# coding=utf-8
# Copyright 2018 Google AI, Google Brain and Carnegie Mellon University Authors and the HuggingFace Inc. team.
# Copyright (c) 2018, NVIDIA CORPORATION. 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.
"""
TF 2.0 XLNet model.
"""
import warnings
from dataclasses import dataclass
from typing import List, Optional, Tuple
import tensorflow as tf
from ...activations_tf import get_tf_activation
from ...file_utils import (
MULTIPLE_CHOICE_DUMMY_INPUTS,
ModelOutput,
add_code_sample_docstrings,
add_start_docstrings,
add_start_docstrings_to_model_forward,
replace_return_docstrings,
)
from ...modeling_tf_utils import (
TFCausalLanguageModelingLoss,
TFMultipleChoiceLoss,
TFPreTrainedModel,
TFQuestionAnsweringLoss,
TFSequenceClassificationLoss,
TFSequenceSummary,
TFSharedEmbeddings,
TFTokenClassificationLoss,
get_initializer,
input_processing,
keras_serializable,
shape_list,
)
from ...utils import logging
from .configuration_xlnet import XLNetConfig
logger = logging.get_logger(__name__)
_CHECKPOINT_FOR_DOC = "xlnet-base-cased"
_CONFIG_FOR_DOC = "XLNetConfig"
_TOKENIZER_FOR_DOC = "XLNetTokenizer"
TF_XLNET_PRETRAINED_MODEL_ARCHIVE_LIST = [
"xlnet-base-cased",
"xlnet-large-cased",
# See all XLNet models at https://huggingface.co/models?filter=xlnet
]
class TFXLNetRelativeAttention(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
if config.d_model % config.n_head != 0:
raise ValueError(
f"The hidden size ({config.d_model}) is not a multiple of the number of attention "
f"heads ({config.n_head}"
)
self.n_head = config.n_head
self.d_head = config.d_head
self.d_model = config.d_model
self.scale = 1 / (config.d_head ** 0.5)
self.initializer_range = config.initializer_range
self.output_attentions = config.output_attentions
self.layer_norm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="layer_norm")
self.dropout = tf.keras.layers.Dropout(config.dropout)
def build(self, input_shape):
initializer = get_initializer(self.initializer_range)
self.q = self.add_weight(
shape=(self.d_model, self.n_head, self.d_head), initializer=initializer, trainable=True, name="q"
)
self.k = self.add_weight(
shape=(self.d_model, self.n_head, self.d_head), initializer=initializer, trainable=True, name="k"
)
self.v = self.add_weight(
shape=(self.d_model, self.n_head, self.d_head), initializer=initializer, trainable=True, name="v"
)
self.o = self.add_weight(
shape=(self.d_model, self.n_head, self.d_head), initializer=initializer, trainable=True, name="o"
)
self.r = self.add_weight(
shape=(self.d_model, self.n_head, self.d_head), initializer=initializer, trainable=True, name="r"
)
self.r_r_bias = self.add_weight(
shape=(self.n_head, self.d_head), initializer="zeros", trainable=True, name="r_r_bias"
)
self.r_s_bias = self.add_weight(
shape=(self.n_head, self.d_head), initializer="zeros", trainable=True, name="r_s_bias"
)
self.r_w_bias = self.add_weight(
shape=(self.n_head, self.d_head), initializer="zeros", trainable=True, name="r_w_bias"
)
self.seg_embed = self.add_weight(
shape=(2, self.n_head, self.d_head), initializer=initializer, trainable=True, name="seg_embed"
)
super().build(input_shape)
def prune_heads(self, heads):
raise NotImplementedError
def rel_shift(self, x, klen=-1):
"""perform relative shift to form the relative attention score."""
x_size = shape_list(x)
x = tf.reshape(x, (x_size[1], x_size[0], x_size[2], x_size[3]))
x = x[1:, ...]
x = tf.reshape(x, (x_size[0], x_size[1] - 1, x_size[2], x_size[3]))
x = x[:, 0:klen, :, :]
# x = torch.index_select(x, 1, torch.arange(klen, device=x.device, dtype=torch.long))
return x
def rel_attn_core(
self, q_head, k_head_h, v_head_h, k_head_r, seg_mat, attn_mask, head_mask, output_attentions, training=False
):
"""Core relative positional attention operations."""
# content based attention score
ac = tf.einsum("ibnd,jbnd->ijbn", q_head + self.r_w_bias, k_head_h)
# position based attention score
bd = tf.einsum("ibnd,jbnd->ijbn", q_head + self.r_r_bias, k_head_r)
bd = self.rel_shift(bd, klen=shape_list(ac)[1])
# segment based attention score
if seg_mat is None:
ef = 0
else:
ef = tf.einsum("ibnd,snd->ibns", q_head + self.r_s_bias, self.seg_embed)
ef = tf.einsum("ijbs,ibns->ijbn", seg_mat, ef)
# merge attention scores and perform masking
attn_score = (ac + bd + ef) * self.scale
if attn_mask is not None:
# attn_score = attn_score * (1 - attn_mask) - 1e30 * attn_mask
if attn_mask.dtype == tf.float16 or attn_mask.dtype == tf.bfloat16:
attn_score = attn_score - 65500 * attn_mask
else:
attn_score = attn_score - 1e30 * attn_mask
# attention probability
attn_prob = tf.nn.softmax(attn_score, axis=1)
attn_prob = self.dropout(attn_prob, training=training)
# Mask heads if we want to
if head_mask is not None:
attn_prob = attn_prob * head_mask
# attention output
attn_vec = tf.einsum("ijbn,jbnd->ibnd", attn_prob, v_head_h)
if output_attentions:
return attn_vec, attn_prob
return attn_vec
def post_attention(self, h, attn_vec, residual=True, training=False):
"""Post-attention processing."""
# post-attention projection (back to `d_model`)
attn_out = tf.einsum("ibnd,hnd->ibh", attn_vec, self.o)
attn_out = self.dropout(attn_out, training=training)
if residual:
attn_out = attn_out + h
output = self.layer_norm(attn_out)
return output
def call(
self,
h,
g,
attn_mask_h,
attn_mask_g,
r,
seg_mat,
mems,
target_mapping,
head_mask,
output_attentions,
training=False,
):
if g is not None:
