# coding=utf-8
# Copyright 2020 Microsoft and the Hugging Face Inc. team.
#
# 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 DeBERTa model. """
import math
from collections.abc import Sequence
import torch
from torch import _softmax_backward_data, nn
from torch.nn import CrossEntropyLoss
from ...activations import ACT2FN
from ...file_utils import add_code_sample_docstrings, add_start_docstrings, add_start_docstrings_to_model_forward
from ...modeling_outputs import (
BaseModelOutput,
MaskedLMOutput,
QuestionAnsweringModelOutput,
SequenceClassifierOutput,
TokenClassifierOutput,
)
from ...modeling_utils import PreTrainedModel
from ...utils import logging
from .configuration_deberta import DebertaConfig
logger = logging.get_logger(__name__)
_CONFIG_FOR_DOC = "DebertaConfig"
_TOKENIZER_FOR_DOC = "DebertaTokenizer"
_CHECKPOINT_FOR_DOC = "microsoft/deberta-base"
DEBERTA_PRETRAINED_MODEL_ARCHIVE_LIST = [
"microsoft/deberta-base",
"microsoft/deberta-large",
"microsoft/deberta-xlarge",
"microsoft/deberta-base-mnli",
"microsoft/deberta-large-mnli",
"microsoft/deberta-xlarge-mnli",
]
class ContextPooler(nn.Module):
def __init__(self, config):
super().__init__()
self.dense = nn.Linear(config.pooler_hidden_size, config.pooler_hidden_size)
self.dropout = StableDropout(config.pooler_dropout)
self.config = config
def forward(self, hidden_states):
# We "pool" the model by simply taking the hidden state corresponding
# to the first token.
context_token = hidden_states[:, 0]
context_token = self.dropout(context_token)
pooled_output = self.dense(context_token)
pooled_output = ACT2FN[self.config.pooler_hidden_act](pooled_output)
return pooled_output
@property
def output_dim(self):
return self.config.hidden_size
class XSoftmax(torch.autograd.Function):
"""
Masked Softmax which is optimized for saving memory
Args:
input (:obj:`torch.tensor`): The input tensor that will apply softmax.
mask (:obj:`torch.IntTensor`): The mask matrix where 0 indicate that element will be ignored in the softmax calculation.
dim (int): The dimension that will apply softmax
Example::
>>> import torch
>>> from transformers.models.deberta.modeling_deberta import XSoftmax
>>> # Make a tensor
>>> x = torch.randn([4,20,100])
>>> # Create a mask
>>> mask = (x>0).int()
>>> y = XSoftmax.apply(x, mask, dim=-1)
"""
@staticmethod
def forward(self, input, mask, dim):
self.dim = dim
rmask = ~(mask.bool())
output = input.masked_fill(rmask, float("-inf"))
output = torch.softmax(output, self.dim)
output.masked_fill_(rmask, 0)
self.save_for_backward(output)
return output
@staticmethod
def backward(self, grad_output):
(output,) = self.saved_tensors
inputGrad = _softmax_backward_data(grad_output, output, self.dim, output)
return inputGrad, None, None
class DropoutContext(object):
def __init__(self):
self.dropout = 0
self.mask = None
self.scale = 1
self.reuse_mask = True
def get_mask(input, local_context):
if not isinstance(local_context, DropoutContext):
dropout = local_context
mask = None
else:
dropout = local_context.dropout
dropout *= local_context.scale
mask = local_context.mask if local_context.reuse_mask else None
if dropout > 0 and mask is None:
mask = (1 - torch.empty_like(input).bernoulli_(1 - dropout)).bool()
if isinstance(local_context, DropoutContext):
if local_context.mask is None:
local_context.mask = mask
return mask, dropout
class XDropout(torch.autograd.Function):
"""Optimized dropout function to save computation and memory by using mask operation instead of multiplication."""
@staticmethod
def forward(ctx, input, local_ctx):
mask, dropout = get_mask(input, local_ctx)
ctx.scale = 1.0 / (1 - dropout)
if dropout > 0:
ctx.save_for_backward(mask)
return input.masked_fill(mask, 0) * ctx.scale
else:
return input
@staticmethod
def backward(ctx, grad_output):
if ctx.scale > 1:
(mask,) = ctx.saved_tensors
return grad_output.masked_fill(mask, 0) * ctx.scale, None
else:
return grad_output, None
class StableDropout(torch.nn.Module):
"""
Optimized dropout module for stabilizing the training
Args:
drop_prob (float): the dropout probabilities
"""
def __init__(self, drop_prob):
super().__init__()
self.drop_prob = drop_prob
self.count = 0
self.context_stack = None
def forward(self, x):
"""
Call the module
Args:
x (:obj:`torch.tensor`): The input tensor to apply dropout
"""
if self.training and self.drop_prob > 0:
return XDropout.apply(x, self.get_context())
return x
def clear_context(self):
self.count = 0
self.context_stack = None
def init_context(self, reuse_mask=True, scale=1):
if self.context_stack is None:
self.context_stack = []
self.count = 0
for c in self.context_stack:
c.reuse_mask = reuse_mask
c.scale = scale
def get_context(self):
if self.context_stack is not None:
if self.count >= len(self.context_stack):
self.context_stack.append(DropoutContext())
ctx = self.context_stack[self.count]
ctx.dropout = self.drop_prob
self.count += 1
return ctx
else:
return self.drop_prob
class DebertaLayerNorm(nn.Module):
"""LayerNorm module in the TF style (epsilon inside the square root)."""
