122 lines
3.8 KiB
Python
122 lines
3.8 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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import logging
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import torch.nn as nn
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from fairseq.model_parallel.modules import (
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ModelParallelTransformerDecoderLayer,
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ModelParallelTransformerEncoderLayer,
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)
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from fairseq.models import register_model
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from fairseq.models.transformer import (
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TransformerDecoder,
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TransformerEncoder,
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TransformerModel,
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)
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try:
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from fairseq.model_parallel.megatron.mpu import (
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copy_to_model_parallel_region,
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gather_from_model_parallel_region,
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VocabParallelEmbedding,
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)
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has_megatron_submodule = True
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except (ImportError, ModuleNotFoundError):
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has_megatron_submodule = False
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logger = logging.getLogger(__name__)
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@register_model("model_parallel_transformer")
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class ModelParallelTransformerModel(TransformerModel):
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"""
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Model parallel Transformer model.
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"""
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@classmethod
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def build_embedding(cls, args, dictionary, embed_dim, path=None):
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if not has_megatron_submodule:
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raise ImportError(
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"\n\nPlease install the megatron submodule:"
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"\n\n git submodule update --init "
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"fairseq/model_parallel/megatron"
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)
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dictionary.pad_to_multiple_(args.model_parallel_size * 8)
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num_embeddings = len(dictionary)
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padding_idx = dictionary.pad()
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def _vocab_init(tensor, **kwargs):
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nn.init.normal_(tensor, mean=0, std=num_embeddings ** -0.5)
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nn.init.constant_(tensor[1], 0)
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emb = VocabParallelEmbedding(
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num_embeddings, embed_dim, padding_idx, init_method=_vocab_init
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)
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# if provided, load from preloaded dictionaries
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if path:
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raise NotImplementedError(
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"Loading of embedding from path is not supported for model parallel"
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)
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return emb
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@classmethod
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def build_encoder(cls, args, src_dict, embed_tokens):
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return ModelParallelTransformerEncoder(args, src_dict, embed_tokens)
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@classmethod
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def build_decoder(cls, args, tgt_dict, embed_tokens):
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return ModelParallelTransformerDecoder(
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args,
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tgt_dict,
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embed_tokens,
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no_encoder_attn=getattr(args, "no_cross_attention", False),
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)
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class ModelParallelTransformerEncoder(TransformerEncoder):
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"""
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Model parallel Transformer encoder consisting of *args.encoder_layers* layers. Each layer
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is a :class:`ModelParallelTransformerEncoderLayer`.
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"""
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def __init__(self, args, dictionary, embed_tokens):
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super().__init__(args, dictionary, embed_tokens)
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if args.no_final_layer_norm:
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self.layer_norm = None
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def build_encoder_layer(self, args):
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return ModelParallelTransformerEncoderLayer(args)
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class ModelParallelTransformerDecoder(TransformerDecoder):
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"""
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Model Parallel Transformer decoder consisting of *args.decoder_layers* layers. Each layer
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is a :class:`ModelParallelTransformerDecoderLayer`.
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"""
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def build_decoder_layer(self, args, no_encoder_attn=False):
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return ModelParallelTransformerDecoderLayer(args, no_encoder_attn)
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def output_layer(self, features, **kwargs):
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"""Project features to the vocabulary size."""
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if not self.share_input_output_embed:
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raise NotImplementedError(
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"Model parallel training currently requires --share-decoder-input-output-embed"
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)
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features = copy_to_model_parallel_region(features)
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# project back to size of vocabulary
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x = self.output_projection(features)
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if getattr(self.args, "criterion") != "vocab_parallel_cross_entropy":
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x = gather_from_model_parallel_region(x).contiguous()
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return x
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