diff --git "a/venv/lib/python3.10/site-packages/transformers/models/led/modeling_led.py" "b/venv/lib/python3.10/site-packages/transformers/models/led/modeling_led.py" new file mode 100644--- /dev/null +++ "b/venv/lib/python3.10/site-packages/transformers/models/led/modeling_led.py" @@ -0,0 +1,2747 @@ +# coding=utf-8 +# Copyright 2021 Iz Beltagy, Matthew E. Peters, Arman Cohan and The HuggingFace Inc. team. All rights reserved. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. +""" PyTorch LED model.""" + + +import math +import warnings +from dataclasses import dataclass +from typing import List, Optional, Tuple, Union + +import torch +import torch.utils.checkpoint +from torch import nn +from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss + +from ...activations import ACT2FN +from ...modeling_attn_mask_utils import _create_4d_causal_attention_mask +from ...modeling_outputs import ( + BaseModelOutputWithPastAndCrossAttentions, + Seq2SeqLMOutput, + Seq2SeqModelOutput, + Seq2SeqQuestionAnsweringModelOutput, + Seq2SeqSequenceClassifierOutput, +) +from ...modeling_utils import PreTrainedModel +from ...utils import ( + ModelOutput, + add_code_sample_docstrings, + add_end_docstrings, + add_start_docstrings, + add_start_docstrings_to_model_forward, + logging, + replace_return_docstrings, +) +from .configuration_led import LEDConfig + + +logger = logging.get_logger(__name__) + +_CHECKPOINT_FOR_DOC = "allenai/led-base-16384" +_CONFIG_FOR_DOC = "LEDConfig" + + +from ..deprecated._archive_maps import LED_PRETRAINED_MODEL_ARCHIVE_LIST # noqa: F401, E402 + + +def shift_tokens_right(input_ids: torch.Tensor, pad_token_id: int, decoder_start_token_id: int): + """ + Shift input ids one token to the right. + """ + shifted_input_ids = input_ids.new_zeros(input_ids.shape) + shifted_input_ids[:, 1:] = input_ids[:, :-1].clone() + shifted_input_ids[:, 0] = decoder_start_token_id + + if pad_token_id is None: + raise ValueError("config.pad_token_id has to be defined.") + # replace possible -100 values in labels by `pad_token_id` + shifted_input_ids.masked_fill_(shifted_input_ids == -100, pad_token_id) + + return shifted_input_ids + + +def _prepare_4d_attention_mask_inverted(mask: torch.Tensor, dtype: torch.dtype, tgt_len: Optional[int] = None): + """ + Expands attention_mask from `[bsz, seq_len]` to `[bsz, 1, tgt_seq_len, src_seq_len]`. + """ + bsz, src_len = mask.size() + tgt_len = tgt_len if tgt_len is not None else src_len + + expanded_mask = mask[:, None, None, :].expand(bsz, 1, tgt_len, src_len).to(dtype) + + inverted_mask = 1.0 - expanded_mask + expanded_attention_mask = inverted_mask.masked_fill(inverted_mask.bool(), torch.finfo(dtype).min) + + # make sure that global_attn_mask is positive + expanded_attention_mask = expanded_attention_mask * inverted_mask + + return expanded_attention_mask + + +class LEDLearnedPositionalEmbedding(nn.Embedding): + """ + This module learns positional embeddings up to a fixed maximum size. + """ + + def __init__(self, num_embeddings: int, embedding_dim: int): + super().__init__(num_embeddings, embedding_dim) + + def forward(self, input_ids_shape: torch.Size, past_key_values_length: int = 0): + """`input_ids_shape` is expected to be [bsz x seqlen].""" + bsz, seq_len = input_ids_shape[:2] + positions = torch.arange( + past_key_values_length, past_key_values_length + seq_len, dtype=torch.long, device=self.weight.device + ) + return super().forward(positions) + + +# Copied from transformers.models.longformer.modeling_longformer.LongformerSelfAttention with Longformer->LEDEncoder +class LEDEncoderSelfAttention(nn.Module): + def __init__(self, config, layer_id): + super().__init__() + if config.hidden_size % config.num_attention_heads != 0: + raise ValueError( + f"The hidden size ({config.hidden_size}) is not a multiple of the number of attention " + f"heads ({config.num_attention_heads})" + ) + self.num_heads = config.num_attention_heads + self.head_dim = int(config.hidden_size / config.num_attention_heads) + self.embed_dim = config.hidden_size + + self.query = nn.Linear(config.hidden_size, self.embed_dim) + self.key = nn.Linear(config.hidden_size, self.embed_dim) + self.value = nn.Linear(config.hidden_size, self.embed_dim) + + # separate projection layers for tokens with global attention + self.query_global = nn.Linear(config.hidden_size, self.embed_dim) + self.key_global = nn.Linear(config.hidden_size, self.embed_dim) + self.value_global = nn.Linear(config.hidden_size, self.embed_dim) + + self.dropout = config.attention_probs_dropout_prob + + self.layer_id = layer_id + attention_window = config.attention_window[self.layer_id] + assert ( + attention_window % 2 == 0 + ), f"`attention_window` for layer {self.layer_id} has to be an even value. Given {attention_window}" + assert ( + attention_window > 0 + ), f"`attention_window` for layer {self.layer_id} has to be positive. Given {attention_window}" + + self.one_sided_attn_window_size = attention_window // 2 + + self.config = config + + def forward( + self, + hidden_states, + attention_mask=None, + layer_head_mask=None, + is_index_masked=None, + is_index_global_attn=None, + is_global_attn=None, + output_attentions=False, + ): + """ + [`LEDEncoderSelfAttention`] expects *len(hidden_states)* to be multiple of *attention_window*. Padding to + *attention_window* happens in [`LEDEncoderModel.forward`] to avoid redoing the padding on each layer. + + The *attention_mask* is changed in [`LEDEncoderModel.forward`] from 0, 1, 2 to: + + - -10000: no attention + - 0: local attention + - +10000: global attention + """ + hidden_states = hidden_states.transpose(0, 1) + + # project hidden states + query_vectors = self.query(hidden_states) + key_vectors = self.key(hidden_states) + value_vectors = self.value(hidden_states) + + seq_len, batch_size, embed_dim = hidden_states.size() + assert ( + embed_dim == self.embed_dim + ), f"hidden_states should have embed_dim = {self.embed_dim}, but has {embed_dim}" + + # normalize query + query_vectors /= math.sqrt(self.head_dim) + + query_vectors = query_vectors.view(seq_len, batch_size, self.num_heads, self.head_dim).transpose(0, 1) + key_vectors = key_vectors.view(seq_len, batch_size, self.num_heads, self.head_dim).transpose(0, 1) + + attn_scores = self._sliding_chunks_query_key_matmul( + query_vectors, key_vectors, self.one_sided_attn_window_size + ) + + # values to pad for attention probs + remove_from_windowed_attention_mask = (attention_mask != 0)[:, :, None, None] + + # cast to fp32/fp16 then replace 1's with -inf + float_mask = remove_from_windowed_attention_mask.type_as(query_vectors).masked_fill( + remove_from_windowed_attention_mask, torch.finfo(query_vectors.dtype).min + ) + # diagonal mask with zeros everywhere and -inf inplace of padding + diagonal_mask = self._sliding_chunks_query_key_matmul( + float_mask.new_ones(size=float_mask.size()), float_mask, self.one_sided_attn_window_size + ) + + # pad local attention probs + attn_scores += diagonal_mask + + assert list(attn_scores.size()) == [ + batch_size, + seq_len, + self.num_heads, + self.one_sided_attn_window_size * 2 + 1, + ], ( + f"local_attn_probs should be of size ({batch_size}, {seq_len}, {self.num_heads}," + f" {self.one_sided_attn_window_size * 2 + 1}), but is of size {attn_scores.size()}" + ) + + # compute local attention probs from global attention keys and contact over window dim + if is_global_attn: + # compute global attn indices required through out forward fn + ( + max_num_global_attn_indices, + is_index_global_attn_nonzero, + is_local_index_global_attn_nonzero, + is_local_index_no_global_attn_nonzero, + ) = self._get_global_attn_indices(is_index_global_attn) + # calculate global attn probs from global key + + global_key_attn_scores = self._concat_with_global_key_attn_probs( + query_vectors=query_vectors, + key_vectors=key_vectors, + max_num_global_attn_indices=max_num_global_attn_indices, + is_index_global_attn_nonzero=is_index_global_attn_nonzero, + is_local_index_global_attn_nonzero=is_local_index_global_attn_nonzero, + is_local_index_no_global_attn_nonzero=is_local_index_no_global_attn_nonzero, + ) + # concat to local_attn_probs + # (batch_size, seq_len, num_heads, extra attention count + 2*window+1) + attn_scores = torch.cat((global_key_attn_scores, attn_scores), dim=-1) + + # free memory + del global_key_attn_scores + + attn_probs = nn.functional.softmax( + attn_scores, dim=-1, dtype=torch.float32 + ) # use fp32 for numerical stability + + if layer_head_mask is not None: + assert layer_head_mask.size() == ( + self.num_heads, + ), f"Head mask for a single layer should be of size {(self.num_heads,)}, but is {layer_head_mask.size()}" + attn_probs = layer_head_mask.view(1, 1, -1, 1) * attn_probs + + # softmax sometimes inserts NaN if all positions are masked, replace them with 0 + attn_probs = torch.masked_fill(attn_probs, is_index_masked[:, :, None, None], 0.0) + attn_probs = attn_probs.type_as(attn_scores) + + # free memory + del attn_scores + + # apply dropout + attn_probs = nn.functional.dropout(attn_probs, p=self.dropout, training=self.training) + + value_vectors = value_vectors.view(seq_len, batch_size, self.num_heads, self.head_dim).transpose(0, 1) + + # compute local attention output with global attention value and add + if is_global_attn: + # compute sum of global and local attn + attn_output = self._compute_attn_output_with_global_indices( + value_vectors=value_vectors, + attn_probs=attn_probs, + max_num_global_attn_indices=max_num_global_attn_indices, + is_index_global_attn_nonzero=is_index_global_attn_nonzero, + is_local_index_global_attn_nonzero=is_local_index_global_attn_nonzero, + ) + else: + # compute local attn only + attn_output = self._sliding_chunks_matmul_attn_probs_value( + attn_probs, value_vectors, self.one_sided_attn_window_size + ) + + assert attn_output.size() == (batch_size, seq_len, self.num_heads, self.head_dim), "Unexpected size" + attn_output = attn_output.transpose(0, 1).reshape(seq_len, batch_size, embed_dim).contiguous() + + # compute value for global attention and overwrite to attention output + # TODO: remove the redundant computation + if is_global_attn: + global_attn_output, global_attn_probs = self._compute_global_attn_output_from_hidden( + hidden_states=hidden_states, + max_num_global_attn_indices=max_num_global_attn_indices, + layer_head_mask=layer_head_mask, + is_local_index_global_attn_nonzero=is_local_index_global_attn_nonzero, + is_index_global_attn_nonzero=is_index_global_attn_nonzero, + is_local_index_no_global_attn_nonzero=is_local_index_no_global_attn_nonzero, + is_index_masked=is_index_masked, + ) + + # get only non zero global attn output + nonzero_global_attn_output = global_attn_output[ + is_local_index_global_attn_nonzero[0], :, is_local_index_global_attn_nonzero[1] + ] + + # overwrite values with global attention + attn_output[is_index_global_attn_nonzero[::-1]] = nonzero_global_attn_output.view( + len(is_local_index_global_attn_nonzero[0]), -1 + ) + # The attention weights for tokens with global attention are + # just filler values, they were never used to compute the output. + # Fill with 0 now, the correct values are in 'global_attn_probs'. + attn_probs[is_index_global_attn_nonzero] = 0 + + outputs = (attn_output.transpose(0, 1),) + + if output_attentions: + outputs += (attn_probs,) + + return outputs + (global_attn_probs,) if (is_global_attn and output_attentions) else outputs + + @staticmethod + def _pad_and_transpose_last_two_dims(hidden_states_padded, padding): + """pads rows and then flips rows and columns""" + hidden_states_padded = nn.functional.pad( + hidden_states_padded, padding + ) # padding value is not important because it will be overwritten + hidden_states_padded = hidden_states_padded.view( + *hidden_states_padded.size()[:-2], hidden_states_padded.size(-1), hidden_states_padded.size(-2) + ) + return hidden_states_padded + + @staticmethod + def _pad_and_diagonalize(chunked_hidden_states): + """ + shift every row 1 step right, converting columns into diagonals. + + Example: + + ```python + chunked_hidden_states: [ + 0.4983, + 2.6918, + -0.0071, + 1.0492, + -1.8348, + 0.7672, + 0.2986, + 0.0285, + -0.7584, + 0.4206, + -0.0405, + 0.1599, + 2.0514, + -1.1600, + 0.5372, + 0.2629, + ] + window_overlap = num_rows = 4 + ``` + + (pad & diagonalize) => [ 0.4983, 2.6918, -0.0071, 1.0492, 0.0000, 0.0000, 0.0000 + 0.0000, -1.8348, 0.7672, 0.2986, 0.0285, 0.0000, 0.0000 0.0000, 0.0000, -0.7584, 0.4206, + -0.0405, 0.1599, 0.0000 0.0000, 0.0000, 0.0000, 2.0514, -1.1600, 0.5372, 0.2629 ] + """ + total_num_heads, num_chunks, window_overlap, hidden_dim = chunked_hidden_states.size() + chunked_hidden_states = nn.functional.pad( + chunked_hidden_states, (0, window_overlap + 1) + ) # total_num_heads x num_chunks x window_overlap x (hidden_dim+window_overlap+1). Padding value is not important because it'll be overwritten + chunked_hidden_states = chunked_hidden_states.view( + total_num_heads, num_chunks, -1 + ) # total_num_heads x num_chunks x window_overlap*window_overlap+window_overlap + chunked_hidden_states = chunked_hidden_states[ + :, :, :-window_overlap + ] # total_num_heads x num_chunks x window_overlap*window_overlap + chunked_hidden_states = chunked_hidden_states.view( + total_num_heads, num_chunks, window_overlap, window_overlap + hidden_dim + ) + chunked_hidden_states = chunked_hidden_states[:, :, :, :-1] + return chunked_hidden_states + + @staticmethod + def _chunk(hidden_states, window_overlap, onnx_export: bool = False): + """convert into overlapping chunks. Chunk size = 2w, overlap size = w""" + if not onnx_export: + # non-overlapping chunks of size = 2w + hidden_states = hidden_states.view( + hidden_states.size(0), + torch.div(hidden_states.size(1), (window_overlap * 2), rounding_mode="trunc"), + window_overlap * 2, + hidden_states.size(2), + ) + # use `as_strided` to make the chunks overlap with an overlap size = window_overlap + chunk_size = list(hidden_states.size()) + chunk_size[1] = chunk_size[1] * 2 - 1 + + chunk_stride = list(hidden_states.stride()) + chunk_stride[1] = chunk_stride[1] // 2 + return hidden_states.as_strided(size=chunk_size, stride=chunk_stride) + + # When exporting to ONNX, use this separate logic + # have to use slow implementation since as_strided, unfold and 2d-tensor indexing aren't supported (yet) in ONNX export + + # TODO replace this with + # > return hidden_states.unfold(dimension=1, size=window_overlap * 2, step=window_overlap).transpose(2, 3) + # once `unfold` is supported + # the case hidden_states.size(1) == window_overlap * 2 can also simply return hidden_states.unsqueeze(1), but that's control flow + + chunk_size = [ + hidden_states.size(0), + torch.div(hidden_states.size(1), window_overlap, rounding_mode="trunc") - 1, + window_overlap * 2, + hidden_states.size(2), + ] + + overlapping_chunks = torch.empty(chunk_size, device=hidden_states.device) + for chunk in range(chunk_size[1]): + overlapping_chunks[:, chunk, :, :] = hidden_states[ + :, chunk * window_overlap : chunk * window_overlap + 2 * window_overlap, : + ] + return overlapping_chunks + + @staticmethod + def _mask_invalid_locations(input_tensor, affected_seq_len) -> torch.Tensor: + beginning_mask_2d = input_tensor.new_ones(affected_seq_len, affected_seq_len + 1).tril().flip(dims=[0]) + beginning_mask = beginning_mask_2d[None, :, None, :] + ending_mask = beginning_mask.flip(dims=(1, 3)) + beginning_input = input_tensor[:, :affected_seq_len, :, : affected_seq_len + 1] + beginning_mask = beginning_mask.expand(beginning_input.size()) + input_tensor[:, :affected_seq_len, :, : affected_seq_len + 1] = torch.full_like( + beginning_input, -float("inf") + ).where(beginning_mask.bool(), beginning_input) + ending_input = input_tensor[:, -affected_seq_len:, :, -(affected_seq_len + 1) :] + ending_mask = ending_mask.expand(ending_input.size()) + input_tensor[:, -affected_seq_len:, :, -(affected_seq_len + 1) :] = torch.full_like( + ending_input, -float("inf") + ).where(ending_mask.bool(), ending_input) + + def _sliding_chunks_query_key_matmul(self, query: torch.Tensor, key: torch.Tensor, window_overlap: int): + """ + Matrix multiplication of query and key tensors using with a sliding window attention pattern. This + implementation splits the input into overlapping chunks of size 2w (e.g. 512 for pretrained LEDEncoder) with an + overlap of size window_overlap + """ + batch_size, seq_len, num_heads, head_dim = query.size() + assert ( + seq_len % (window_overlap * 2) == 0 + ), f"Sequence length should be multiple of {window_overlap * 2}. Given {seq_len}" + assert query.size() == key.size() + + chunks_count = torch.div(seq_len, window_overlap, rounding_mode="trunc") - 1 + + # group batch_size and num_heads dimensions into one, then chunk seq_len into chunks of size window_overlap * 2 + query = query.transpose(1, 2).reshape(batch_size * num_heads, seq_len, head_dim) + key = key.transpose(1, 2).reshape(batch_size * num_heads, seq_len, head_dim) + + query = self._chunk(query, window_overlap, getattr(self.config, "onnx_export", False)) + key = self._chunk(key, window_overlap, getattr(self.config, "onnx_export", False)) + + # matrix multiplication + # bcxd: batch_size * num_heads x chunks x 2window_overlap x head_dim + # bcyd: batch_size * num_heads x chunks x 2window_overlap x head_dim + # bcxy: batch_size * num_heads x chunks x 2window_overlap x 2window_overlap + diagonal_chunked_attention_scores = torch.einsum("bcxd,bcyd->bcxy", (query, key)) # multiply + + # convert diagonals into columns + diagonal_chunked_attention_scores = self._pad_and_transpose_last_two_dims( + diagonal_chunked_attention_scores, padding=(0, 0, 0, 1) + ) + + # allocate space for the overall attention matrix where the chunks are combined. The last dimension + # has (window_overlap * 2 + 1) columns. The first (window_overlap) columns are the window_overlap lower triangles (attention from a word to + # window_overlap previous words). The following column is attention score from each word to itself, then + # followed by window_overlap columns for the upper triangle. + + diagonal_attention_scores = diagonal_chunked_attention_scores.new_zeros( + (batch_size * num_heads, chunks_count + 1, window_overlap, window_overlap * 2 + 1) + ) + + # copy parts from diagonal_chunked_attention_scores into the combined matrix of attentions + # - copying the main diagonal and the upper triangle + diagonal_attention_scores[:, :-1, :, window_overlap:] = diagonal_chunked_attention_scores[ + :, :, :window_overlap, : window_overlap + 1 + ] + diagonal_attention_scores[:, -1, :, window_overlap:] = diagonal_chunked_attention_scores[ + :, -1, window_overlap:, : window_overlap + 1 + ] + # - copying the lower triangle + diagonal_attention_scores[:, 1:, :, :window_overlap] = diagonal_chunked_attention_scores[ + :, :, -(window_overlap + 1) : -1, window_overlap + 1 : + ] + + diagonal_attention_scores[:, 0, 1:window_overlap, 1:window_overlap] = diagonal_chunked_attention_scores[ + :, 0, : window_overlap - 1, 1 - window_overlap : + ] + + # separate batch_size and num_heads dimensions again + diagonal_attention_scores = diagonal_attention_scores.view( + batch_size, num_heads, seq_len, 2 * window_overlap + 1 + ).transpose(2, 1) + + self._mask_invalid_locations(diagonal_attention_scores, window_overlap) + return diagonal_attention_scores + + def _sliding_chunks_matmul_attn_probs_value( + self, attn_probs: torch.Tensor, value: torch.Tensor, window_overlap: int + ): + """ + Same as _sliding_chunks_query_key_matmul but for attn_probs and value tensors. Returned tensor will be of the + same shape as `attn_probs` + """ + batch_size, seq_len, num_heads, head_dim = value.size() + + assert seq_len % (window_overlap * 2) == 0 + assert attn_probs.size()[:3] == value.size()[:3] + assert attn_probs.size(3) == 2 * window_overlap + 1 + chunks_count = torch.div(seq_len, window_overlap, rounding_mode="trunc") - 1 + # group batch_size and num_heads dimensions into one, then chunk seq_len into chunks of size 2 window overlap + + chunked_attn_probs = attn_probs.transpose(1, 2).reshape( + batch_size * num_heads, + torch.div(seq_len, window_overlap, rounding_mode="trunc"), + window_overlap, + 2 * window_overlap + 1, + ) + + # group batch_size and num_heads dimensions into one + value = value.transpose(1, 2).reshape(batch_size * num_heads, seq_len, head_dim) + + # pad seq_len with w at the beginning of the sequence and another window overlap at the end + padded_value = nn.functional.pad(value, (0, 0, window_overlap, window_overlap), value=-1) + + # chunk padded_value into chunks of size 3 window overlap and an overlap of size window overlap + chunked_value_size = (batch_size * num_heads, chunks_count + 1, 3 * window_overlap, head_dim) + chunked_value_stride = padded_value.stride() + chunked_value_stride = ( + chunked_value_stride[0], + window_overlap * chunked_value_stride[1], + chunked_value_stride[1], + chunked_value_stride[2], + ) + chunked_value = padded_value.as_strided(size=chunked_value_size, stride=chunked_value_stride) + + chunked_attn_probs = self._pad_and_diagonalize(chunked_attn_probs) + + context = torch.einsum("bcwd,bcdh->bcwh", (chunked_attn_probs, chunked_value)) + return context.view(batch_size, num_heads, seq_len, head_dim).transpose(1, 2) + + @staticmethod + def _get_global_attn_indices(is_index_global_attn): + """compute global attn indices required throughout forward pass""" + # helper variable + num_global_attn_indices = is_index_global_attn.long().sum(dim=1) + + # max number of global attn indices in batch + max_num_global_attn_indices = num_global_attn_indices.max() + + # indices of global attn + is_index_global_attn_nonzero = is_index_global_attn.nonzero(as_tuple=True) + + # helper variable + is_local_index_global_attn = torch.arange( + max_num_global_attn_indices, device=is_index_global_attn.device + ) < num_global_attn_indices.unsqueeze(dim=-1) + + # location of the non-padding values within global attention indices + is_local_index_global_attn_nonzero = is_local_index_global_attn.nonzero(as_tuple=True) + + # location of the padding values within global attention indices + is_local_index_no_global_attn_nonzero = (is_local_index_global_attn == 0).nonzero(as_tuple=True) + return ( + max_num_global_attn_indices, + is_index_global_attn_nonzero, + is_local_index_global_attn_nonzero, + is_local_index_no_global_attn_nonzero, + ) + + def _concat_with_global_key_attn_probs( + self, + key_vectors, + query_vectors, + max_num_global_attn_indices, + is_index_global_attn_nonzero, + is_local_index_global_attn_nonzero, + is_local_index_no_global_attn_nonzero, + ): + batch_size = key_vectors.shape[0] + + # create only global key vectors + key_vectors_only_global = key_vectors.new_zeros( + batch_size, max_num_global_attn_indices, self.num_heads, self.head_dim + ) + + key_vectors_only_global[is_local_index_global_attn_nonzero] = key_vectors[is_index_global_attn_nonzero] + + # (batch_size, seq_len, num_heads, max_num_global_attn_indices) + attn_probs_from_global_key = torch.einsum("blhd,bshd->blhs", (query_vectors, key_vectors_only_global)) + + # need to transpose since ONNX export only supports consecutive indexing: https://pytorch.org/docs/stable/onnx.html#writes-sets + attn_probs_from_global_key = attn_probs_from_global_key.transpose(1, 3) + attn_probs_from_global_key[ + is_local_index_no_global_attn_nonzero[0], is_local_index_no_global_attn_nonzero[1], :, : + ] = torch.finfo(attn_probs_from_global_key.dtype).min + attn_probs_from_global_key = attn_probs_from_global_key.transpose(1, 3) + + return attn_probs_from_global_key + + def _compute_attn_output_with_global_indices( + self, + value_vectors, + attn_probs, + max_num_global_attn_indices, + is_index_global_attn_nonzero, + is_local_index_global_attn_nonzero, + ): + batch_size = attn_probs.shape[0] + + # cut local attn probs to global only + attn_probs_only_global = attn_probs.narrow(-1, 0, max_num_global_attn_indices) + # get value vectors for global only + value_vectors_only_global = value_vectors.new_zeros( + batch_size, max_num_global_attn_indices, self.num_heads, self.head_dim + ) + value_vectors_only_global[is_local_index_global_attn_nonzero] = value_vectors[is_index_global_attn_nonzero] + + # use `matmul` because `einsum` crashes sometimes with fp16 + # attn = torch.einsum('blhs,bshd->blhd', (selected_attn_probs, selected_v)) + # compute attn output only global + attn_output_only_global = torch.matmul( + attn_probs_only_global.transpose(1, 2).clone(), value_vectors_only_global.transpose(1, 2).clone() + ).transpose(1, 2) + + # reshape attn probs + attn_probs_without_global = attn_probs.narrow( + -1, max_num_global_attn_indices, attn_probs.size(-1) - max_num_global_attn_indices + ).contiguous() + + # compute attn output with global + attn_output_without_global = self._sliding_chunks_matmul_attn_probs_value( + attn_probs_without_global, value_vectors, self.one_sided_attn_window_size + ) + return attn_output_only_global + attn_output_without_global + + def _compute_global_attn_output_from_hidden( + self, + hidden_states, + max_num_global_attn_indices, + layer_head_mask, + is_local_index_global_attn_nonzero, + is_index_global_attn_nonzero, + is_local_index_no_global_attn_nonzero, + is_index_masked, + ): + seq_len, batch_size = hidden_states.shape[:2] + + # prepare global hidden states + global_attn_hidden_states = hidden_states.new_zeros(max_num_global_attn_indices, batch_size, self.embed_dim) + global_attn_hidden_states[is_local_index_global_attn_nonzero[::-1]] = hidden_states[ + is_index_global_attn_nonzero[::-1] + ] + + # global key, query, value + global_query_vectors_only_global = self.query_global(global_attn_hidden_states) + global_key_vectors = self.key_global(hidden_states) + global_value_vectors = self.value_global(hidden_states) + + # normalize + global_query_vectors_only_global /= math.sqrt(self.head_dim) + + # reshape + global_query_vectors_only_global = ( + global_query_vectors_only_global.contiguous() + .view(max_num_global_attn_indices, batch_size * self.num_heads, self.head_dim) + .transpose(0, 1) + ) # (batch_size * self.num_heads, max_num_global_attn_indices, head_dim) + global_key_vectors = ( + global_key_vectors.contiguous().view(-1, batch_size * self.num_heads, self.head_dim).transpose(0, 1) + ) # batch_size * self.num_heads, seq_len, head_dim) + global_value_vectors = ( + global_value_vectors.contiguous().view(-1, batch_size * self.num_heads, self.head_dim).transpose(0, 1) + ) # batch_size * self.num_heads, seq_len, head_dim) + + # compute attn scores + global_attn_scores = torch.bmm(global_query_vectors_only_global, global_key_vectors.transpose(1, 2)) + + assert list(global_attn_scores.size()) == [ + batch_size * self.num_heads, + max_num_global_attn_indices, + seq_len, + ], ( + "global_attn_scores have the wrong size. Size should be" + f" {(batch_size * self.num_heads, max_num_global_attn_indices, seq_len)}, but