def __init__(self, size, eps=1e-12):
super().__init__()
self.weight = nn.Parameter(torch.ones(size))
self.bias = nn.Parameter(torch.zeros(size))
self.variance_epsilon = eps
def forward(self, hidden_states):
input_type = hidden_states.dtype
hidden_states = hidden_states.float()
mean = hidden_states.mean(-1, keepdim=True)
variance = (hidden_states - mean).pow(2).mean(-1, keepdim=True)
hidden_states = (hidden_states - mean) / torch.sqrt(variance + self.variance_epsilon)
hidden_states = hidden_states.to(input_type)
y = self.weight * hidden_states + self.bias
return y
class DebertaSelfOutput(nn.Module):
def __init__(self, config):
super().__init__()
self.dense = nn.Linear(config.hidden_size, config.hidden_size)
self.LayerNorm = DebertaLayerNorm(config.hidden_size, config.layer_norm_eps)
self.dropout = StableDropout(config.hidden_dropout_prob)
def forward(self, hidden_states, input_tensor):
hidden_states = self.dense(hidden_states)
hidden_states = self.dropout(hidden_states)
hidden_states = self.LayerNorm(hidden_states + input_tensor)
return hidden_states
class DebertaAttention(nn.Module):
def __init__(self, config):
super().__init__()
self.self = DisentangledSelfAttention(config)
self.output = DebertaSelfOutput(config)
self.config = config
def forward(
self,
hidden_states,
attention_mask,
return_att=False,
query_states=None,
relative_pos=None,
rel_embeddings=None,
):
self_output = self.self(
hidden_states,
attention_mask,
return_att,
query_states=query_states,
relative_pos=relative_pos,
rel_embeddings=rel_embeddings,
)
if return_att:
self_output, att_matrix = self_output
if query_states is None:
query_states = hidden_states
attention_output = self.output(self_output, query_states)
if return_att:
return (attention_output, att_matrix)
else:
return attention_output
# Copied from transformers.models.bert.modeling_bert.BertIntermediate with Bert->Deberta
class DebertaIntermediate(nn.Module):
def __init__(self, config):
super().__init__()
self.dense = nn.Linear(config.hidden_size, config.intermediate_size)
if isinstance(config.hidden_act, str):
self.intermediate_act_fn = ACT2FN[config.hidden_act]
else:
self.intermediate_act_fn = config.hidden_act
def forward(self, hidden_states):
hidden_states = self.dense(hidden_states)
hidden_states = self.intermediate_act_fn(hidden_states)
return hidden_states
class DebertaOutput(nn.Module):
def __init__(self, config):
super().__init__()
self.dense = nn.Linear(config.intermediate_size, config.hidden_size)
self.LayerNorm = DebertaLayerNorm(config.hidden_size, config.layer_norm_eps)
self.dropout = StableDropout(config.hidden_dropout_prob)
self.config = config
def forward(self, hidden_states, input_tensor):
hidden_states = self.dense(hidden_states)
hidden_states = self.dropout(hidden_states)
hidden_states = self.LayerNorm(hidden_states + input_tensor)
return hidden_states
class DebertaLayer(nn.Module):
def __init__(self, config):
super().__init__()
self.attention = DebertaAttention(config)
self.intermediate = DebertaIntermediate(config)
self.output = DebertaOutput(config)
def forward(
self,
hidden_states,
attention_mask,
return_att=False,
query_states=None,
relative_pos=None,
rel_embeddings=None,
):
attention_output = self.attention(
hidden_states,
attention_mask,
return_att=return_att,
query_states=query_states,
relative_pos=relative_pos,
rel_embeddings=rel_embeddings,
)
if return_att:
attention_output, att_matrix = attention_output
intermediate_output = self.intermediate(attention_output)
layer_output = self.output(intermediate_output, attention_output)
if return_att:
return (layer_output, att_matrix)
else:
return layer_output
class DebertaEncoder(nn.Module):
"""Modified BertEncoder with relative position bias support"""
def __init__(self, config):
super().__init__()
self.layer = nn.ModuleList([DebertaLayer(config) for _ in range(config.num_hidden_layers)])
self.relative_attention = getattr(config, "relative_attention", False)
if self.relative_attention:
self.max_relative_positions = getattr(config, "max_relative_positions", -1)
if self.max_relative_positions < 1:
self.max_relative_positions = config.max_position_embeddings
self.rel_embeddings = nn.Embedding(self.max_relative_positions * 2, config.hidden_size)
def get_rel_embedding(self):
rel_embeddings = self.rel_embeddings.weight if self.relative_attention else None
return rel_embeddings
def get_attention_mask(self, attention_mask):
if attention_mask.dim() <= 2:
extended_attention_mask = attention_mask.unsqueeze(1).unsqueeze(2)
attention_mask = extended_attention_mask * extended_attention_mask.squeeze(-2).unsqueeze(-1)
attention_mask = attention_mask.byte()
elif attention_mask.dim() == 3:
attention_mask = attention_mask.unsqueeze(1)
return attention_mask
def get_rel_pos(self, hidden_states, query_states=None, relative_pos=None):
if self.relative_attention and relative_pos is None:
q = query_states.size(-2) if query_states is not None else hidden_states.size(-2)
relative_pos = build_relative_position(q, hidden_states.size(-2), hidden_states.device)
return relative_pos
def forward(
self,
hidden_states,
attention_mask,
output_hidden_states=True,
output_attentions=False,
query_states=None,
relative_pos=None,
return_dict=True,
):
attention_mask = self.get_attention_mask(attention_mask)