# Two-stream attention with relative positional encoding.
# content based attention score
if mems is not None and len(shape_list(mems)) > 1:
cat = tf.concat([mems, h], axis=0)
else:
cat = h
# content-based key head
k_head_h = tf.einsum("ibh,hnd->ibnd", cat, self.k)
# content-based value head
v_head_h = tf.einsum("ibh,hnd->ibnd", cat, self.v)
# position-based key head
k_head_r = tf.einsum("ibh,hnd->ibnd", r, self.r)
# h-stream
# content-stream query head
q_head_h = tf.einsum("ibh,hnd->ibnd", h, self.q)
# core attention ops
attn_vec_h = self.rel_attn_core(
q_head_h,
k_head_h,
v_head_h,
k_head_r,
seg_mat,
attn_mask_h,
head_mask,
output_attentions,
training=training,
)
if output_attentions:
attn_vec_h, attn_prob_h = attn_vec_h
# post processing
output_h = self.post_attention(h, attn_vec_h, training=training)
# g-stream
# query-stream query head
q_head_g = tf.einsum("ibh,hnd->ibnd", g, self.q)
# core attention ops
if target_mapping is not None:
q_head_g = tf.einsum("mbnd,mlb->lbnd", q_head_g, target_mapping)
attn_vec_g = self.rel_attn_core(
q_head_g,
k_head_h,
v_head_h,
k_head_r,
seg_mat,
attn_mask_g,
head_mask,
output_attentions,
training=training,
)
if output_attentions:
attn_vec_g, attn_prob_g = attn_vec_g
attn_vec_g = tf.einsum("lbnd,mlb->mbnd", attn_vec_g, target_mapping)
else:
attn_vec_g = self.rel_attn_core(
q_head_g,
k_head_h,
v_head_h,
k_head_r,
seg_mat,
attn_mask_g,
head_mask,
output_attentions,
training=training,
)
if output_attentions:
attn_vec_g, attn_prob_g = attn_vec_g
# post processing
output_g = self.post_attention(g, attn_vec_g, training=training)
if output_attentions:
attn_prob = attn_prob_h, attn_prob_g
else:
# Multi-head attention with relative positional encoding
if mems is not None and len(shape_list(mems)) > 1:
cat = tf.concat([mems, h], axis=0)
else:
cat = h
# content heads
q_head_h = tf.einsum("ibh,hnd->ibnd", h, self.q)
k_head_h = tf.einsum("ibh,hnd->ibnd", cat, self.k)
v_head_h = tf.einsum("ibh,hnd->ibnd", cat, self.v)
# positional heads
k_head_r = tf.einsum("ibh,hnd->ibnd", r, self.r)
# core attention ops
attn_vec = self.rel_attn_core(
q_head_h,
k_head_h,
v_head_h,
k_head_r,
seg_mat,
attn_mask_h,
head_mask,
output_attentions,
training=training,
)
if output_attentions:
attn_vec, attn_prob = attn_vec
# post processing
output_h = self.post_attention(h, attn_vec, training=training)
output_g = None
outputs = (output_h, output_g)
if output_attentions:
outputs = outputs + (attn_prob,)
return outputs
class TFXLNetFeedForward(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.layer_norm = tf.keras.layers.LayerNormalization(epsilon=config.layer_norm_eps, name="layer_norm")
self.layer_1 = tf.keras.layers.Dense(
config.d_inner, kernel_initializer=get_initializer(config.initializer_range), name="layer_1"
)
self.layer_2 = tf.keras.layers.Dense(
config.d_model, kernel_initializer=get_initializer(config.initializer_range), name="layer_2"
)
self.dropout = tf.keras.layers.Dropout(config.dropout)
if isinstance(config.ff_activation, str):
self.activation_function = get_tf_activation(config.ff_activation)
else:
self.activation_function = config.ff_activation
def call(self, inp, training=False):
output = inp
output = self.layer_1(output)
output = self.activation_function(output)
output = self.dropout(output, training=training)
output = self.layer_2(output)
output = self.dropout(output, training=training)
output = self.layer_norm(output + inp)
return output
class TFXLNetLayer(tf.keras.layers.Layer):
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.rel_attn = TFXLNetRelativeAttention(config, name="rel_attn")
self.ff = TFXLNetFeedForward(config, name="ff")
self.dropout = tf.keras.layers.Dropout(config.dropout)
def call(
self,
output_h,
output_g,
non_tgt_mask,
attn_mask,
pos_emb,
seg_mat,
mems,
target_mapping,
head_mask,
output_attentions,
training=False,
):
outputs = self.rel_attn(
output_h,
output_g,
non_tgt_mask,
attn_mask,
pos_emb,
seg_mat,
mems,
target_mapping,
head_mask,
output_attentions,
training=training,
)
output_h, output_g = outputs[:2]
if output_g is not None:
output_g = self.ff(output_g, training=training)
output_h = self.ff(output_h, training=training)
outputs = (output_h, output_g) + outputs[2:] # Add again attentions if there are there
return outputs
class TFXLNetLMHead(tf.keras.layers.Layer):
def __init__(self, config, input_embeddings, **kwargs):
super().__init__(**kwargs)
self.vocab_size = config.vocab_size
# The output weights are the same as the input embeddings, but there is
# an output-only bias for each token.
self.input_embeddings = input_embeddings
def build(self, input_shape):
self.bias = self.add_weight(shape=(self.vocab_size,), initializer="zeros", trainable=True, name="bias")
super().build(input_shape)
def get_output_embeddings(self):
return self.input_embeddings
def set_output_embeddings(self, value):
self.input_embeddings.weight = value
self.input_embeddings.vocab_size = shape_list(value)[0]
def get_bias(self):
return {"bias": self.bias}
def set_bias(self, value):
self.bias = value["bias"]
self.vocab_size = shape_list(value["bias"])[0]
def call(self, hidden_states):
hidden_states = self.input_embeddings(hidden_states, mode="linear")
hidden_states = hidden_states + self.bias
return hidden_states
@keras_serializable
class TFXLNetMainLayer(tf.keras.layers.Layer):
config_class = XLNetConfig
def __init__(self, config, **kwargs):
super().__init__(**kwargs)
self.config = config
self.output_hidden_states = config.output_hidden_states
self.output_attentions = config.output_attentions
self.return_dict = config.return_dict
self.mem_len = config.mem_len
self.reuse_len = config.reuse_len
self.d_model = config.d_model
self.same_length = config.same_length
self.attn_type = config.attn_type
self.bi_data = config.bi_data
self.clamp_len = config.clamp_len
self.n_layer = config.n_layer
self.use_bfloat16 = config.use_bfloat16
self.initializer_range = config.initializer_range
self.word_embedding = TFSharedEmbeddings(
config.vocab_size, config.d_model, initializer_range=config.initializer_range, name="word_embedding"
)
self.layer = [TFXLNetLayer(config, name=f"layer_._{i}") for i in range(config.n_layer)]
self.dropout = tf.keras.layers.Dropout(config.dropout)
self.use_mems_eval = config.use_mems_eval
self.use_mems_train = config.use_mems_train
def get_input_embeddings(self):
return self.word_embedding
def set_input_embeddings(self, value):
self.word_embedding.weight = value
self.word_embedding.vocab_size = shape_list(value)[0]
def build(self, input_shape):
initializer = get_initializer(self.initializer_range)
self.mask_emb = self.add_weight(
shape=(1, 1, self.d_model), initializer=initializer, trainable=True, name="mask_emb"
)
def _prune_heads(self, heads_to_prune):
raise NotImplementedError
def create_mask(self, qlen, mlen):
"""
Creates causal attention mask. Float mask where 1.0 indicates masked, 0.0 indicates not-masked.
