diff --git "a/src/modeling_t5.py" "b/src/modeling_t5.py" new file mode 100644--- /dev/null +++ "b/src/modeling_t5.py" @@ -0,0 +1,2943 @@ +# coding=utf-8 +# Copyright 2018 Mesh TensorFlow authors, T5 Authors and HuggingFace 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 T5 model.""" + +import copy +import math +import os +import warnings +from typing import List, Optional, Tuple, Union + +import torch +from torch import nn +from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss + +from transformers.activations import ACT2FN +from transformers.cache_utils import ( + Cache, + DynamicCache, + EncoderDecoderCache, + StaticCache, +) +from transformers.generation import GenerationMixin +from transformers.modeling_attn_mask_utils import AttentionMaskConverter +from transformers.modeling_outputs import ( + BaseModelOutput, + BaseModelOutputWithPastAndCrossAttentions, + Seq2SeqLMOutput, + Seq2SeqModelOutput, + Seq2SeqQuestionAnsweringModelOutput, + Seq2SeqSequenceClassifierOutput, + TokenClassifierOutput, +) +from transformers.modeling_utils import PreTrainedModel +from transformers.pytorch_utils import ( + ALL_LAYERNORM_LAYERS, + find_pruneable_heads_and_indices, + prune_linear_layer, +) +from transformers.utils import ( + DUMMY_INPUTS, + DUMMY_MASK, + add_start_docstrings, + add_start_docstrings_to_model_forward, + is_torch_fx_proxy, + is_torchdynamo_compiling, + logging, + replace_return_docstrings, +) +from transformers.utils.model_parallel_utils import ( + assert_device_map, + get_device_map, +) +from transformers.models.t5.configuration_t5 import T5Config + + +logger = logging.get_logger(__name__) + +_CONFIG_FOR_DOC = "T5Config" +_CHECKPOINT_FOR_DOC = "google-t5/t5-small" + +#################################################### +# This dict contains ids and associated url +# for the pretrained weights provided with the models +#################################################### + + +#################################################### +# This is a conversion method from TF 1.0 to PyTorch +# More details: https://medium.com/huggingface/from-tensorflow-to-pytorch-265f40ef2a28 +#################################################### +def load_tf_weights_in_t5(model, config, tf_checkpoint_path): + """Load tf checkpoints in a pytorch model.""" + try: + import re + + import numpy as np + import tensorflow as tf + except ImportError: + logger.error( + "Loading a TensorFlow model in PyTorch, requires TensorFlow to be installed. Please see " + "https://www.tensorflow.org/install/ for installation instructions." + ) + raise + tf_path = os.path.abspath(tf_checkpoint_path) + logger.info(f"Converting TensorFlow checkpoint from {tf_path}") + # Load weights from TF model + init_vars = tf.train.list_variables(tf_path) + names = [] + tf_weights = {} + for name, shape in init_vars: + logger.info(f"Loading TF weight {name} with shape {shape}") + array = tf.train.load_variable(tf_path, name) + names.append(name) + tf_weights[name] = array + + for txt_name in names: + name = txt_name.split("/") + # adam_v and adam_m are variables used in AdamWeightDecayOptimizer to calculated m and v + # which are not required for using pretrained model + if any( + n + in [ + "adam_v", + "adam_m", + "AdamWeightDecayOptimizer", + "AdamWeightDecayOptimizer_1", + "global_step", + ] + for n in name + ): + logger.info(f"Skipping {'/'.join(name)}") + tf_weights.pop(txt_name, None) + continue + if "_slot_" in name[-1]: + logger.info(f"Skipping {'/'.join(name)}") + tf_weights.pop(txt_name, None) + continue + pointer = model + array = tf_weights[txt_name] + + for m_name in name: + if re.fullmatch(r"[A-Za-z]+_\d+", m_name): + scope_names = re.split(r"_(\d+)", m_name) + else: + scope_names = [m_name] + if scope_names[0] in ["kernel", "scale", "embedding"]: + pointer = getattr(pointer, "weight") + elif scope_names[0] == "self_attention": + pointer = getattr(pointer, "layer") + pointer = pointer[0] + elif scope_names[0] == "enc_dec_attention": + pointer = getattr(pointer, "layer") + pointer = pointer[1] + elif scope_names[0] == "dense_relu_dense": + pointer = getattr(pointer, "layer") + pointer = pointer[2] + elif scope_names[0] == "rms_norm": + if hasattr(pointer, "layer_norm"): + pointer = getattr(pointer, "layer_norm") + elif hasattr(pointer, "final_layer_norm"): + pointer = getattr(pointer, "final_layer_norm") + elif scope_names[0] == "scale": + pointer = getattr(pointer, "weight") + elif scope_names[0] == "output_bias" or scope_names[0] == "beta": + pointer = getattr(pointer, "bias") + elif scope_names[0] == "squad": + pointer = getattr(pointer, "classifier") + elif scope_names[0] == "decoder" and name[1] == "logits": + continue + elif scope_names[0] == "logits": + pointer = getattr(pointer, "lm_head") + elif ( + scope_names[0] == "wi" + and len(scope_names) > 1 + and scope_names[1].isdigit() + ): + pointer = getattr(pointer, f"wi_{scope_names[1]}") + continue + else: + try: + pointer = getattr(pointer, scope_names[0]) + except AttributeError: + logger.info(f"Skipping {'/'.join(name)}") + continue + if len(scope_names) >= 2: + num = int(scope_names[1]) + pointer = pointer[num] + if scope_names[0] not in ["kernel", "scale", "embedding"]: + pointer = getattr(pointer, "weight") + if scope_names[0] != "embedding": + logger.info(f"Transposing numpy weight of shape {array.shape} for {name}") + array = np.transpose(array) + try: + if pointer.shape != array.shape: + raise ValueError( + f"Pointer shape {pointer.shape} and array shape {array.shape} mismatched" + ) + except AssertionError as e: + e.args += (pointer.shape, array.shape) + raise + logger.info(f"Initialize PyTorch weight {name}") + pointer.data = torch.from_numpy(array.astype(np.float32)) + tf_weights.pop(txt_name, None) + + logger.info(f"Weights not copied to PyTorch model: {', '.join(tf_weights.keys())}.") + return model + + +#################################################### +# PyTorch Models are constructed by sub-classing +# - torch.nn.Module for the layers and +# - PreTrainedModel for the models (it-self a sub-class of nn.Module) +#################################################### +PARALLELIZE_DOCSTRING = r""" + This is an experimental feature and is a subject to change at a moment's notice. + + Uses a device map to distribute attention modules of the model across several devices. If no device map is given, + it will evenly distribute blocks across all devices. + + Args: + device_map (`Dict[int, list]`, *optional*): + A dictionary that maps attention modules to devices. Note that the embedding module and LMHead are always + automatically mapped to the first device (for esoteric reasons). That means that the first device should + have fewer attention modules mapped to it than other devices. For reference, the t5 models have the + following number of attention modules: + + - google-t5/t5-small: 6 + - google-t5/t5-base: 12 + - google-t5/t5-large: 24 + - google-t5/t5-3b: 24 + - google-t5/t5-11b: 24 + + Example: + + ```python + # Here is an example of a device map on a machine with 4 GPUs using google-t5/t5-3b, which has a total of 24 attention modules: + model = T5ForConditionalGeneration.from_pretrained("google-t5/t5-3b") + device_map = { + 0: [0, 1, 2], + 1: [3, 4, 5, 6, 7, 8, 9], + 2: [10, 11, 12, 13, 14, 15, 16], + 3: [17, 18, 19, 20, 21, 22, 23], + } + model.parallelize(device_map) + ``` +""" +DEPARALLELIZE_DOCSTRING = r""" + Moves the model to cpu from a model parallel state. + + Example: + + ```python + # On a 4 GPU machine with google-t5/t5-3b: + model = T5ForConditionalGeneration.from_pretrained("google-t5/t5-3b") + device_map = { + 0: [0, 1, 2], + 1: [3, 4, 5, 6, 7, 8, 9], + 2: [10, 11, 12, 13, 14, 15, 16], + 3: [17, 18, 19, 20, 21, 22, 23], + } + model.parallelize(device_map) # Splits the model across several devices + model.deparallelize() # Put the model back on cpu and cleans memory by calling torch.cuda.empty_cache() + ``` +""" + + +class T5LayerNorm(nn.Module): + def __init__(self, hidden_size, eps=1e-6): + """ + Construct a layernorm module in the T5 style. No bias and no subtraction of mean. + """ + super().__init__() + self.weight = nn.Parameter(torch.ones(hidden_size)) + self.variance_epsilon = eps + + def forward(self, hidden_states): + # T5 uses a layer_norm which only scales and doesn't shift, which is also known as Root Mean + # Square Layer Normalization https://arxiv.org/abs/1910.07467 thus varience is calculated + # w/o mean and there is no bias. Additionally we want to make sure that the accumulation for + # half-precision inputs is done in fp32 + + variance = hidden_states.to(torch.float32).pow(2).mean(-1, keepdim=True) + hidden_states = hidden_states * torch.rsqrt(variance + self.variance_epsilon) + + # convert into half-precision if necessary + if self.weight.dtype in [torch.float16, torch.bfloat16]: + hidden_states = hidden_states.to(self.weight.dtype) + + return self.weight * hidden_states + + +try: + from apex.normalization import FusedRMSNorm + + T5LayerNorm = FusedRMSNorm # noqa + + logger.info( + "Discovered apex.normalization.FusedRMSNorm - will use it instead of T5LayerNorm" + ) +except ImportError: + # using the normal T5LayerNorm + pass +except Exception: + logger.warning("discovered apex but it failed to load, falling back to T5LayerNorm") + pass + +ALL_LAYERNORM_LAYERS.append(T5LayerNorm) + + +class T5DenseActDense(nn.Module): + def __init__(self, config: T5Config): + super().__init__() + self.wi = nn.Linear(config.d_model, config.d_ff, bias=False) + self.wo = nn.Linear(config.d_ff, config.d_model, bias=False) + self.dropout = nn.Dropout(config.dropout_rate) + self.act = ACT2FN[config.dense_act_fn] + + def forward(self, hidden_states): + hidden_states = self.wi(hidden_states) + hidden_states = self.act(hidden_states) + hidden_states = self.dropout(hidden_states) + if ( + isinstance(self.wo.weight, torch.Tensor) + and hidden_states.dtype != self.wo.weight.dtype + and self.wo.weight.dtype != torch.int8 + ): + hidden_states = hidden_states.to(self.wo.weight.dtype) + hidden_states = self.wo(hidden_states) + return hidden_states + + +class T5DenseGatedActDense(nn.Module): + def __init__(self, config: T5Config): + super().__init__() + self.wi_0 = nn.Linear(config.d_model, config.d_ff, bias=False) + self.wi_1 = nn.Linear(config.d_model, config.d_ff, bias=False) + self.wo = nn.Linear(config.d_ff, config.d_model, bias=False) + self.dropout = nn.Dropout(config.dropout_rate) + self.act = ACT2FN[config.dense_act_fn] + + def forward(self, hidden_states): + hidden_gelu = self.act(self.wi_0(hidden_states)) + hidden_linear = self.wi_1(hidden_states) + hidden_states = hidden_gelu * hidden_linear + hidden_states = self.dropout(hidden_states) + + # To make 8bit quantization work for google/flan-t5-xxl, self.wo is kept in float32. + # See https://github.com/huggingface/transformers/issues/20287 + # we also make sure the weights are not in `int8` in case users will force `_keep_in_fp32_modules` to be `None`` + if ( + isinstance(self.wo.weight, torch.Tensor) + and hidden_states.dtype != self.wo.weight.dtype + and self.wo.weight.dtype != torch.int8 + ): + hidden_states = hidden_states.to(self.wo.weight.dtype) + + hidden_states = self.wo(hidden_states) + return hidden_states + + +class T5LayerFF(nn.Module): + def __init__(self, config: T5Config): + super().__init__() + if config.is_gated_act: + self.DenseReluDense = T5DenseGatedActDense(config) + else: + self.DenseReluDense = T5DenseActDense(config) + + self.layer_norm = T5LayerNorm(config.d_model, eps=config.layer_norm_epsilon) + self.dropout = nn.Dropout(config.dropout_rate) + + def forward(self, hidden_states): + forwarded_states = self.layer_norm(hidden_states) + forwarded_states = self.DenseReluDense(forwarded_states) + hidden_states = hidden_states + self.dropout(forwarded_states) + return hidden_states + + +class T5Attention(nn.Module): + def __init__( + self, + config: T5Config, + has_relative_attention_bias=False, + layer_idx: Optional[int] = None, + ): + super().__init__() + self.is_decoder = config.is_decoder + self.has_relative_attention_bias = has_relative_attention_bias + self.relative_attention_num_buckets = config.relative_attention_num_buckets + self.relative_attention_max_distance = config.relative_attention_max_distance + self.d_model = config.d_model + self.key_value_proj_dim = config.d_kv + self.n_heads = config.num_heads + self.dropout = config.dropout_rate + self.inner_dim = self.n_heads * self.key_value_proj_dim + self.layer_idx = layer_idx + if layer_idx is None and self.is_decoder: + logger.warning_once( + f"Instantiating a decoder {self.__class__.