relative_pos = self.get_rel_pos(hidden_states, query_states, relative_pos)
all_hidden_states = () if output_hidden_states else None
all_attentions = () if output_attentions else None
if isinstance(hidden_states, Sequence):
next_kv = hidden_states[0]
else:
next_kv = hidden_states
rel_embeddings = self.get_rel_embedding()
for i, layer_module in enumerate(self.layer):
if output_hidden_states:
all_hidden_states = all_hidden_states + (hidden_states,)
hidden_states = layer_module(
next_kv,
attention_mask,
output_attentions,
query_states=query_states,
relative_pos=relative_pos,
rel_embeddings=rel_embeddings,
)
if output_attentions:
hidden_states, att_m = hidden_states
if query_states is not None:
query_states = hidden_states
if isinstance(hidden_states, Sequence):
next_kv = hidden_states[i + 1] if i + 1 < len(self.layer) else None
else:
next_kv = hidden_states
if output_attentions:
all_attentions = all_attentions + (att_m,)
if output_hidden_states:
all_hidden_states = all_hidden_states + (hidden_states,)
if not return_dict:
return tuple(v for v in [hidden_states, all_hidden_states, all_attentions] if v is not None)
return BaseModelOutput(
last_hidden_state=hidden_states, hidden_states=all_hidden_states, attentions=all_attentions
)
def build_relative_position(query_size, key_size, device):
"""
Build relative position according to the query and key
We assume the absolute position of query :math:`P_q` is range from (0, query_size) and the absolute position of key
:math:`P_k` is range from (0, key_size), The relative positions from query to key is :math:`R_{q \\rightarrow k} =
P_q - P_k`
Args:
query_size (int): the length of query
key_size (int): the length of key
Return:
:obj:`torch.LongTensor`: A tensor with shape [1, query_size, key_size]
"""
q_ids = torch.arange(query_size, dtype=torch.long, device=device)
k_ids = torch.arange(key_size, dtype=torch.long, device=device)
rel_pos_ids = q_ids[:, None] - k_ids.view(1, -1).repeat(query_size, 1)
rel_pos_ids = rel_pos_ids[:query_size, :]
rel_pos_ids = rel_pos_ids.unsqueeze(0)
return rel_pos_ids
@torch.jit.script
def c2p_dynamic_expand(c2p_pos, query_layer, relative_pos):
return c2p_pos.expand([query_layer.size(0), query_layer.size(1), query_layer.size(2), relative_pos.size(-1)])
@torch.jit.script
def p2c_dynamic_expand(c2p_pos, query_layer, key_layer):
return c2p_pos.expand([query_layer.size(0), query_layer.size(1), key_layer.size(-2), key_layer.size(-2)])
@torch.jit.script
def pos_dynamic_expand(pos_index, p2c_att, key_layer):
return pos_index.expand(p2c_att.size()[:2] + (pos_index.size(-2), key_layer.size(-2)))
class DisentangledSelfAttention(torch.nn.Module):
"""
Disentangled self-attention module
Parameters:
config (:obj:`str`):
A model config class instance with the configuration to build a new model. The schema is similar to
`BertConfig`, for more details, please refer :class:`~transformers.DebertaConfig`
"""
def __init__(self, config):
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_attention_heads = config.num_attention_heads
self.attention_head_size = int(config.hidden_size / config.num_attention_heads)
self.all_head_size = self.num_attention_heads * self.attention_head_size
self.in_proj = torch.nn.Linear(config.hidden_size, self.all_head_size * 3, bias=False)
self.q_bias = torch.nn.Parameter(torch.zeros((self.all_head_size), dtype=torch.float))
self.v_bias = torch.nn.Parameter(torch.zeros((self.all_head_size), dtype=torch.float))
self.pos_att_type = config.pos_att_type if config.pos_att_type is not None else []
self.relative_attention = getattr(config, "relative_attention", False)
self.talking_head = getattr(config, "talking_head", False)
if self.talking_head:
self.head_logits_proj = torch.nn.Linear(config.num_attention_heads, config.num_attention_heads, bias=False)
self.head_weights_proj = torch.nn.Linear(
config.num_attention_heads, config.num_attention_heads, bias=False
)
if self.relative_attention:
self.max_relative_positions = getattr(config, "max_relative_positions", -1)
if self.max_relative_positions < 1:
self.max_relative_positions = config.max_position_embeddings
self.pos_dropout = StableDropout(config.hidden_dropout_prob)
if "c2p" in self.pos_att_type or "p2p" in self.pos_att_type:
self.pos_proj = torch.nn.Linear(config.hidden_size, self.all_head_size, bias=False)
if "p2c" in self.pos_att_type or "p2p" in self.pos_att_type:
self.pos_q_proj = torch.nn.Linear(config.hidden_size, self.all_head_size)
self.dropout = StableDropout(config.attention_probs_dropout_prob)
def transpose_for_scores(self, x):
new_x_shape = x.size()[:-1] + (self.num_attention_heads, -1)
x = x.view(*new_x_shape)
return x.permute(0, 2, 1, 3)
def forward(
self,
hidden_states,
attention_mask,
return_att=False,
query_states=None,
relative_pos=None,
rel_embeddings=None,
):
"""
Call the module
Args:
hidden_states (:obj:`torch.FloatTensor`):
Input states to the module usually the output from previous layer, it will be the Q,K and V in
`Attention(Q,K,V)`
attention_mask (:obj:`torch.ByteTensor`):
An attention mask matrix of shape [`B`, `N`, `N`] where `B` is the batch size, `N` is the maximum
sequence length in which element [i,j] = `1` means the `i` th token in the input can attend to the `j`
th token.