is" + f" {global_attn_scores.size()}." + ) + + global_attn_scores = global_attn_scores.view(batch_size, self.num_heads, max_num_global_attn_indices, seq_len) + + # need to transpose since ONNX export only supports consecutive indexing: https://pytorch.org/docs/stable/onnx.html#writes-sets + global_attn_scores = global_attn_scores.transpose(1, 2) + global_attn_scores[ + is_local_index_no_global_attn_nonzero[0], is_local_index_no_global_attn_nonzero[1], :, : + ] = torch.finfo(global_attn_scores.dtype).min + global_attn_scores = global_attn_scores.transpose(1, 2) + + global_attn_scores = global_attn_scores.masked_fill( + is_index_masked[:, None, None, :], + torch.finfo(global_attn_scores.dtype).min, + ) + + global_attn_scores = global_attn_scores.view(batch_size * self.num_heads, max_num_global_attn_indices, seq_len) + + # compute global attn probs + global_attn_probs_float = nn.functional.softmax( + global_attn_scores, dim=-1, dtype=torch.float32 + ) # use fp32 for numerical stability + + # apply layer head masking + if layer_head_mask is not None: + assert layer_head_mask.size() == ( + self.num_heads, + ), f"Head mask for a single layer should be of size {(self.num_heads,)}, but is {layer_head_mask.size()}" + global_attn_probs_float = layer_head_mask.view(1, -1, 1, 1) * global_attn_probs_float.view( + batch_size, self.num_heads, max_num_global_attn_indices, seq_len + ) + global_attn_probs_float = global_attn_probs_float.view( + batch_size * self.num_heads, max_num_global_attn_indices, seq_len + ) + + global_attn_probs = nn.functional.dropout( + global_attn_probs_float.type_as(global_attn_scores), p=self.dropout, training=self.training + ) + + # global attn output + global_attn_output = torch.bmm(global_attn_probs, global_value_vectors) + + assert list(global_attn_output.size()) == [ + batch_size * self.num_heads, + max_num_global_attn_indices, + self.head_dim, + ], ( + "global_attn_output tensor has the wrong size. Size should be" + f" {(batch_size * self.num_heads, max_num_global_attn_indices, self.head_dim)}, but is" + f" {global_attn_output.size()}." + ) + + global_attn_probs = global_attn_probs.view(batch_size, self.num_heads, max_num_global_attn_indices, seq_len) + global_attn_output = global_attn_output.view( + batch_size, self.num_heads, max_num_global_attn_indices, self.head_dim + ) + return global_attn_output, global_attn_probs + + +class LEDEncoderAttention(nn.Module): + def __init__(self, config, layer_id): + super().__init__() + self.longformer_self_attn = LEDEncoderSelfAttention(config, layer_id=layer_id) + self.output = nn.Linear(config.d_model, config.d_model) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.Tensor] = None, + layer_head_mask: Optional[torch.Tensor] = None, + is_index_masked: Optional[torch.Tensor] = None, + is_index_global_attn: Optional[torch.Tensor] = None, + is_global_attn: Optional[bool] = None, + output_attentions: bool = False, + ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]: + """Input shape: Batch x Time x Channel""" + + self_outputs = self.longformer_self_attn( + hidden_states=hidden_states, + attention_mask=attention_mask, + layer_head_mask=layer_head_mask, + is_index_masked=is_index_masked, + is_index_global_attn=is_index_global_attn, + is_global_attn=is_global_attn, + output_attentions=output_attentions, + ) + + attn_output = self.output(self_outputs[0]) + outputs = (attn_output,) + self_outputs[1:] + + return outputs + + +class LEDDecoderAttention(nn.Module): + """Multi-headed attention from 'Attention Is All You Need' paper""" + + def __init__( + self, + embed_dim: int, + num_heads: int, + dropout: float = 0.0, + is_decoder: bool = False, + bias: bool = True, + ): + super().__init__() + self.embed_dim = embed_dim + self.num_heads = num_heads + self.dropout = dropout + self.head_dim = embed_dim // num_heads + if self.head_dim * num_heads != self.embed_dim: + raise ValueError( + f"embed_dim must be divisible by num_heads (got `embed_dim`: {self.embed_dim} and `num_heads`:" + f" {num_heads})." + ) + self.scaling = self.head_dim**-0.5 + self.is_decoder = is_decoder + + self.k_proj = nn.Linear(embed_dim, embed_dim, bias=bias) + self.v_proj = nn.Linear(embed_dim, embed_dim, bias=bias) + self.q_proj = nn.Linear(embed_dim, embed_dim, bias=bias) + self.out_proj = nn.Linear(embed_dim, embed_dim, bias=bias) + + def _shape(self, tensor: torch.Tensor, seq_len: int, bsz: int): + return tensor.view(bsz, seq_len, self.num_heads, self.head_dim).transpose(1, 2).contiguous() + + def forward( + self, + hidden_states: torch.Tensor, + key_value_states: Optional[torch.Tensor] = None, + past_key_value: Optional[Tuple[torch.Tensor]] = None, + attention_mask: Optional[torch.Tensor] = None, + layer_head_mask: Optional[torch.Tensor] = None, + output_attentions: bool = False, + ) -> Tuple[torch.Tensor, Optional[torch.Tensor], Optional[Tuple[torch.Tensor]]]: + """Input shape: Batch x Time x Channel""" + + # if key_value_states are provided this layer is used as a cross-attention layer + # for the decoder + is_cross_attention = key_value_states is not None + bsz, tgt_len, embed_dim = hidden_states.size() + + # get query proj + query_states = self.q_proj(hidden_states) * self.scaling + # get key, value proj + if is_cross_attention and past_key_value is not None: + # reuse k,v, cross_attentions + key_states = past_key_value[0] + value_states = past_key_value[1] + elif is_cross_attention: + # cross_attentions + key_states = self._shape(self.k_proj(key_value_states), -1, bsz) + value_states = self._shape(self.v_proj(key_value_states), -1, bsz) + elif past_key_value is not None: + # reuse k, v, self_attention + key_states = self._shape(self.k_proj(hidden_states), -1, bsz) + value_states = self._shape(self.v_proj(hidden_states), -1, bsz) + key_states = torch.cat([past_key_value[0], key_states], dim=2) + value_states = torch.cat([past_key_value[1], value_states], dim=2) + else: + # self_attention + key_states = self._shape(self.k_proj(hidden_states), -1, bsz) + value_states = self._shape(self.v_proj(hidden_states), -1, bsz) + + if self.is_decoder: + # if cross_attention save Tuple(torch.Tensor, torch.Tensor) of all cross attention key/value_states. + # Further calls to cross_attention layer can then reuse all cross-attention + # key/value_states (first "if" case) + # if uni-directional self-attention (decoder) save Tuple(torch.Tensor, torch.Tensor) of + # all previous decoder key/value_states. Further calls to uni-directional self-attention + # can concat previous decoder key/value_states to current projected key/value_states (third "elif" case) + # if encoder bi-directional self-attention `past_key_value` is always `None` + past_key_value = (key_states, value_states) + + proj_shape = (bsz * self.num_heads, -1, self.head_dim) + query_states = self._shape(query_states, tgt_len, bsz).view(*proj_shape) + key_states = key_states.view(*proj_shape) + value_states = value_states.view(*proj_shape) + + src_len = key_states.size(1) + attn_weights = torch.bmm(query_states, key_states.transpose(1, 2)) + + if attn_weights.size() != (bsz * self.num_heads, tgt_len, src_len): + raise ValueError( + f"Attention weights should be of size {(bsz * self.num_heads, tgt_len, src_len)}, but is" + f" {attn_weights.size()}" + ) + + if attention_mask is not None: + if attention_mask.size() != (bsz, 1, tgt_len, src_len): + raise ValueError( + f"Attention mask should be of size {(bsz, 1, tgt_len, src_len)}, but is {attention_mask.size()}" + ) + attn_weights = attn_weights.view(bsz, self.num_heads, tgt_len, src_len) + attention_mask + attn_weights = attn_weights.view(bsz * self.num_heads, tgt_len, src_len) + + attn_weights = nn.functional.softmax(attn_weights, dim=-1) + if layer_head_mask is not None: + if layer_head_mask.size() != (self.num_heads,): + raise ValueError( + f"Head mask for a single layer should be of size {(self.num_heads,)}, but is" + f" {layer_head_mask.size()}" + ) + attn_weights = layer_head_mask.view(1, -1, 1, 1) * attn_weights.view(bsz, self.num_heads, tgt_len, src_len) + attn_weights = attn_weights.view(bsz * self.num_heads, tgt_len, src_len) + + if output_attentions: + # this operation is a bit awkward, but it's required to + # make sure that attn_weights keeps its gradient. + # In order to do so, attn_weights have to be reshaped + # twice and have to be reused in the following + attn_weights_reshaped = attn_weights.view(bsz, self.num_heads, tgt_len, src_len) + attn_weights = attn_weights_reshaped.view(bsz * self.num_heads, tgt_len, src_len) + else: + attn_weights_reshaped = None + + attn_probs = nn.functional.dropout(attn_weights, p=self.dropout, training=self.training) + + attn_output = torch.bmm(attn_probs, value_states) + + if attn_output.size() != (bsz * self.num_heads, tgt_len, self.head_dim): + raise ValueError( + f"`attn_output` should be of size {(bsz, self.num_heads, tgt_len, self.head_dim)}, but is" + f" {attn_output.size()}" + ) + + attn_output = ( + attn_output.view(bsz, self.num_heads, tgt_len, self.head_dim) + .transpose(1, 2) + .reshape(bsz, tgt_len, embed_dim) + ) + + attn_output = self.out_proj(attn_output) + + return attn_output, attn_weights_reshaped, past_key_value + + +class LEDEncoderLayer(nn.Module): + def __init__(self, config: LEDConfig, layer_id: int): + super().__init__() + self.embed_dim = config.d_model + self.self_attn = LEDEncoderAttention(config, layer_id) + self.self_attn_layer_norm = nn.LayerNorm(self.embed_dim) + self.dropout = config.dropout + self.activation_fn = ACT2FN[config.activation_function] + self.activation_dropout = config.activation_dropout + self.fc1 = nn.Linear(self.embed_dim, config.encoder_ffn_dim) + self.fc2 = nn.Linear(config.encoder_ffn_dim, self.embed_dim) + self.final_layer_norm = nn.LayerNorm(self.embed_dim) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: torch.Tensor, + layer_head_mask: torch.Tensor, + is_index_masked=None, + is_index_global_attn=None, + is_global_attn=None, + output_attentions=False, + ): + """ + Args: + hidden_states (`torch.FloatTensor`): input to the layer of shape *(batch, seq_len, embed_dim)* + attention_mask (`torch.FloatTensor`): attention mask of size + *(batch, 1, tgt_len, src_len)* where padding elements are indicated by very large negative values. + layer_head_mask (`torch.FloatTensor`): mask for attention heads in a given layer of size + *(encoder_attention_heads,)*. + """ + residual = hidden_states + attn_outputs = self.self_attn( + hidden_states=hidden_states, + attention_mask=attention_mask, + layer_head_mask=layer_head_mask, + is_index_masked=is_index_masked, + is_index_global_attn=is_index_global_attn, + is_global_attn=is_global_attn, + output_attentions=output_attentions, + ) + hidden_states = attn_outputs[0] + hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) + hidden_states = residual + hidden_states + hidden_states = self.self_attn_layer_norm(hidden_states) + + residual = hidden_states + hidden_states = self.activation_fn(self.fc1(hidden_states)) + hidden_states = nn.functional.dropout(hidden_states, p=self.activation_dropout, training=self.training) + hidden_states = self.fc2(hidden_states) + hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) + hidden_states = residual + hidden_states + hidden_states = self.final_layer_norm(hidden_states) + + if hidden_states.dtype == torch.float16 and ( + torch.isinf(hidden_states).any() or torch.isnan(hidden_states).any() + ): + clamp_value = torch.finfo(hidden_states.dtype).max - 1000 + hidden_states = torch.clamp(hidden_states, min=-clamp_value, max=clamp_value) + return (hidden_states,) + attn_outputs[1:] + + +class LEDDecoderLayer(nn.Module): + def __init__(self, config: LEDConfig): + super().