__name__} without passing `layer_idx` is not recommended and " + "will to errors during the forward call, if caching is used. Please make sure to provide a `layer_idx` " + "when creating this class." + ) + + # Mesh TensorFlow initialization to avoid scaling before softmax + self.q = nn.Linear(self.d_model, self.inner_dim, bias=False) + self.k = nn.Linear(self.d_model, self.inner_dim, bias=False) + self.v = nn.Linear(self.d_model, self.inner_dim, bias=False) + self.o = nn.Linear(self.inner_dim, self.d_model, bias=False) + + if self.has_relative_attention_bias: + self.relative_attention_bias = nn.Embedding( + self.relative_attention_num_buckets, self.n_heads + ) + self.pruned_heads = set() + self.gradient_checkpointing = False + + def prune_heads(self, heads): + if len(heads) == 0: + return + heads, index = find_pruneable_heads_and_indices( + heads, self.n_heads, self.key_value_proj_dim, self.pruned_heads + ) + # Prune linear layers + self.q = prune_linear_layer(self.q, index) + self.k = prune_linear_layer(self.k, index) + self.v = prune_linear_layer(self.v, index) + self.o = prune_linear_layer(self.o, index, dim=1) + # Update hyper params + self.n_heads = self.n_heads - len(heads) + self.inner_dim = self.key_value_proj_dim * self.n_heads + self.pruned_heads = self.pruned_heads.union(heads) + + @staticmethod + def _relative_position_bucket( + relative_position, bidirectional=True, num_buckets=32, max_distance=128 + ): + """ + Adapted from Mesh Tensorflow: + https://github.com/tensorflow/mesh/blob/0cb87fe07da627bf0b7e60475d59f95ed6b5be3d/mesh_tensorflow/transformer/transformer_layers.py#L593 + + Translate relative position to a bucket number for relative attention. The relative position is defined as + memory_position - query_position, i.e. the distance in tokens from the attending position to the attended-to + position. If bidirectional=False, then positive relative positions are invalid. We use smaller buckets for + small absolute relative_position and larger buckets for larger absolute relative_positions. All relative + positions >=max_distance map to the same bucket. All relative positions <=-max_distance map to the same bucket. + This should allow for more graceful generalization to longer sequences than the model has been trained on + + Args: + relative_position: an int32 Tensor + bidirectional: a boolean - whether the attention is bidirectional + num_buckets: an integer + max_distance: an integer + + Returns: + a Tensor with the same shape as relative_position, containing int32 values in the range [0, num_buckets) + """ + relative_buckets = 0 + if bidirectional: + num_buckets //= 2 + relative_buckets += (relative_position > 0).to(torch.long) * num_buckets + relative_position = torch.abs(relative_position) + else: + relative_position = -torch.min( + relative_position, torch.zeros_like(relative_position) + ) + # now relative_position is in the range [0, inf) + + # half of the buckets are for exact increments in positions + max_exact = num_buckets // 2 + is_small = relative_position < max_exact + + # The other half of the buckets are for logarithmically bigger bins in positions up to max_distance + relative_position_if_large = max_exact + ( + torch.log(relative_position.float() / max_exact) + / math.log(max_distance / max_exact) + * (num_buckets - max_exact) + ).to(torch.long) + relative_position_if_large = torch.min( + relative_position_if_large, + torch.full_like(relative_position_if_large, num_buckets - 1), + ) + + relative_buckets += torch.where( + is_small, relative_position, relative_position_if_large + ) + return relative_buckets + + def compute_bias(self, query_length, key_length, device=None, cache_position=None): + """Compute binned relative position bias""" + if device is None: + device = self.relative_attention_bias.weight.device + if cache_position is None: + context_position = torch.arange( + query_length, dtype=torch.long, device=device + )[:, None] + else: + context_position = cache_position[:, None].to(device) + memory_position = torch.arange(key_length, dtype=torch.long, device=device)[ + None, : + ] + relative_position = ( + memory_position - context_position + ) # shape (query_length, key_length) + relative_position_bucket = self._relative_position_bucket( + relative_position, # shape (query_length, key_length) + bidirectional=(not self.is_decoder), + num_buckets=self.relative_attention_num_buckets, + max_distance=self.relative_attention_max_distance, + ) + values = self.relative_attention_bias( + relative_position_bucket + ) # shape (query_length, key_length, num_heads) + values = values.permute([2, 0, 1]).unsqueeze( + 0 + ) # shape (1, num_heads, query_length, key_length) + return values + + def forward( + self, + hidden_states, + mask=None, + key_value_states=None, + position_bias=None, + past_key_value=None, + layer_head_mask=None, + query_length=None, + use_cache=False, + output_attentions=False, + cache_position=None, + ): + """ + Self-attention (if key_value_states is None) or attention over source sentence (provided by key_value_states). + """ + # Input is (batch_size, seq_length, dim) + # Mask is (batch_size, 1, 1, key_length) (non-causal encoder) or (batch_size, 1, seq_length, key_length) (causal decoder) + batch_size, seq_length = hidden_states.shape[:2] + + # if key_value_states are provided this layer is used as a cross-attention layer for the decoder + is_cross_attention = key_value_states is not None + + query_states = self.q(hidden_states) + query_states = query_states.view( + batch_size, -1, self.n_heads, self.key_value_proj_dim + ).transpose(1, 2) + + if past_key_value is not None: + is_updated = past_key_value.is_updated.get(self.layer_idx) + if is_cross_attention: + # after the first generated id, we can subsequently re-use all key/value_states from cache + curr_past_key_value = past_key_value.cross_attention_cache + else: + curr_past_key_value = past_key_value.self_attention_cache + + current_states = key_value_states if is_cross_attention else hidden_states + if is_cross_attention and past_key_value is not None and is_updated: + # reuse k,v, cross_attentions + key_states = curr_past_key_value.key_cache[self.layer_idx] + value_states = curr_past_key_value.value_cache[self.layer_idx] + else: + key_states = self.k(current_states) + value_states = self.v(current_states) + key_states = key_states.view( + batch_size, -1, self.n_heads, self.key_value_proj_dim + ).transpose(1, 2) + value_states = value_states.view( + batch_size, -1, self.n_heads, self.key_value_proj_dim + ).transpose(1, 2) + + if past_key_value is not None: + # save all key/value_states to cache to be re-used for fast auto-regressive generation + cache_position = cache_position if not is_cross_attention else None + key_states, value_states = curr_past_key_value.update( + key_states, + value_states, + self.layer_idx, + {"cache_position": cache_position}, + ) + # set flag that curr layer for cross-attn is already updated so we can re-use in subsequent calls + if is_cross_attention: + past_key_value.is_updated[self.layer_idx] = True + + # compute scores, equivalent of torch.einsum("bnqd,bnkd->bnqk", query_states, key_states), compatible with onnx op>9 + scores = torch.matmul(query_states, key_states.transpose(3, 2)) + + if position_bias is None: + key_length = key_states.shape[-2] + # cache position is 0-indexed so we add 1 to get the real length of queries (aka with past) + real_seq_length = ( + query_length if query_length is not None else cache_position[-1] + 1 + ) + if not self.has_relative_attention_bias: + position_bias = torch.zeros( + (1, self.n_heads, seq_length, key_length), + device=scores.device, + dtype=scores.dtype, + ) + if self.gradient_checkpointing and self.training: + position_bias.requires_grad = True + else: + position_bias = self.compute_bias( + real_seq_length, + key_length, + device=scores.device, + cache_position=cache_position, + ) + position_bias = position_bias[:, :, -seq_length:, :] + + if mask is not None: + causal_mask = mask[:, :, :, : key_states.shape[-2]] + position_bias = position_bias + causal_mask + + if self.pruned_heads: + mask = torch.ones(position_bias.shape[1]) + mask[list(self.pruned_heads)] = 0 + position_bias_masked = position_bias[:, mask.bool()] + else: + position_bias_masked = position_bias + + scores += position_bias_masked + + # (batch_size, n_heads, seq_length, key_length) + attn_weights = nn.functional.softmax(scores.float(), dim=-1).type_as(scores) + attn_weights = nn.functional.dropout( + attn_weights, p=self.dropout, training=self.training + ) + + # Mask heads if we want to + if layer_head_mask is not None: + attn_weights = attn_weights * layer_head_mask + + attn_output = torch.matmul(attn_weights, value_states) + + attn_output = attn_output.transpose(1, 2).contiguous() + attn_output = attn_output.view(batch_size, -1, self.inner_dim) + attn_output = self.o(attn_output) + + outputs = (attn_output, past_key_value, position_bias) + + if output_attentions: + outputs = outputs + (attn_weights,) + return outputs + + +class T5LayerSelfAttention(nn.Module): + def __init__( + self, config, has_relative_attention_bias=False, layer_idx: Optional[int] = None + ): + super().__init__() + self.SelfAttention = T5Attention( + config, + has_relative_attention_bias=has_relative_attention_bias, + layer_idx=layer_idx, + ) + self.layer_norm = T5LayerNorm(config.d_model, eps=config.layer_norm_epsilon) + self.dropout = nn.Dropout(config.dropout_rate) + + def forward( + self, + hidden_states, + attention_mask=None, + position_bias=None, + layer_head_mask=None, + past_key_value=None, + use_cache=False, + output_attentions=False, + cache_position=None, + ): + normed_hidden_states = self.layer_norm(hidden_states) + attention_output = self.SelfAttention( + normed_hidden_states, + mask=attention_mask, + position_bias=position_bias, + layer_head_mask=layer_head_mask, + past_key_value=past_key_value, + use_cache=use_cache, + output_attentions=output_attentions, + cache_position=cache_position, + ) + hidden_states = hidden_states + self.dropout(attention_output[0]) + outputs = (hidden_states,) + attention_output[ + 1: + ] # add attentions if we output them + return outputs + + +class T5LayerCrossAttention(nn.Module): + def __init__(self, config, layer_idx: Optional[int] = None): + super().__init__() + self.EncDecAttention = T5Attention( + config, has_relative_attention_bias=False, layer_idx=layer_idx + ) + self.layer_norm = T5LayerNorm(config.d_model, eps=config.layer_norm_epsilon) + self.dropout = nn.Dropout(config.dropout_rate) + + def forward( + self, + hidden_states, + key_value_states, + attention_mask=None, + position_bias=None, + layer_head_mask=None, + past_key_value=None, + use_cache=False, + query_length=None, + output_attentions=False, + cache_position=None, + ): + normed_hidden_states = self.layer_norm(hidden_states) + attention_output = self.EncDecAttention( + normed_hidden_states, + mask=attention_mask, + key_value_states=key_value_states, + position_bias=position_bias, + layer_head_mask=layer_head_mask, + past_key_value=past_key_value, + use_cache=use_cache, + query_length=query_length, + output_attentions=output_attentions, + cache_position=cache_position, + ) + layer_output = hidden_states + self.dropout(attention_output[0]) + outputs = (layer_output,) + attention_output[ + 1: + ] # add attentions if we output them + return outputs + + +class T5Block(nn.Module): + def __init__( + self, config, has_relative_attention_bias=False, layer_idx: Optional[int] = None + ): + super().