paddlenlp.transformers.opt.modeling 源代码

# Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
# Copyright 2018 The OpenAI Team Authors and HuggingFace Inc. team.
# Copyright (c) 2018, NVIDIA CORPORATION.  All rights reserved.
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# Licensed under the Apache License, Version 2.0 (the "License");
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#     http://www.apache.org/licenses/LICENSE-2.0
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import collections
from typing import Optional, List, Dict, Any

import paddle
import paddle.nn as nn
from paddle.nn import LayerNorm, Layer
import paddle.nn.functional as F
import paddle.tensor as tensor
from paddle.fluid import layers
from paddle.nn.layer.transformer import _convert_param_attr_to_list
from paddlenlp.transformers.gpt.modeling import MultiHeadAttention, TransformerDecoderLayer
from paddlenlp.transformers.model_utils import PretrainedModel, register_base_model

__all__ = [
    "OPTModel",
    "OPTPretrainedModel",
    "OPTForCausalLM",
]


class TransformerDecoder(Layer):
    """
    TransformerDecoder is a stack of N decoder layers.
    """

    def __init__(
        self,
        decoder_layers: List[Layer],
        num_layers: int,
        hidden_size: int,
        word_embed_proj_dim: int,
        norm: Optional[Layer] = None,
        normalize_before: bool = False,
    ):
        super(TransformerDecoder, self).__init__()

        if word_embed_proj_dim != hidden_size:
            self.project_out = nn.Linear(hidden_size, word_embed_proj_dim, bias_attr=False)
        else:
            self.project_out = None

        self.num_layers = num_layers
        self.layers = decoder_layers

        if normalize_before:
            self.final_layer_norm = nn.LayerNorm(hidden_size)
        else:
            self.final_layer_norm = None

        self.checkpoints = []

    def forward(self, tgt, memory, tgt_mask=None, memory_mask=None, use_cache: bool = False, cache=None):
        r"""
        Applies a stack of N Transformer decoder layers on inputs. If `norm` is
        provided, also applies layer normalization on the output of last decoder
        layer.
        """
        output = tgt
        new_caches = []
        self.checkpoints = []

        for i, mod in enumerate(self.layers):
            if cache is None:
                if use_cache:
                    output, new_cache = mod(output, memory, tgt_mask=tgt_mask, use_cache=use_cache, cache=cache)
                    new_caches.append(new_cache)
                else:
                    output = mod(output, memory, tgt_mask=tgt_mask, use_cache=use_cache, cache=cache)

            else:
                output, new_cache = mod(output, memory, tgt_mask=tgt_mask, use_cache=use_cache, cache=cache[i])
                new_caches.append(new_cache)
            self.checkpoints.append(output.name)

        if self.final_layer_norm:
            output = self.final_layer_norm(output)

        if self.project_out:
            output = self.project_out(output)

        return output if use_cache is False else (output, new_caches)

    def gen_cache(self, memory, do_zip=False):
        r"""
        Generates cache for `forward` usage. The generated cache is a list, and
        each element in it is a tuple( :code:`(incremental_cache, static_cache)` )
        produced by `TransformerDecoderLayer.gen_cache`. See `TransformerDecoderLayer.gen_cache`
        for more details. If `do_zip` is True, apply `zip` on these tuples to get
        a list with two elements.
        """
        cache = [layer.gen_cache(memory) for layer in self.layers]
        if do_zip:
            cache = list(zip(*cache))
        return cache


class OPTLearnedPositionEmbedding(nn.Embedding):
    """this module learns postional embeddings up to a fixed maximum size"""

    def __init__(self, num_embeddings: int, embedding_dim: int, initializer_range: float):
        """OPT is set up so taht if padding_idx is specified then offset the embedding ids by 2
        and adjust num_embeddings appropriately. Other models don't have this hack

        Args:
            num_embeddings (int): the number of embedding size
            embedding_dim (int): the dim of embedding
        """
        self.offset = 2
        super().__init__(num_embeddings + self.offset, embedding_dim)

    def forward(self, position_ids, past_key_values_length: int = 0):
        """get the position embedding with attention mask

        Args:
            position_ids: (paddle.Tensor): the tensor of position ids
            past_key_values_length (int, optional): the past key value which will . Defaults to 0.