return_att (:obj:`bool`, optional):
Whether return the attention matrix.
query_states (:obj:`torch.FloatTensor`, optional):
The `Q` state in `Attention(Q,K,V)`.
relative_pos (:obj:`torch.LongTensor`):
The relative position encoding between the tokens in the sequence. It's of shape [`B`, `N`, `N`] with
values ranging in [`-max_relative_positions`, `max_relative_positions`].
rel_embeddings (:obj:`torch.FloatTensor`):
The embedding of relative distances. It's a tensor of shape [:math:`2 \\times
\\text{max_relative_positions}`, `hidden_size`].
"""
if query_states is None:
qp = self.in_proj(hidden_states) # .split(self.all_head_size, dim=-1)
query_layer, key_layer, value_layer = self.transpose_for_scores(qp).chunk(3, dim=-1)
else:
def linear(w, b, x):
if b is not None:
return torch.matmul(x, w.t()) + b.t()
else:
return torch.matmul(x, w.t()) # + b.t()
ws = self.in_proj.weight.chunk(self.num_attention_heads * 3, dim=0)
qkvw = [torch.cat([ws[i * 3 + k] for i in range(self.num_attention_heads)], dim=0) for k in range(3)]
qkvb = [None] * 3
q = linear(qkvw[0], qkvb[0], query_states)
k, v = [linear(qkvw[i], qkvb[i], hidden_states) for i in range(1, 3)]
query_layer, key_layer, value_layer = [self.transpose_for_scores(x) for x in [q, k, v]]
query_layer = query_layer + self.transpose_for_scores(self.q_bias[None, None, :])
value_layer = value_layer + self.transpose_for_scores(self.v_bias[None, None, :])
rel_att = None
# Take the dot product between "query" and "key" to get the raw attention scores.
scale_factor = 1 + len(self.pos_att_type)
scale = math.sqrt(query_layer.size(-1) * scale_factor)
query_layer = query_layer / scale
attention_scores = torch.matmul(query_layer, key_layer.transpose(-1, -2))
if self.relative_attention:
rel_embeddings = self.pos_dropout(rel_embeddings)
rel_att = self.disentangled_att_bias(query_layer, key_layer, relative_pos, rel_embeddings, scale_factor)
if rel_att is not None:
attention_scores = attention_scores + rel_att
# bxhxlxd
if self.talking_head:
attention_scores = self.head_logits_proj(attention_scores.permute(0, 2, 3, 1)).permute(0, 3, 1, 2)
attention_probs = XSoftmax.apply(attention_scores, attention_mask, -1)
attention_probs = self.dropout(attention_probs)
if self.talking_head:
attention_probs = self.head_weights_proj(attention_probs.permute(0, 2, 3, 1)).permute(0, 3, 1, 2)
context_layer = torch.matmul(attention_probs, value_layer)
context_layer = context_layer.permute(0, 2, 1, 3).contiguous()
new_context_layer_shape = context_layer.size()[:-2] + (-1,)
context_layer = context_layer.view(*new_context_layer_shape)
if return_att:
return (context_layer, attention_probs)
else:
return context_layer
def disentangled_att_bias(self, query_layer, key_layer, relative_pos, rel_embeddings, scale_factor):
if relative_pos is None:
q = query_layer.size(-2)
relative_pos = build_relative_position(q, key_layer.size(-2), query_layer.device)
if relative_pos.dim() == 2:
relative_pos = relative_pos.unsqueeze(0).unsqueeze(0)
elif relative_pos.dim() == 3:
relative_pos = relative_pos.unsqueeze(1)
# bxhxqxk
elif relative_pos.dim() != 4:
raise ValueError(f"Relative position ids must be of dim 2 or 3 or 4. {relative_pos.dim()}")
att_span = min(max(query_layer.size(-2), key_layer.size(-2)), self.max_relative_positions)
relative_pos = relative_pos.long().to(query_layer.device)
rel_embeddings = rel_embeddings[
self.max_relative_positions - att_span : self.max_relative_positions + att_span, :
].unsqueeze(0)
if "c2p" in self.pos_att_type or "p2p" in self.pos_att_type:
pos_key_layer = self.pos_proj(rel_embeddings)
pos_key_layer = self.transpose_for_scores(pos_key_layer)
if "p2c" in self.pos_att_type or "p2p" in self.pos_att_type:
pos_query_layer = self.pos_q_proj(rel_embeddings)
pos_query_layer = self.transpose_for_scores(pos_query_layer)
score = 0
# content->position
if "c2p" in self.pos_att_type:
c2p_att = torch.matmul(query_layer, pos_key_layer.transpose(-1, -2))
c2p_pos = torch.clamp(relative_pos + att_span, 0, att_span * 2 - 1)
c2p_att = torch.gather(c2p_att, dim=-1, index=c2p_dynamic_expand(c2p_pos, query_layer, relative_pos))
score += c2p_att
# position->content
if "p2c" in self.pos_att_type or "p2p" in self.pos_att_type:
pos_query_layer /= math.sqrt(pos_query_layer.size(-1) * scale_factor)