__init__() + self.is_decoder = config.is_decoder + self.layer = nn.ModuleList() + self.layer.append( + T5LayerSelfAttention( + config, + has_relative_attention_bias=has_relative_attention_bias, + layer_idx=layer_idx, + ) + ) + if self.is_decoder: + self.layer.append(T5LayerCrossAttention(config, layer_idx=layer_idx)) + + self.layer.append(T5LayerFF(config)) + + def forward( + self, + hidden_states, + attention_mask=None, + position_bias=None, + encoder_hidden_states=None, + encoder_attention_mask=None, + encoder_decoder_position_bias=None, + layer_head_mask=None, + cross_attn_layer_head_mask=None, + past_key_value=None, + use_cache=False, + output_attentions=False, + return_dict=True, + cache_position=None, + ): + self_attention_outputs = self.layer[0]( + hidden_states, + attention_mask=attention_mask, + position_bias=position_bias, + layer_head_mask=layer_head_mask, + past_key_value=past_key_value, + use_cache=use_cache, + output_attentions=output_attentions, + cache_position=cache_position, + ) + hidden_states, past_key_value = self_attention_outputs[:2] + attention_outputs = self_attention_outputs[ + 2: + ] # Keep self-attention outputs and relative position weights + + # clamp inf values to enable fp16 training + if hidden_states.dtype == torch.float16: + clamp_value = torch.where( + torch.isinf(hidden_states).any(), + torch.finfo(hidden_states.dtype).max - 1000, + torch.finfo(hidden_states.dtype).max, + ) + hidden_states = torch.clamp( + hidden_states, min=-clamp_value, max=clamp_value + ) + + do_cross_attention = self.is_decoder and encoder_hidden_states is not None + if do_cross_attention: + cross_attention_outputs = self.layer[1]( + hidden_states, + key_value_states=encoder_hidden_states, + attention_mask=encoder_attention_mask, + position_bias=encoder_decoder_position_bias, + layer_head_mask=cross_attn_layer_head_mask, + past_key_value=past_key_value, + query_length=cache_position[-1] + 1, + use_cache=use_cache, + output_attentions=output_attentions, + ) + hidden_states, past_key_value = cross_attention_outputs[:2] + + # clamp inf values to enable fp16 training + if hidden_states.dtype == torch.float16: + clamp_value = torch.where( + torch.isinf(hidden_states).any(), + torch.finfo(hidden_states.dtype).max - 1000, + torch.finfo(hidden_states.dtype).max, + ) + hidden_states = torch.clamp( + hidden_states, min=-clamp_value, max=clamp_value + ) + + # Keep cross-attention outputs and relative position weights + attention_outputs = attention_outputs + cross_attention_outputs[2:] + + # Apply Feed Forward layer + hidden_states = self.layer[-1](hidden_states) + + # clamp inf values to enable fp16 training + if hidden_states.dtype == torch.float16: + clamp_value = torch.where( + torch.isinf(hidden_states).any(), + torch.finfo(hidden_states.dtype).max - 1000, + torch.finfo(hidden_states.dtype).max, + ) + hidden_states = torch.clamp( + hidden_states, min=-clamp_value, max=clamp_value + ) + + outputs = (hidden_states,) + + if use_cache: + outputs = outputs + (past_key_value,) + attention_outputs + else: + outputs = outputs + attention_outputs + + return outputs # hidden-states, past_key_value, (self-attention position bias), (self-attention weights), (cross-attention position bias), (cross-attention weights) + + +from transformers.activations import NewGELUActivation + +# Current +# class T5ClassificationHead(nn.Module): +# """Head for sentence-level classification tasks.""" + +# def __init__(self, config: T5Config): +# super().__init__() +# # self.dense_0 = nn.Linear(config.d_model, config.d_model) +# # self.norm_0 = T5LayerNorm(config.d_model) +# # self.relu_0 = NewGELUActivation() +# # self.dropout_0 = nn.Dropout(p=config.classifier_dropout) + +# self.dense_0 = nn.Linear(config.d_model, config.d_model // 4) +# self.norm_0 = T5LayerNorm(config.d_model // 4) +# self.relu_0 = NewGELUActivation() +# self.dropout_0 = nn.Dropout(p=config.classifier_dropout) + +# self.dense_1 = nn.Linear(config.d_model // 4, config.d_model // 16) +# self.norm_1 = T5LayerNorm(config.d_model // 16) +# self.relu_1 = NewGELUActivation() +# self.dropout_1 = nn.Dropout(p=config.classifier_dropout) + +# self.dense_2 = nn.Linear(config.d_model // 16, config.d_model // 64) +# self.norm_2 = T5LayerNorm(config.d_model // 64) +# self.relu_2 = NewGELUActivation() +# self.dropout_2 = nn.Dropout(p=config.classifier_dropout) + +# # self.dense_4 = nn.Linear(config.d_model // 16, config.d_model // 32) +# # self.norm_4 = T5LayerNorm(config.d_model // 32) +# # self.relu_4 = NewGELUActivation() +# # self.dropout_4 = nn.Dropout(p=config.classifier_dropout) + +# self.out_proj = nn.Linear(config.d_model // 64, config.num_labels) + +# def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: +# hidden_states = self.relu_0( +# self.dropout_0(self.norm_0(self.dense_0(hidden_states))) +# ) +# hidden_states = self.relu_1( +# self.dropout_1(self.norm_1(self.dense_1(hidden_states))) +# ) +# hidden_states = self.relu_2( +# self.dropout_2(self.norm_2(self.dense_2(hidden_states))) +# ) +# # hidden_states = self.relu_3( +# # self.dropout_3(self.norm_3(self.dense_3(hidden_states))) +# # ) +# # hidden_states = self.relu_4( +# # self.dropout_4(self.norm_4(self.dense_4(hidden_states))) +# # ) + +# out = self.out_proj(hidden_states) + +# return out + + +class T5ClassificationHead(nn.Module): + """Head for sentence-level classification tasks.""" + + def __init__(self, config: T5Config): + super().__init__() + # self.dense_0 = nn.Linear(config.d_model, config.d_model) + # self.norm_0 = T5LayerNorm(config.d_model) + # self.relu_0 = NewGELUActivation() + # self.dropout_0 = nn.Dropout(p=config.classifier_dropout) + + self.dense_0 = nn.Linear(config.d_model, config.d_model // 4) + self.norm_0 = T5LayerNorm(config.d_model // 4) + self.relu_0 = NewGELUActivation() + self.dropout_0 = nn.Dropout(p=config.classifier_dropout) + + self.dense_1 = nn.Linear(config.d_model // 4, config.d_model // 16) + self.norm_1 = T5LayerNorm(config.d_model // 16) + self.relu_1 = NewGELUActivation() + self.dropout_1 = nn.Dropout(p=config.classifier_dropout) + + self.dense_2 = nn.Linear(config.d_model // 16, config.d_model // 64) + self.norm_2 = T5LayerNorm(config.d_model // 64) + self.relu_2 = NewGELUActivation() + self.dropout_2 = nn.Dropout(p=config.classifier_dropout) + + # self.dense_4 = nn.Linear(config.d_model // 16, config.d_model // 32) + # self.norm_4 = T5LayerNorm(config.d_model // 32) + # self.relu_4 = NewGELUActivation() + # self.dropout_4 = nn.Dropout(p=config.classifier_dropout) + + self.out_proj = nn.Linear(config.d_model // 64, config.num_labels) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + hidden_states = self.dropout_0( + self.relu_0(self.norm_0(self.dense_0(hidden_states))) + ) + hidden_states = self.dropout_1( + self.relu_1(self.norm_1(self.dense_1(hidden_states))) + ) + hidden_states = self.dropout_2( + self.relu_2(self.norm_2(self.dense_2(hidden_states))) + ) + + out = self.out_proj(hidden_states) + + return out + + +class T5PreTrainedModel(PreTrainedModel): + """ + An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained + models. + """ + + config_class = T5Config + load_tf_weights = load_tf_weights_in_t5 + base_model_prefix = "transformer" + is_parallelizable = True + supports_gradient_checkpointing = True + _supports_quantized_cache = False # enc-dec models don't support yet + _supports_static_cache = True + _supports_cache_class = True + _no_split_modules = ["T5Block"] + _keep_in_fp32_modules = ["wo"] + + @property + def dummy_inputs(self): + input_ids = torch.tensor(DUMMY_INPUTS) + input_mask = torch.tensor(DUMMY_MASK) + dummy_inputs = { + "decoder_input_ids": input_ids, + "input_ids": input_ids, + "decoder_attention_mask": input_mask, + } + return dummy_inputs + + def _init_weights(self, module): + """Initialize the weights""" + factor = ( + self.config.initializer_factor + ) # Used for testing weights initialization + if isinstance(module, T5LayerNorm): + module.weight.data.fill_(factor * 1.0) + elif isinstance( + module, + ( + T5Model, + T5ForConditionalGeneration, + T5EncoderModel, + T5ForQuestionAnswering, + ), + ): + # Mesh TensorFlow embeddings initialization + # See https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/layers.py#L1624 + module.shared.weight.data.normal_(mean=0.0, std=factor * 1.0) + if hasattr(module, "lm_head") and not self.config.tie_word_embeddings: + module.lm_head.weight.data.normal_(mean=0.0, std=factor * 1.0) + if hasattr(module, "qa_outputs"): + module.qa_outputs.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model) ** -0.5) + ) + module.qa_outputs.bias.data.zero_() + elif isinstance(module, T5ForTokenClassification): + if hasattr(module, "classifier"): + module.classifier.weight.data.normal_(mean=0.0, std=factor * 1.0) + module.classifier.bias.data.zero_() + elif isinstance(module, T5ClassificationHead): + module.dense_0.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model) ** -0.5) + ) + if hasattr(module.dense_0, "bias") and module.dense_0.bias is not None: + module.dense_0.bias.data.zero_() + + module.dense_1.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model // 4) ** -0.5) + ) + if hasattr(module.dense_1, "bias") and module.dense_1.bias is not None: + module.dense_1.bias.data.zero_() + + module.dense_2.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model // 16) ** -0.5) + ) + if hasattr(module.dense_2, "bias") and module.dense_2.bias is not None: + module.dense_2.bias.data.zero_() + + # module.dense_3.weight.data.normal_( + # mean=0.0, std=factor * ((self.config.d_model // 16) ** -0.5) + # ) + # if hasattr(module.dense_3, "bias") and module.dense_3.bias is not None: + # module.dense_3.bias.data.zero_() + + # module.dense_4.weight.data.normal_( + # mean=0.0, std=factor * ((self.config.d_model // 16) ** -0.5) + # ) + # if hasattr(module.dense_4, "bias") and module.dense_4.bias is not None: + # module.dense_4.bias.data.zero_() + + # module.dense_5.weight.data.normal_( + # mean=0.0, std=factor * ((self.config.d_model // 32) ** -0.5) + # ) + # if hasattr(module.dense_5, "bias") and module.dense_5.bias is not None: + # module.dense_5.bias.data.zero_() + + module.out_proj.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model // 64) ** -0.5) + ) + if hasattr(module.out_proj, "bias") and module.out_proj.bias is not None: + module.out_proj.bias.data.zero_() + elif isinstance(module, T5DenseActDense): + # Mesh TensorFlow FF initialization + # See https://github.com/tensorflow/mesh/blob/master/mesh_tensorflow/transformer/transformer_layers.py#L56 + # and https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/layers.py#L89 + module.wi.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model) ** -0.5) + ) + if hasattr(module.wi, "bias") and module.wi.bias is not None: + module.wi.bias.data.zero_() + module.wo.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_ff) ** -0.5) + ) + if hasattr(module.wo, "bias") and module.wo.bias is not None: + module.wo.bias.data.zero_() + elif isinstance(module, T5DenseGatedActDense): + module.wi_0.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model) ** -0.5) + ) + if hasattr(module.wi_0, "bias") and module.wi_0.bias is not None: + module.wi_0.bias.data.zero_() + module.wi_1.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_model) ** -0.5) + ) + if hasattr(module.wi_1, "bias") and module.wi_1.bias is not None: + module.wi_1.bias.data.zero_() + module.wo.weight.data.normal_( + mean=0.0, std=factor * ((self.config.d_ff) ** -0.5) + ) + if hasattr(module.wo, "bias") and module.wo.bias is not None: + module.wo.bias.data.zero_() + elif isinstance(module, T5Attention): + # Mesh TensorFlow attention initialization to avoid scaling before softmax + # See https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/transformer/attention.py#L136 + d_model = self.config.d_model + key_value_proj_dim = self.config.d_kv + n_heads = self.config.num_heads + module.q.weight.data.normal_( + mean=0.0, std=factor * ((d_model * key_value_proj_dim) ** -0.5) + ) + module.k.weight.data.normal_(mean=0.0, std=factor * (d_model**-0.5)) + module.v.weight.data.normal_(mean=0.0, std=factor * (d_model**-0.5)) + module.o.weight.data.normal_( + mean=0.0, std=factor * ((n_heads * key_value_proj_dim) ** -0.5) + ) + if module.has_relative_attention_bias: + module.relative_attention_bias.weight.data.normal_( + mean=0.0, std=factor * ((d_model) ** -0.5) + ) + + def _shift_right(self, input_ids): + decoder_start_token_id = self.config.decoder_start_token_id + pad_token_id = self.config.pad_token_id + + if decoder_start_token_id is None: + raise ValueError( + "self.model.config.decoder_start_token_id has to be defined. In T5 it is usually set to the pad_token_id. " + "See T5 docs for more information." + ) + + # shift inputs to the right + if is_torch_fx_proxy(input_ids): + # Item assignment is not supported natively for proxies. + shifted_input_ids = torch.full( + input_ids.shape[:-1] + (1,), decoder_start_token_id + ) + shifted_input_ids = torch.cat( + [shifted_input_ids, input_ids[..., :-1]], dim=-1 + ) + else: + shifted_input_ids = input_ids.new_zeros(input_ids.shape) + shifted_input_ids[..., 1:] = input_ids[..., :-1].clone() + shifted_input_ids[..., 0] = decoder_start_token_id + + if pad_token_id is None: + raise ValueError("self.model.config.pad_token_id has to be defined.") + # replace possible -100 values in labels by `pad_token_id` + shifted_input_ids.masked_fill_(shifted_input_ids == -100, pad_token_id) + + return shifted_input_ids + + +class T5Stack(T5PreTrainedModel): + def __init__(self, config, embed_tokens=None): + super().