        Returns:
            paddle.Tensor: the position embedding
        """
        # cut positions if `past_key_values_length` is > 0
        position_ids = position_ids[:, past_key_values_length:]
        return super().forward(position_ids + self.offset)


class OPTEmbeddings(Layer):
    """
    Include embeddings from word and position embeddings.
    """

    def __init__(
        self,
        vocab_size: int,
        hidden_size: int = 768,
        word_embed_proj_dim: int = 768,
        padding_idx: int = 1,
        hidden_dropout_prob: float = 0.1,
        max_position_embeddings: int = 512,
        type_vocab_size: Optional[int] = None,
        initializer_range=0.02,
    ):
        super(OPTEmbeddings, self).__init__()
        self.word_embeddings = nn.Embedding(
            vocab_size,
            word_embed_proj_dim,
            # padding_idx=padding_idx,
            weight_attr=paddle.ParamAttr(initializer=nn.initializer.Normal(mean=0.0, std=initializer_range)),
        )

        if word_embed_proj_dim != hidden_size:
            self.project_in = nn.Linear(word_embed_proj_dim, hidden_size, bias_attr=False)
        else:
            self.project_in = None

        self.position_embeddings = OPTLearnedPositionEmbedding(
            num_embeddings=max_position_embeddings, embedding_dim=hidden_size, initializer_range=initializer_range
        )

        self.dropout = nn.Dropout(hidden_dropout_prob)

    def forward(self, input_ids, position_ids=None):
        if position_ids is None:
            ones = paddle.ones_like(input_ids, dtype="int64")
            seq_length = paddle.cumsum(ones, axis=-1)
            position_ids = seq_length - ones

        input_embeddings = self.word_embeddings(input_ids)

        if self.project_in:
            input_embeddings = self.project_in(input_embeddings)

        position_embeddings = self.position_embeddings(position_ids)

        embeddings = input_embeddings + position_embeddings
        embeddings = self.dropout(embeddings)
        return embeddings