if query_layer.size(-2) != key_layer.size(-2):
r_pos = build_relative_position(key_layer.size(-2), key_layer.size(-2), query_layer.device)
else:
r_pos = relative_pos
p2c_pos = torch.clamp(-r_pos + att_span, 0, att_span * 2 - 1)
if query_layer.size(-2) != key_layer.size(-2):
pos_index = relative_pos[:, :, :, 0].unsqueeze(-1)
if "p2c" in self.pos_att_type:
p2c_att = torch.matmul(key_layer, pos_query_layer.transpose(-1, -2))
p2c_att = torch.gather(
p2c_att, dim=-1, index=p2c_dynamic_expand(p2c_pos, query_layer, key_layer)
).transpose(-1, -2)
if query_layer.size(-2) != key_layer.size(-2):
p2c_att = torch.gather(p2c_att, dim=-2, index=pos_dynamic_expand(pos_index, p2c_att, key_layer))
score += p2c_att
return score
class DebertaEmbeddings(nn.Module):
"""Construct the embeddings from word, position and token_type embeddings."""
def __init__(self, config):
super().__init__()
pad_token_id = getattr(config, "pad_token_id", 0)
self.embedding_size = getattr(config, "embedding_size", config.hidden_size)
self.word_embeddings = nn.Embedding(config.vocab_size, self.embedding_size, padding_idx=pad_token_id)
self.position_biased_input = getattr(config, "position_biased_input", True)
if not self.position_biased_input:
self.position_embeddings = None
else:
self.position_embeddings = nn.Embedding(config.max_position_embeddings, self.embedding_size)
if config.type_vocab_size > 0:
self.token_type_embeddings = nn.Embedding(config.type_vocab_size, self.embedding_size)
if self.embedding_size != config.hidden_size:
self.embed_proj = nn.Linear(self.embedding_size, config.hidden_size, bias=False)
self.LayerNorm = DebertaLayerNorm(config.hidden_size, config.layer_norm_eps)
self.dropout = StableDropout(config.hidden_dropout_prob)
self.config = config
# position_ids (1, len position emb) is contiguous in memory and exported when serialized
self.register_buffer("position_ids", torch.arange(config.max_position_embeddings).expand((1, -1)))
def forward(self, input_ids=None, token_type_ids=None, position_ids=None, mask=None, inputs_embeds=None):
if input_ids is not None:
input_shape = input_ids.size()
else:
input_shape = inputs_embeds.size()[:-1]
seq_length = input_shape[1]
if position_ids is None:
position_ids = self.position_ids[:, :seq_length]
if token_type_ids is None:
token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=self.position_ids.device)
if inputs_embeds is None:
inputs_embeds = self.word_embeddings(input_ids)
if self.position_embeddings is not None:
position_embeddings = self.position_embeddings(position_ids.long())
else:
position_embeddings = torch.zeros_like(inputs_embeds)
embeddings = inputs_embeds
if self.position_biased_input:
embeddings += position_embeddings
if self.config.type_vocab_size > 0:
token_type_embeddings = self.token_type_embeddings(token_type_ids)
embeddings += token_type_embeddings
if self.embedding_size != self.config.hidden_size:
embeddings = self.embed_proj(embeddings)
embeddings = self.LayerNorm(embeddings)
if mask is not None:
if mask.dim() != embeddings.dim():
if mask.dim() == 4:
mask = mask.squeeze(1).squeeze(1)
mask = mask.unsqueeze(2)
mask = mask.to(embeddings.dtype)
embeddings = embeddings * mask
embeddings = self.dropout(embeddings)
return embeddings
[docs]class DebertaPreTrainedModel(PreTrainedModel):
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = DebertaConfig
base_model_prefix = "deberta"
_keys_to_ignore_on_load_missing = ["position_ids"]
_keys_to_ignore_on_load_unexpected = ["position_embeddings"]
def __init__(self, config):
super().__init__(config)
self._register_load_state_dict_pre_hook(self._pre_load_hook)
def _init_weights(self, module):
"""Initialize the weights."""
if isinstance(module, nn.Linear):
# Slightly different from the TF version which uses truncated_normal for initialization
# cf https://github.com/pytorch/pytorch/pull/5617
module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
if module.bias is not None:
module.bias.data.zero_()
elif isinstance(module, nn.Embedding):
module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
if module.padding_idx is not None:
module.weight.data[module.padding_idx].zero_()
def _pre_load_hook(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
"""
Removes the classifier if it doesn't have the correct number of labels.