__init__() + self.embed_dim = config.d_model + + self.self_attn = LEDDecoderAttention( + embed_dim=self.embed_dim, + num_heads=config.decoder_attention_heads, + dropout=config.attention_dropout, + is_decoder=True, + ) + self.dropout = config.dropout + self.activation_fn = ACT2FN[config.activation_function] + self.activation_dropout = config.activation_dropout + + self.self_attn_layer_norm = nn.LayerNorm(self.embed_dim) + self.encoder_attn = LEDDecoderAttention( + self.embed_dim, + config.decoder_attention_heads, + dropout=config.attention_dropout, + is_decoder=True, + ) + self.encoder_attn_layer_norm = nn.LayerNorm(self.embed_dim) + self.fc1 = nn.Linear(self.embed_dim, config.decoder_ffn_dim) + self.fc2 = nn.Linear(config.decoder_ffn_dim, self.embed_dim) + self.final_layer_norm = nn.LayerNorm(self.embed_dim) + + def forward( + self, + hidden_states: torch.Tensor, + attention_mask: Optional[torch.Tensor] = None, + encoder_hidden_states: Optional[torch.Tensor] = None, + encoder_attention_mask: Optional[torch.Tensor] = None, + layer_head_mask: Optional[torch.Tensor] = None, + cross_attn_layer_head_mask: Optional[torch.Tensor] = None, + past_key_value: Optional[Tuple[torch.Tensor]] = None, + output_attentions: Optional[bool] = False, + use_cache: Optional[bool] = True, + ): + """ + Args: + hidden_states (`torch.FloatTensor`): input to the layer of shape *(batch, seq_len, embed_dim)* + attention_mask (`torch.FloatTensor`): attention mask of size + *(batch, 1, tgt_len, src_len)* where padding elements are indicated by very large negative values. + encoder_hidden_states (`torch.FloatTensor`): + cross attention input to the layer of shape *(batch, seq_len, embed_dim)* + encoder_attention_mask (`torch.FloatTensor`): encoder attention mask of size + *(batch, 1, tgt_len, src_len)* where padding elements are indicated by very large negative values. + layer_head_mask (`torch.FloatTensor`): mask for attention heads in a given layer of size + *(decoder_attention_heads,)*. + cross_attn_layer_head_mask (`torch.FloatTensor`): mask for encoder attention heads in a given layer of + size *(decoder_attention_heads,)*. + past_key_value (`Tuple(torch.FloatTensor)`): cached past key and value projection states + output_attentions (`bool`): Whether the base model outputs attentions. + This requires the attentions tensor to be reshaped in this function. + """ + residual = hidden_states + + # Self-Attention + # decoder uni-directional self-attention cached key/values tuple is at positions 1,2 + self_attn_past_key_value = past_key_value[:2] if past_key_value is not None else None + # add present self-attn cache to positions 1,2 of present_key_value tuple + hidden_states, self_attn_weights, present_key_value = self.self_attn( + hidden_states=hidden_states, + past_key_value=self_attn_past_key_value, + attention_mask=attention_mask, + layer_head_mask=layer_head_mask, + output_attentions=output_attentions, + ) + hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) + hidden_states = residual + hidden_states + hidden_states = self.self_attn_layer_norm(hidden_states) + + # Cross-Attention Block + cross_attn_present_key_value = None + cross_attn_weights = None + if encoder_hidden_states is not None: + residual = hidden_states + + # cross_attn cached key/values tuple is at positions 3,4 of present_key_value tuple + cross_attn_past_key_value = past_key_value[-2:] if past_key_value is not None else None + hidden_states, cross_attn_weights, cross_attn_present_key_value = self.encoder_attn( + hidden_states=hidden_states, + key_value_states=encoder_hidden_states, + attention_mask=encoder_attention_mask, + layer_head_mask=cross_attn_layer_head_mask, + past_key_value=cross_attn_past_key_value, + output_attentions=output_attentions, + ) + hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) + hidden_states = residual + hidden_states + hidden_states = self.encoder_attn_layer_norm(hidden_states) + + # add cross-attn to positions 3,4 of present_key_value tuple + present_key_value = present_key_value + cross_attn_present_key_value + + # Fully Connected + residual = hidden_states + hidden_states = self.activation_fn(self.fc1(hidden_states)) + hidden_states = nn.functional.dropout(hidden_states, p=self.activation_dropout, training=self.training) + hidden_states = self.fc2(hidden_states) + hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) + hidden_states = residual + hidden_states + hidden_states = self.final_layer_norm(hidden_states) + + outputs = (hidden_states,) + + if output_attentions: + outputs += (self_attn_weights, cross_attn_weights) + + if use_cache: + outputs += (present_key_value,) + + return outputs + + +class LEDClassificationHead(nn.Module): + """Head for sentence-level classification tasks.""" + + def __init__( + self, + input_dim: int, + inner_dim: int, + num_classes: int, + pooler_dropout: float, + ): + super().__init__() + self.dense = nn.Linear(input_dim, inner_dim) + self.dropout = nn.Dropout(p=pooler_dropout) + self.out_proj = nn.Linear(inner_dim, num_classes) + + def forward(self, hidden_states: torch.Tensor): + hidden_states = self.dropout(hidden_states) + hidden_states = self.dense(hidden_states) + hidden_states = torch.tanh(hidden_states) + hidden_states = self.dropout(hidden_states) + hidden_states = self.out_proj(hidden_states) + return hidden_states + + +class LEDPreTrainedModel(PreTrainedModel): + config_class = LEDConfig + base_model_prefix = "led" + supports_gradient_checkpointing = True + + def _init_weights(self, module): + std = self.config.init_std + if isinstance(module, nn.Linear): + module.weight.data.normal_(mean=0.0, std=std) + if module.bias is not None: + module.bias.data.zero_() + elif isinstance(module, nn.Embedding): + module.weight.data.normal_(mean=0.0, std=std) + if module.padding_idx is not None: + module.weight.data[module.padding_idx].zero_() + + @property + def dummy_inputs(self): + pad_token = self.config.pad_token_id + input_ids = torch.tensor([[0, 6, 10, 4, 2], [0, 8, 12, 2, pad_token]], device=self.device) + dummy_inputs = { + "attention_mask": input_ids.ne(pad_token), + "input_ids": input_ids, + } + return dummy_inputs + + +@dataclass +# Copied from transformers.models.longformer.modeling_longformer.LongformerBaseModelOutput with Longformer->LEDEncoder +class LEDEncoderBaseModelOutput(ModelOutput): + """ + Base class for LEDEncoder's outputs, with potential hidden states, local and global attentions. + + Args: + last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`): + Sequence of hidden-states at the output of the last layer of the model. + hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the model at the output of each layer plus the initial embedding outputs. + attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, x + + attention_window + 1)`, where `x` is the number of tokens with global attention mask. + + Local attentions weights after the attention softmax, used to compute the weighted average in the + self-attention heads. Those are the attention weights from every token in the sequence to every token with + global attention (first `x` values) and to every token in the attention window (remaining `attention_window + + 1` values). Note that the first `x` values refer to tokens with fixed positions in the text, but the + remaining `attention_window + 1` values refer to tokens with relative positions: the attention weight of a + token to itself is located at index `x + attention_window / 2` and the `attention_window / 2` preceding + (succeeding) values are the attention weights to the `attention_window / 2` preceding (succeeding) tokens. + If the attention window contains a token with global attention, the attention weight at the corresponding + index is set to 0; the value should be accessed from the first `x` attention weights. If a token has global + attention, the attention weights to all other tokens in `attentions` is set to 0, the values should be + accessed from `global_attentions`. + global_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, x)`, + where `x` is the number of tokens with global attention mask. + + Global attentions weights after the attention softmax, used to compute the weighted average in the + self-attention heads. Those are the attention weights from every token with global attention to every token + in the sequence. + """ + + last_hidden_state: torch.FloatTensor + hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + global_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + + +@dataclass +class LEDSeq2SeqModelOutput(ModelOutput): + """ + Base class for model encoder's outputs that also contains : pre-computed hidden states that can speed up sequential + decoding. + + Args: + last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`): + Sequence of hidden-states at the output of the last layer of the decoder of the model. + + If `past_key_values` is used only the last hidden-state of the sequences of shape `(batch_size, 1, + hidden_size)` is output. + past_key_values (`List[torch.FloatTensor]`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + List of `torch.FloatTensor` of length `config.n_layers`, with each tensor of shape `(2, batch_size, + num_heads, sequence_length, embed_size_per_head)`). + + Contains pre-computed hidden-states (key and values in the attention blocks) of the decoder that can be + used (see `past_key_values` input) to speed up sequential decoding. + decoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the decoder at the output of each layer plus the initial embedding outputs. + decoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder's cross-attention layer, after the attention softmax, used to compute the + weighted average in the cross-attention heads. + encoder_last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Sequence of hidden-states at the output of the last layer of the encoder of the model. + encoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the encoder at the output of each layer plus the initial embedding outputs. + encoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the encoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + encoder_global_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, x)`, + where `x` is the number of tokens with global attention mask. + + Global attentions weights after the attention softmax, used to compute the weighted average in the + self-attention heads. Those are the attention weights from every token with global attention to every token + in the sequence. + """ + + last_hidden_state: torch.FloatTensor = None + past_key_values: Optional[List[torch.FloatTensor]] = None + decoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + decoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + cross_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_last_hidden_state: Optional[torch.FloatTensor] = None + encoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_global_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + + +@dataclass +class LEDSeq2SeqLMOutput(ModelOutput): + """ + Base class for sequence-to-sequence language models outputs. + + Args: + loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided): + Language modeling loss. + logits (`torch.FloatTensor` of shape `(batch_size, sequence_length, config.vocab_size)`): + Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax). + past_key_values (`List[torch.FloatTensor]`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + List of `torch.FloatTensor` of length `config.n_layers`, with each tensor of shape `(2, batch_size, + num_heads, sequence_length, embed_size_per_head)`). + + Contains pre-computed hidden-states (key and values in the attention blocks) of the decoder that can be + used (see `past_key_values` input) to speed up sequential decoding. + decoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the decoder at the output of each layer plus the initial embedding outputs. + decoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder's cross-attention layer, after the attention softmax, used to compute the + weighted average in the cross-attention heads. + encoder_last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Sequence of hidden-states at the output of the last layer of the encoder of the model. + encoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the encoder at the output of each layer plus the initial embedding outputs. + encoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the encoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + encoder_global_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, x)`, + where `x` is the number of tokens with global attention mask. + + Global attentions weights after the attention softmax, used to compute the weighted average in the + self-attention heads. Those are the attention weights from every token with global attention to every token + in the sequence. + """ + + loss: Optional[torch.FloatTensor] = None + logits: torch.FloatTensor = None + past_key_values: Optional[List[torch.FloatTensor]] = None + decoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + decoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + cross_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_last_hidden_state: Optional[torch.FloatTensor] = None + encoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_global_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + + +@dataclass +class LEDSeq2SeqSequenceClassifierOutput(ModelOutput): + """ + Base class for outputs of sequence-to-sequence sentence classification models. + + Args: + loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `label` is provided): + Classification (or regression if config.num_labels==1) loss. + logits (`torch.FloatTensor` of shape `(batch_size, config.num_labels)`): + Classification (or regression if config.num_labels==1) scores (before SoftMax). + past_key_values (`List[torch.FloatTensor]`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + List of `torch.FloatTensor` of length `config.n_layers`, with each tensor of shape `(2, batch_size, + num_heads, sequence_length, embed_size_per_head)`). + + Contains pre-computed hidden-states (key and values in the attention blocks) of the decoder that can be + used (see `past_key_values` input) to speed up sequential decoding. + decoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the decoder at the output of each layer plus the initial embedding outputs. + decoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder's cross-attention layer, after the attention softmax, used to compute the + weighted average in the cross-attention heads. + encoder_last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Sequence of hidden-states at the output of the last layer of the encoder of the model. + encoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the encoder at the output of each layer plus the initial embedding outputs. + encoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the encoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + encoder_global_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, x)`, + where `x` is the number of tokens with global attention mask. + + Global attentions