[文档]class OPTPretrainedModel(PretrainedModel): """ An abstract class for pretrained OPT models. It provides OPT related `model_config_file`, `resource_files_names`, `pretrained_resource_files_map`, `pretrained_init_configuration`, `base_model_prefix` for downloading and loading pretrained models. See :class:`~paddlenlp.transformers.model_utils.PretrainedModel` for more details. """ pretrained_init_configuration = {} pretrained_resource_files_map = {"model_state": {}} base_model_prefix = "opt"
[文档] def init_weights(self, layer): """Initialization hook""" if isinstance(layer, (nn.Linear, nn.Embedding)): # In the dygraph mode, use the `set_value` to reset the parameter directly, # and reset the `state_dict` to update parameter in static mode. if isinstance(layer.weight, paddle.Tensor): layer.weight.set_value( paddle.tensor.normal( mean=0.0, std=self.initializer_range if hasattr(self, "initializer_range") else self.opt.config["initializer_range"], shape=layer.weight.shape, ) )
[文档]@register_base_model class OPTModel(OPTPretrainedModel): r""" The bare OPT Model transformer outputting raw hidden-states. This model inherits from :class:`~paddlenlp.transformers.model_utils.PretrainedModel`. Refer to the superclass documentation for the generic methods. This model is also a Paddle `paddle.nn.Layer <https://www.paddlepaddle.org.cn/documentation /docs/en/api/paddle/fluid/dygraph/layers/Layer_en.html>`__ subclass. Use it as a regular Paddle Layer and refer to the Paddle documentation for all matter related to general usage and behavior. Args: vocab_size (int): Vocabulary size of `inputs_ids` in `OPTModel`. Also is the vocab size of token embedding matrix. Defines the number of different tokens that can be represented by the `inputs_ids` passed when calling `OPTModel`. hidden_size (int, optional): Dimensionality of the embedding layer and decoder layer. Defaults to `768`. num_hidden_layers (int, optional): Number of hidden layers in the Transformer decoder. Defaults to `12`. num_attention_heads (int, optional): Number of attention heads for each attention layer in the Transformer decoder. Defaults to `12`. intermediate_size (int, optional): Dimensionality of the feed-forward (ff) layer in the decoder. Input tensors to ff layers are firstly projected from `hidden_size` to `intermediate_size`, and then projected back to `hidden_size`. Typically `intermediate_size` is larger than `hidden_size`. Defaults to `3072`. hidden_act (str, optional): The non-linear activation function in the feed-forward layer. ``"gelu"``, ``"relu"`` and any other paddle supported activation functions are supported. Defaults to `"relu"`. hidden_dropout_prob (float, optional): The dropout probability for all fully connected layers in the embeddings and decoder. Defaults to `0.1`. attention_probs_dropout_prob (float, optional): The dropout probability used in MultiHeadAttention in all decoder layers to drop some attention target. Defaults to `0.1`. max_position_embeddings (int, optional): The maximum value of the dimensionality of position encoding, which dictates the maximum supported length of an input sequence. Defaults to `512`. type_vocab_size (int, optional): The vocabulary size of the `token_type_ids`. Defaults to `16`. .. note:: Please NOT using `type_vocab_size`, for it will be obsolete in the future.. initializer_range (float, optional): The standard deviation of the normal initializer. Default to `0.02`. .. note:: A normal_initializer initializes weight matrices as normal distributions. See :meth:`OPTPretrainedModel._init_weights()` for how weights are initialized in `OPTModel`. pad_token_id(int, optional): The index of padding token in the token vocabulary. to `0`. """ def __init__( self, vocab_size: int, hidden_size: int = 768, word_embed_proj_dim: int = 768, num_hidden_layers: int = 12, num_attention_heads: int = 12, intermediate_size: int = 3072, hidden_act: str = "relu", hidden_dropout_prob: float = 0.1, attention_probs_dropout_prob: float = 0.1, max_position_embeddings: int = 512, type_vocab_size: int = 16, initializer_range: float = 0.02, pad_token_id: int = 0, eos_token_id: int = 7, bos_token_id: int = 0, eol_token_id: int = 3, normalize_before: bool = True, **kwargs ): super(OPTModel, self).