"""
self_state = self.state_dict()
if (
("classifier.weight" in self_state)
and ("classifier.weight" in state_dict)
and self_state["classifier.weight"].size() != state_dict["classifier.weight"].size()
):
logger.warning(
f"The checkpoint classifier head has a shape {state_dict['classifier.weight'].size()} and this model "
f"classifier head has a shape {self_state['classifier.weight'].size()}. Ignoring the checkpoint "
f"weights. You should train your model on new data."
)
del state_dict["classifier.weight"]
if "classifier.bias" in state_dict:
del state_dict["classifier.bias"]
DEBERTA_START_DOCSTRING = r"""
The DeBERTa model was proposed in `DeBERTa: Decoding-enhanced BERT with Disentangled Attention
<https://arxiv.org/abs/2006.03654>`_ by Pengcheng He, Xiaodong Liu, Jianfeng Gao, Weizhu Chen. It's build on top of
BERT/RoBERTa with two improvements, i.e. disentangled attention and enhanced mask decoder. With those two
improvements, it out perform BERT/RoBERTa on a majority of tasks with 80GB pretraining data.
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 all matter related to
general usage and behavior.```
Parameters:
config (:class:`~transformers.DebertaConfig`): 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 :meth:`~transformers.PreTrainedModel.from_pretrained` method to load the model
weights.
"""
DEBERTA_INPUTS_DOCSTRING = r"""
Args:
input_ids (:obj:`torch.LongTensor` of shape :obj:`{0}`):
Indices of input sequence tokens in the vocabulary.
Indices can be obtained using :class:`transformers.DebertaTokenizer`. See
:func:`transformers.PreTrainedTokenizer.encode` and :func:`transformers.PreTrainedTokenizer.__call__` for
details.
`What are input IDs? <../glossary.html#input-ids>`__
attention_mask (:obj:`torch.FloatTensor` of shape :obj:`{0}`, `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.html#attention-mask>`__
token_type_ids (:obj:`torch.LongTensor` of shape :obj:`{0}`, `optional`):
Segment token indices to indicate first and second portions of the inputs. Indices are selected in ``[0,
1]``:
- 0 corresponds to a `sentence A` token,
- 1 corresponds to a `sentence B` token.
`What are token type IDs? <../glossary.html#token-type-ids>`_
position_ids (:obj:`torch.LongTensor` of shape :obj:`{0}`, `optional`):
Indices of positions of each input sequence tokens in the position embeddings. Selected in the range ``[0,
config.max_position_embeddings - 1]``.
`What are position IDs? <../glossary.html#position-ids>`_
inputs_embeds (:obj:`torch.FloatTensor` of shape :obj:`(batch_size, sequence_length, hidden_size)`, `optional`):
Optionally, instead of passing :obj:`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 (:obj:`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 (:obj:`bool`, `optional`):
Whether or not to return the hidden states of all layers. See ``hidden_states`` under returned tensors for
more detail.
return_dict (:obj:`bool`, `optional`):
Whether or not to return a :class:`~transformers.file_utils.ModelOutput` instead of a plain tuple.
"""
[docs]@add_start_docstrings(
"The bare DeBERTa Model transformer outputting raw hidden-states without any specific head on top.",
DEBERTA_START_DOCSTRING,
)
class DebertaModel(DebertaPreTrainedModel):
def __init__(self, config):
super().__init__(config)
self.embeddings = DebertaEmbeddings(config)
self.encoder = DebertaEncoder(config)
self.z_steps = 0
self.config = config
self.init_weights()
def get_input_embeddings(self):
return self.embeddings.word_embeddings
def set_input_embeddings(self, new_embeddings):
self.embeddings.word_embeddings = new_embeddings
def _prune_heads(self, heads_to_prune):
"""
Prunes heads of the model. heads_to_prune: dict of {layer_num: list of heads to prune in this layer} See base
class PreTrainedModel
"""
raise NotImplementedError("The prune function is not implemented in DeBERTa model.")
