looking forward in time (default: None).
|
||||
before_softmax (bool, optional): return the raw attention
|
||||
weights and values before the attention softmax.
|
||||
need_head_weights (bool, optional): return the attention
|
||||
weights for each head. Implies *need_weights*. Default:
|
||||
return the average attention weights over all heads.
|
||||
"""
|
||||
if need_head_weights:
|
||||
need_weights = True
|
||||
|
||||
tgt_len, bsz, embed_dim = query.size()
|
||||
assert embed_dim == self.embed_dim
|
||||
assert list(query.size()) == [tgt_len, bsz, embed_dim]
|
||||
|
||||
if incremental_state is not None:
|
||||
saved_state = self._get_input_buffer(incremental_state)
|
||||
if saved_state is not None and "prev_key" in saved_state:
|
||||
# previous time steps are cached - no need to recompute
|
||||
# key and value if they are static
|
||||
if static_kv:
|
||||
assert self.encoder_decoder_attention and not self.self_attention
|
||||
key = value = None
|
||||
else:
|
||||
saved_state = None
|
||||
|
||||
if self.self_attention:
|
||||
q = self.q_proj(query)
|
||||
|
||||
k_input = query.permute(1, 2, 0).contiguous() # B * C * T
|
||||
k_input = (
|
||||
F.linear(k_input, self.compress_k.weight[:, 0:tgt_len])
|
||||
.permute(2, 0, 1)
|
||||
.contiguous()
|
||||
)
|
||||
k = self.k_proj(k_input)
|
||||
|
||||
v_input = query.permute(1, 2, 0).contiguous() # B * C * T
|
||||
if self.shared_kv_compressed == 0:
|
||||
v_input = (
|
||||
F.linear(v_input, self.compress_v.weight[:, 0:tgt_len])
|
||||
.permute(2, 0, 1)
|
||||
.contiguous()
|
||||
)
|
||||
if self.shared_kv_compressed == 1: # use shared kv compressed linear layer
|
||||
v_input = (
|
||||
F.linear(v_input, self.compress_k.weight[:, 0:tgt_len])
|
||||
.permute(2, 0, 1)
|
||||
.contiguous()
|
||||
)
|
||||
v = self.v_proj(v_input)
|
||||
elif self.encoder_decoder_attention:
|
||||
# encoder-decoder attention
|
||||
q = self.q_proj(query)
|
||||
if key is None:
|
||||
assert value is None
|
||||
k = v = None
|
||||
else:
|
||||
k = self.k_proj(key)
|
||||
v = self.v_proj(key)
|
||||
|
||||
else:
|
||||
assert key is not None and value is not None
|
||||
q = self.q_proj(query)
|
||||
k = self.k_proj(key)
|
||||
v = self.v_proj(value)
|
||||
q *= self.scaling
|
||||
|
||||
if self.bias_k is not None:
|
||||
assert self.bias_v is not None
|
||||
k = torch.cat([k, self.bias_k.repeat(1, bsz, 1)])
|
||||
v = torch.cat([v, self.bias_v.repeat(1, bsz, 1)])
|
||||
if attn_mask is not None:
|
||||
attn_mask = torch.cat(
|
||||
[attn_mask, attn_mask.new_zeros(attn_mask.size(0), 1)], dim=1
|
||||
)
|
||||
if key_padding_mask is not None:
|
||||
key_padding_mask = torch.cat(
|
||||
[
|
||||
key_padding_mask,
|
||||
key_padding_mask.new_zeros(key_padding_mask.size(0), 1),
|
||||
],
|
||||
dim=1,
|
||||
)
|
||||
|
||||
q = (
|
||||
q.contiguous()
|
||||
.view(tgt_len, bsz * self.num_heads, self.head_dim)
|
||||
.transpose(0, 1)
|
||||
)
|
||||
if k is not None:
|
||||
k = (
|
||||
k.contiguous()
|
||||
.view(-1, bsz * self.num_heads, self.head_dim)
|
||||
.transpose(0, 1)
|
||||
)
|
||||
if v is not None:
|
||||
v = (
|
||||
v.contiguous()
|
||||
.view(-1, bsz * self.num_heads, self.head_dim)
|
||||
.transpose(0, 1)
|
||||
)
|
||||
|
||||
if saved_state is not None:
|
||||
# saved states are stored with shape (bsz, num_heads, seq_len, head_dim)
|
||||
if "prev_key" in saved_state:
|
||||
_prev_key = saved_state["prev_key"]
|
||||
assert _prev_key is not None
|
||||
prev_key = _prev_key.view(bsz * self.num_heads, -1, self.head_dim)
|
||||
if static_kv:
|
||||
k = prev_key
|
||||
else:
|
||||
assert k is not None
|
||||
k = torch.cat([prev_key, k], dim=1)
|
||||
if "prev_value" in saved_state:
|
||||
_prev_value = saved_state["prev_value"]
|
||||