__init__() self.pad_token_id = pad_token_id self.initializer_range = initializer_range self.hidden_size = hidden_size self.vocab_size = vocab_size self.embeddings = OPTEmbeddings( vocab_size=vocab_size, hidden_size=hidden_size, word_embed_proj_dim=word_embed_proj_dim, padding_idx=pad_token_id, hidden_dropout_prob=hidden_dropout_prob, max_position_embeddings=max_position_embeddings, type_vocab_size=type_vocab_size, initializer_range=initializer_range, ) decoder_layers = nn.LayerList() for i in range(num_hidden_layers): decoder_layers.append( TransformerDecoderLayer( d_model=hidden_size, nhead=num_attention_heads, dim_feedforward=intermediate_size, dropout=hidden_dropout_prob, activation=hidden_act, attn_dropout=attention_probs_dropout_prob, act_dropout=hidden_dropout_prob, weight_attr=paddle.ParamAttr( initializer=nn.initializer.Normal(mean=0.0, std=self.initializer_range) ), bias_attr=None, normalize_before=normalize_before, ) ) self.decoder = TransformerDecoder( decoder_layers, num_hidden_layers, norm="LayerNorm", hidden_size=hidden_size, normalize_before=normalize_before, word_embed_proj_dim=word_embed_proj_dim, ) self.apply(self.init_weights) self.checkpoints = []
[文档] def forward(self, input_ids, position_ids=None, attention_mask=None, use_cache=False, cache=None): r""" The OPTModel forward method, overrides the `__call__()` special method. Args: input_ids (Tensor): Indices of input sequence tokens in the vocabulary. They are numerical representations of tokens that build the input sequence. Its data type should be `int64` and it has a shape of [batch_size, sequence_length]. position_ids(Tensor, optional): Indices of positions of each input sequence tokens in the position embeddings. Selected in the range ``[0, max_position_embeddings - 1]``. Shape as `(batch_size, num_tokens)` and dtype as int64. Defaults to `None`. attention_mask (Tensor, optional): Mask used in self attention to avoid performing attention to some unwanted positions, usually the subsequent positions. It is a tensor with shape broadcasted to `[batch_size, num_attention_heads, sequence_length, sequence_length]`. It is a tensor with shape broadcasted to `[batch_size, num_attention_heads, sequence_length, sequence_length]`. For example, its shape can be [batch_size, sequence_length], [batch_size, sequence_length, sequence_length], [batch_size, num_attention_heads, sequence_length, sequence_length]. Its data type should be float32. The `masked` tokens have `-1e-9` values, and the `unmasked` tokens have `0` values. Defaults to `None`, which means nothing needed to be prevented attention to. use_cache (bool, optional): Whether or not to use cache. Defaults to `False`. If set to `True`, key value states will be returned and can be used to speed up decoding. cache (list, optional): It is a list, and each element in the list is a tuple `(incremental_cache, static_cache)`. See `TransformerDecoder.gen_cache <https://github.com/PaddlePaddle/Paddle/blob/release/2.1/python/paddle/nn/layer/transformer.py#L1060>`__ for more details. It is only used for inference and should be None for training. Default to `None`. Returns: Tensor: Returns tensor `encoder_output`, which is the output at the last layer of the model. Its data type should be float32 and has a shape of [batch_size, sequence_length, hidden_size]. Example: .. code-block:: import paddle from paddlenlp.transformers import OPTModel, GPTTokenizer tokenizer = GPTTokenizer.from_pretrained('facebook/opt-125m') model = OPTModel.from_pretrained('facebook/opt-125m') inputs = tokenizer("Welcome to use PaddlePaddle and PaddleNLimage.pngP!", return_token_type_ids=False) inputs = {k:paddle.to_tensor([v]) for (k, v) in inputs.items()} output = model(**inputs) """ self.checkpoints = [] if position_ids is None: past_length = 0 if cache is not None: past_length = paddle.shape(cache[0].k)[-2] position_ids = paddle.arange(past_length, paddle.shape(input_ids)[-1] + past_length, dtype=input_ids.dtype) position_ids = position_ids.unsqueeze(0) position_ids = paddle.expand_as(position_ids, input_ids) embedding_output = self.embeddings(input_ids=input_ids, position_ids=position_ids) # TODO, use registered buffer causal_mask = paddle.tensor.triu( paddle.ones((paddle.shape(input_ids)[-1], paddle.shape(input_ids)[-1])) * -1e4, diagonal=1 ) if attention_mask is not None: if len(attention_mask.shape) == 2: attention_mask = attention_mask[:, None, None, :] attention_mask = attention_mask + causal_mask else: attention_mask = causal_mask # The tensor returned by triu not in static graph. attention_mask.stop_gradient = True decoder_outputs = self.decoder( embedding_output, memory=None, tgt_mask=attention_mask, use_cache=use_cache, cache=cache ) self.checkpoints.extend(self.decoder.checkpoints) return decoder_outputs