Args:
qlen: TODO Lysandre didn't fill
mlen: TODO Lysandre didn't fill
::
same_length=False: same_length=True:
<mlen > < qlen > <mlen > < qlen >
^ [0 0 0 0 0 1 1 1 1] [0 0 0 0 0 1 1 1 1]
[0 0 0 0 0 0 1 1 1] [1 0 0 0 0 0 1 1 1]
qlen [0 0 0 0 0 0 0 1 1] [1 1 0 0 0 0 0 1 1]
[0 0 0 0 0 0 0 0 1] [1 1 1 0 0 0 0 0 1]
v [0 0 0 0 0 0 0 0 0] [1 1 1 1 0 0 0 0 0]
"""
attn_mask = tf.ones([qlen, qlen])
mask_u = tf.matrix_band_part(attn_mask, 0, -1)
mask_dia = tf.matrix_band_part(attn_mask, 0, 0)
attn_mask_pad = tf.zeros([qlen, mlen])
ret = tf.concat([attn_mask_pad, mask_u - mask_dia], 1)
if self.same_length:
mask_l = tf.matrix_band_part(attn_mask, -1, 0)
ret = tf.concat([ret[:, :qlen] + mask_l - mask_dia, ret[:, qlen:]], 1)
return ret
def cache_mem(self, curr_out, prev_mem):
# cache hidden states into memory.
if self.reuse_len is not None and self.reuse_len > 0:
curr_out = curr_out[: self.reuse_len]
if self.mem_len is None or self.mem_len == 0:
# If :obj:`use_mems` is active but no `mem_len` is defined, the model behaves like GPT-2 at inference time
# and returns all of the past and current hidden states.
cutoff = 0
else:
# If :obj:`use_mems` is active and `mem_len` is defined, the model returns the last `mem_len` hidden
# states. This is the preferred setting for training and long-form generation.
cutoff = -self.mem_len
if prev_mem is None:
# if :obj:`use_mems` is active and `mem_len` is defined, the model
new_mem = curr_out[cutoff:]
else:
new_mem = tf.concat([prev_mem, curr_out], 0)[cutoff:]
return tf.stop_gradient(new_mem)
@staticmethod
def positional_embedding(pos_seq, inv_freq, bsz=None):
sinusoid_inp = tf.einsum("i,d->id", pos_seq, inv_freq)
pos_emb = tf.concat([tf.sin(sinusoid_inp), tf.cos(sinusoid_inp)], axis=-1)
pos_emb = pos_emb[:, None, :]
if bsz is not None:
pos_emb = tf.tile(pos_emb, [1, bsz, 1])
return pos_emb
def relative_positional_encoding(self, qlen, klen, bsz=None):
"""create relative positional encoding."""
freq_seq = tf.range(0, self.d_model, 2.0)
inv_freq = 1 / (10000 ** (freq_seq / self.d_model))
if self.attn_type == "bi":
# beg, end = klen - 1, -qlen
beg, end = klen, -qlen
elif self.attn_type == "uni":
# beg, end = klen - 1, -1
beg, end = klen, -1
else:
raise ValueError(f"Unknown `attn_type` {self.attn_type}.")
if self.bi_data:
fwd_pos_seq = tf.range(beg, end, -1.0)
bwd_pos_seq = tf.range(-beg, -end, 1.0)
if self.clamp_len > 0:
fwd_pos_seq = tf.clip_by_value(fwd_pos_seq, -self.clamp_len, self.clamp_len)
bwd_pos_seq = tf.clip_by_value(bwd_pos_seq, -self.clamp_len, self.clamp_len)
if bsz is not None:
assert bsz % 2 == 0, f"With bi_data, the batch size {bsz} should be divisible by 2"
fwd_pos_emb = self.positional_embedding(fwd_pos_seq, inv_freq, bsz // 2)
bwd_pos_emb = self.positional_embedding(bwd_pos_seq, inv_freq, bsz // 2)
else:
fwd_pos_emb = self.positional_embedding(fwd_pos_seq, inv_freq)
bwd_pos_emb = self.positional_embedding(bwd_pos_seq, inv_freq)
pos_emb = tf.concat([fwd_pos_emb, bwd_pos_emb], axis=1)
else:
fwd_pos_seq = tf.range(beg, end, -1.0)
if self.clamp_len > 0:
fwd_pos_seq = tf.clip_by_value(fwd_pos_seq, -self.clamp_len, self.clamp_len)
pos_emb = self.positional_embedding(fwd_pos_seq, inv_freq, bsz)
return pos_emb
def call(
self,
input_ids=None,
attention_mask=None,
mems=None,
perm_mask=None,
target_mapping=None,
token_type_ids=None,
input_mask=None,
head_mask=None,
inputs_embeds=None,
use_mems=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
training=False,
**kwargs,
):
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
mems=mems,
perm_mask=perm_mask,
target_mapping=target_mapping,
token_type_ids=token_type_ids,
input_mask=input_mask,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
use_mems=use_mems,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
training=training,
kwargs_call=kwargs,
)
if training and inputs["use_mems"] is None:
inputs["use_mems"] = self.use_mems_train
else:
inputs["use_mems"] = self.use_mems_eval
# the original code for XLNet uses shapes [len, bsz] with the batch dimension at the end
# but we want a unified interface in the library with the batch size on the first dimension
# so we move here the first dimension (batch) to the end
if inputs["input_ids"] is not None and inputs["inputs_embeds"] is not None:
raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time")
elif inputs["input_ids"] is not None:
inputs["input_ids"] = tf.transpose(inputs["input_ids"], perm=(1, 0))
qlen, bsz = shape_list(inputs["input_ids"])[:2]
elif inputs["inputs_embeds"] is not None:
inputs["inputs_embeds"] = tf.transpose(inputs["inputs_embeds"], perm=(1, 0, 2))
qlen, bsz = shape_list(inputs["inputs_embeds"])[:2]
else:
raise ValueError("You have to specify either input_ids or inputs_embeds")
inputs["token_type_ids"] = (
tf.transpose(inputs["token_type_ids"], perm=(1, 0)) if inputs["token_type_ids"] is not None else None
)
inputs["input_mask"] = (
tf.transpose(inputs["input_mask"], perm=(1, 0)) if inputs["input_mask"] is not None else None
)
inputs["attention_mask"] = (
tf.transpose(inputs["attention_mask"], perm=(1, 0)) if inputs["attention_mask"] is not None else None
)
inputs["perm_mask"] = (
tf.transpose(inputs["perm_mask"], perm=(1, 2, 0)) if inputs["perm_mask"] is not None else None
)
inputs["target_mapping"] = (
tf.transpose(inputs["target_mapping"], perm=(1, 2, 0)) if inputs["target_mapping"] is not None else None
)
mlen = shape_list(inputs["mems"][0])[0] if inputs["mems"] is not None and inputs["mems"][0] is not None else 0
klen = mlen + qlen
# Attention mask
# causal attention mask
if self.attn_type == "uni":
attn_mask = self.create_mask(qlen, mlen)
attn_mask = attn_mask[:, :, None, None]
elif self.attn_type == "bi":
attn_mask = None
else:
raise ValueError(f"Unsupported attention type: {self.attn_type}")
# data mask: input mask & perm mask
assert inputs["input_mask"] is None or inputs["attention_mask"] is None, (
"You can only use one of input_mask (uses 1 for padding) "
"or attention_mask (uses 0 for padding, added for compatibility with BERT). Please choose one."