weights after the attention softmax, used to compute the weighted average in the + self-attention heads. Those are the attention weights from every token with global attention to every token + in the sequence. + """ + + loss: Optional[torch.FloatTensor] = None + logits: torch.FloatTensor = None + past_key_values: Optional[List[torch.FloatTensor]] = None + decoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + decoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + cross_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_last_hidden_state: Optional[torch.FloatTensor] = None + encoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_global_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + + +@dataclass +class LEDSeq2SeqQuestionAnsweringModelOutput(ModelOutput): + """ + Base class for outputs of sequence-to-sequence question answering models. + + Args: + loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided): + Total span extraction loss is the sum of a Cross-Entropy for the start and end positions. + start_logits (`torch.FloatTensor` of shape `(batch_size, sequence_length)`): + Span-start scores (before SoftMax). + end_logits (`torch.FloatTensor` of shape `(batch_size, sequence_length)`): + Span-end scores (before SoftMax). + past_key_values (`List[torch.FloatTensor]`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + List of `torch.FloatTensor` of length `config.n_layers`, with each tensor of shape `(2, batch_size, + num_heads, sequence_length, embed_size_per_head)`). + + Contains pre-computed hidden-states (key and values in the attention blocks) of the decoder that can be + used (see `past_key_values` input) to speed up sequential decoding. + decoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the decoder at the output of each layer plus the initial embedding outputs. + decoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + cross_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the decoder's cross-attention layer, after the attention softmax, used to compute the + weighted average in the cross-attention heads. + encoder_last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Sequence of hidden-states at the output of the last layer of the encoder of the model. + encoder_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`): + Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each layer) of + shape `(batch_size, sequence_length, hidden_size)`. + + Hidden-states of the encoder at the output of each layer plus the initial embedding outputs. + encoder_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, + sequence_length)`. + + Attentions weights of the encoder, after the attention softmax, used to compute the weighted average in the + self-attention heads. + encoder_global_attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`): + Tuple of `torch.FloatTensor` (one for each layer) of shape `(batch_size, num_heads, sequence_length, x)`, + where `x` is the number of tokens with global attention mask. + + Global attentions weights after the attention softmax, used to compute the weighted average in the + self-attention heads. Those are the attention weights from every token with global attention to every token + in the sequence. + """ + + loss: Optional[torch.FloatTensor] = None + start_logits: torch.FloatTensor = None + end_logits: torch.FloatTensor = None + past_key_values: Optional[List[torch.FloatTensor]] = None + decoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + decoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + cross_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_last_hidden_state: Optional[torch.FloatTensor] = None + encoder_hidden_states: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + encoder_global_attentions: Optional[Tuple[torch.FloatTensor, ...]] = None + + +LED_START_DOCSTRING = r""" + This model inherits from [`PreTrainedModel`]. See the superclass documentation for the generic methods the library + implements for all its models (such as downloading or saving, resizing the input embeddings, pruning heads etc.) + + This model is also a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) subclass. + Use it as a regular PyTorch Module and refer to the PyTorch documentation for general usage and behavior. + + Parameters: + config ([`LEDConfig`]): + Model configuration class with all the parameters of the model. Initializing with a config file does not + load the weights associated with the model, only the configuration. Check out the + [`~PreTrainedModel.from_pretrained`] method to load the model weights. +""" + +LED_GENERATION_EXAMPLE = r""" + Summarization example: + + ```python + >>> import torch + >>> from transformers import AutoTokenizer, LEDForConditionalGeneration + + >>> model = LEDForConditionalGeneration.from_pretrained("allenai/led-large-16384-arxiv") + >>> tokenizer = AutoTokenizer.from_pretrained("allenai/led-large-16384-arxiv") + + >>> ARTICLE_TO_SUMMARIZE = '''Transformers (Vaswani et al., 2017) have achieved state-of-the-art + ... results in a wide range of natural language tasks including generative language modeling + ... (Dai et al., 2019; Radford et al., 2019) and discriminative ... language understanding (Devlin et al., 2019). + ... This success is partly due to the self-attention component which enables the network to capture contextual + ... information from the entire sequence. While powerful, the memory and computational requirements of + ... self-attention grow quadratically with sequence length, making it infeasible (or very expensive) to + ... process long sequences. To address this limitation, we present Longformer, a modified Transformer + ... architecture with a self-attention operation that scales linearly with the sequence length, making it + ... versatile for processing long documents (Fig 1). This is an advantage for natural language tasks such as + ... long document classification, question answering (QA), and coreference resolution, where existing approaches + ... partition or shorten the long context into smaller sequences that fall within the typical 512 token limit + ... of BERT-style pretrained models. Such partitioning could potentially result in loss of important + ... cross-partition information, and to mitigate this problem, existing methods often rely on complex + ... architectures to address such interactions. On the other hand, our proposed Longformer is able to build + ... contextual representations of the entire context using multiple layers of attention, reducing the need for + ... task-specific architectures.''' + >>> inputs = tokenizer.encode(ARTICLE_TO_SUMMARIZE, return_tensors="pt") + + >>> # Global attention on the first token (cf. Beltagy et al. 2020) + >>> global_attention_mask = torch.zeros_like(inputs) + >>> global_attention_mask[:, 0] = 1 + + >>> # Generate Summary + >>> summary_ids = model.generate(inputs, global_attention_mask=global_attention_mask, num_beams=3, max_length=32) + >>> print(tokenizer.decode(summary_ids[0], skip_special_tokens=True, clean_up_tokenization_spaces=True)) + ``` +""" + +LED_INPUTS_DOCSTRING = r""" + Args: + input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`): + Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you provide + it. + + Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for details. + + [What are input IDs?](../glossary#input-ids) + attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`: + + - 1 for tokens that are **not masked**, + - 0 for tokens that are **masked**. + + [What are attention masks?](../glossary#attention-mask) + decoder_input_ids (`torch.LongTensor` of shape `(batch_size, target_sequence_length)`, *optional*): + Indices of decoder input sequence tokens in the vocabulary. + + Indices can be obtained using [`LedTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for details. + + [What are input IDs?](../glossary#input-ids) + + LED uses the `eos_token_id` as the starting token for `decoder_input_ids` generation. If `past_key_values` + is used, optionally only the last `decoder_input_ids` have to be input (see `past_key_values`). + decoder_attention_mask (`torch.LongTensor` of shape `(batch_size, target_sequence_length)`, *optional*): + Default behavior: generate a tensor that ignores pad tokens in `decoder_input_ids`. Causal mask will also + be used by default. + + If you want to change padding behavior, you should read [`modeling_led._prepare_decoder_inputs`] and modify + to your needs. See diagram 1 in [the paper](https://arxiv.org/abs/1910.13461) for more information on the + default strategy. + global_attention_mask (`torch.FloatTensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to decide the attention given on each token, local attention or global attention for the encoder. + Tokens with global attention attends to all other tokens, and all other tokens attend to them. This is + important for task-specific finetuning because it makes the model more flexible at representing the task. + For example, for classification, the token should be given global attention. For QA, all question + tokens should also have global attention. Please refer to the [Longformer + paper](https://arxiv.org/abs/2004.05150) for more details. Mask values selected in `[0, 1]`: + + - 0 for local attention (a sliding window attention), + - 1 for global attention (tokens that attend to all other tokens, and all other tokens attend to them). + head_mask (`torch.Tensor` of shape `(encoder_layers, encoder_attention_heads)`, *optional*): + Mask to nullify selected heads of the attention modules in the encoder. Mask values selected in `[0, 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + decoder_head_mask (`torch.Tensor` of shape `(decoder_layers, decoder_attention_heads)`, *optional*): + Mask to nullify selected heads of the attention modules in the decoder. Mask values selected in `[0, 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + cross_attn_head_mask (`torch.Tensor` of shape `(decoder_layers, decoder_attention_heads)`, *optional*): + Mask to nullify selected heads of the cross-attention modules in the decoder. Mask values selected in `[0, + 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + encoder_outputs (`tuple(tuple(torch.FloatTensor)`, *optional*): + Tuple consists of (`last_hidden_state`, *optional*: `hidden_states`, *optional*: `attentions`) + `last_hidden_state` of shape `(batch_size, sequence_length, hidden_size)`, *optional*) is a sequence of + hidden-states at the output of the last layer of the encoder. Used in the cross-attention of the decoder. + past_key_values (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of shape + `(batch_size, num_heads, sequence_length, embed_size_per_head)`) and 2 additional tensors of shape + `(batch_size, num_heads, encoder_sequence_length, embed_size_per_head)`. + + Contains pre-computed hidden-states (key and values in the self-attention blocks and in the cross-attention + blocks) that can be used (see `past_key_values` input) to speed up sequential decoding. + + If `past_key_values` are used, the user can optionally input only the last `decoder_input_ids` (those that + don't have their past key value states given to this model) of shape `(batch_size, 1)` instead of all + `decoder_input_ids` of shape `(batch_size, sequence_length)`. + inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This + is useful if you want more control over how to convert `input_ids` indices into associated vectors than the + model's internal embedding lookup matrix. + decoder_inputs_embeds (`torch.FloatTensor` of shape `(batch_size, target_sequence_length, hidden_size)`, *optional*): + Optionally, instead of passing `decoder_input_ids` you can choose to directly pass an embedded + representation. If `past_key_values` is used, optionally only the last `decoder_inputs_embeds` have to be + input (see `past_key_values`). This is useful if you want more control over how to convert + `decoder_input_ids` indices into associated vectors than the model's internal embedding lookup matrix. + + If `decoder_input_ids` and `decoder_inputs_embeds` are both unset, `decoder_inputs_embeds` takes the value + of `inputs_embeds`. + use_cache (`bool`, *optional*): + If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see + `past_key_values`). + output_attentions (`bool`, *optional*): + Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned + tensors for more detail. + output_hidden_states (`bool`, *optional*): + Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for + more detail. + return_dict (`bool`, *optional*): + Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. +""" + + +class LEDEncoder(LEDPreTrainedModel): + """ + Transformer encoder consisting of *config.encoder_layers* self-attention layers. Each layer is a + [`LEDEncoderLayer`]. + + Args: + config: LEDConfig + embed_tokens (nn.Embedding): output embedding + """ + + def __init__(self, config: LEDConfig, embed_tokens: Optional[nn.Embedding] = None): + super().