__init__(config) + + self.embed_tokens = embed_tokens + self.is_decoder = config.is_decoder + + self.block = nn.ModuleList( + [ + T5Block(config, has_relative_attention_bias=bool(i == 0), layer_idx=i) + for i in range(config.num_layers) + ] + ) + self.final_layer_norm = T5LayerNorm( + config.d_model, eps=config.layer_norm_epsilon + ) + self.dropout = nn.Dropout(config.dropout_rate) + + # Initialize weights and apply final processing + self.post_init() + # Model parallel + self.model_parallel = False + self.device_map = None + self.gradient_checkpointing = False + + @add_start_docstrings(PARALLELIZE_DOCSTRING) + def parallelize(self, device_map=None): + warnings.warn( + "`T5Stack.parallelize` is deprecated and will be removed in v5 of Transformers, you should load your model" + " with `device_map='balanced'` in the call to `from_pretrained`. You can also provide your own" + " `device_map` but it needs to be a dictionary module_name to device, so for instance {'block.0': 0," + " 'block.1': 1, ...}", + FutureWarning, + ) + # Check validity of device_map + self.device_map = ( + get_device_map(len(self.block), range(torch.cuda.device_count())) + if device_map is None + else device_map + ) + assert_device_map(self.device_map, len(self.block)) + self.model_parallel = True + self.first_device = ( + "cpu" + if "cpu" in self.device_map.keys() + else "cuda:" + str(min(self.device_map.keys())) + ) + self.last_device = "cuda:" + str(max(self.device_map.keys())) + # Load onto devices + for k, v in self.device_map.items(): + for layer in v: + cuda_device = "cuda:" + str(k) + self.block[layer] = self.block[layer].to(cuda_device) + + # Set embed_tokens to first layer + self.embed_tokens = self.embed_tokens.to(self.first_device) + # Set final layer norm to last device + self.final_layer_norm = self.final_layer_norm.to(self.last_device) + + @add_start_docstrings(DEPARALLELIZE_DOCSTRING) + def deparallelize(self): + warnings.warn( + "Like `parallelize`, `deparallelize` is deprecated and will be removed in v5 of Transformers.", + FutureWarning, + ) + self.model_parallel = False + self.device_map = None + self.first_device = "cpu" + self.last_device = "cpu" + for i in range(len(self.block)): + self.block[i] = self.block[i].to("cpu") + self.embed_tokens = self.embed_tokens.to("cpu") + self.final_layer_norm = self.final_layer_norm.to("cpu") + torch.cuda.empty_cache() + + def get_input_embeddings(self): + return self.embed_tokens + + def set_input_embeddings(self, new_embeddings): + self.embed_tokens = new_embeddings + + def forward( + self, + input_ids=None, + attention_mask=None, + encoder_hidden_states=None, + encoder_attention_mask=None, + inputs_embeds=None, + head_mask=None, + cross_attn_head_mask=None, + past_key_values=None, + use_cache=None, + output_attentions=None, + output_hidden_states=None, + return_dict=None, + cache_position=None, + ): + # Model parallel + if self.model_parallel: + torch.cuda.set_device(self.first_device) + self.embed_tokens = self.embed_tokens.to(self.first_device) + use_cache = use_cache if use_cache is not None else self.config.use_cache + 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: + err_msg_prefix = "decoder_" if self.is_decoder else "" + raise ValueError( + f"You cannot specify both {err_msg_prefix}input_ids and {err_msg_prefix}inputs_embeds at the same time" + ) + elif input_ids is not None: + input_shape = input_ids.size() + input_ids = input_ids.view(-1, input_shape[-1]) + elif inputs_embeds is not None: + input_shape = inputs_embeds.size()[:-1] + else: + err_msg_prefix = "decoder_" if self.is_decoder else "" + raise ValueError( + f"You have to specify either {err_msg_prefix}input_ids or {err_msg_prefix}inputs_embeds" + ) + + if self.gradient_checkpointing and self.training: + if use_cache: + logger.warning_once( + "`use_cache=True` is incompatible with gradient checkpointing. Setting `use_cache=False`..." + ) + use_cache = False + + if inputs_embeds is None: + if self.embed_tokens is None: + raise ValueError( + "You have to initialize the model with valid token embeddings" + ) + inputs_embeds = self.embed_tokens(input_ids) + + batch_size, seq_length = input_shape + + if use_cache is True: + if not self.is_decoder: + raise ValueError( + f"`use_cache` can only be set to `True` if {self} is used as a decoder" + ) + + # initialize past_key_values + return_legacy_cache = False + return_self_attention_cache = False + if self.is_decoder and (use_cache or past_key_values is not None): + if isinstance(past_key_values, Cache) and not isinstance( + past_key_values, EncoderDecoderCache + ): + return_self_attention_cache = True + past_key_values = EncoderDecoderCache(past_key_values, DynamicCache()) + elif not isinstance(past_key_values, EncoderDecoderCache): + return_legacy_cache = True + logger.warning_once( + "Passing a tuple of `past_key_values` is deprecated and will be removed in Transformers v4.48.0. " + "You should pass an instance of `EncoderDecoderCache` instead, e.g. " + "`past_key_values=EncoderDecoderCache.from_legacy_cache(past_key_values)`." + ) + past_key_values = EncoderDecoderCache.from_legacy_cache(past_key_values) + elif past_key_values is None: + past_key_values = EncoderDecoderCache(DynamicCache(), DynamicCache()) + elif not self.is_decoder: + # do not pass cache object down the line for encoder stack + # it messes indexing later in decoder-stack because cache object is modified in-place + past_key_values = None + + past_key_values_length = ( + past_key_values.get_seq_length() if past_key_values is not None else 0 + ) + if cache_position is None: + cache_position = torch.arange( + past_key_values_length, + past_key_values_length + seq_length, + device=inputs_embeds.device, + ) + + if attention_mask is None and not is_torchdynamo_compiling(): + # required mask seq length can be calculated via length of past cache + mask_seq_length = past_key_values_length + seq_length + attention_mask = torch.ones( + batch_size, mask_seq_length, device=inputs_embeds.device + ) + + if self.config.is_decoder: + causal_mask = self._update_causal_mask( + attention_mask, + inputs_embeds, + cache_position, + ( + past_key_values.self_attention_cache + if past_key_values is not None + else None + ), + output_attentions, + ) + elif attention_mask is not None: + causal_mask = attention_mask[:, None, None, :] + causal_mask = causal_mask.to(dtype=inputs_embeds.dtype) + causal_mask = (1.0 - causal_mask) * torch.finfo(inputs_embeds.dtype).min + else: + causal_mask = None + + # If a 2D or 3D attention mask is provided for the cross-attention + # we need to make broadcastable to [batch_size, num_heads, seq_length, seq_length] + if self.is_decoder and encoder_hidden_states is not None: + encoder_batch_size, encoder_sequence_length, _ = ( + encoder_hidden_states.size() + ) + encoder_hidden_shape = (encoder_batch_size, encoder_sequence_length) + if encoder_attention_mask is None: + encoder_attention_mask = torch.ones( + encoder_hidden_shape, device=inputs_embeds.device, dtype=torch.long + ) + encoder_extended_attention_mask = self.invert_attention_mask( + encoder_attention_mask + ) + else: + encoder_extended_attention_mask = None + + # Prepare head mask if needed + head_mask = self.get_head_mask(head_mask, self.config.num_layers) + cross_attn_head_mask = self.get_head_mask( + cross_attn_head_mask, self.config.num_layers + ) + all_hidden_states = () if output_hidden_states else None + all_attentions = () if output_attentions else None + all_cross_attentions = () if (output_attentions and self.is_decoder) else None + position_bias = None + encoder_decoder_position_bias = None + + hidden_states = self.dropout(inputs_embeds) + + for i, layer_module in enumerate(self.block): + layer_head_mask = head_mask[i] + cross_attn_layer_head_mask = cross_attn_head_mask[i] + # Model parallel + if self.model_parallel: + torch.cuda.set_device(hidden_states.device) + # Ensure that attention_mask is always on the same device as hidden_states + if causal_mask is not None: + causal_mask = causal_mask.to(hidden_states.device) + if position_bias is not None: + position_bias = position_bias.to(hidden_states.device) + if encoder_hidden_states is not None: + encoder_hidden_states = encoder_hidden_states.to( + hidden_states.device + ) + if encoder_extended_attention_mask is not None: + encoder_extended_attention_mask = ( + encoder_extended_attention_mask.to(hidden_states.device) + ) + if encoder_decoder_position_bias is not None: + encoder_decoder_position_bias = encoder_decoder_position_bias.to( + hidden_states.device + ) + if layer_head_mask is not None: + layer_head_mask = layer_head_mask.to(hidden_states.device) + if cross_attn_layer_head_mask is not None: + cross_attn_layer_head_mask = cross_attn_layer_head_mask.to( + hidden_states.device + ) + if output_hidden_states: + all_hidden_states = all_hidden_states + (hidden_states,) + + if self.gradient_checkpointing and self.training: + layer_outputs = self._gradient_checkpointing_func( + layer_module.forward, + hidden_states, + causal_mask, + position_bias, + encoder_hidden_states, + encoder_extended_attention_mask, + encoder_decoder_position_bias, + layer_head_mask, + cross_attn_layer_head_mask, + None, # past_key_value is always None with gradient checkpointing + use_cache, + output_attentions, + return_dict, + cache_position, + ) + else: + layer_outputs = layer_module( + hidden_states, + attention_mask=causal_mask, + position_bias=position_bias, + encoder_hidden_states=encoder_hidden_states, + encoder_attention_mask=encoder_extended_attention_mask, + encoder_decoder_position_bias=encoder_decoder_position_bias, + layer_head_mask=layer_head_mask, + cross_attn_layer_head_mask=cross_attn_layer_head_mask, + past_key_value=past_key_values, + use_cache=use_cache, + output_attentions=output_attentions, + return_dict=return_dict, + cache_position=cache_position, + ) + + # layer_outputs is a tuple with: + # hidden-states, key-value-states, (self-attention position bias), (self-attention weights), (cross-attention position bias), (cross-attention weights) + if use_cache is False: + layer_outputs = layer_outputs[:1] + (None,) + layer_outputs[1:] + + hidden_states, next_decoder_cache = layer_outputs[:2] + + # We share the position biases between the layers - the first layer store them + # layer_outputs = hidden-states, key-value-states (self-attention position bias), (self-attention weights), + # (cross-attention position bias), (cross-attention weights) + position_bias = layer_outputs[2] + if self.is_decoder and encoder_hidden_states is not None: + encoder_decoder_position_bias = layer_outputs[ + 4 if output_attentions else 3 + ] + + if output_attentions: + all_attentions = all_attentions + (layer_outputs[3],) + if self.is_decoder: + all_cross_attentions = all_cross_attentions + (layer_outputs[5],) + + # Model Parallel: If it's the last layer for that device, put things on the next device + if self.model_parallel: + for k, v in self.device_map.items(): + if i == v[-1] and "cuda:" + str(k) != self.last_device: + hidden_states = hidden_states.to("cuda:" + str(k + 1)) + + hidden_states = self.final_layer_norm(hidden_states) + hidden_states = self.dropout(hidden_states) + + # Add last layer + if output_hidden_states: + all_hidden_states = all_hidden_states + (hidden_states,) + + next_cache = next_decoder_cache if use_cache else None + if return_self_attention_cache: + next_cache = past_key_values.self_attention_cache + if return_legacy_cache: + next_cache = past_key_values.to_legacy_cache() + + if not return_dict: + return tuple( + v + for v in [ + hidden_states, + next_cache, + all_hidden_states, + all_attentions, + all_cross_attentions, + ] + if v is not None + ) + return BaseModelOutputWithPastAndCrossAttentions( + last_hidden_state=hidden_states, + past_key_values=next_cache, + hidden_states=all_hidden_states, + attentions=all_attentions, + cross_attentions=all_cross_attentions, + ) + + # Copied from transformers.models.llama.modeling_llama.LlamaModel._update_causal_mask + def _update_causal_mask( + self, + attention_mask: torch.Tensor, + input_tensor: torch.Tensor, + cache_position: torch.Tensor, + past_key_values: Cache, + output_attentions: bool, + ): + if self.config._attn_implementation == "flash_attention_2": + if attention_mask is not None and 0.0 in attention_mask: + return attention_mask + return None + + # For SDPA, when possible, we will rely on its `is_causal` argument instead of its `attn_mask` argument, in + # order to dispatch on Flash Attention 2. This feature is not compatible with static cache, as SDPA will fail + # to infer the attention mask. + past_seen_tokens = ( + past_key_values.get_seq_length() if past_key_values is not None else 0 + ) + using_static_cache = isinstance(past_key_values, StaticCache) + + # When output attentions is True, sdpa implementation's forward method calls the eager implementation's forward + if ( + self.config._attn_implementation == "sdpa" + and not using_static_cache + and not output_attentions + ): + if AttentionMaskConverter._ignore_causal_mask_sdpa( + attention_mask, + inputs_embeds=input_tensor, + past_key_values_length=past_seen_tokens, + is_training=self.training, + ): + return None + + dtype, device = input_tensor.dtype, input_tensor.device + sequence_length = input_tensor.shape[1] + if using_static_cache: + target_length = past_key_values.get_max_cache_shape() + else: + target_length = ( + attention_mask.shape[-1] + if isinstance(attention_mask, torch.Tensor) + else past_seen_tokens + sequence_length + 1 + ) + + # In case the provided `attention` mask is 2D, we generate a causal mask here (4D). + causal_mask = self._prepare_4d_causal_attention_mask_with_cache_position( + attention_mask, + sequence_length=sequence_length, + target_length=target_length, + dtype=dtype, + device=device, + cache_position=cache_position, + batch_size=input_tensor.shape[0], + ) + + if ( + self.config._attn_implementation == "sdpa" + and attention_mask is not None + and attention_mask.device.type == "cuda" + and not output_attentions + ): + # Attend to all tokens in fully masked rows in the causal_mask, for example the relevant first rows when + # using left padding. This is required by F.scaled_dot_product_attention memory-efficient attention path. + # Details: https://github.com/pytorch/pytorch/issues/110213 + min_dtype = torch.finfo(dtype).min + causal_mask = AttentionMaskConverter._unmask_unattended( + causal_mask, min_dtype + ) + + return causal_mask + + @staticmethod + # Copied from transformers.models.llama.modeling_llama.LlamaPreTrainedModel._prepare_4d_causal_attention_mask_with_cache_position + def _prepare_4d_causal_attention_mask_with_cache_position( + attention_mask: torch.Tensor, + sequence_length: int, + target_length: int, + dtype: torch.dtype, + device: torch.device, + cache_position: torch.Tensor, + batch_size: int, + **kwargs, + ): + """ + Creates a causal 4D mask of shape `(batch_size, 1, query_length, key_value_length)` from a 2D mask of shape + `(batch_size, key_value_length)`, or if the input `attention_mask` is already 4D, do nothing. + + Args: + attention_mask (`torch.Tensor`): + A 2D attention mask of shape `(batch_size, key_value_length)` or a 4D attention mask of shape + `(batch_size, 1, query_length, key_value_length)`. + sequence_length (`int`): + The sequence length being processed. + target_length (`int`): + The target length: when generating with static cache, the mask should be as long as the static cache, + to account for the 0 padding, the part of the cache that is not filled yet. + dtype (`torch.dtype`): + The dtype to use for the 4D attention mask. + device (`torch.device`): + The device to plcae the 4D attention mask on. + cache_position (`torch.Tensor`): + Indices depicting the position of the input sequence tokens in the sequence. + batch_size (`torch.Tensor`): + Batch size. + """ + if attention_mask is not None and attention_mask.dim() == 4: + # In this case we assume that the mask comes already in inverted form and requires no inversion or slicing. + causal_mask = attention_mask + else: + min_dtype = torch.finfo(dtype).min + causal_mask = torch.full( + (sequence_length, target_length), + fill_value=min_dtype, + dtype=dtype, + device=device, + ) + if sequence_length != 1: + causal_mask = torch.triu(causal_mask, diagonal=1) + causal_mask *= torch.arange( + target_length, device=device + ) > cache_position.reshape(-1, 1) + causal_mask = causal_mask[None, None, :, :].expand(batch_size, 1, -1, -1) + if attention_mask is not None: + causal_mask = ( + causal_mask.clone() + ) # copy to contiguous memory for in-place edit + mask_length = attention_mask.shape[-1] + padding_mask = ( + causal_mask[:, :, :, :mask_length] + + attention_mask[:, None, None, :] + ) + padding_mask = padding_mask == 0 + causal_mask[:, :, :, :mask_length] = causal_mask[ + :, :, :, :mask_length + ].masked_fill(padding_mask, min_dtype) + + return causal_mask + + +T5_START_DOCSTRING = r""" + + The T5 model was proposed in [Exploring the Limits of Transfer Learning with a Unified Text-to-Text + Transformer](https://arxiv.org/abs/1910.10683) by Colin Raffel, Noam Shazeer, Adam Roberts, Katherine Lee, Sharan + Narang, Michael Matena, Yanqi Zhou, Wei Li, Peter J. Liu. It's an encoder decoder transformer pre-trained in a + text-to-text denoising generative setting. + + This model inherits from [`PreTrainedModel`]. 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 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 ([`T5Config`]): Model configuration class with all the parameters of the model. + Initializing with a config file does not load the weights associated with the model, only the + configuration. Check out the [`~PreTrainedModel.from_pretrained`] method to load the model weights. +""" + +T5_INPUTS_DOCSTRING = r""" + Args: + input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`): + Indices of input sequence tokens in the vocabulary. T5 is a model with relative position embeddings so you + should be able to pad the inputs on both the right and the left. + + Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for detail. + + [What are input IDs?](../glossary#input-ids) + + To know more on how to prepare `input_ids` for pretraining take a look a [T5 Training](./t5#training). + attention_mask (`torch.FloatTensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`: + + - 1 for tokens that are **not masked**, + - 0 for tokens that are **masked**. + + [What are attention masks?](../glossary#attention-mask) + decoder_input_ids (`torch.LongTensor` of shape `(batch_size, target_sequence_length)`, *optional*): + Indices of decoder input sequence tokens in the vocabulary. + + Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for details. + + [What are decoder input IDs?](../glossary#decoder-input-ids) + + T5 uses the `pad_token_id` as the starting token for `decoder_input_ids` generation. If `past_key_values` + is used, optionally only the last `decoder_input_ids` have to be input (see `past_key_values`). + + To know more on how to prepare `decoder_input_ids` for pretraining take a look at [T5 + Training](./t5#training). + decoder_attention_mask (`torch.BoolTensor` of shape `(batch_size, target_sequence_length)`, *optional*): + Default behavior: generate a tensor that ignores pad tokens in `decoder_input_ids`. Causal mask will also + be used by default. + head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*): + Mask to nullify selected heads of the self-attention modules in the encoder. Mask values selected in `[0, + 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + decoder_head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*): + Mask to nullify selected heads of the self-attention modules in the decoder. Mask values selected in `[0, + 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + cross_attn_head_mask (`torch.Tensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*): + Mask to nullify selected heads of the cross-attention modules in the decoder. Mask values selected in + `[0, 1]`: + + - 1 indicates the head is **not masked**, + - 0 indicates the head is **masked**. + + encoder_outputs (`tuple(tuple(torch.FloatTensor)`, *optional*): + Tuple consists of (`last_hidden_state`, `optional`: *hidden_states*, `optional`: *attentions*) + `last_hidden_state` of shape `(batch_size, sequence_length, hidden_size)` is a sequence of hidden states at + the output of the last layer of the encoder. Used in the cross-attention of the decoder. + past_key_values (`tuple(tuple(torch.FloatTensor))` of length `config.n_layers` with each tuple having 4 tensors of shape `(batch_size, num_heads, sequence_length - 1, embed_size_per_head)`): + Contains precomputed key and value hidden states of the attention blocks. Can be used to speed up decoding. + + If `past_key_values` are used, the user can optionally input only the last `decoder_input_ids` (those that + don't have their past key value states given to this model) of shape `(batch_size, 1)` instead of all + `decoder_input_ids` of shape `(batch_size, sequence_length)`. + inputs_embeds (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This + is useful if you want more control over how to convert `input_ids` indices into associated vectors than the + model's internal embedding lookup matrix. + decoder_inputs_embeds (`torch.FloatTensor` of shape `(batch_size, target_sequence_length, hidden_size)`, *optional*): + Optionally, instead of passing `decoder_input_ids` you can choose to directly pass an embedded + representation. If `past_key_values` is used, optionally only the last `decoder_inputs_embeds` have to be + input (see `past_key_values`). This is useful if you want more control over how to convert + `decoder_input_ids` indices into associated vectors than the model's internal embedding lookup matrix. + + If `decoder_input_ids` and `decoder_inputs_embeds` are both unset, `decoder_inputs_embeds` takes the value + of `inputs_embeds`. + + use_cache (`bool`, *optional*): + If set to `True`, `past_key_values` key value states are returned and can be used to speed up decoding (see + `past_key_values`). + + output_attentions (`bool`, *optional*): + Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned + tensors for more detail. + output_hidden_states (`bool`, *optional*): + Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for + more detail. + return_dict (`bool`, *optional*): + Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. + cache_position (`torch.LongTensor` of shape `(sequence_length)`, *optional*): + Indices depicting the position of the input sequence tokens in the sequence. It is used to update the + cache in the correct position and to infer the complete sequence length. +""" + +T5_ENCODER_INPUTS_DOCSTRING = r""" + Args: + input_ids (`torch.LongTensor` of shape `(batch_size, sequence_length)`): + Indices of input sequence tokens in the vocabulary. T5 is a model with relative position embeddings so you + should be able to pad the inputs on both the right and the left. + + Indices can be obtained using [`AutoTokenizer`]. See [`PreTrainedTokenizer.encode`] and + [`PreTrainedTokenizer.__call__`] for detail. + + To know more on how to prepare `input_ids` for pretraining take a look a [T5 Training](./t5#training). + attention_mask (`torch.FloatTensor` of shape `(batch_size, sequence_length)`, *optional*): + Mask to avoid performing attention on padding token indices. Mask values selected in `[0, 1]`: + + - 1 for tokens that are **not masked**, + - 0 for tokens that are **masked**. + + [What are attention masks?](../glossary#attention-mask) + head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(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 (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`, *optional*): + Optionally, instead of passing `input_ids` you can choose to directly pass an embedded representation. This + is useful if you want more control over how to convert `input_ids` indices into associated vectors than the + model's internal embedding lookup matrix. + output_attentions (`bool`, *optional*): + Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned + tensors for more detail. + output_hidden_states (`bool`, *optional*): + Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for + more detail. + return_dict (`bool`, *optional*): + Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple. +""" + +# Warning message for FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask +__HEAD_MASK_WARNING_MSG = """ +The input argument `head_mask` was split into two arguments `head_mask` and `decoder_head_mask`. Currently, +`decoder_head_mask` is set to copy `head_mask`, but this feature is deprecated and will be removed in future versions. +If you do not want to use any `decoder_head_mask` now, please set `decoder_head_mask = torch.ones(num_layers, +num_heads)`. +""" + + +@add_start_docstrings( + "The bare T5 Model transformer outputting raw hidden-states without any specific head on top.", + T5_START_DOCSTRING, +) +class T5Model(T5PreTrainedModel): + _keys_to_ignore_on_load_unexpected = [ + "decoder.block.0.layer.1.EncDecAttention.relative_attention_bias.weight", + ] + _tied_weights_keys = ["encoder.embed_tokens.weight", "decoder.embed_tokens.weight"] + + def __init__(self, config: T5Config): + super().