)
if inputs["input_mask"] is None and inputs["attention_mask"] is not None:
one_cst = tf.constant(1.0)
inputs["input_mask"] = 1.0 - tf.cast(inputs["attention_mask"], dtype=one_cst.dtype)
if inputs["input_mask"] is not None and inputs["perm_mask"] is not None:
data_mask = inputs["input_mask"][None] + inputs["perm_mask"]
elif inputs["input_mask"] is not None and inputs["perm_mask"] is None:
data_mask = inputs["input_mask"][None]
elif inputs["input_mask"] is None and inputs["perm_mask"] is not None:
data_mask = inputs["perm_mask"]
else:
data_mask = None
if data_mask is not None:
# all mems can be attended to
if mlen > 0:
mems_mask = tf.zeros([shape_list(data_mask)[0], mlen, bsz])
data_mask = tf.concat([mems_mask, data_mask], axis=1)
if attn_mask is None:
attn_mask = data_mask[:, :, :, None]
else:
attn_mask += data_mask[:, :, :, None]
if attn_mask is not None:
attn_mask = tf.cast(attn_mask > 0, dtype=attn_mask.dtype)
if attn_mask is not None:
non_tgt_mask = -tf.eye(qlen)
if mlen > 0:
non_tgt_mask = tf.concat([tf.zeros([qlen, mlen]), non_tgt_mask], axis=-1)
non_tgt_mask = tf.cast((attn_mask + non_tgt_mask[:, :, None, None]) > 0, dtype=non_tgt_mask.dtype)
else:
non_tgt_mask = None
# Word embeddings and prepare h & g hidden states
if inputs["inputs_embeds"] is not None:
word_emb_k = inputs["inputs_embeds"]
else:
word_emb_k = self.word_embedding(inputs["input_ids"])
output_h = self.dropout(word_emb_k, training=inputs["training"])
if inputs["target_mapping"] is not None:
word_emb_q = tf.tile(self.mask_emb, [shape_list(inputs["target_mapping"])[0], bsz, 1])
# else: # We removed the inp_q input which was same as target mapping
# inp_q_ext = inp_q[:, :, None]
# word_emb_q = inp_q_ext * self.mask_emb + (1 - inp_q_ext) * word_emb_k
output_g = self.dropout(word_emb_q, training=inputs["training"])
else:
output_g = None
# Segment embedding
if inputs["token_type_ids"] is not None:
# Convert `token_type_ids` to one-hot `seg_mat`
if mlen > 0:
mem_pad = tf.zeros([mlen, bsz], dtype=inputs["token_type_ids"].dtype)
cat_ids = tf.concat([mem_pad, inputs["token_type_ids"]], 0)
else:
cat_ids = inputs["token_type_ids"]
# `1` indicates not in the same segment [qlen x klen x bsz]
seg_mat = tf.cast(
tf.logical_not(tf.equal(inputs["token_type_ids"][:, None], cat_ids[None, :])),
dtype=inputs["token_type_ids"].dtype,
)
seg_mat = tf.one_hot(seg_mat, 2)
else:
seg_mat = None
# Positional encoding
pos_emb = self.relative_positional_encoding(qlen, klen, bsz=bsz)
pos_emb = self.dropout(pos_emb, training=inputs["training"])
# Prepare head mask if needed
# 1.0 in head_mask indicate we keep the head
# attention_probs has shape bsz x n_heads x N x N
# input head_mask has shape [num_heads] or [num_hidden_layers x num_heads] (a head_mask for each layer)
# and head_mask is converted to shape [num_hidden_layers x qlen x klen x bsz x n_head]
if inputs["head_mask"] is not None:
raise NotImplementedError
else:
inputs["head_mask"] = [None] * self.n_layer
new_mems = ()
if inputs["mems"] is None:
inputs["mems"] = [None] * len(self.layer)
attentions = [] if inputs["output_attentions"] else None
hidden_states = [] if inputs["output_hidden_states"] else None
for i, layer_module in enumerate(self.layer):
# cache new mems
if inputs["use_mems"]:
new_mems = new_mems + (self.cache_mem(output_h, inputs["mems"][i]),)
if inputs["output_hidden_states"]:
hidden_states.append((output_h, output_g) if output_g is not None else output_h)
outputs = layer_module(
output_h,
output_g,
non_tgt_mask,
attn_mask,
pos_emb,
seg_mat,
inputs["mems"][i],
inputs["target_mapping"],
inputs["head_mask"][i],
inputs["output_attentions"],
training=inputs["training"],
)
output_h, output_g = outputs[:2]
if inputs["output_attentions"]:
attentions.append(outputs[2])
# Add last hidden state
if inputs["output_hidden_states"]:
hidden_states.append((output_h, output_g) if output_g is not None else output_h)
output = self.dropout(output_g if output_g is not None else output_h, training=inputs["training"])
# Prepare outputs, we transpose back here to shape [bsz, len, hidden_dim] (cf. beginning of forward() method)
output = tf.transpose(output, perm=(1, 0, 2))
if not inputs["use_mems"]:
new_mems = None
if inputs["output_hidden_states"]:
if output_g is not None:
hidden_states = tuple(tf.transpose(h, perm=(1, 0, 2)) for hs in hidden_states for h in hs)
else:
hidden_states = tuple(tf.transpose(hs, perm=(1, 0, 2)) for hs in hidden_states)
if inputs["output_attentions"]:
attentions = tuple(tf.transpose(t, perm=(2, 3, 0, 1)) for t in attentions)
if not inputs["return_dict"]:
return tuple(v for v in [output, new_mems, hidden_states, attentions] if v is not None)
return TFXLNetModelOutput(
last_hidden_state=output, mems=new_mems, hidden_states=hidden_states, attentions=attentions
)
class TFXLNetPreTrainedModel(TFPreTrainedModel):
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = XLNetConfig
base_model_prefix = "transformer"
[docs]@dataclass
class TFXLNetModelOutput(ModelOutput):
"""
Output type of :class:`~transformers.TFXLNetModel`.
Args:
last_hidden_state (:obj:`tf.Tensor` of shape :obj:`(batch_size, num_predict, hidden_size)`):
Sequence of hidden-states at the last layer of the model.
``num_predict`` corresponds to ``target_mapping.shape[1]``. If ``target_mapping`` is ``None``, then
``num_predict`` corresponds to ``sequence_length``.
mems (:obj:`List[tf.Tensor]` of length :obj:`config.n_layers`):
Contains pre-computed hidden-states. Can be used (see :obj:`mems` input) to speed up sequential decoding.
The token ids which have their past given to this model should not be passed as :obj:`input_ids` as they
have already been computed.
hidden_states (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_hidden_states=True`` is passed or when ``config.output_hidden_states=True``):
Tuple of :obj:`tf.Tensor` (one for the output of the embeddings + one for the output of each layer) of
shape :obj:`(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_attentions=True`` is passed or when ``config.output_attentions=True``):
Tuple of :obj:`tf.Tensor` (one for each layer) of shape :obj:`(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
"""
last_hidden_state: tf.Tensor = None
mems: Optional[List[tf.Tensor]] = None
hidden_states: Optional[Tuple[tf.Tensor]] = None
attentions: Optional[Tuple[tf.Tensor]] = None
[docs]@dataclass
class TFXLNetLMHeadModelOutput(ModelOutput):
"""
Output type of :class:`~transformers.TFXLNetLMHeadModel`.