__init__(config) + + self.dropout = config.dropout + self.layerdrop = config.encoder_layerdrop + + embed_dim = config.d_model + self.padding_idx = config.pad_token_id + self.max_source_positions = config.max_encoder_position_embeddings + + if isinstance(config.attention_window, int): + if config.attention_window % 2 != 0: + raise ValueError("`config.attention_window` has to be an even value") + if config.attention_window <= 0: + raise ValueError("`config.attention_window` has to be positive") + config.attention_window = [config.attention_window] * config.num_hidden_layers # one value per layer + else: + if len(config.attention_window) != config.num_hidden_layers: + raise ValueError( + "`len(config.attention_window)` should equal `config.num_hidden_layers`. " + f"Expected {config.num_hidden_layers}, given {len(config.attention_window)}" + ) + + if embed_tokens is not None: + self.embed_tokens = embed_tokens + else: + self.embed_tokens = nn.Embedding(config.vocab_size, embed_dim, self.padding_idx) + + self.embed_positions = LEDLearnedPositionalEmbedding( + self.max_source_positions, + embed_dim, + ) + self.layers = nn.ModuleList([LEDEncoderLayer(config, i) for i in range(config.encoder_layers)]) + self.layernorm_embedding = nn.LayerNorm(embed_dim) + + self.gradient_checkpointing = False + # Initialize weights and apply final processing + self.post_init() + + def _merge_to_attention_mask(self, attention_mask: torch.Tensor, global_attention_mask: torch.Tensor): + # longformer self-attention expects attention mask to have 0 (no attn), 1 (local attn), 2 (global attn) + # (global_attention_mask + 1) => 1 for local attention, 2 for global attention + # => final attention_mask => 0 for no attention, 1 for local attention 2 for global attention + if attention_mask is not None: + attention_mask = attention_mask * (global_attention_mask + 1) + else: + # simply use `global_attention_mask` as `attention_mask` + # if no `attention_mask` is given + attention_mask = global_attention_mask + 1 + return attention_mask + + def _pad_to_window_size( + self, + input_ids: torch.Tensor, + attention_mask: torch.Tensor, + inputs_embeds: torch.Tensor, + pad_token_id: int, + ): + """A helper function to pad tokens and mask to work with implementation of Longformer self-attention.""" + # padding + attention_window = ( + self.config.attention_window + if isinstance(self.config.attention_window, int) + else max(self.config.attention_window) + ) + + if attention_window % 2 != 0: + raise ValueError(f"`attention_window` should be an even value. Given {attention_window}") + input_shape = input_ids.shape if input_ids is not None else inputs_embeds.shape + batch_size, seq_len = input_shape[:2] + + padding_len = (attention_window - seq_len % attention_window) % attention_window + if padding_len > 0: + logger.warning_once( + f"Input ids are automatically padded from {seq_len} to {seq_len + padding_len} to be a multiple of " + f"`config.attention_window`: {attention_window}" + ) + if input_ids is not None: + input_ids = nn.functional.pad(input_ids, (0, padding_len), value=pad_token_id) + if inputs_embeds is not None: + input_ids_padding = inputs_embeds.new_full( + (batch_size, padding_len), + self.config.pad_token_id, + dtype=torch.long, + ) + inputs_embeds_padding = self.embed_tokens(input_ids_padding) + inputs_embeds = torch.cat([inputs_embeds, inputs_embeds_padding], dim=-2) + + attention_mask = nn.functional.pad( + attention_mask, (0, padding_len), value=False + ) # no attention on the padding tokens + + return padding_len, input_ids, attention_mask, inputs_embeds + + def forward( + self, + input_ids=None, + attention_mask=None, + global_attention_mask=None, + head_mask=None, + inputs_embeds=None, + output_attentions=None, + output_hidden_states=None, + return_dict=None, + ): + r""" + Args: + input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`): + Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you + provide it. + + Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for details. + + [What are input IDs?](../glossary#input-ids) + attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`: + + - 1 for tokens that are **not masked**, + - 0 for tokens that are **masked**. + + [What are attention masks?](../glossary#attention-mask) + global_attention_mask (`torch.FloatTensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to decide the attention given on each token, local attention or global attention for the encoder. + Tokens with global attention attends to all other tokens, and all other tokens attend to them. This is + important for task-specific finetuning because it makes the model more flexible at representing the + task. For example, for classification, the token should be given global attention. For QA, all + question tokens should also have global attention. Please refer to the [Longformer + paper](https://arxiv.org/abs/2004.05150) for more details. Mask values selected in `[0, 1]`: + + - 0 for local attention (a sliding window attention), + - 1 for global attention (tokens that attend to all other tokens, and all other tokens attend to them). + head_mask (`torch.Tensor` of shape `(encoder_layers, encoder_attention_heads)`, *optional*): + Mask to nullify selected heads of the attention modules. Mask values selected in `[0, 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. + This is useful if you want more control over how to convert `input_ids` indices into associated vectors + than the model's internal embedding lookup matrix. + output_attentions (`bool`, *optional*): + Whether or not to return the attentions tensors of all attention layers. See `attentions` under + returned tensors for more detail. + output_hidden_states (`bool`, *optional*): + Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors + for more detail. + return_dict (`bool`, *optional*): + Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. + """ + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + # check input_ids and inputs_embeds + if input_ids is not None and inputs_embeds is not None: + raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time") + elif input_ids is None and inputs_embeds is None: + raise ValueError("You have to specify either input_ids or inputs_embeds") + + if inputs_embeds is None: + inputs_embeds = self.embed_tokens(input_ids) + + # create default attention_mask + if attention_mask is None: + attention_mask = torch.ones(inputs_embeds.size()[:-1], device=inputs_embeds.device, dtype=torch.long) + + # merge `global_attention_mask` and `attention_mask` + if global_attention_mask is not None: + attention_mask = self._merge_to_attention_mask(attention_mask, global_attention_mask) + + # pad input if necessary + padding_len, input_ids, attention_mask, inputs_embeds = self._pad_to_window_size( + input_ids=input_ids, + attention_mask=attention_mask, + inputs_embeds=inputs_embeds, + pad_token_id=self.config.pad_token_id, + ) + + # retrieve input_shape + if input_ids is not None: + input_shape = input_ids.size() + input_ids = input_ids.view(-1, input_shape[-1]) + elif inputs_embeds is not None: + input_shape = inputs_embeds.size()[:-1] + + # convert attention_mask to float + if attention_mask is not None: + # [bsz, seq_len] -> [bsz, seq_len]; 1 -> 0.0; 0 -> "-inf" + attention_mask = _prepare_4d_attention_mask_inverted(attention_mask, inputs_embeds.dtype)[:, 0, 0, :] + + # get masking tensors + is_index_masked = attention_mask < 0 + is_index_global_attn = attention_mask > 0 + is_global_attn = is_index_global_attn.flatten().any().item() + + embed_pos = self.embed_positions(input_shape) + + hidden_states = inputs_embeds + embed_pos + hidden_states = self.layernorm_embedding(hidden_states) + hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) + + encoder_states = () if output_hidden_states else None + all_attentions = () if output_attentions else None + all_global_attentions = () if (output_attentions and is_global_attn) else None + + # check if head_mask has a correct number of layers specified if desired + if head_mask is not None: + if head_mask.size()[0] != len(self.layers): + raise ValueError( + f"The head_mask should be specified for {len(self.layers)} layers, but it is for" + f" {head_mask.size()[0]}." + ) + for idx, encoder_layer in enumerate(self.layers): + if output_hidden_states: + encoder_states = encoder_states + (hidden_states,) + # add LayerDrop (see https://arxiv.org/abs/1909.11556 for description) + dropout_probability = torch.rand([]) + + if self.training and (dropout_probability < self.layerdrop): # skip the layer + layer_outputs = (None, None, None) + else: + if self.gradient_checkpointing and self.training: + layer_outputs = self._gradient_checkpointing_func( + encoder_layer.__call__, + hidden_states, + attention_mask, + head_mask[idx] if head_mask is not None else None, + is_index_masked, + is_index_global_attn, + is_global_attn, + output_attentions, + ) + else: + layer_outputs = encoder_layer( + hidden_states, + attention_mask=attention_mask, + layer_head_mask=(head_mask[idx] if head_mask is not None else None), + is_index_masked=is_index_masked, + is_index_global_attn=is_index_global_attn, + is_global_attn=is_global_attn, + output_attentions=output_attentions, + ) + hidden_states = layer_outputs[0] + + if output_attentions: + # bzs x seq_len x num_attn_heads x (num_global_attn + attention_window_len + 1) => bzs x num_attn_heads x seq_len x (num_global_attn + attention_window_len + 1) + all_attentions = all_attentions + (layer_outputs[1].transpose(1, 2),) + + if is_global_attn: + # bzs x num_attn_heads x num_global_attn x seq_len => bzs x num_attn_heads x seq_len x num_global_attn + all_global_attentions = all_global_attentions + (layer_outputs[2].transpose(2, 3),) + + if output_hidden_states: + encoder_states = encoder_states + (hidden_states,) + + # undo padding + if padding_len > 0: + # unpad `hidden_states` because the calling function is expecting a length == input_ids.size(1) + hidden_states = hidden_states[:, :-padding_len] + if output_hidden_states: + encoder_states = tuple([state[:, :-padding_len] for state in encoder_states]) + + if output_attentions: + all_attentions = tuple([state[:, :, :-padding_len, :] for state in all_attentions]) + + if not return_dict: + return tuple( + v for v in [hidden_states, encoder_states, all_attentions, all_global_attentions] if v is not None + ) + return LEDEncoderBaseModelOutput( + last_hidden_state=hidden_states, + hidden_states=encoder_states, + attentions=all_attentions, + global_attentions=all_global_attentions, + ) + + +class LEDDecoder(LEDPreTrainedModel): + """ + Transformer decoder consisting of *config.decoder_layers* layers. Each layer is a [`LEDDecoderLayer`] + + Args: + config: LEDConfig + embed_tokens (nn.Embedding): output embedding + """ + + def __init__(self, config: LEDConfig, embed_tokens: Optional[nn.Embedding] = None): + super().__init__(config) + self.dropout = config.dropout + self.layerdrop = config.decoder_layerdrop + self.padding_idx = config.pad_token_id + self.max_target_positions = config.max_decoder_position_embeddings + + if embed_tokens is not None: + self.embed_tokens = embed_tokens + else: + self.embed_tokens = nn.Embedding(config.vocab_size, config.d_model, self.padding_idx) + + self.embed_positions = LEDLearnedPositionalEmbedding( + self.max_target_positions, + config.d_model, + ) + self.layers = nn.ModuleList([LEDDecoderLayer(config) for _ in range(config.decoder_layers)]) + self.layernorm_embedding = nn.LayerNorm(config.d_model) + + self.gradient_checkpointing = False + # Initialize weights and apply final processing + self.post_init() + + def forward( + self, + input_ids=None, + attention_mask=None, + global_attention_mask=None, + encoder_hidden_states=None, + encoder_attention_mask=None, + head_mask=None, + cross_attn_head_mask=None, + past_key_values=None, + inputs_embeds=None, + use_cache=None, + output_attentions=None, + output_hidden_states=None, + return_dict=None, + ): + r""" + Args: + input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`): + Indices of input sequence tokens in the vocabulary. Padding will be ignored by default should you + provide it. + + Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for details. + + [What are input IDs?](../glossary#input-ids) + attention_mask (`torch.Tensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`: + + - 1 for tokens that are **not masked**, + - 0 for tokens that are **masked**. + + [What are attention masks?](../glossary#attention-mask) + global_attention_mask (`torch.FloatTensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to decide the attention given on each token, local attention or global attention. Tokens with + global attention attends to all other tokens, and all other tokens attend to them. This is important + for task-specific finetuning because it makes the model more flexible at representing the task. For + example, for classification, the token should be given global attention. For QA, all question + tokens should also have global attention. Please refer to the [Longformer + paper](https://arxiv.org/abs/2004.05150) for more details. Mask values selected in `[0, 1]`: + + - 0 for local attention (a sliding window attention), + - 1 for global attention (tokens that attend to all other tokens, and all other tokens attend to them). + encoder_hidden_states (`torch.FloatTensor` of shape `(batch_size, encoder_sequence_length, hidden_size)`, *optional*): + Sequence of hidden-states at the output of the last layer of the encoder. Used in the cross-attention + of the decoder. + encoder_attention_mask (`torch.LongTensor` of shape `(batch_size, encoder_sequence_length)`, *optional*): + Mask to avoid performing cross-attention on padding tokens indices of encoder input_ids. Mask values + selected in `[0, 1]`: + + - 1 for tokens that are **not masked**, + - 0 for tokens that are **masked**. + + [What