class OPTLMHead(Layer): def __init__(self, hidden_size: int, vocab_size: int, embedding_weights=None): super(OPTLMHead, self).__init__() self.decoder_weight = ( self.create_parameter(shape=[vocab_size, hidden_size], dtype=paddle.get_default_dtype(), is_bias=True) if embedding_weights is None else embedding_weights ) def forward(self, hidden_states): logits = paddle.tensor.matmul(hidden_states, self.decoder_weight, transpose_y=True) return logits
[文档]class OPTForCausalLM(OPTPretrainedModel): """ The OPT Model with a `language modeling` head on top. Args: opt (:class:`OPTModel`): An instance of :class:`OPTModel`. """ def __init__(self, opt: OPTModel): super(OPTForCausalLM, self).__init__() self.opt = opt self.lm_head = OPTLMHead( hidden_size=self.opt.config["hidden_size"], vocab_size=self.opt.config["vocab_size"], embedding_weights=self.opt.embeddings.word_embeddings.weight, )
[文档] def forward(self, input_ids, position_ids=None, attention_mask=None, use_cache=False, cache=None): r""" Args: input_ids (Tensor): See :class:`OPTModel`. position_ids (Tensor, optional): See :class:`OPTModel`. attention_mask (Tensor, optional): See :class:`OPTModel`. use_cache (bool, optional): See :class:`OPTModel`. cache (Tensor, optional): See :class:`OPTModel`. Returns: Tensor or tuple: Returns tensor `logits` or tuple `(logits, cached_kvs)`. If `use_cache` is True, tuple (`logits, cached_kvs`) will be returned. Otherwise, tensor `logits` will be returned. `logits` is the output of the opt model. `cache_kvs` is the cache output of opt model if `use_cache` is True. Example: .. code-block:: import paddle from paddlenlp.transformers import OPTForCausalLM, GPTTokenizer tokenizer = GPTTokenizer.from_pretrained('facebook/opt-125m') model = OPTForCausalLM.from_pretrained('facebook/opt-125m') inputs = tokenizer("Welcome to use PaddlePaddle and PaddleNLP!") inputs = {k:paddle.to_tensor([v]) for (k, v) in inputs.items()} output_ids, score = model.generate(input_ids=inputs['input_ids']) print(tokenizer.batch_decode(output_ids[0])) """ outputs = self.opt( input_ids, position_ids=position_ids, attention_mask=attention_mask, use_cache=use_cache, cache=cache ) if use_cache: encoder_outputs, cached_kvs = outputs[:2] else: encoder_outputs = outputs logits = self.lm_head(encoder_outputs) if use_cache: return logits, cached_kvs else: return logits
def prepare_faster_entry(self, kwargs: Dict[str, Any]): # import FasterOPT at here to avoid cycling import from paddlenlp.ops import FasterOPT use_fp16_decoding = kwargs.get("use_fp16_decoding", False) decode_strategy = kwargs.get("decode_strategy") # decoding_lib can be passed into FasterOPT decoding_lib = kwargs.get("decoding_lib", None) if decode_strategy == "beam_search": raise AttributeError("'beam_search' is not supported yet in the faster version of OPT") # Currently, FasterTransformer only support restricted size_per_head. size_per_head = self.opt.config["hidden_size"] // self.opt.config["num_attention_heads"] if size_per_head not in [32, 64, 80, 96, 128]: raise AttributeError( "'size_per_head = %d' is not supported yet in the faster version of OPT" % size_per_head ) if kwargs["forced_bos_token_id"] is not None: # not support for min_length yet in the faster version raise AttributeError("'forced_bos_token_id != None' is not supported yet in the faster version") if kwargs["min_length"] != 0: # not support for min_length yet in the faster version raise AttributeError("'min_length != 0' is not supported yet in the faster version") self._faster_entry = FasterOPT(self, use_fp16_decoding=use_fp16_decoding, decoding_lib=decoding_lib).forward return self._faster_entry def prepare_inputs_for_generation(self, input_ids, use_cache=False, cache=None, **kwargs): # only last token for inputs_ids if cache is defined in kwargs position_ids = kwargs.get("position_ids", None) attention_mask = kwargs.get("attention_mask", None) if attention_mask is not None: if len(attention_mask.shape) == 4: attention_mask = attention_mask[:, -1, -1, :] if "int" in paddle.common_ops_import.convert_dtype(attention_mask.dtype): attention_mask = (1.0 - attention_mask) * -1e4 if cache is not None: input_ids = input_ids[:, -1].unsqueeze(-1) if position_ids is not None: position_ids = position_ids[:, -1].unsqueeze(-1) position_ids += 2 return { "input_ids": input_ids, "position_ids": position_ids, "attention_mask": attention_mask, "use_cache": use_cache, "cache": cache, } def __getattr__(self, name): try: return super().__getattr__(name) except AttributeError as e: try: return getattr(getattr(self, self.base_model_prefix), name) except AttributeError: try: return getattr(self, self.base_model_prefix).config[name] except KeyError: raise e