[docs] @add_start_docstrings_to_model_forward(DEBERTA_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=SequenceClassifierOutput,
config_class=_CONFIG_FOR_DOC,
)
def forward(
self,
input_ids=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
inputs_embeds=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
):
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
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 not None:
input_shape = input_ids.size()
elif inputs_embeds is not None:
input_shape = inputs_embeds.size()[:-1]
else:
raise ValueError("You have to specify either input_ids or inputs_embeds")
device = input_ids.device if input_ids is not None else inputs_embeds.device
if attention_mask is None:
attention_mask = torch.ones(input_shape, device=device)
if token_type_ids is None:
token_type_ids = torch.zeros(input_shape, dtype=torch.long, device=device)
embedding_output = self.embeddings(
input_ids=input_ids,
token_type_ids=token_type_ids,
position_ids=position_ids,
mask=attention_mask,
inputs_embeds=inputs_embeds,
)
encoder_outputs = self.encoder(
embedding_output,
attention_mask,
output_hidden_states=True,
output_attentions=output_attentions,
return_dict=return_dict,
)
encoded_layers = encoder_outputs[1]
if self.z_steps > 1:
hidden_states = encoded_layers[-2]
layers = [self.encoder.layer[-1] for _ in range(self.z_steps)]
query_states = encoded_layers[-1]
rel_embeddings = self.encoder.get_rel_embedding()
attention_mask = self.encoder.get_attention_mask(attention_mask)
rel_pos = self.encoder.get_rel_pos(embedding_output)
for layer in layers[1:]:
query_states = layer(
hidden_states,
attention_mask,
return_att=False,
query_states=query_states,
relative_pos=rel_pos,
rel_embeddings=rel_embeddings,
)
encoded_layers.append(query_states)
sequence_output = encoded_layers[-1]
if not return_dict:
return (sequence_output,) + encoder_outputs[(1 if output_hidden_states else 2) :]
return BaseModelOutput(
last_hidden_state=sequence_output,
hidden_states=encoder_outputs.hidden_states if output_hidden_states else None,
attentions=encoder_outputs.attentions,
)
# copied from transformers.models.bert.BertPredictionHeadTransform with bert -> deberta
class DebertaPredictionHeadTransform(nn.Module):
def __init__(self, config):
super().__init__()
self.dense = nn.Linear(config.hidden_size, config.hidden_size)
if isinstance(config.hidden_act, str):
self.transform_act_fn = ACT2FN[config.hidden_act]
else:
self.transform_act_fn = config.hidden_act
self.LayerNorm = nn.LayerNorm(config.hidden_size, eps=config.layer_norm_eps)
def forward(self, hidden_states):
hidden_states = self.dense(hidden_states)
hidden_states = self.transform_act_fn(hidden_states)
hidden_states = self.LayerNorm(hidden_states)
return hidden_states
# copied from transformers.models.bert.BertLMPredictionHead with bert -> deberta
class DebertaLMPredictionHead(nn.Module):
def __init__(self, config):
super().__init__()
self.transform = DebertaPredictionHeadTransform(config)
# The output weights are the same as the input embeddings, but there is
# an output-only bias for each token.
self.decoder = nn.Linear(config.hidden_size, config.vocab_size, bias=False)
self.bias = nn.Parameter(torch.zeros(config.vocab_size))
# Need a link between the two variables so that the bias is correctly resized with `resize_token_embeddings`
self.decoder.bias = self.bias
def forward(self, hidden_states):
hidden_states = self.transform(hidden_states)
hidden_states = self.decoder(hidden_states)
return hidden_states
# copied from transformers.models.bert.BertOnlyMLMHead with bert -> deberta
class DebertaOnlyMLMHead(nn.Module):
def __init__(self, config):
super().__init__()
self.predictions = DebertaLMPredictionHead(config)
def forward(self, sequence_output):
prediction_scores = self.predictions(sequence_output)
return prediction_scores
[docs]@add_start_docstrings(
"""
DeBERTa Model transformer with a sequence classification/regression head on top (a linear layer on top of the
pooled output) e.g. for GLUE tasks.