are attention masks?](../glossary#attention-mask) + head_mask (`torch.Tensor` of shape `(decoder_layers, decoder_attention_heads)`, *optional*): + Mask to nullify selected heads of the attention modules. Mask values selected in `[0, 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + cross_attn_head_mask (`torch.Tensor` of shape `(decoder_layers, decoder_attention_heads)`, *optional*): + Mask to nullify selected heads of the cross-attention modules. Mask values selected in `[0, 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + past_key_values (`tuple(tuple(torch.FloatTensor))`, *optional*, returned when `use_cache=True` is passed or when `config.use_cache=True`): + Tuple of `tuple(torch.FloatTensor)` of length `config.n_layers`, with each tuple having 2 tensors of + shape `(batch_size, num_heads, sequence_length, embed_size_per_head)`) and 2 additional tensors of + shape `(batch_size, num_heads, encoder_sequence_length, embed_size_per_head)`. + + Contains pre-computed hidden-states (key and values in the self-attention blocks and in the + cross-attention blocks) that can be used (see `past_key_values` input) to speed up sequential decoding. + + If `past_key_values` are used, the user can optionally input only the last `decoder_input_ids` (those + that don't have their past key value states given to this model) of shape `(batch_size, 1)` instead of + all `decoder_input_ids` of shape `(batch_size, sequence_length)`. + inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. + This is useful if you want more control over how to convert `input_ids` indices into associated vectors + than the model's internal embedding lookup matrix. + output_attentions (`bool`, *optional*): + Whether or not to return the attentions tensors of all attention layers. See `attentions` under + returned tensors for more detail. + output_hidden_states (`bool`, *optional*): + Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors + for more detail. + return_dict (`bool`, *optional*): + Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. + """ + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + use_cache = use_cache if use_cache is not None else self.config.use_cache + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + # retrieve input_ids and inputs_embeds + if input_ids is not None and inputs_embeds is not None: + raise ValueError("You cannot specify both decoder_input_ids and decoder_inputs_embeds at the same time") + elif input_ids is not None: + input_shape = input_ids.size() + input_ids = input_ids.view(-1, input_shape[-1]) + elif inputs_embeds is not None: + input_shape = inputs_embeds.size()[:-1] + else: + raise ValueError("You have to specify either decoder_input_ids or decoder_inputs_embeds") + + # past_key_values_length + past_key_values_length = past_key_values[0][0].shape[2] if past_key_values is not None else 0 + + if inputs_embeds is None: + inputs_embeds = self.embed_tokens(input_ids) + + # create causal mask + # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len] + combined_attention_mask = None + if input_shape[-1] > 1: + combined_attention_mask = _create_4d_causal_attention_mask( + input_shape, inputs_embeds.dtype, inputs_embeds.device, past_key_values_length=past_key_values_length + ) + + if attention_mask is not None and combined_attention_mask is not None: + # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len] + combined_attention_mask = combined_attention_mask + _prepare_4d_attention_mask_inverted( + attention_mask, inputs_embeds.dtype, tgt_len=input_shape[-1] + ) + + # expand encoder attention mask + if encoder_hidden_states is not None and encoder_attention_mask is not None: + # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len] + encoder_attention_mask = _prepare_4d_attention_mask_inverted( + encoder_attention_mask, inputs_embeds.dtype, tgt_len=input_shape[-1] + ) + + # embed positions + positions = self.embed_positions(input_shape, past_key_values_length) + + hidden_states = inputs_embeds + positions + hidden_states = self.layernorm_embedding(hidden_states) + + hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) + + if self.gradient_checkpointing and self.training: + if use_cache: + logger.warning_once( + "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`..." + ) + use_cache = False + + # decoder layers + all_hidden_states = () if output_hidden_states else None + all_self_attns = () if output_attentions else None + all_cross_attentions = () if output_attentions else None + next_decoder_cache = () if use_cache else None + + # check if head_mask/cross_attn_head_mask has a correct number of layers specified if desired + for attn_mask, mask_name in zip([head_mask, cross_attn_head_mask], ["head_mask", "cross_attn_head_mask"]): + if attn_mask is not None: + if attn_mask.size()[0] != len(self.layers): + raise ValueError( + f"The `{mask_name}` should be specified for {len(self.layers)} layers, but it is for" + f" {head_mask.size()[0]}." + ) + for idx, decoder_layer in enumerate(self.layers): + # add LayerDrop (see https://arxiv.org/abs/1909.11556 for description) + if output_hidden_states: + all_hidden_states += (hidden_states,) + if self.training: + dropout_probability = torch.rand([]) + if dropout_probability < self.layerdrop: + continue + + past_key_value = past_key_values[idx] if past_key_values is not None else None + + if self.gradient_checkpointing and self.training: + layer_outputs = self._gradient_checkpointing_func( + decoder_layer.__call__, + hidden_states, + combined_attention_mask, + encoder_hidden_states, + encoder_attention_mask, + head_mask[idx] if head_mask is not None else None, + cross_attn_head_mask[idx] if cross_attn_head_mask is not None else None, + None, + output_attentions, + use_cache, + ) + else: + layer_outputs = decoder_layer( + hidden_states, + attention_mask=combined_attention_mask, + encoder_hidden_states=encoder_hidden_states, + encoder_attention_mask=encoder_attention_mask, + layer_head_mask=(head_mask[idx] if head_mask is not None else None), + cross_attn_layer_head_mask=( + cross_attn_head_mask[idx] if cross_attn_head_mask is not None else None + ), + past_key_value=past_key_value, + output_attentions=output_attentions, + use_cache=use_cache, + ) + + hidden_states = layer_outputs[0] + + if use_cache: + next_decoder_cache += (layer_outputs[3 if output_attentions else 1],) + + if output_attentions: + all_self_attns += (layer_outputs[1],) + all_cross_attentions += (layer_outputs[2],) + + # add hidden states from the last decoder layer + if output_hidden_states: + all_hidden_states += (hidden_states,) + + next_cache = next_decoder_cache if use_cache else None + if not return_dict: + return tuple( + v + for v in [hidden_states, next_cache, all_hidden_states, all_self_attns, all_cross_attentions] + if v is not None + ) + return BaseModelOutputWithPastAndCrossAttentions( + last_hidden_state=hidden_states, + past_key_values=next_cache, + hidden_states=all_hidden_states, + attentions=all_self_attns, + cross_attentions=all_cross_attentions, + ) + + +@add_start_docstrings( + "The bare LED Model outputting raw hidden-states without any specific head on top.", + LED_START_DOCSTRING, +) +class LEDModel(LEDPreTrainedModel): + _tied_weights_keys = ["decoder.embed_tokens.weight", "encoder.embed_tokens.weight"] + + def __init__(self, config: LEDConfig): + super().__init__(config) + + padding_idx, vocab_size = config.pad_token_id, config.vocab_size + self.shared = nn.Embedding(vocab_size, config.d_model, padding_idx) + + self.encoder = LEDEncoder(config, self.shared) + self.decoder = LEDDecoder(config, self.shared) + + # Initialize weights and apply final processing + self.post_init() + + def get_input_embeddings(self): + return self.shared + + def set_input_embeddings(self, value): + self.shared = value + self.encoder.embed_tokens = self.shared + self.decoder.embed_tokens = self.shared + + def get_encoder(self): + return self.encoder + + def get_decoder(self): + return self.decoder + + @add_start_docstrings_to_model_forward(LED_INPUTS_DOCSTRING) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_DOC, + output_type=Seq2SeqModelOutput, + config_class=_CONFIG_FOR_DOC, + ) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.Tensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.LongTensor] = None, + head_mask: Optional[torch.Tensor] = None, + decoder_head_mask: Optional[torch.Tensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + global_attention_mask: Optional[torch.FloatTensor] = None, + past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + decoder_inputs_embeds: Optional[torch.FloatTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], LEDSeq2SeqModelOutput]: + output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions + output_hidden_states = ( + output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states + ) + use_cache = use_cache if use_cache is not None else self.config.use_cache + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + # Using this like Bart, as LED is derived from it. So far + # No checkpoint on the hub exists that uses that in practice. + # https://github.com/huggingface/transformers/blob/ac3cb660cad283163f7c73cad511124e845ca388/src/transformers/models/bart/modeling_bart.py#L1153 + if decoder_input_ids is None and decoder_inputs_embeds is None: + decoder_input_ids = shift_tokens_right( + input_ids, self.config.pad_token_id, self.config.decoder_start_token_id + ) + + if encoder_outputs is None: + encoder_outputs = self.encoder( + input_ids=input_ids, + attention_mask=attention_mask, + global_attention_mask=global_attention_mask, + head_mask=head_mask, + inputs_embeds=inputs_embeds, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + # If the user passed a tuple for encoder_outputs, we wrap it in a LEDEncoderBaseModelOutput when return_dict=False + elif return_dict and not isinstance(encoder_outputs, LEDEncoderBaseModelOutput): + encoder_outputs = LEDEncoderBaseModelOutput( + last_hidden_state=encoder_outputs[0], + hidden_states=encoder_outputs[1] if len(encoder_outputs) > 1 else None, + attentions=encoder_outputs[2] if len(encoder_outputs) > 2 else None, + global_attentions=encoder_outputs[3] if len(encoder_outputs) > 3 else None, + ) + + # decoder outputs consists of (dec_features, past_key_value, dec_hidden, dec_attn) + decoder_outputs = self.decoder( + input_ids=decoder_input_ids, + attention_mask=decoder_attention_mask, + encoder_hidden_states=encoder_outputs[0], + encoder_attention_mask=attention_mask, + head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + past_key_values=past_key_values, + inputs_embeds=decoder_inputs_embeds, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + if not return_dict: + return decoder_outputs + encoder_outputs + + return LEDSeq2SeqModelOutput( + last_hidden_state=decoder_outputs.last_hidden_state, + past_key_values=decoder_outputs.past_key_values, + decoder_hidden_states=decoder_outputs.hidden_states, + decoder_attentions=decoder_outputs.attentions, + cross_attentions=decoder_outputs.cross_attentions, + encoder_last_hidden_state=encoder_outputs.last_hidden_state, + encoder_hidden_states=encoder_outputs.hidden_states, + encoder_attentions=encoder_outputs.attentions, + encoder_global_attentions=encoder_outputs.global_attentions, + ) + + +@add_start_docstrings( + "The LED Model with a language modeling head. Can be used for summarization.", LED_START_DOCSTRING +) +class LEDForConditionalGeneration(LEDPreTrainedModel): + base_model_prefix = "led" + _keys_to_ignore_on_load_missing = ["final_logits_bias"] + _tied_weights_keys = ["decoder.embed_tokens.weight", "encoder.embed_tokens.weight", "lm_head.weight"] + + def __init__(self, config: LEDConfig): + super().