__init__(config) + self.shared = nn.Embedding(config.vocab_size, config.d_model) + + encoder_config = copy.deepcopy(config) + encoder_config.is_decoder = False + encoder_config.use_cache = False + encoder_config.is_encoder_decoder = False + self.encoder = T5Stack(encoder_config, self.shared) + + decoder_config = copy.deepcopy(config) + decoder_config.is_decoder = True + decoder_config.is_encoder_decoder = False + decoder_config.num_layers = config.num_decoder_layers + self.decoder = T5Stack(decoder_config, self.shared) + + # Initialize weights and apply final processing + self.post_init() + + # Model parallel + self.model_parallel = False + self.device_map = None + + @add_start_docstrings(PARALLELIZE_DOCSTRING) + def parallelize(self, device_map=None): + warnings.warn( + "`T5Model.parallelize` is deprecated and will be removed in v5 of Transformers, you should load your model" + " with `device_map='balanced'` in the call to `from_pretrained`. You can also provide your own" + " `device_map` but it needs to be a dictionary module_name to device, so for instance {'encoder.block.0':" + " 0, 'encoder.block.1': 1, ...}", + FutureWarning, + ) + self.device_map = ( + get_device_map(len(self.encoder.block), range(torch.cuda.device_count())) + if device_map is None + else device_map + ) + assert_device_map(self.device_map, len(self.encoder.block)) + self.encoder.parallelize(self.device_map) + self.decoder.parallelize(self.device_map) + self.model_parallel = True + + @add_start_docstrings(DEPARALLELIZE_DOCSTRING) + def deparallelize(self): + warnings.warn( + "Like `parallelize`, `deparallelize` is deprecated and will be removed in v5 of Transformers.", + FutureWarning, + ) + self.encoder.deparallelize() + self.decoder.deparallelize() + self.encoder = self.encoder.to("cpu") + self.decoder = self.decoder.to("cpu") + self.model_parallel = False + self.device_map = None + torch.cuda.empty_cache() + + def get_input_embeddings(self): + return self.shared + + def set_input_embeddings(self, new_embeddings): + self.shared = new_embeddings + self.encoder.set_input_embeddings(new_embeddings) + self.decoder.set_input_embeddings(new_embeddings) + + def _tie_weights(self): + if self.config.tie_word_embeddings: + self._tie_or_clone_weights(self.encoder.embed_tokens, self.shared) + self._tie_or_clone_weights(self.decoder.embed_tokens, self.shared) + + def get_encoder(self): + return self.encoder + + def get_decoder(self): + return self.decoder + + 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 + """ + for layer, heads in heads_to_prune.items(): + self.encoder.layer[layer].attention.prune_heads(heads) + + @add_start_docstrings_to_model_forward(T5_INPUTS_DOCSTRING) + @replace_return_docstrings( + output_type=Seq2SeqModelOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.FloatTensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.BoolTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + decoder_head_mask: Optional[torch.FloatTensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + past_key_values: Optional[Tuple[Tuple[torch.FloatTensor]]] = None, + inputs_embeds: Optional[torch.Tensor] = None, + decoder_inputs_embeds: Optional[torch.Tensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + cache_position: Optional[torch.LongTensor] = None, + ) -> Union[Tuple[torch.FloatTensor], Seq2SeqModelOutput]: + r""" + Returns: + + Example: + + ```python + >>> from transformers import AutoTokenizer, T5Model + + >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-small") + >>> model = T5Model.from_pretrained("google-t5/t5-small") + + >>> input_ids = tokenizer( + ... "Studies have been shown that owning a dog is good for you", return_tensors="pt" + ... ).input_ids # Batch size 1 + >>> decoder_input_ids = tokenizer("Studies show that", return_tensors="pt").input_ids # Batch size 1 + + >>> # preprocess: Prepend decoder_input_ids with start token which is pad token for T5Model. + >>> # This is not needed for torch's T5ForConditionalGeneration as it does this internally using labels arg. + >>> decoder_input_ids = model._shift_right(decoder_input_ids) + + >>> # forward pass + >>> outputs = model(input_ids=input_ids, decoder_input_ids=decoder_input_ids) + >>> last_hidden_states = outputs.last_hidden_state + ```""" + use_cache = use_cache if use_cache is not None else self.config.use_cache + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + # FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask + if head_mask is not None and decoder_head_mask is None: + if self.config.num_layers == self.config.num_decoder_layers: + warnings.warn(__HEAD_MASK_WARNING_MSG, FutureWarning) + decoder_head_mask = head_mask + + # Encode if needed (training, first prediction pass) + if encoder_outputs is None: + encoder_outputs = self.encoder( + input_ids=input_ids, + attention_mask=attention_mask, + inputs_embeds=inputs_embeds, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + elif return_dict and not isinstance(encoder_outputs, BaseModelOutput): + encoder_outputs = BaseModelOutput( + last_hidden_state=encoder_outputs[0], + hidden_states=encoder_outputs[1] if len(encoder_outputs) > 1 else None, + attentions=encoder_outputs[2] if len(encoder_outputs) > 2 else None, + ) + + hidden_states = encoder_outputs[0] + + # Set device for model parallelism + if self.model_parallel: + torch.cuda.set_device(self.decoder.first_device) + hidden_states = hidden_states.to(self.decoder.first_device) + if decoder_input_ids is not None: + decoder_input_ids = decoder_input_ids.to(self.decoder.first_device) + if attention_mask is not None: + attention_mask = attention_mask.to(self.decoder.first_device) + if decoder_attention_mask is not None: + decoder_attention_mask = decoder_attention_mask.to( + self.decoder.first_device + ) + + # Decode + decoder_outputs = self.decoder( + input_ids=decoder_input_ids, + attention_mask=decoder_attention_mask, + inputs_embeds=decoder_inputs_embeds, + past_key_values=past_key_values, + encoder_hidden_states=hidden_states, + encoder_attention_mask=attention_mask, + head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + cache_position=cache_position, + ) + + if not return_dict: + return decoder_outputs + encoder_outputs + + return Seq2SeqModelOutput( + last_hidden_state=decoder_outputs.last_hidden_state, + past_key_values=decoder_outputs.past_key_values, + decoder_hidden_states=decoder_outputs.hidden_states, + decoder_attentions=decoder_outputs.attentions, + cross_attentions=decoder_outputs.cross_attentions, + encoder_last_hidden_state=encoder_outputs.last_hidden_state, + encoder_hidden_states=encoder_outputs.hidden_states, + encoder_attentions=encoder_outputs.attentions, + ) + + +@add_start_docstrings( + """T5 Model with a `language modeling` head on top.""", T5_START_DOCSTRING +) +class T5ForConditionalGeneration(T5PreTrainedModel, GenerationMixin): + _keys_to_ignore_on_load_unexpected = [ + "decoder.block.0.layer.1.EncDecAttention.relative_attention_bias.weight", + ] + _tied_weights_keys = [ + "encoder.embed_tokens.weight", + "decoder.embed_tokens.weight", + "lm_head.weight", + ] + + def __init__(self, config: T5Config): + super().__init__(config) + self.model_dim = config.d_model + + self.shared = nn.Embedding(config.vocab_size, config.d_model) + + encoder_config = copy.deepcopy(config) + encoder_config.is_decoder = False + encoder_config.use_cache = False + encoder_config.is_encoder_decoder = False + self.encoder = T5Stack(encoder_config, self.shared) + + decoder_config = copy.deepcopy(config) + decoder_config.is_decoder = True + decoder_config.is_encoder_decoder = False + decoder_config.num_layers = config.num_decoder_layers + self.decoder = T5Stack(decoder_config, self.shared) + + self.lm_head = nn.Linear(config.d_model, config.vocab_size, bias=False) + + # Initialize weights and apply final processing + self.post_init() + + # Model parallel + self.model_parallel = False + self.device_map = None + + @add_start_docstrings(PARALLELIZE_DOCSTRING) + def parallelize(self, device_map=None): + warnings.warn( + "`T5ForConditionalGeneration.parallelize` is deprecated and will be removed in v5 of Transformers, you" + " should load your model with `device_map='balanced'` in the call to `from_pretrained`. You can also" + " provide your own `device_map` but it needs to be a dictionary module_name to device, so for instance" + " {'encoder.block.0': 0, 'encoder.block.1': 1, ...}", + FutureWarning, + ) + self.device_map = ( + get_device_map(len(self.encoder.block), range(torch.cuda.device_count())) + if device_map is None + else device_map + ) + assert_device_map(self.device_map, len(self.encoder.block)) + self.encoder.parallelize(self.device_map) + self.decoder.parallelize(self.device_map) + self.lm_head = self.lm_head.to(self.decoder.first_device) + self.model_parallel = True + + @add_start_docstrings(DEPARALLELIZE_DOCSTRING) + def deparallelize(self): + warnings.warn( + "Like `parallelize`, `deparallelize` is deprecated and will be removed in v5 of Transformers.", + FutureWarning, + ) + self.encoder.deparallelize() + self.decoder.deparallelize() + self.encoder = self.encoder.to("cpu") + self.decoder = self.decoder.to("cpu") + self.lm_head = self.lm_head.to("cpu") + self.model_parallel = False + self.device_map = None + torch.cuda.empty_cache() + + def get_input_embeddings(self): + return self.shared + + def set_input_embeddings(self, new_embeddings): + self.shared = new_embeddings + self.encoder.set_input_embeddings(new_embeddings) + self.decoder.set_input_embeddings(new_embeddings) + + def _tie_weights(self): + if self.config.tie_word_embeddings: + self._tie_or_clone_weights(self.encoder.embed_tokens, self.shared) + self._tie_or_clone_weights(self.decoder.embed_tokens, self.shared) + + def set_output_embeddings(self, new_embeddings): + self.lm_head = new_embeddings + + def get_output_embeddings(self): + return self.lm_head + + def get_encoder(self): + return self.encoder + + def get_decoder(self): + return self.decoder + + @add_start_docstrings_to_model_forward(T5_INPUTS_DOCSTRING) + @replace_return_docstrings( + output_type=Seq2SeqLMOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.FloatTensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.BoolTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + decoder_head_mask: Optional[torch.FloatTensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[Tuple[Tuple[torch.Tensor]]] = None, + past_key_values: Optional[Tuple[Tuple[torch.Tensor]]] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + decoder_inputs_embeds: Optional[torch.FloatTensor] = None, + labels: Optional[torch.LongTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + cache_position: Optional[torch.LongTensor] = None, + ) -> Union[Tuple[torch.FloatTensor], Seq2SeqLMOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the sequence classification/regression loss. Indices should be in `[-100, 0, ..., + config.vocab_size - 1]`. All labels set to `-100` are ignored (masked), the loss is only computed for + labels in `[0, ..., config.vocab_size]` + + Returns: + + Examples: + + ```python + >>> from transformers import AutoTokenizer, T5ForConditionalGeneration + + >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-small") + >>> model = T5ForConditionalGeneration.from_pretrained("google-t5/t5-small") + + >>> # training + >>> input_ids = tokenizer("The walks in park", return_tensors="pt").input_ids + >>> labels = tokenizer(" cute dog the ", return_tensors="pt").input_ids + >>> outputs = model(input_ids=input_ids, labels=labels) + >>> loss = outputs.loss + >>> logits = outputs.logits + + >>> # inference + >>> input_ids = tokenizer( + ... "summarize: studies have shown that owning a dog is good for you", return_tensors="pt" + ... ).input_ids # Batch size 1 + >>> outputs = model.generate(input_ids) + >>> print(tokenizer.decode(outputs[0], skip_special_tokens=True)) + >>> # studies have shown that owning a dog is good for you. + ```""" + use_cache = use_cache if use_cache is not None else self.config.use_cache + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + # FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask + if head_mask is not None and decoder_head_mask is None: + if self.config.num_layers == self.config.num_decoder_layers: + warnings.warn(__HEAD_MASK_WARNING_MSG, FutureWarning) + decoder_head_mask = head_mask + + # Encode if needed (training, first prediction pass) + if encoder_outputs is None: + # Convert encoder inputs in embeddings if needed + encoder_outputs = self.encoder( + input_ids=input_ids, + attention_mask=attention_mask, + inputs_embeds=inputs_embeds, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + elif