Args:
loss (:obj:`tf.Tensor` of shape `(1,)`, `optional`, returned when ``labels`` is provided)
Language modeling loss (for next-token prediction).
logits (:obj:`tf.Tensor` of shape :obj:`(batch_size, num_predict, config.vocab_size)`):
Prediction scores of the language modeling head (scores for each vocabulary token before SoftMax).
``num_predict`` corresponds to ``target_mapping.shape[1]``. If ``target_mapping`` is ``None``, then
``num_predict`` corresponds to ``sequence_length``.
mems (:obj:`List[tf.Tensor]` of length :obj:`config.n_layers`):
Contains pre-computed hidden-states. Can be used (see :obj:`mems` input) to speed up sequential decoding.
The token ids which have their past given to this model should not be passed as :obj:`input_ids` as they
have already been computed.
hidden_states (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_hidden_states=True`` is passed or when ``config.output_hidden_states=True``):
Tuple of :obj:`tf.Tensor` (one for the output of the embeddings + one for the output of each layer) of
shape :obj:`(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_attentions=True`` is passed or when ``config.output_attentions=True``):
Tuple of :obj:`tf.Tensor` (one for each layer) of shape :obj:`(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
"""
loss: Optional[tf.Tensor] = None
logits: tf.Tensor = None
mems: Optional[List[tf.Tensor]] = None
hidden_states: Optional[Tuple[tf.Tensor]] = None
attentions: Optional[Tuple[tf.Tensor]] = None
[docs]@dataclass
class TFXLNetForSequenceClassificationOutput(ModelOutput):
"""
Output type of :class:`~transformers.TFXLNetForSequenceClassification`.
Args:
loss (:obj:`tf.Tensor` of shape :obj:`(1,)`, `optional`, returned when :obj:`label` is provided):
Classification (or regression if config.num_labels==1) loss.
logits (:obj:`tf.Tensor` of shape :obj:`(batch_size, config.num_labels)`):
Classification (or regression if config.num_labels==1) scores (before SoftMax).
mems (:obj:`List[tf.Tensor]` of length :obj:`config.n_layers`):
Contains pre-computed hidden-states. Can be used (see :obj:`mems` input) to speed up sequential decoding.
The token ids which have their past given to this model should not be passed as :obj:`input_ids` as they
have already been computed.
hidden_states (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_hidden_states=True`` is passed or when ``config.output_hidden_states=True``):
Tuple of :obj:`tf.Tensor` (one for the output of the embeddings + one for the output of each layer) of
shape :obj:`(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_attentions=True`` is passed or when ``config.output_attentions=True``):
Tuple of :obj:`tf.Tensor` (one for each layer) of shape :obj:`(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
"""
loss: Optional[tf.Tensor] = None
logits: tf.Tensor = None
mems: Optional[List[tf.Tensor]] = None
hidden_states: Optional[Tuple[tf.Tensor]] = None
attentions: Optional[Tuple[tf.Tensor]] = None
[docs]@dataclass
class TFXLNetForTokenClassificationOutput(ModelOutput):
"""
Output type of :class:`~transformers.TFXLNetForTokenClassificationOutput`.
Args:
loss (:obj:`tf.Tensor` of shape :obj:`(1,)`, `optional`, returned when ``labels`` is provided) :
Classification loss.
logits (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length, config.num_labels)`):
Classification scores (before SoftMax).
mems (:obj:`List[tf.Tensor]` of length :obj:`config.n_layers`):
Contains pre-computed hidden-states. Can be used (see :obj:`mems` input) to speed up sequential decoding.
The token ids which have their past given to this model should not be passed as :obj:`input_ids` as they
have already been computed.
hidden_states (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_hidden_states=True`` is passed or when ``config.output_hidden_states=True``):
Tuple of :obj:`tf.Tensor` (one for the output of the embeddings + one for the output of each layer) of
shape :obj:`(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_attentions=True`` is passed or when ``config.output_attentions=True``):
Tuple of :obj:`tf.Tensor` (one for each layer) of shape :obj:`(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
"""
loss: Optional[tf.Tensor] = None
logits: tf.Tensor = None
mems: Optional[List[tf.Tensor]] = None
hidden_states: Optional[Tuple[tf.Tensor]] = None
attentions: Optional[Tuple[tf.Tensor]] = None
[docs]@dataclass
class TFXLNetForQuestionAnsweringSimpleOutput(ModelOutput):
"""
Output type of :class:`~transformers.TFXLNetForQuestionAnsweringSimple`.
Args:
loss (:obj:`tf.Tensor` of shape :obj:`(1,)`, `optional`, returned when :obj:`labels` is provided):
Total span extraction loss is the sum of a Cross-Entropy for the start and end positions.
start_logits (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length,)`):
Span-start scores (before SoftMax).
end_logits (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length,)`):
Span-end scores (before SoftMax).
mems (:obj:`List[tf.Tensor]` of length :obj:`config.n_layers`):
Contains pre-computed hidden-states. Can be used (see :obj:`mems` input) to speed up sequential decoding.
The token ids which have their past given to this model should not be passed as :obj:`input_ids` as they
have already been computed.
hidden_states (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_hidden_states=True`` is passed or when ``config.output_hidden_states=True``):
Tuple of :obj:`tf.Tensor` (one for the output of the embeddings + one for the output of each layer) of
shape :obj:`(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (:obj:`tuple(tf.Tensor)`, `optional`, returned when ``output_attentions=True`` is passed or when ``config.output_attentions=True``):
Tuple of :obj:`tf.Tensor` (one for each layer) of shape :obj:`(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
"""
loss: Optional[tf.Tensor] = None
start_logits: tf.Tensor = None
end_logits: tf.Tensor = None
mems: Optional[List[tf.Tensor]] = None
hidden_states: Optional[Tuple[tf.Tensor]] = None
attentions: Optional[Tuple[tf.Tensor]] = None
XLNET_START_DOCSTRING = r"""
This model inherits from :class:`~transformers.TFPreTrainedModel`. Check the superclass documentation for the
generic methods the library implements for all its model (such as downloading or saving, resizing the input
embeddings, pruning heads etc.)
This model is also a `tf.keras.Model <https://www.tensorflow.org/api_docs/python/tf/keras/Model>`__ subclass. Use
it as a regular TF 2.0 Keras Model and refer to the TF 2.0 documentation for all matter related to general usage
and behavior.
.. note::
TF 2.0 models accepts two formats as inputs:
- having all inputs as keyword arguments (like PyTorch models), or
- having all inputs as a list, tuple or dict in the first positional arguments.
This second option is useful when using :meth:`tf.keras.Model.fit` method which currently requires having all
the tensors in the first argument of the model call function: :obj:`model(inputs)`.
If you choose this second option, there are three possibilities you can use to gather all the input Tensors in
the first positional argument :
- a single Tensor with :obj:`input_ids` only and nothing else: :obj:`model(inputs_ids)`
- a list of varying length with one or several input Tensors IN THE ORDER given in the docstring:
:obj:`model([input_ids, attention_mask])` or :obj:`model([input_ids, attention_mask, token_type_ids])`
- a dictionary with one or several input Tensors associated to the input names given in the docstring:
:obj:`model({"input_ids": input_ids, "token_type_ids": token_type_ids})`
Parameters:
config (:class:`~transformers.XLNetConfig`): 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.
