diff --git "a/t5.py" "b/t5.py" new file mode 100644--- /dev/null +++ "b/t5.py" @@ -0,0 +1,3223 @@ +# 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 +import torch.nn.functional as F +from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss +from transformers import PretrainedConfig, add_start_docstrings, PreTrainedModel +from transformers.activations import ACT2FN +from transformers.modeling_attn_mask_utils import _prepare_4d_causal_attention_mask, \ + _prepare_4d_attention_mask_for_sdpa, _prepare_4d_causal_attention_mask_for_sdpa +from transformers.modeling_outputs import BaseModelOutput, BaseModelOutputWithPastAndCrossAttentions, Seq2SeqLMOutput, \ + Seq2SeqModelOutput, Seq2SeqQuestionAnsweringModelOutput, Seq2SeqSequenceClassifierOutput, TokenClassifierOutput +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_to_model_forward, is_torch_fx_proxy, \ + logging, replace_return_docstrings, is_flash_attn_greater_or_equal_2_10, is_flash_attn_2_available +from transformers.utils.model_parallel_utils import assert_device_map, get_device_map + +if is_flash_attn_2_available(): + from flash_attn import flash_attn_func, flash_attn_varlen_func + from flash_attn.bert_padding import index_first_axis, pad_input, unpad_input # noqa + + + +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 +#################################################### + + # noqa: F401, E402 + + +#################################################### +# This is a conversion method from TF 1.0 to PyTorch +# More details: https://medium.com/huggingface/from-tensorflow-to-pytorch-265f40ef2a28 +#################################################### + + +class T5Config(PretrainedConfig): + r""" + This is the configuration class to store the configuration of a [`T5Model`] or a [`TFT5Model`]. It is used to + instantiate a T5 model according to the specified arguments, defining the model architecture. Instantiating a + configuration with the defaults will yield a similar configuration to that of the T5 + [google-t5/t5-small](https://huggingface.co/google-t5/t5-small) architecture. + + Configuration objects inherit from [`PretrainedConfig`] and can be used to control the model outputs. Read the + documentation from [`PretrainedConfig`] for more information. + + Arguments: + vocab_size (`int`, *optional*, defaults to 32128): + Vocabulary size of the T5 model. Defines the number of different tokens that can be represented by the + `inputs_ids` passed when calling [`T5Model`] or [`TFT5Model`]. + d_model (`int`, *optional*, defaults to 512): + Size of the encoder layers and the pooler layer. + d_kv (`int`, *optional*, defaults to 64): + Size of the key, query, value projections per attention head. The `inner_dim` of the projection layer will + be defined as `num_heads * d_kv`. + d_ff (`int`, *optional*, defaults to 2048): + Size of the intermediate feed forward layer in each `T5Block`. + num_layers (`int`, *optional*, defaults to 6): + Number of hidden layers in the Transformer encoder. + num_decoder_layers (`int`, *optional*): + Number of hidden layers in the Transformer decoder. Will use the same value as `num_layers` if not set. + num_heads (`int`, *optional*, defaults to 8): + Number of attention heads for each attention layer in the Transformer encoder. + relative_attention_num_buckets (`int`, *optional*, defaults to 32): + The number of buckets to use for each attention layer. + relative_attention_max_distance (`int`, *optional*, defaults to 128): + The maximum distance of the longer sequences for the bucket separation. + dropout_rate (`float`, *optional*, defaults to 0.1): + The ratio for all dropout layers. + classifier_dropout (`float`, *optional*, defaults to 0.0): + The dropout ratio for classifier. + layer_norm_eps (`float`, *optional*, defaults to 1e-6): + The epsilon used by the layer normalization layers. + initializer_factor (`float`, *optional*, defaults to 1): + A factor for initializing all weight matrices (should be kept to 1, used internally for initialization + testing). + feed_forward_proj (`string`, *optional*, defaults to `"relu"`): + Type of feed forward layer to be used. Should be one of `"relu"` or `"gated-gelu"`. T5v1.1 uses the + `"gated-gelu"` feed forward projection. Original