return_dict and not isinstance(encoder_outputs, BaseModelOutput): + encoder_outputs = BaseModelOutput( + last_hidden_state=encoder_outputs[0], + hidden_states=encoder_outputs[1] if len(encoder_outputs) > 1 else None, + attentions=encoder_outputs[2] if len(encoder_outputs) > 2 else None, + ) + + hidden_states = encoder_outputs[0] + + if self.model_parallel: + torch.cuda.set_device(self.decoder.first_device) + + if ( + labels is not None + and decoder_input_ids is None + and decoder_inputs_embeds is None + ): + # get decoder inputs from shifting lm labels to the right + decoder_input_ids = self._shift_right(labels) + + # Set device for model parallelism + if self.model_parallel: + torch.cuda.set_device(self.decoder.first_device) + hidden_states = hidden_states.to(self.decoder.first_device) + if decoder_input_ids is not None: + decoder_input_ids = decoder_input_ids.to(self.decoder.first_device) + if attention_mask is not None: + attention_mask = attention_mask.to(self.decoder.first_device) + if decoder_attention_mask is not None: + decoder_attention_mask = decoder_attention_mask.to( + self.decoder.first_device + ) + + # Decode + decoder_outputs = self.decoder( + input_ids=decoder_input_ids, + attention_mask=decoder_attention_mask, + inputs_embeds=decoder_inputs_embeds, + past_key_values=past_key_values, + encoder_hidden_states=hidden_states, + encoder_attention_mask=attention_mask, + head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + cache_position=cache_position, + ) + + sequence_output = decoder_outputs[0] + + # Set device for model parallelism + if self.model_parallel: + torch.cuda.set_device(self.encoder.first_device) + self.lm_head = self.lm_head.to(self.encoder.first_device) + sequence_output = sequence_output.to(self.lm_head.weight.device) + + if self.config.tie_word_embeddings: + # Rescale output before projecting on vocab + # See https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/transformer/transformer.py#L586 + sequence_output = sequence_output * (self.model_dim**-0.5) + + lm_logits = self.lm_head(sequence_output) + + loss = None + if labels is not None: + loss_fct = CrossEntropyLoss(ignore_index=-100) + # move labels to correct device to enable PP + labels = labels.to(lm_logits.device) + loss = loss_fct(lm_logits.view(-1, lm_logits.size(-1)), labels.view(-1)) + # TODO(thom): Add z_loss https://github.com/tensorflow/mesh/blob/fa19d69eafc9a482aff0b59ddd96b025c0cb207d/mesh_tensorflow/layers.py#L666 + + if not return_dict: + output = (lm_logits,) + decoder_outputs[1:] + encoder_outputs + return ((loss,) + output) if loss is not None else output + + return Seq2SeqLMOutput( + loss=loss, + logits=lm_logits, + past_key_values=decoder_outputs.past_key_values, + decoder_hidden_states=decoder_outputs.hidden_states, + decoder_attentions=decoder_outputs.attentions, + cross_attentions=decoder_outputs.cross_attentions, + encoder_last_hidden_state=encoder_outputs.last_hidden_state, + encoder_hidden_states=encoder_outputs.hidden_states, + encoder_attentions=encoder_outputs.attentions, + ) + + def prepare_decoder_input_ids_from_labels(self, labels: torch.Tensor): + return self._shift_right(labels) + + def _reorder_cache(self, past_key_values, beam_idx): + # if decoder past is not included in output + # speedy decoding is disabled and no need to reorder + if past_key_values is None: + logger.warning( + "You might want to consider setting `use_cache=True` to speed up decoding" + ) + return past_key_values + + reordered_decoder_past = () + for layer_past_states in past_key_values: + # get the correct batch idx from layer past batch dim + # batch dim of `past` is at 2nd position + reordered_layer_past_states = () + for layer_past_state in layer_past_states: + # need to set correct `past` for each of the four key / value states + reordered_layer_past_states = reordered_layer_past_states + ( + layer_past_state.index_select( + 0, beam_idx.to(layer_past_state.device) + ), + ) + + if reordered_layer_past_states[0].shape != layer_past_states[0].shape: + raise ValueError( + f"reordered_layer_past_states[0] shape {reordered_layer_past_states[0].shape} and layer_past_states[0] shape {layer_past_states[0].shape} mismatched" + ) + if len(reordered_layer_past_states) != len(layer_past_states): + raise ValueError( + f"length of reordered_layer_past_states {len(reordered_layer_past_states)} and length of layer_past_states {len(layer_past_states)} mismatched" + ) + + reordered_decoder_past = reordered_decoder_past + ( + reordered_layer_past_states, + ) + return reordered_decoder_past + + +@add_start_docstrings( + "The bare T5 Model transformer outputting encoder's raw hidden-states without any specific head on top.", + T5_START_DOCSTRING, +) +class T5EncoderModel(T5PreTrainedModel): + _tied_weights_keys = ["encoder.embed_tokens.weight"] + _keys_to_ignore_on_load_unexpected = [r"decoder"] + + def __init__(self, config: T5Config): + super().__init__(config) + self.shared = nn.Embedding(config.vocab_size, config.d_model) + + encoder_config = copy.deepcopy(config) + encoder_config.use_cache = False + encoder_config.is_encoder_decoder = False + self.encoder = T5Stack(encoder_config, self.shared) + + # Initialize weights and apply final processing + self.post_init() + + # Model parallel + self.model_parallel = False + self.device_map = None + + @add_start_docstrings(PARALLELIZE_DOCSTRING) + def parallelize(self, device_map=None): + warnings.warn( + "`T5EncoderModel.parallelize` is deprecated and will be removed in v5 of Transformers, you should load" + " your model with `device_map='balanced'` in the call to `from_pretrained`. You can also provide your own" + " `device_map` but it needs to be a dictionary module_name to device, so for instance {'block.0': 0," + " 'block.1': 1, ...}", + FutureWarning, + ) + self.device_map = ( + get_device_map(len(self.encoder.block), range(torch.cuda.device_count())) + if device_map is None + else device_map + ) + assert_device_map(self.device_map, len(self.encoder.block)) + self.encoder.parallelize(self.device_map) + self.model_parallel = True + + @add_start_docstrings(DEPARALLELIZE_DOCSTRING) + def deparallelize(self): + warnings.warn( + "Like `parallelize`, `deparallelize` is deprecated and will be removed in v5 of Transformers.", + FutureWarning, + ) + self.encoder.deparallelize() + self.encoder = self.encoder.to("cpu") + self.model_parallel = False + self.device_map = None + torch.cuda.empty_cache() + + def get_input_embeddings(self): + return self.shared + + def set_input_embeddings(self, new_embeddings): + self.shared = new_embeddings + self.encoder.set_input_embeddings(new_embeddings) + + def _tie_weights(self): + if self.config.tie_word_embeddings: + self._tie_or_clone_weights(self.encoder.embed_tokens, self.shared) + + def get_encoder(self): + return self.encoder + + 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 + """ + for layer, heads in heads_to_prune.items(): + self.encoder.block[layer].layer[0].SelfAttention.prune_heads(heads) + + @add_start_docstrings_to_model_forward(T5_ENCODER_INPUTS_DOCSTRING) + @replace_return_docstrings( + output_type=BaseModelOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.FloatTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.FloatTensor], BaseModelOutput]: + r""" + Returns: + + Example: + + ```python + >>> from transformers import AutoTokenizer, T5EncoderModel + + >>> tokenizer = AutoTokenizer.from_pretrained("google-t5/t5-small") + >>> model = T5EncoderModel.from_pretrained("google-t5/t5-small") + >>> input_ids = tokenizer( + ... "Studies have been shown that owning a dog is good for you", return_tensors="pt" + ... ).input_ids # Batch size 1 + >>> outputs = model(input_ids=input_ids) + >>> last_hidden_states = outputs.last_hidden_state + ```""" + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + encoder_outputs = self.encoder( + input_ids=input_ids, + attention_mask=attention_mask, + inputs_embeds=inputs_embeds, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + return encoder_outputs + + +# def nt_xent_loss(features, labels, temperature=0.1): +# assert len(features.size()) == 2 + +# # Cosine similarity +# xcs = torch.nn.functional.cosine_similarity( +# features[None, :, :], features[:, None, :], dim=-1 +# ) +# xcs[torch.eye(features.size(0)).bool()] = float("-inf") + +# # create labels mask +# labels = labels.unsqueeze(0) +# target = labels.eq(labels.T).float() +# target[torch.eye(features.size(0)).bool()] = 0 + +# return torch.nn.functional.cross_entropy( +# (xcs / temperature).sigmoid(), target, reduction="mean" +# ) + + +def nt_xent_loss(features, labels): + assert len(features.size()) == 2 + + xcs = torch.nn.functional.cosine_similarity( + features[None, :, :], features[:, None, :], dim=-1 + ) + xcs = (xcs + 1) / 2 + xcs[torch.eye(features.size(0)).bool()] = 0 + + labels = labels.unsqueeze(0) + target = labels.eq(labels.T).float() + target[torch.eye(features.size(0)).bool()] = 0 + + return torch.nn.functional.cross_entropy(xcs, target, reduction="mean") + + +def contrastive_learning_loss( + logits: torch.Tensor, labels: torch.Tensor, temperature: float = 0.5 +) -> torch.Tensor: + """ + Computes contrastive loss using logits and labels. + + Args: + logits (torch.Tensor): Model output embeddings of shape (batch_size, embedding_dim). + labels (torch.Tensor): Corresponding class labels of shape (batch_size,). + temperature (float): Temperature parameter to scale similarity (default: 0.5). + + Returns: + torch.Tensor: Scalar loss value for the batch. + """ + # Normalize logits to unit vectors + logits_ = torch.nn.functional.normalize(logits, p=2, dim=1) + + # Compute pairwise cosine similarity + pairwise_similarities = torch.mm(logits_, logits_.T) / temperature + + # Exponential similarities for contrastive learning + exp_similarities = torch.exp(pairwise_similarities) + + # Create positive and negative masks + labels = labels.unsqueeze(1) # Shape: (batch_size, 1) + positive_mask = labels.eq( + labels.T + ).float() # Positive pairs: 1 if labels match, else 0 + + # Mask to exclude self-similarity (diagonal elements) + mask = torch.eye(logits_.size(0), device=logits_.device) + positive_mask = positive_mask * (1 - mask) + + # Compute contrastive loss + # For each example: log(sum(exp_similarities for positives) / sum(exp_similarities for all)) + numerator = exp_similarities * positive_mask + denominator = exp_similarities.sum( + dim=1, keepdim=True + ) - exp_similarities.diag().view(-1, 1) + + loss = -torch.log((numerator.sum(dim=1) + 1e-8) / (denominator + 1e-8).squeeze()) + return loss.mean() + + +@add_start_docstrings( + """ + T5 model with a sequence classification/head on top (a linear layer on top of the pooled output) e.g. for GLUE + tasks. + """, + T5_START_DOCSTRING, +) +class T5ForSequenceClassification(T5PreTrainedModel): + _keys_to_ignore_on_load_unexpected = [ + "decoder.block.0.layer.1.EncDecAttention.relative_attention_bias.weight" + ] + _tied_weights_keys = ["encoder.embed_tokens.weight", "decoder.embed_tokens.weight"] + + def __init__(self, config: T5Config): + super().__init__(config) + self.transformer = T5Model(config) + self.classification_head = T5ClassificationHead(config) + + # Initialize weights and apply final processing + self.post_init() + + self.model_parallel = False + + @add_start_docstrings_to_model_forward(T5_INPUTS_DOCSTRING) + @replace_return_docstrings( + output_type=Seq2SeqSequenceClassifierOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: torch.LongTensor = None, + attention_mask: Optional[torch.Tensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.LongTensor] = None, + head_mask: Optional[torch.Tensor] = None, + decoder_head_mask: Optional[torch.Tensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[List[torch.FloatTensor]] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + decoder_inputs_embeds: Optional[torch.FloatTensor] = None, + labels: Optional[torch.LongTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple, Seq2SeqSequenceClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for computing the sequence classification/regression loss. Indices should be in `[0, ..., + config.num_labels - 1]`. If `config.num_labels > 1` a classification loss is computed (Cross-Entropy). + Returns: + """ + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + if labels is not None: + use_cache = False + + if input_ids is None and inputs_embeds is not None: + raise NotImplementedError( + f"Passing input embeddings is currently not supported for {self.__class__.