"""
XLNET_INPUTS_DOCSTRING = r"""
Args:
input_ids (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`({0})`):
Indices of input sequence tokens in the vocabulary.
Indices can be obtained using :class:`~transformers.BertTokenizer`. See
:func:`transformers.PreTrainedTokenizer.__call__` and :func:`transformers.PreTrainedTokenizer.encode` for
details.
`What are input IDs? <../glossary.html#input-ids>`__
attention_mask (:obj:`Numpy array` or :obj:`tf.Tensor` 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>`__
mems (:obj:`List[torch.FloatTensor]` of length :obj:`config.n_layers`):
Contains pre-computed hidden-states (see :obj:`mems` output below) . Can be used to speed up sequential
decoding. The token ids which have their past given to this model should not be passed as :obj:`input_ids`
as they have already been computed.
:obj::obj:`use_mems` has to be set to :obj:`True` to make use of :obj:`mems`.
perm_mask (:obj:`tf.Tensor` or :obj:`Numpy array` of shape :obj:`(batch_size, sequence_length, sequence_length)`, `optional`):
Mask to indicate the attention pattern for each input token with values selected in ``[0, 1]``:
- if ``perm_mask[k, i, j] = 0``, i attend to j in batch k;
- if ``perm_mask[k, i, j] = 1``, i does not attend to j in batch k.
If not set, each token attends to all the others (full bidirectional attention). Only used during
pretraining (to define factorization order) or for sequential decoding (generation).
target_mapping (:obj:`tf.Tensor` or :obj:`Numpy array` of shape :obj:`(batch_size, num_predict, sequence_length)`, `optional`):
Mask to indicate the output tokens to use. If ``target_mapping[k, i, j] = 1``, the i-th predict in batch k
is on the j-th token.
token_type_ids (:obj:`Numpy array` or :obj:`tf.Tensor` 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>`__
input_mask (:obj:`tf.Tensor` or :obj:`Numpy array` of shape :obj:`({0})`, `optional`):
Mask to avoid performing attention on padding token indices. Negative of :obj:`attention_mask`, i.e. with 0
for real tokens and 1 for padding which is kept for compatibility with the original code base.
Mask values selected in ``[0, 1]``:
- 1 for tokens that are **masked**,
- 0 for tokens that are **not maked**.
You can only uses one of :obj:`input_mask` and :obj:`attention_mask`.
head_mask (:obj:`Numpy array` or :obj:`tf.Tensor` of shape :obj:`(num_heads,)` or :obj:`(num_layers, num_heads)`, `optional`):
Mask to nullify selected heads of the self-attention modules. Mask values selected in ``[0, 1]``:
- 1 indicates the head is **not masked**,
- 0 indicates the head is **masked**.
inputs_embeds (:obj:`tf.Tensor` of shape :obj:`({0}, 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 :obj:`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. This argument can be used only in eager mode, in graph mode the value in the
config will be used instead.
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. This argument can be used only in eager mode, in graph mode the value in the config will be
used instead.
return_dict (:obj:`bool`, `optional`):
Whether or not to return a :class:`~transformers.file_utils.ModelOutput` instead of a plain tuple. This
argument can be used in eager mode, in graph mode the value will always be set to True.
training (:obj:`bool`, `optional`, defaults to :obj:`False`):
Whether or not to use the model in training mode (some modules like dropout modules have different
behaviors between training and evaluation).
"""
[docs]@add_start_docstrings(
"The bare XLNet Model transformer outputting raw hidden-states without any specific head on top.",
XLNET_START_DOCSTRING,
)
class TFXLNetModel(TFXLNetPreTrainedModel):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFXLNetMainLayer(config, name="transformer")
[docs] @add_start_docstrings_to_model_forward(XLNET_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=TFXLNetModelOutput,
config_class=_CONFIG_FOR_DOC,
)
def call(
self,
input_ids=None,
attention_mask=None,
mems=None,
perm_mask=None,
target_mapping=None,
token_type_ids=None,
input_mask=None,
head_mask=None,
inputs_embeds=None,
use_mems=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
training=False,
**kwargs,
):
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
mems=mems,
perm_mask=perm_mask,
target_mapping=target_mapping,
token_type_ids=token_type_ids,
input_mask=input_mask,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
use_mems=use_mems,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
training=training,
kwargs_call=kwargs,
)
outputs = self.transformer(
input_ids=inputs["input_ids"],
attention_mask=inputs["attention_mask"],
mems=inputs["mems"],
perm_mask=inputs["perm_mask"],
target_mapping=inputs["target_mapping"],
token_type_ids=inputs["token_type_ids"],
input_mask=inputs["input_mask"],
head_mask=inputs["head_mask"],
inputs_embeds=inputs["inputs_embeds"],
use_mems=inputs["use_mems"],
output_attentions=inputs["output_attentions"],
output_hidden_states=inputs["output_hidden_states"],
return_dict=inputs["return_dict"],
training=inputs["training"],
)
return outputs
def serving_output(self, output):
hs = tf.convert_to_tensor(output.hidden_states) if self.config.output_hidden_states else None
attns = tf.convert_to_tensor(output.attentions) if self.config.output_attentions else None
mems = tf.convert_to_tensor(output.mems) if output.mems is not None else None
return TFXLNetModelOutput(
last_hidden_state=output.last_hidden_state, mems=mems, hidden_states=hs, attentions=attns
)
[docs]@add_start_docstrings(
"""
XLNet Model with a language modeling head on top (linear layer with weights tied to the input embeddings).
""",
XLNET_START_DOCSTRING,
)
class TFXLNetLMHeadModel(TFXLNetPreTrainedModel, TFCausalLanguageModelingLoss):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFXLNetMainLayer(config, name="transformer")
self.lm_loss = TFXLNetLMHead(config, self.transformer.word_embedding, name="lm_loss")
def get_lm_head(self):
return self.lm_loss
def get_prefix_bias_name(self):
warnings.warn("The method get_prefix_bias_name is deprecated. Please use `get_bias` instead.", FutureWarning)
return self.name + "/" + self.lm_loss.name
def prepare_inputs_for_generation(self, inputs, past, use_mems=None, **kwargs):