__init__(config) + self.led = LEDModel(config) + self.register_buffer("final_logits_bias", torch.zeros((1, self.led.shared.num_embeddings))) + self.lm_head = nn.Linear(config.d_model, self.led.shared.num_embeddings, bias=False) + + # Initialize weights and apply final processing + self.post_init() + + def get_encoder(self): + return self.led.get_encoder() + + def get_decoder(self): + return self.led.get_decoder() + + def resize_token_embeddings(self, new_num_tokens: int, pad_to_multiple_of: Optional[int] = None) -> nn.Embedding: + new_embeddings = super().resize_token_embeddings(new_num_tokens, pad_to_multiple_of) + self._resize_final_logits_bias(new_embeddings.weight.shape[0]) + return new_embeddings + + def _resize_final_logits_bias(self, new_num_tokens: int) -> None: + old_num_tokens = self.final_logits_bias.shape[-1] + if new_num_tokens <= old_num_tokens: + new_bias = self.final_logits_bias[:, :new_num_tokens] + else: + extra_bias = torch.zeros((1, new_num_tokens - old_num_tokens), device=self.final_logits_bias.device) + new_bias = torch.cat([self.final_logits_bias, extra_bias], dim=1) + self.register_buffer("final_logits_bias", new_bias) + + def get_output_embeddings(self): + return self.lm_head + + def set_output_embeddings(self, new_embeddings): + self.lm_head = new_embeddings + + @add_start_docstrings_to_model_forward(LED_INPUTS_DOCSTRING) + @replace_return_docstrings(output_type=Seq2SeqLMOutput, config_class=_CONFIG_FOR_DOC) + @add_end_docstrings(LED_GENERATION_EXAMPLE) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.Tensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.LongTensor] = None, + head_mask: Optional[torch.Tensor] = None, + decoder_head_mask: Optional[torch.Tensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + global_attention_mask: Optional[torch.FloatTensor] = None, + past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + decoder_inputs_embeds: Optional[torch.FloatTensor] = None, + labels: Optional[torch.LongTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], LEDSeq2SeqLMOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*): + Labels for computing the masked language modeling loss. Indices should either be in `[0, ..., + config.vocab_size]` or -100 (see `input_ids` docstring). Tokens with indices set to `-100` are ignored + (masked), the loss is only computed for the tokens with labels in `[0, ..., config.vocab_size]`. + + Returns: + + Conditional generation example: + + ```python + >>> from transformers import AutoTokenizer, LEDForConditionalGeneration + + >>> tokenizer = AutoTokenizer.from_pretrained("allenai/led-base-16384") + >>> TXT = "My friends are but they eat too many carbs." + + >>> model = LEDForConditionalGeneration.from_pretrained("allenai/led-base-16384") + >>> input_ids = tokenizer([TXT], return_tensors="pt")["input_ids"] + + >>> prediction = model.generate(input_ids)[0] + >>> print(tokenizer.decode(prediction, skip_special_tokens=True)) + ```""" + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + + if labels is not None: + if use_cache: + logger.warning("The `use_cache` argument is changed to `False` since `labels` is provided.") + use_cache = False + if decoder_input_ids is None and decoder_inputs_embeds is None: + decoder_input_ids = shift_tokens_right( + labels, self.config.pad_token_id, self.config.decoder_start_token_id + ) + + outputs = self.led( + input_ids, + attention_mask=attention_mask, + decoder_input_ids=decoder_input_ids, + decoder_attention_mask=decoder_attention_mask, + encoder_outputs=encoder_outputs, + global_attention_mask=global_attention_mask, + head_mask=head_mask, + decoder_head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + past_key_values=past_key_values, + inputs_embeds=inputs_embeds, + decoder_inputs_embeds=decoder_inputs_embeds, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + lm_logits = self.lm_head(outputs[0]) + self.final_logits_bias + + masked_lm_loss = None + if labels is not None: + loss_fct = CrossEntropyLoss() + masked_lm_loss = loss_fct(lm_logits.view(-1, self.config.vocab_size), labels.view(-1)) + + if not return_dict: + output = (lm_logits,) + outputs[1:] + return ((masked_lm_loss,) + output) if masked_lm_loss is not None else output + + return LEDSeq2SeqLMOutput( + loss=masked_lm_loss, + logits=lm_logits, + past_key_values=outputs.past_key_values, + decoder_hidden_states=outputs.decoder_hidden_states, + decoder_attentions=outputs.decoder_attentions, + cross_attentions=outputs.cross_attentions, + encoder_last_hidden_state=outputs.encoder_last_hidden_state, + encoder_hidden_states=outputs.encoder_hidden_states, + encoder_attentions=outputs.encoder_attentions, + encoder_global_attentions=outputs.encoder_global_attentions, + ) + + def prepare_inputs_for_generation( + self, + decoder_input_ids, + past_key_values=None, + attention_mask=None, + global_attention_mask=None, + head_mask=None, + decoder_head_mask=None, + cross_attn_head_mask=None, + use_cache=None, + encoder_outputs=None, + **kwargs, + ): + # cut decoder_input_ids if past is used + if past_key_values is not None: + decoder_input_ids = decoder_input_ids[:, -1:] + + return { + "input_ids": None, # encoder_outputs is defined. input_ids not needed + "encoder_outputs": encoder_outputs, + "past_key_values": past_key_values, + "decoder_input_ids": decoder_input_ids, + "attention_mask": attention_mask, + "global_attention_mask": global_attention_mask, + "head_mask": head_mask, + "decoder_head_mask": decoder_head_mask, + "cross_attn_head_mask": cross_attn_head_mask, + "use_cache": use_cache, # change this to avoid caching (presumably for debugging) + } + + def prepare_decoder_input_ids_from_labels(self, labels: torch.Tensor): + return shift_tokens_right(labels, self.config.pad_token_id, self.config.decoder_start_token_id) + + @staticmethod + def _reorder_cache(past_key_values, beam_idx): + reordered_past = () + for layer_past in past_key_values: + # cached cross_attention states don't have to be reordered -> they are always the same + reordered_past += ( + tuple(past_state.index_select(0, beam_idx.to(past_state.device)) for past_state in layer_past[:2]) + + layer_past[2:], + ) + return reordered_past + + +@add_start_docstrings( + """ + LED model with a sequence classification/head on top (a linear layer on top of the pooled output) e.g. for GLUE + tasks. + """, + LED_START_DOCSTRING, +) +class LEDForSequenceClassification(LEDPreTrainedModel): + _tied_weights_keys = ["decoder.embed_tokens.weight", "encoder.embed_tokens.weight"] + + def __init__(self, config: LEDConfig, **kwargs): + warnings.warn( + "The `transformers.LEDForSequenceClassification` class is deprecated and will be removed in version 5 of" + " Transformers. No actual method were provided in the original paper on how to perfom" + " sequence classification.", + FutureWarning, + ) + super().__init__(config, **kwargs) + self.led = LEDModel(config) + self.classification_head = LEDClassificationHead( + config.d_model, + config.d_model, + config.num_labels, + config.classifier_dropout, + ) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(LED_INPUTS_DOCSTRING) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_DOC, + output_type=Seq2SeqSequenceClassifierOutput, + config_class=_CONFIG_FOR_DOC, + ) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.Tensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.LongTensor] = None, + head_mask: Optional[torch.Tensor] = None, + decoder_head_mask: Optional[torch.Tensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + global_attention_mask: Optional[torch.FloatTensor] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + decoder_inputs_embeds: Optional[torch.FloatTensor] = None, + labels: Optional[torch.LongTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], LEDSeq2SeqSequenceClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the sequence classification/regression loss. Indices should be in `[0, ..., + config.num_labels - 1]`. If `config.num_labels > 1` a classification loss is computed (Cross-Entropy). + """ + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + if labels is not None: + use_cache = False + + if input_ids is None and inputs_embeds is not None: + raise NotImplementedError( + f"Passing input embeddings is currently not supported for {self.__class__.__name__}" + ) + + outputs = self.led( + input_ids, + attention_mask=attention_mask, + decoder_input_ids=decoder_input_ids, + decoder_attention_mask=decoder_attention_mask, + global_attention_mask=global_attention_mask, + head_mask=head_mask, + decoder_head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + encoder_outputs=encoder_outputs, + inputs_embeds=inputs_embeds, + decoder_inputs_embeds=decoder_inputs_embeds, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + hidden_states = outputs[0] # last hidden state + + eos_mask = input_ids.eq(self.config.eos_token_id).to(hidden_states.device) + + if len(torch.unique_consecutive(eos_mask.sum(1))) > 1: + raise ValueError("All examples must have the same number of tokens.") + sentence_representation = hidden_states[eos_mask, :].view(hidden_states.size(0), -1, hidden_states.size(-1))[ + :, -1, : + ] + logits = self.classification_head(sentence_representation) + + loss = None + if labels is not None: + if self.config.problem_type is None: + if self.config.num_labels == 1: + self.config.problem_type = "regression" + elif self.config.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int): + self.config.problem_type = "single_label_classification" + else: + self.config.problem_type = "multi_label_classification" + + if self.config.problem_type == "regression": + loss_fct = MSELoss() + if self.config.num_labels == 1: + loss = loss_fct(logits.squeeze(), labels.squeeze()) + else: + loss = loss_fct(logits, labels) + elif self.config.problem_type == "single_label_classification": + loss_fct = CrossEntropyLoss() + loss = loss_fct(logits.view(-1, self.config.num_labels), labels.view(-1)) + elif self.config.problem_type == "multi_label_classification": + loss_fct = BCEWithLogitsLoss() + loss = loss_fct(logits, labels) + if not return_dict: + output = (logits,) + outputs[1:] + return ((loss,) + output) if loss is not None else output + + return LEDSeq2SeqSequenceClassifierOutput( + loss=loss, + logits=logits, + past_key_values=outputs.past_key_values, + decoder_hidden_states=outputs.decoder_hidden_states, + decoder_attentions=outputs.decoder_attentions, + cross_attentions=outputs.cross_attentions, + encoder_last_hidden_state=outputs.encoder_last_hidden_state, + encoder_hidden_states=outputs.encoder_hidden_states, + encoder_attentions=outputs.encoder_attentions, + encoder_global_attentions=outputs.encoder_global_attentions, + ) + + +@add_start_docstrings( + """ + LED Model with a span classification head on top for extractive question-answering tasks like SQuAD (a linear layer + on top of the hidden-states output to compute `span start logits` and `span end logits`). + """, + LED_START_DOCSTRING, +) +class LEDForQuestionAnswering(LEDPreTrainedModel): + _tied_weights_keys = ["decoder.embed_tokens.weight", "encoder.embed_tokens.weight"] + + def __init__(self, config): + super().__init__(config) + + config.num_labels = 2 + self.num_labels = config.num_labels + + self.led = LEDModel(config) + self.qa_outputs = nn.Linear(config.hidden_size, config.num_labels) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(LED_INPUTS_DOCSTRING) + @add_code_sample_docstrings( + checkpoint=_CHECKPOINT_FOR_DOC, + output_type=Seq2SeqQuestionAnsweringModelOutput, + config_class=_CONFIG_FOR_DOC, + ) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.Tensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.LongTensor] = None, + head_mask: Optional[torch.Tensor] = None, + decoder_head_mask: Optional[torch.Tensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + global_attention_mask: Optional[torch.FloatTensor] = None, + start_positions: Optional[torch.LongTensor] = None, + end_positions: Optional[torch.LongTensor] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + decoder_inputs_embeds: Optional[torch.FloatTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], LEDSeq2SeqQuestionAnsweringModelOutput]: + r""" + start_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for position (index) of the start of the labelled span for computing the token classification loss. + Positions are clamped to the length of the sequence (*sequence_length*). Position outside of the sequence + are not taken into account for computing the loss. + end_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for position (index) of the end of the labelled span for computing the token classification loss. + Positions are clamped to the length of the sequence (*sequence_length*). Position outside of the sequence + are not taken into account for computing the loss. + """ + return_dict = return_dict if return_dict is not None else self.config.use_return_dict + if start_positions is not None and end_positions is not None: + use_cache = False + + outputs = self.led( + input_ids, + attention_mask=attention_mask, + decoder_input_ids=decoder_input_ids, + decoder_attention_mask=decoder_attention_mask, + global_attention_mask=global_attention_mask, + head_mask=head_mask, + decoder_head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + encoder_outputs=encoder_outputs, + inputs_embeds=inputs_embeds, + decoder_inputs_embeds=decoder_inputs_embeds, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + sequence_output = outputs[0] + + logits = self.qa_outputs(sequence_output) + start_logits, end_logits = logits.split(1, dim=-1) + start_logits = start_logits.squeeze(-1).contiguous() + end_logits = end_logits.squeeze(-1).contiguous() + + total_loss = None + if start_positions is not None and end_positions is not None: + # If we are on multi-GPU, split add a dimension + if len(start_positions.size()) > 1: + start_positions = start_positions.squeeze(-1) + if len(end_positions.size()) > 1: + end_positions = end_positions.squeeze(-1) + # sometimes the start/end positions are outside our model inputs, we ignore these terms + ignored_index = start_logits.size(1) + start_positions = start_positions.clamp(0, ignored_index) + end_positions = end_positions.clamp(0, ignored_index) + + loss_fct = CrossEntropyLoss(ignore_index=ignored_index) + start_loss = loss_fct(start_logits, start_positions) + end_loss = loss_fct(end_logits, end_positions) + total_loss = (start_loss + end_loss) / 2 + + if not return_dict: + output = ( + start_logits, + end_logits, + ) + outputs[1:] + return ((total_loss,) + output) if total_loss is not None else output + + return LEDSeq2SeqQuestionAnsweringModelOutput( + loss=total_loss, + start_logits=start_logits, + end_logits=end_logits, + past_key_values=outputs.past_key_values, + decoder_hidden_states=outputs.decoder_hidden_states, + decoder_attentions=outputs.decoder_attentions, + cross_attentions=outputs.cross_attentions, + encoder_last_hidden_state=outputs.encoder_last_hidden_state, + encoder_hidden_states=outputs.encoder_hidden_states, + encoder_attentions=outputs.encoder_attentions, + encoder_global_attentions=outputs.encoder_global_attentions, + )