__name__}" + ) + + # Copied from models.bart.modeling_bart.BartModel.forward different to other models, T5 automatically creates + # decoder_input_ids from input_ids if no decoder_input_ids are provided + if decoder_input_ids is None and decoder_inputs_embeds is None: + if input_ids is None: + raise ValueError( + "If no `decoder_input_ids` or `decoder_inputs_embeds` are " + "passed, `input_ids` cannot be `None`. Please pass either " + "`input_ids` or `decoder_input_ids` or `decoder_inputs_embeds`." + ) + decoder_input_ids = self._shift_right(input_ids) + + outputs = self.transformer( + input_ids, + attention_mask=attention_mask, + decoder_input_ids=decoder_input_ids, + decoder_attention_mask=decoder_attention_mask, + head_mask=head_mask, + decoder_head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + encoder_outputs=encoder_outputs, + inputs_embeds=inputs_embeds, + decoder_inputs_embeds=decoder_inputs_embeds, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + sequence_output = outputs[0] + + eos_mask = input_ids.eq(self.config.eos_token_id).to(sequence_output.device) + + if len(torch.unique_consecutive(eos_mask.sum(1))) > 1: + raise ValueError("All examples must have the same number of tokens.") + batch_size, _, hidden_size = sequence_output.shape + sentence_representation = sequence_output[eos_mask, :].view( + batch_size, -1, hidden_size + )[:, -1, :] + logits = self.classification_head(sentence_representation) + + loss = None + if labels is not None: + labels = labels.to(logits.device) + if self.config.problem_type is None: + if self.config.num_labels == 1: + self.config.problem_type = "regression" + elif self.config.num_labels > 1 and ( + labels.dtype == torch.long or labels.dtype == torch.int + ): + self.config.problem_type = "single_label_classification" + else: + self.config.problem_type = "multi_label_classification" + + if self.config.problem_type == "regression": + loss_fct = MSELoss() + if self.config.num_labels == 1: + loss = loss_fct(logits.squeeze(), labels.squeeze()) + else: + loss = loss_fct(logits, labels) + elif self.config.problem_type == "single_label_classification": + loss_fct = CrossEntropyLoss() + cls_loss = loss_fct( + logits.view(-1, self.config.num_labels), labels.view(-1) + ) + # contrastive_loss = contrastive_learning_loss(logits, labels) + + # loss = contrastive_loss * 0.1 + cls_loss * 0.9 + loss = cls_loss + + elif self.config.problem_type == "multi_label_classification": + loss_fct = BCEWithLogitsLoss() + loss = loss_fct(logits, labels) + if not return_dict: + output = (logits,) + outputs[1:] + return ((loss,) + output) if loss is not None else output + + return Seq2SeqSequenceClassifierOutput( + loss=loss, + logits=logits, + past_key_values=outputs.past_key_values, + decoder_hidden_states=outputs.decoder_hidden_states, + decoder_attentions=outputs.decoder_attentions, + cross_attentions=outputs.cross_attentions, + encoder_last_hidden_state=outputs.encoder_last_hidden_state, + encoder_hidden_states=outputs.encoder_hidden_states, + encoder_attentions=outputs.encoder_attentions, + ) + + +@add_start_docstrings( + """ + T5 Encoder 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. + """, + T5_START_DOCSTRING, +) +class T5ForTokenClassification(T5PreTrainedModel): + _tied_weights_keys = ["transformer.encoder.embed_tokens.weight"] + + def __init__(self, config: T5Config): + super().__init__(config) + self.num_labels = config.num_labels + + self.transformer = T5EncoderModel(config) + self.dropout = nn.Dropout(config.classifier_dropout) + self.classifier = nn.Linear(config.hidden_size, config.num_labels) + + # Initialize weights and apply final processing + self.post_init() + + @add_start_docstrings_to_model_forward(T5_INPUTS_DOCSTRING) + @replace_return_docstrings( + output_type=TokenClassifierOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: Optional[torch.Tensor] = None, + attention_mask: Optional[torch.Tensor] = None, + head_mask: Optional[torch.Tensor] = None, + inputs_embeds: Optional[torch.Tensor] = None, + labels: Optional[torch.Tensor] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.Tensor], TokenClassifierOutput]: + r""" + labels (`torch.LongTensor` of shape `(batch_size, sequence_length)`, *optional*): + Labels for computing the token classification loss. Indices should be in `[0, ..., config.num_labels - 1]`. + Returns: + """ + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + outputs = self.transformer( + input_ids, + attention_mask=attention_mask, + head_mask=head_mask, + inputs_embeds=inputs_embeds, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + hidden_states = outputs[0] + hidden_states = self.dropout(hidden_states) + logits = self.classifier(hidden_states) + + loss = None + if labels is not None: + loss_fct = CrossEntropyLoss() + loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1)) + + if not return_dict: + output = (logits, outputs[2:-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, + ) + + +@add_start_docstrings( + """ + T5 Model with a span classification head on top for extractive question-answering tasks like SQuAD (linear layers + on top of the hidden-states output to compute `span start logits` and `span end logits`). + """, + T5_START_DOCSTRING, +) +class T5ForQuestionAnswering(T5PreTrainedModel): + _keys_to_ignore_on_load_unexpected = [ + "decoder.block.0.layer.1.EncDecAttention.relative_attention_bias.weight" + ] + _tied_weights_keys = ["encoder.embed_tokens.weight", "decoder.embed_tokens.weight"] + + def __init__(self, config: T5Config): + super().__init__(config) + self.model_dim = config.d_model + + self.shared = nn.Embedding(config.vocab_size, config.d_model) + + encoder_config = copy.deepcopy(config) + encoder_config.is_decoder = False + encoder_config.use_cache = False + encoder_config.is_encoder_decoder = False + self.encoder = T5Stack(encoder_config, self.shared) + + decoder_config = copy.deepcopy(config) + decoder_config.is_decoder = True + decoder_config.is_encoder_decoder = False + decoder_config.num_layers = config.num_decoder_layers + self.decoder = T5Stack(decoder_config, self.shared) + + self.num_labels = config.num_labels + self.qa_outputs = nn.Linear(config.hidden_size, config.num_labels) + + # Initialize weights and apply final processing + self.post_init() + + self.model_parallel = False + + def get_input_embeddings(self): + return self.shared + + def set_input_embeddings(self, new_embeddings): + self.shared = new_embeddings + self.encoder.set_input_embeddings(new_embeddings) + self.decoder.set_input_embeddings(new_embeddings) + + def _tie_weights(self): + if self.config.tie_word_embeddings: + self._tie_or_clone_weights(self.encoder.embed_tokens, self.shared) + self._tie_or_clone_weights(self.decoder.embed_tokens, self.shared) + + def get_encoder(self): + return self.encoder + + def get_decoder(self): + return self.decoder + + @add_start_docstrings_to_model_forward(T5_INPUTS_DOCSTRING) + @replace_return_docstrings( + output_type=Seq2SeqQuestionAnsweringModelOutput, config_class=_CONFIG_FOR_DOC + ) + def forward( + self, + input_ids: Optional[torch.LongTensor] = None, + attention_mask: Optional[torch.FloatTensor] = None, + decoder_input_ids: Optional[torch.LongTensor] = None, + decoder_attention_mask: Optional[torch.BoolTensor] = None, + head_mask: Optional[torch.FloatTensor] = None, + decoder_head_mask: Optional[torch.FloatTensor] = None, + cross_attn_head_mask: Optional[torch.Tensor] = None, + encoder_outputs: Optional[Tuple[Tuple[torch.Tensor]]] = None, + start_positions: Optional[torch.LongTensor] = None, + end_positions: Optional[torch.LongTensor] = None, + inputs_embeds: Optional[torch.FloatTensor] = None, + decoder_inputs_embeds: Optional[torch.FloatTensor] = None, + use_cache: Optional[bool] = None, + output_attentions: Optional[bool] = None, + output_hidden_states: Optional[bool] = None, + return_dict: Optional[bool] = None, + ) -> Union[Tuple[torch.FloatTensor], Seq2SeqQuestionAnsweringModelOutput]: + r""" + start_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for position (index) of the start of the labelled span for computing the token classification loss. + Positions are clamped to the length of the sequence (*sequence_length*). Position outside of the sequence + are not taken into account for computing the loss. + end_positions (`torch.LongTensor` of shape `(batch_size,)`, *optional*): + Labels for position (index) of the end of the labelled span for computing the token classification loss. + Positions are clamped to the length of the sequence (*sequence_length*). Position outside of the sequence + are not taken into account for computing the loss. + Returns: + """ + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + use_cache = use_cache if use_cache is not None else self.config.use_cache + if start_positions is not None and end_positions is not None: + use_cache = False + + # Copied from models.bart.modeling_bart.BartModel.forward + # different to other models, T5 automatically creates decoder_input_ids from + # input_ids if no decoder_input_ids are provided + if decoder_input_ids is None and decoder_inputs_embeds is None: + if input_ids is None: + raise ValueError( + "If no `decoder_input_ids` or `decoder_inputs_embeds` are " + "passed, `input_ids` cannot be `None`. Please pass either " + "`input_ids` or `decoder_input_ids` or `decoder_inputs_embeds`." + ) + decoder_input_ids = self._shift_right(input_ids) + + use_cache = use_cache if use_cache is not None else self.config.use_cache + return_dict = ( + return_dict if return_dict is not None else self.config.use_return_dict + ) + + # FutureWarning: head_mask was separated into two input args - head_mask, decoder_head_mask + if head_mask is not None and decoder_head_mask is None: + if self.config.num_layers == self.config.num_decoder_layers: + warnings.warn(__HEAD_MASK_WARNING_MSG, FutureWarning) + decoder_head_mask = head_mask + + # Encode if needed (training, first prediction pass) + if encoder_outputs is None: + encoder_outputs = self.encoder( + input_ids=input_ids, + attention_mask=attention_mask, + inputs_embeds=inputs_embeds, + head_mask=head_mask, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + elif return_dict and not isinstance(encoder_outputs, BaseModelOutput): + encoder_outputs = BaseModelOutput( + last_hidden_state=encoder_outputs[0], + hidden_states=encoder_outputs[1] if len(encoder_outputs) > 1 else None, + attentions=encoder_outputs[2] if len(encoder_outputs) > 2 else None, + ) + + hidden_states = encoder_outputs[0] + + # Decode + decoder_outputs = self.decoder( + input_ids=decoder_input_ids, + attention_mask=decoder_attention_mask, + inputs_embeds=decoder_inputs_embeds, + past_key_values=None, + encoder_hidden_states=hidden_states, + encoder_attention_mask=attention_mask, + head_mask=decoder_head_mask, + cross_attn_head_mask=cross_attn_head_mask, + use_cache=use_cache, + output_attentions=output_attentions, + output_hidden_states=output_hidden_states, + return_dict=return_dict, + ) + + sequence_output = decoder_outputs[0] + + logits = self.qa_outputs(sequence_output) + start_logits, end_logits = logits.split(1, dim=-1) + start_logits = start_logits.squeeze(-1).contiguous() + end_logits = end_logits.squeeze(-1).contiguous() + + total_loss = None + if start_positions is not None and end_positions is not None: + # If we are on multi-GPU, split add a dimension + if len(start_positions.size()) > 1: + start_positions = start_positions.squeeze(-1).to(start_logits.device) + if len(end_positions.size()) > 1: + end_positions = end_positions.squeeze(-1).to(end_logits.device) + # sometimes the start/end positions are outside our model inputs, we ignore these terms + ignored_index = start_logits.size(1) + start_positions = start_positions.clamp(0, ignored_index) + end_positions = end_positions.clamp(0, ignored_index) + + loss_fct = CrossEntropyLoss(ignore_index=ignored_index) + start_loss = loss_fct(start_logits, start_positions) + end_loss = loss_fct(end_logits, end_positions) + total_loss = (start_loss + end_loss) / 2 + + if not return_dict: + output = (start_logits, end_logits) + decoder_outputs[1:] + encoder_outputs + return ((total_loss,) + output) if total_loss is not None else output + + return Seq2SeqQuestionAnsweringModelOutput( + loss=total_loss, + start_logits=start_logits, + end_logits=end_logits, + past_key_values=decoder_outputs.past_key_values, + decoder_hidden_states=decoder_outputs.hidden_states, + decoder_attentions=decoder_outputs.attentions, + cross_attentions=decoder_outputs.cross_attentions, + encoder_last_hidden_state=encoder_outputs.last_hidden_state, + encoder_hidden_states=encoder_outputs.hidden_states, + encoder_attentions=encoder_outputs.attentions, + )