# Add dummy token at the end (no attention on this one)
# At every pass, the attention values for the new token and the two last generated tokens
# are computed, the rest is reloaded from the `past` cache. A purely auto-regressive model would have
# offset = 1; offset = 2 seems to have slightly better computation.
offset = 2
effective_batch_size = inputs.shape[0]
dummy_token = tf.zeros((effective_batch_size, 1), dtype=inputs.dtype)
if past:
inputs = tf.concat([inputs[:, -offset:], dummy_token], axis=1)
else:
inputs = tf.concat([inputs, dummy_token], axis=1)
# Build permutation mask so that previous tokens don't see last token
sequence_length = inputs.shape[1]
perm_mask = tf.zeros((effective_batch_size, sequence_length, sequence_length - 1))
perm_mask_seq_end = tf.ones((effective_batch_size, sequence_length, 1))
perm_mask = tf.concat([perm_mask, perm_mask_seq_end], axis=-1)
# We'll only predict the last token
target_mapping = tf.zeros((effective_batch_size, 1, sequence_length - 1))
target_mapping_seq_end = tf.ones((effective_batch_size, 1, 1))
target_mapping = tf.concat([target_mapping, target_mapping_seq_end], axis=-1)
inputs = {
"input_ids": inputs,
"perm_mask": perm_mask,
"target_mapping": target_mapping,
"use_mems": kwargs.get("use_mems"),
}
# if past is defined in model kwargs then use it for faster decoding
if past:
inputs["mems"] = tuple(layer_past[:-offset, :, :] for layer_past in past)
return inputs
[docs] @add_start_docstrings_to_model_forward(XLNET_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@replace_return_docstrings(output_type=TFXLNetLMHeadModelOutput, config_class=_CONFIG_FOR_DOC)
def call(
self,
input_ids=None,
attention_mask=None,
mems=None,
perm_mask=None,
target_mapping=None,
token_type_ids=None,
input_mask=None,
head_mask=None,
inputs_embeds=None,
use_mems=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
labels=None,
training=False,
**kwargs,
):
r"""
labels (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length)`, `optional`):
Labels for computing the cross entropy classification loss. Indices should be in ``[0, ...,
config.vocab_size - 1]``.
Return:
Examples::
>>> import tensorflow as tf
>>> import numpy as np
>>> from transformers import XLNetTokenizer, TFXLNetLMHeadModel
>>> tokenizer = XLNetTokenizer.from_pretrained('xlnet-large-cased')
>>> model = TFXLNetLMHeadModel.from_pretrained('xlnet-large-cased')
>>> # We show how to setup inputs to predict a next token using a bi-directional context.
>>> input_ids = tf.constant(tokenizer.encode("Hello, my dog is very <mask>", add_special_tokens=True))[None, :] # We will predict the masked token
>>> perm_mask = np.zeros((1, input_ids.shape[1], input_ids.shape[1]))
>>> perm_mask[:, :, -1] = 1.0 # Previous tokens don't see last token
>>> target_mapping = np.zeros((1, 1, input_ids.shape[1])) # Shape [1, 1, seq_length] => let's predict one token
>>> target_mapping[0, 0, -1] = 1.0 # Our first (and only) prediction will be the last token of the sequence (the masked token)
>>> outputs = model(input_ids, perm_mask=tf.constant(perm_mask, dtype=tf.float32), target_mapping=tf.constant(target_mapping, dtype=tf.float32))
>>> next_token_logits = outputs[0] # Output has shape [target_mapping.size(0), target_mapping.size(1), config.vocab_size]
"""
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
mems=mems,
perm_mask=perm_mask,
target_mapping=target_mapping,
token_type_ids=token_type_ids,
input_mask=input_mask,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
use_mems=use_mems,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
labels=labels,
training=training,
kwargs_call=kwargs,
)
transformer_outputs = self.transformer(
input_ids=inputs["input_ids"],
attention_mask=inputs["attention_mask"],
mems=inputs["mems"],
perm_mask=inputs["perm_mask"],
target_mapping=inputs["target_mapping"],
token_type_ids=inputs["token_type_ids"],
input_mask=inputs["input_mask"],
head_mask=inputs["head_mask"],
inputs_embeds=inputs["inputs_embeds"],
use_mems=inputs["use_mems"],
output_attentions=inputs["output_attentions"],
output_hidden_states=inputs["output_hidden_states"],
return_dict=inputs["return_dict"],
training=inputs["training"],
)
hidden_state = transformer_outputs[0]
logits = self.lm_loss(hidden_state, training=inputs["training"])
loss = None
if inputs["labels"] is not None:
# shift labels to the left and cut last logit token
logits = logits[:, :-1]
labels = inputs["labels"][:, 1:]
loss = self.compute_loss(labels, logits)
if not inputs["return_dict"]:
output = (logits,) + transformer_outputs[1:]
return ((loss,) + output) if loss is not None else output
return TFXLNetLMHeadModelOutput(
loss=loss,
logits=logits,
mems=transformer_outputs.mems,
hidden_states=transformer_outputs.hidden_states,
attentions=transformer_outputs.attentions,
)
def serving_output(self, output):
hs = tf.convert_to_tensor(output.hidden_states) if self.config.output_hidden_states else None
attns = tf.convert_to_tensor(output.attentions) if self.config.output_attentions else None
mems = tf.convert_to_tensor(output.mems) if output.mems is not None else None
return TFXLNetLMHeadModelOutput(logits=output.logits, mems=mems, hidden_states=hs, attentions=attns)
[docs]@add_start_docstrings(
"""
XLNet Model with a sequence classification/regression head on top (a linear layer on top of the pooled output) e.g.
for GLUE tasks.
""",
XLNET_START_DOCSTRING,
)
class TFXLNetForSequenceClassification(TFXLNetPreTrainedModel, TFSequenceClassificationLoss):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.num_labels = config.num_labels
self.transformer = TFXLNetMainLayer(config, name="transformer")
self.sequence_summary = TFSequenceSummary(
config, initializer_range=config.initializer_range, name="sequence_summary"
)
self.logits_proj = tf.keras.layers.Dense(
config.num_labels, kernel_initializer=get_initializer(config.initializer_range), name="logits_proj"
)
[docs] @add_start_docstrings_to_model_forward(XLNET_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=TFXLNetForSequenceClassificationOutput,
config_class=_CONFIG_FOR_DOC,
)
def call(
self,
input_ids=None,
attention_mask=None,
mems=None,
perm_mask=None,
target_mapping=None,
token_type_ids=None,
input_mask=None,
head_mask=None,
inputs_embeds=None,
use_mems=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
labels=None,
training=False,
**kwargs,
):
r"""
labels (:obj:`tf.Tensor` of shape :obj:`(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 regression loss is computed (Mean-Square loss),
If ``config.num_labels > 1`` a classification loss is computed (Cross-Entropy).
"""
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
mems=mems,
perm_mask=perm_mask,
target_mapping=target_mapping,
token_type_ids=token_type_ids,
input_mask=input_mask,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
use_mems=use_mems,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
labels=labels,
training=training,
kwargs_call=kwargs,
)
transformer_outputs = self.transformer(
input_ids=inputs["input_ids"],
attention_mask=inputs["attention_mask"],
mems=inputs["mems"],
perm_mask=inputs["perm_mask"],
target_mapping=inputs["target_mapping"],
token_type_ids=inputs["token_type_ids"],
input_mask=inputs["input_mask"],
head_mask=inputs["head_mask"],
inputs_embeds=inputs["inputs_embeds"],
use_mems=inputs["use_mems"],
output_attentions=inputs["output_attentions"],
output_hidden_states=inputs["output_hidden_states"],
return_dict=return_dict,
training=inputs["training"],
)
output = transformer_outputs[0]
output = self.sequence_summary(output)
logits = self.logits_proj(output)
loss = None if inputs["labels"] is None else self.compute_loss(inputs["labels"], logits)
if not inputs["return_dict"]:
output = (logits,) + transformer_outputs[1:]
return ((loss,) + output) if loss is not None else output
return TFXLNetForSequenceClassificationOutput(
loss=loss,
logits=logits,
mems=transformer_outputs.mems,
hidden_states=transformer_outputs.hidden_states,
attentions=transformer_outputs.attentions,
)
def serving_output(self, output):
hs = tf.convert_to_tensor(output.hidden_states) if self.config.output_hidden_states else None
attns = tf.convert_to_tensor(output.attentions) if self.config.output_attentions else None
mems = tf.convert_to_tensor(output.mems) if output.mems is not None else None
return TFXLNetForSequenceClassificationOutput(
logits=output.logits, mems=mems, hidden_states=hs, attentions=attns
)
[docs]@add_start_docstrings(
"""
XLNet 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.