""",
DEBERTA_START_DOCSTRING,
)
class DebertaForSequenceClassification(DebertaPreTrainedModel):
def __init__(self, config):
super().__init__(config)
num_labels = getattr(config, "num_labels", 2)
self.num_labels = num_labels
self.deberta = DebertaModel(config)
self.pooler = ContextPooler(config)
output_dim = self.pooler.output_dim
self.classifier = torch.nn.Linear(output_dim, num_labels)
drop_out = getattr(config, "cls_dropout", None)
drop_out = self.config.hidden_dropout_prob if drop_out is None else drop_out
self.dropout = StableDropout(drop_out)
self.init_weights()
def get_input_embeddings(self):
return self.deberta.get_input_embeddings()
def set_input_embeddings(self, new_embeddings):
self.deberta.set_input_embeddings(new_embeddings)
[docs] @add_start_docstrings_to_model_forward(DEBERTA_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=SequenceClassifierOutput,
config_class=_CONFIG_FOR_DOC,
)
def forward(
self,
input_ids=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
inputs_embeds=None,
labels=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
):
r"""
labels (:obj:`torch.LongTensor` of shape :obj:`(batch_size,)`, `optional`):
Labels for computing the sequence classification/regression loss. Indices should be in :obj:`[0, ...,
config.num_labels - 1]`. If :obj:`config.num_labels == 1` a regression loss is computed (Mean-Square loss),
If :obj:`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
outputs = self.deberta(
input_ids,
token_type_ids=token_type_ids,
attention_mask=attention_mask,
position_ids=position_ids,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
encoder_layer = outputs[0]
pooled_output = self.pooler(encoder_layer)
pooled_output = self.dropout(pooled_output)
logits = self.classifier(pooled_output)
loss = None
if labels is not None:
if self.num_labels == 1:
# regression task
loss_fn = torch.nn.MSELoss()
logits = logits.view(-1).to(labels.dtype)
loss = loss_fn(logits, labels.view(-1))
elif labels.dim() == 1 or labels.size(-1) == 1:
label_index = (labels >= 0).nonzero()
labels = labels.long()
if label_index.size(0) > 0:
labeled_logits = torch.gather(logits, 0, label_index.expand(label_index.size(0), logits.size(1)))
labels = torch.gather(labels, 0, label_index.view(-1))
loss_fct = CrossEntropyLoss()
loss = loss_fct(labeled_logits.view(-1, self.num_labels).float(), labels.view(-1))
else:
loss = torch.tensor(0).to(logits)
else:
log_softmax = torch.nn.LogSoftmax(-1)
loss = -((log_softmax(logits) * labels).sum(-1)).mean()
if not return_dict:
output = (logits,) + outputs[1:]
return ((loss,) + output) if loss is not None else output
else:
return SequenceClassifierOutput(
loss=loss,
logits=logits,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
)
[docs]@add_start_docstrings(
"""
DeBERTa Model with a token classification head on top (a linear layer on top of the hidden-states output) e.g. for
Named-Entity-Recognition (NER) tasks.
""",
DEBERTA_START_DOCSTRING,
)
class DebertaForTokenClassification(DebertaPreTrainedModel):
_keys_to_ignore_on_load_unexpected = [r"pooler"]
def __init__(self, config):
super().__init__(config)
self.num_labels = config.num_labels
self.deberta = DebertaModel(config)
self.dropout = nn.Dropout(config.hidden_dropout_prob)
self.classifier = nn.Linear(config.hidden_size, config.num_labels)
self.init_weights()
[docs] @add_start_docstrings_to_model_forward(DEBERTA_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=TokenClassifierOutput,
config_class=_CONFIG_FOR_DOC,
)
def forward(
self,
input_ids=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
inputs_embeds=None,
labels=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
):
r"""
labels (:obj:`torch.LongTensor` of shape :obj:`(batch_size, sequence_length)`, `optional`):
Labels for computing the token classification loss. Indices should be in ``[0, ..., config.num_labels -
1]``.
"""
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
outputs = self.deberta(
input_ids,
attention_mask=attention_mask,
token_type_ids=token_type_ids,
position_ids=position_ids,
inputs_embeds=inputs_embeds,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
sequence_output = outputs[0]
sequence_output = self.dropout(sequence_output)
logits = self.classifier(sequence_output)
loss = None
if labels is not None:
loss_fct = CrossEntropyLoss()
# Only keep active parts of the loss
if attention_mask is not None:
active_loss = attention_mask.view(-1) == 1
active_logits = logits.view(-1, self.num_labels)
active_labels = torch.where(
active_loss, labels.view(-1), torch.tensor(loss_fct.ignore_index).type_as(labels)
)
loss = loss_fct(active_logits, active_labels)
else:
loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
if not return_dict:
output = (logits,) + outputs[1:]
return ((loss,) + output) if loss is not None else output
return TokenClassifierOutput(
loss=loss,
logits=logits,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
)
[docs]@add_start_docstrings(
"""
DeBERTa Model with a span classification head on top for extractive question-answering tasks like SQuAD (a linear
layers on top of the hidden-states output to compute `span start logits` and `span end logits`).
""",
DEBERTA_START_DOCSTRING,
)
class DebertaForQuestionAnswering(DebertaPreTrainedModel):
_keys_to_ignore_on_load_unexpected = [r"pooler"]
def __init__(self, config):
super().__init__(config)
self.num_labels = config.num_labels
self.deberta = DebertaModel(config)
self.qa_outputs = nn.Linear(config.hidden_size, config.num_labels)
self.init_weights()
[docs] @add_start_docstrings_to_model_forward(DEBERTA_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=QuestionAnsweringModelOutput,
config_class=_CONFIG_FOR_DOC,
)
def forward(
self,
input_ids=None,
attention_mask=None,
token_type_ids=None,
position_ids=None,
inputs_embeds=None,
start_positions=None,
end_positions=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
):
r"""
start_positions (:obj:`torch.LongTensor` of shape :obj:`(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 (:obj:`sequence_length`). Position outside of the
sequence are not taken into account for computing the loss.
end_positions (:obj:`torch.LongTensor` of shape :obj:`(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 (:obj:`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
outputs = self.deberta(
input_ids,
attention_mask=attention_mask,
token_type_ids=token_type_ids,
position_ids=position_ids,
inputs_embeds=inputs_embeds,
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)
end_logits = end_logits.squeeze(-1)
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.clamp_(0, ignored_index)
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 QuestionAnsweringModelOutput(
loss=total_loss,
start_logits=start_logits,
end_logits=end_logits,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
)