assert _prev_value is not None
|
||||
prev_value = _prev_value.view(bsz * self.num_heads, -1, self.head_dim)
|
||||
if static_kv:
|
||||
v = prev_value
|
||||
else:
|
||||
assert v is not None
|
||||
v = torch.cat([prev_value, v], dim=1)
|
||||
prev_key_padding_mask: Optional[Tensor] = None
|
||||
if "prev_key_padding_mask" in saved_state:
|
||||
prev_key_padding_mask = saved_state["prev_key_padding_mask"]
|
||||
assert k is not None and v is not None
|
||||
key_padding_mask = MultiheadLinearAttention._append_prev_key_padding_mask(
|
||||
key_padding_mask=key_padding_mask,
|
||||
prev_key_padding_mask=prev_key_padding_mask,
|
||||
batch_size=bsz,
|
||||
src_len=k.size(1),
|
||||
static_kv=static_kv,
|
||||
)
|
||||
|
||||
saved_state["prev_key"] = k.view(bsz, self.num_heads, -1, self.head_dim)
|
||||
saved_state["prev_value"] = v.view(bsz, self.num_heads, -1, self.head_dim)
|
||||
saved_state["prev_key_padding_mask"] = key_padding_mask
|
||||
# In this branch incremental_state is never None
|
||||
assert incremental_state is not None
|
||||
incremental_state = self._set_input_buffer(incremental_state, saved_state)
|
||||
assert k is not None
|
||||
src_len = k.size(1)
|
||||
|
||||
if self.add_zero_attn:
|
||||
assert v is not None
|
||||
src_len += 1
|
||||
k = torch.cat([k, k.new_zeros((k.size(0), 1) + k.size()[2:])], dim=1)
|
||||
v = torch.cat([v, v.new_zeros((v.size(0), 1) + v.size()[2:])], dim=1)
|
||||
if attn_mask is not None:
|
||||
attn_mask = torch.cat(
|
||||
[attn_mask, attn_mask.new_zeros(attn_mask.size(0), 1)], dim=1
|
||||
)
|
||||
|
||||
attn_weights = torch.bmm(q, k.transpose(1, 2))
|
||||
attn_weights = MultiheadLinearAttention.apply_sparse_mask(
|
||||
attn_weights, tgt_len, src_len, bsz
|
||||
)
|
||||
|
||||
assert list(attn_weights.size()) == [bsz * self.num_heads, tgt_len, src_len]
|
||||
|
||||
if attn_mask is not None:
|
||||
attn_mask = attn_mask.unsqueeze(0)
|
||||
if self.onnx_trace:
|
||||
attn_mask = attn_mask.repeat(attn_weights.size(0), 1, 1)
|
||||
attn_weights += attn_mask
|
||||
|
||||
if before_softmax:
|
||||
return attn_weights, v
|
||||
|
||||
attn_weights_float = utils.softmax(
|
||||
attn_weights, dim=-1, onnx_trace=self.onnx_trace
|
||||
)
|
||||
attn_weights = attn_weights_float.type_as(attn_weights)
|
||||
attn_probs = F.dropout(
|
||||
attn_weights,
|
||||
p=self.dropout,
|
||||
training=self.training,
|
||||
)
|
||||
assert v is not None
|
||||
attn = torch.bmm(attn_probs, v)
|
||||
assert list(attn.size()) == [bsz * self.num_heads, tgt_len, self.head_dim]
|
||||
if self.onnx_trace and attn.size(1) == 1:
|
||||
# when ONNX tracing a single decoder step (sequence length == 1)
|
||||
# the transpose is a no-op copy before view, thus unnecessary
|
||||
attn = attn.contiguous().view(tgt_len, bsz, embed_dim)
|
||||
else:
|
||||
attn = attn.transpose(0, 1).contiguous().view(tgt_len, bsz, embed_dim)
|
||||
attn = self.out_proj(attn)
|
||||
attn_weights: Optional[Tensor] = None
|
||||
if need_weights:
|
||||
attn_weights = attn_weights_float.view(
|
||||
bsz, self.num_heads, tgt_len, src_len
|
||||
).transpose(1, 0)
|
||||
if not need_head_weights:
|
||||
# average attention weights over heads
|
||||
attn_weights = attn_weights.mean(dim=0)
|
||||
|
||||
return attn, attn_weights
|
||||
|
||||
@staticmethod
|
||||
def _append_prev_key_padding_mask(
|
||||
key_padding_mask: Optional[Tensor],
|
||||
prev_key_padding_mask: Optional[Tensor],
|
||||
batch_size: int,
|
||||
src_len: int,
|
||||
static_kv: bool,
|
||||
) -> Optional[Tensor]:
|
||||
# saved key padding masks have shape (bsz, seq_len)
|
||||
if prev_key_padding_mask is not None and static_kv:
|
||||
new_key_padding_mask = prev_key_padding_mask
|
||||
elif prev_key_padding_mask is not None and key_padding_mask is not None:
|
||||
new_key_padding_mask = torch.cat(
|
||||
[prev_key_padding_mask.float(), key_padding_mask.float()], dim=1
|
||||
)
|
||||
# During incremental decoding, as the padding token enters and
|
||||
# leaves the frame, there will be a time when prev or current
|
||||
# is None
|
||||
elif prev_key_padding_mask is not None:
|
||||
filler = torch.zeros(
|
||||
(batch_size, src_len - prev_key_padding_mask.size(1)),
|
||||
device=prev_key_padding_mask.device,
|
||||
)
|
||||
new_key_padding_mask = torch.cat(
|
||||
[prev_key_padding_mask.float(), filler.float()], dim=1
|
||||
)
|
||||
elif key_padding_mask is not None:
|
||||
filler = torch.zeros(
|
||||
(batch_size, src_len - key_padding_mask.size(1)),
|
||||
device=key_padding_mask.device,
|
||||
)
|
||||
new_key_padding_mask = torch.cat(
|
||||
[filler.float(), key_padding_mask.float()], dim=1
|
||||
)
|
||||
else:
|
||||
new_key_padding_mask = prev_key_padding_mask
|
||||
return new_key_padding_mask
|
||||
|
||||
@torch.jit.export
|
||||
def reorder_incremental_state(
|
||||
self,
|
||||
incremental_state: Dict[str, Dict[str, Optional[Tensor]]],
|
||||
new_order: Tensor,
|
||||
):
|
||||
"""Reorder buffered internal state (for incremental generation)."""
|
||||
input_buffer = self._get_input_buffer(incremental_state)
|
||||
if input_buffer is not None:
|
||||
for k in input_buffer.keys():
|
||||
input_buffer_k = input_buffer[k]
|
||||
if input_buffer_k is not None:
|
||||
if self.encoder_decoder_attention and input_buffer_k.size(
|
||||
0
|
||||
) == new_order.size(0):
|
||||
break
|
||||
input_buffer[k] = input_buffer_k.index_select(0, new_order)
|
||||
incremental_state = self._set_input_buffer(incremental_state, input_buffer)
|
||||
return incremental_state
|
||||
|
||||
def _get_input_buffer(
|
||||
self, incremental_state: Optional[Dict[str, Dict[str, Optional[Tensor]]]]
|
||||
) -> Dict[str, Optional[Tensor]]:
|
||||
result = self.get_incremental_state(incremental_state, "attn_state")
|
||||
if result is not None:
|
||||
return result
|
||||
else:
|
||||
empty_result: Dict[str, Optional[Tensor]] = {}
|
||||
return empty_result
|
||||
|
||||
def _set_input_buffer(
|
||||
self,
|
||||
incremental_state: Dict[str, Dict[str, Optional[Tensor]]],
|
||||
buffer: Dict[str, Optional[Tensor]],
|
||||
):
|
||||
return self.set_incremental_state(incremental_state, "attn_state", buffer)
|
||||
|
||||
def apply_sparse_mask(attn_weights, tgt_len: int, src_len: int, bsz: int):
|
||||
return attn_weights
|
||||
|
||||
def upgrade_state_dict_named(self, state_dict, name):
|
||||
prefix = name + "." if name != "" else ""
|
||||
items_to_add = {}
|
||||
keys_to_remove = []
|
||||
for k in state_dict.keys():
|
||||
if k.endswith(prefix + "in_proj_weight"):
|
||||
# in_proj_weight used to be q + k + v with same dimensions
|
||||
dim = int(state_dict[k].shape[0] / 3)
|
||||
items_to_add[prefix + "q_proj.weight"] = state_dict[k][:dim]
|
||||
items_to_add[prefix + "k_proj.weight"] = state_dict[k][dim : 2 * dim]
|
||||
items_to_add[prefix + "v_proj.weight"] = state_dict[k][2 * dim :]
|
||||
|
||||
keys_to_remove.append(k)
|
||||
|
||||
k_bias = prefix + "in_proj_bias"
|
||||
if k_bias in state_dict.keys():
|
||||
dim = int(state_dict[k].shape[0] / 3)
|
||||
items_to_add[prefix + "q_proj.bias"] = state_dict[k_bias][:dim]
|
||||
items_to_add[prefix + "k_proj.bias"] = state_dict[k_bias][
|
||||
dim : 2 * dim
|
||||
]
|
||||
items_to_add[prefix + "v_proj.bias"] = state_dict[k_bias][2 * dim :]
|
||||
|
||||
keys_to_remove.append(prefix + "in_proj_bias")
|
||||
|
||||
for k in keys_to_remove:
|
||||
del state_dict[k]
|
||||
|
||||
for key, value in items_to_add.items():
|
||||
state_dict[key] = value
|
||||
Reference in New Issue
Block a user