""",
XLNET_START_DOCSTRING,
)
class TFXLNetForTokenClassification(TFXLNetPreTrainedModel, TFTokenClassificationLoss):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.num_labels = config.num_labels
self.transformer = TFXLNetMainLayer(config, name="transformer")
self.classifier = tf.keras.layers.Dense(
config.num_labels, kernel_initializer=get_initializer(config.initializer_range), name="classifier"
)
[docs] @add_start_docstrings_to_model_forward(XLNET_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=TFXLNetForTokenClassificationOutput,
config_class=_CONFIG_FOR_DOC,
)
def call(
self,
input_ids=None,
attention_mask=None,
mems=None,
perm_mask=None,
target_mapping=None,
token_type_ids=None,
input_mask=None,
head_mask=None,
inputs_embeds=None,
use_mems=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
labels=None,
training=False,
**kwargs,
):
r"""
labels (:obj:`tf.Tensor` of shape :obj:`(batch_size, sequence_length)`, `optional`):
Labels for computing the token classification loss. Indices should be in ``[0, ..., config.num_labels -
1]``.
"""
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
mems=mems,
perm_mask=perm_mask,
target_mapping=target_mapping,
token_type_ids=token_type_ids,
input_mask=input_mask,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
use_mems=use_mems,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
labels=labels,
training=training,
kwargs_call=kwargs,
)
transformer_outputs = self.transformer(
input_ids=inputs["input_ids"],
attention_mask=inputs["attention_mask"],
mems=inputs["mems"],
perm_mask=inputs["perm_mask"],
target_mapping=inputs["target_mapping"],
token_type_ids=inputs["token_type_ids"],
input_mask=inputs["input_mask"],
head_mask=inputs["head_mask"],
inputs_embeds=inputs["inputs_embeds"],
use_mems=inputs["use_mems"],
output_attentions=inputs["output_attentions"],
output_hidden_states=inputs["output_hidden_states"],
return_dict=inputs["return_dict"],
training=inputs["training"],
)
output = transformer_outputs[0]
logits = self.classifier(output)
loss = None if inputs["labels"] is None else self.compute_loss(inputs["labels"], logits)
if not inputs["return_dict"]:
output = (logits,) + transformer_outputs[1:]
return ((loss,) + output) if loss is not None else output
return TFXLNetForTokenClassificationOutput(
loss=loss,
logits=logits,
mems=transformer_outputs.mems,
hidden_states=transformer_outputs.hidden_states,
attentions=transformer_outputs.attentions,
)
def serving_output(self, output):
hs = tf.convert_to_tensor(output.hidden_states) if self.config.output_hidden_states else None
attns = tf.convert_to_tensor(output.attentions) if self.config.output_attentions else None
mems = tf.convert_to_tensor(output.mems) if output.mems is not None else None
return TFXLNetForTokenClassificationOutput(logits=output.logits, mems=mems, hidden_states=hs, attentions=attns)
[docs]@add_start_docstrings(
"""
XLNet 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`).
""",
XLNET_START_DOCSTRING,
)
class TFXLNetForQuestionAnsweringSimple(TFXLNetPreTrainedModel, TFQuestionAnsweringLoss):
def __init__(self, config, *inputs, **kwargs):
super().__init__(config, *inputs, **kwargs)
self.transformer = TFXLNetMainLayer(config, name="transformer")
self.qa_outputs = tf.keras.layers.Dense(
config.num_labels, kernel_initializer=get_initializer(config.initializer_range), name="qa_outputs"
)
[docs] @add_start_docstrings_to_model_forward(XLNET_INPUTS_DOCSTRING.format("batch_size, sequence_length"))
@add_code_sample_docstrings(
tokenizer_class=_TOKENIZER_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=TFXLNetForQuestionAnsweringSimpleOutput,
config_class=_CONFIG_FOR_DOC,
)
def call(
self,
input_ids=None,
attention_mask=None,
mems=None,
perm_mask=None,
target_mapping=None,
token_type_ids=None,
input_mask=None,
head_mask=None,
inputs_embeds=None,
use_mems=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
start_positions=None,
end_positions=None,
training=False,
**kwargs,
):
r"""
start_positions (:obj:`tf.Tensor` 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:`tf.Tensor` 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.
"""
inputs = input_processing(
func=self.call,
config=self.config,
input_ids=input_ids,
attention_mask=attention_mask,
mems=mems,
perm_mask=perm_mask,
target_mapping=target_mapping,
token_type_ids=token_type_ids,
input_mask=input_mask,
head_mask=head_mask,
inputs_embeds=inputs_embeds,
use_mems=use_mems,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
start_positions=start_positions,
end_positions=end_positions,
training=training,
kwargs_call=kwargs,
)
transformer_outputs = self.transformer(
input_ids=inputs["input_ids"],
attention_mask=inputs["attention_mask"],
mems=inputs["mems"],
perm_mask=inputs["perm_mask"],
target_mapping=inputs["target_mapping"],
token_type_ids=inputs["token_type_ids"],
input_mask=inputs["input_mask"],
head_mask=inputs["head_mask"],
inputs_embeds=inputs["inputs_embeds"],
use_mems=inputs["use_mems"],
output_attentions=inputs["output_attentions"],
output_hidden_states=inputs["output_hidden_states"],
return_dict=inputs["return_dict"],
training=inputs["training"],
)
sequence_output = transformer_outputs[0]
logits = self.qa_outputs(sequence_output)
start_logits, end_logits = tf.split(logits, 2, axis=-1)
start_logits = tf.squeeze(start_logits, axis=-1)
end_logits = tf.squeeze(end_logits, axis=-1)
loss = None
if inputs["start_positions"] is not None and inputs["end_positions"] is not None:
labels = {"start_position": inputs["start_positions"]}
labels["end_position"] = inputs["end_positions"]
loss = self.compute_loss(labels, (start_logits, end_logits))
if not inputs["return_dict"]:
output = (start_logits, end_logits) + transformer_outputs[1:]
return ((loss,) + output) if loss is not None else output
return TFXLNetForQuestionAnsweringSimpleOutput(
loss=loss,
start_logits=start_logits,
end_logits=end_logits,
mems=transformer_outputs.mems,
hidden_states=transformer_outputs.hidden_states,
attentions=transformer_outputs.attentions,
)
def serving_output(self, output):
hs = tf.convert_to_tensor(output.hidden_states) if self.config.output_hidden_states else None
attns = tf.convert_to_tensor(output.attentions) if self.config.output_attentions else None
mems = tf.convert_to_tensor(output.mems) if output.mems is not None else None
return TFXLNetForQuestionAnsweringSimpleOutput(
start_logits=output.start_logits,
end_logits=output.end_logits,
mems=mems,
hidden_states=hs,
attentions=attns,
)