T5 uses `"relu"`. + use_cache (`bool`, *optional*, defaults to `True`): + Whether or not the model should return the last key/values attentions (not used by all models). + """ + + model_type = "t5" + keys_to_ignore_at_inference = ["past_key_values"] + attribute_map = {"hidden_size": "d_model", "num_attention_heads": "num_heads", "num_hidden_layers": "num_layers"} + + def __init__( + self, + vocab_size=32128, + d_model=512, + d_kv=64, + d_ff=2048, + num_layers=6, + num_decoder_layers=None, + num_heads=8, + relative_attention_num_buckets=32, + relative_attention_max_distance=128, + dropout_rate=0.1, + layer_norm_epsilon=1e-6, + initializer_factor=1.0, + feed_forward_proj="relu", + is_encoder_decoder=True, + use_cache=True, + pad_token_id=0, + eos_token_id=1, + classifier_dropout=0.0, + rope_theta=10000.0, + rope_scaling=None, + max_position_embeddings=1024, + **kwargs, + ): + self.vocab_size = vocab_size + self.d_model = d_model + self.d_kv = d_kv + self.d_ff = d_ff + self.num_layers = num_layers + self.num_decoder_layers = ( + num_decoder_layers if num_decoder_layers is not None else self.num_layers + ) # default = symmetry + self.num_heads = num_heads + self.relative_attention_num_buckets = relative_attention_num_buckets + self.relative_attention_max_distance = relative_attention_max_distance + self.dropout_rate = dropout_rate + self.classifier_dropout = classifier_dropout + self.layer_norm_epsilon = layer_norm_epsilon + self.initializer_factor = initializer_factor + self.feed_forward_proj = feed_forward_proj + self.use_cache = use_cache + self.rope_theta = rope_theta + self.rope_scaling=rope_scaling + self.max_position_embeddings = max_position_embeddings + + act_info = self.feed_forward_proj.split("-") + self.dense_act_fn = act_info[-1] + self.is_gated_act = act_info[0] == "gated" + + if len(act_info) > 1 and act_info[0] != "gated" or len(act_info) > 2: + raise ValueError( + f"`feed_forward_proj`: {feed_forward_proj} is not a valid activation function of the dense layer. " + "Please make sure `feed_forward_proj` is of the format `gated-{ACT_FN}` or `{ACT_FN}`, e.g. " + "'gated-gelu' or 'relu'" + ) + + # for backwards compatibility + if feed_forward_proj == "gated-gelu": + self.dense_act_fn = "gelu_new" + + super().__init__( + pad_token_id=pad_token_id, + eos_token_id=eos_token_id, + is_encoder_decoder=is_encoder_decoder, + **kwargs, + ) +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, defaults to None): + 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() + ``` +""" +def _get_unpad_data(attention_mask): + seqlens_in_batch = attention_mask.sum(dim=-1, dtype=torch.int32) + indices = torch.nonzero(attention_mask.flatten(), as_tuple=False).flatten() + max_seqlen_in_batch = seqlens_in_batch.max().item() + cu_seqlens = F.pad(torch.cumsum(seqlens_in_batch, dim=0, dtype=torch.int32), (1, 0)) + return ( + indices, + cu_seqlens, + max_seqlen_in_batch, + ) +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 T5RotaryEmbedding(nn.Module): + def __init__(self, dim, max_position_embeddings=512, base=10000, device=None): + super().__init__() + + self.dim = dim + self.max_position_embeddings = max_position_embeddings + self.base = base + inv_freq = 1.0 / (self.base ** (torch.arange(0, self.dim, 2).float().to(device) / self.dim)) + self.register_buffer("inv_freq", inv_freq, persistent=False) + + # Build here to make `torch.jit.trace` work. + self._set_cos_sin_cache( + seq_len=max_position_embeddings, device=self.inv_freq.device, dtype=torch.get_default_dtype() + ) + + def _set_cos_sin_cache(self, seq_len, device, dtype): + self.max_seq_len_cached = seq_len + t = torch.arange(self.max_seq_len_cached, device=device, dtype=self.inv_freq.dtype) + + freqs = torch.einsum("i,j->ij", t, self.inv_freq) + emb = torch.cat((freqs, freqs), dim=-1) + self.register_buffer("cos_cached", emb.cos().to(dtype), persistent=False) + self.register_buffer("sin_cached", emb.sin().to(dtype), persistent=False) + + def forward(self, x, seq_len=None): + if seq_len > self.max_seq_len_cached: + self._set_cos_sin_cache(seq_len=seq_len, device=x.device, dtype=x.dtype) + + return ( + self.cos_cached[:seq_len].to(dtype=x.dtype), + self.sin_cached[:seq_len].to(dtype=x.dtype), + ) + + +class T5LinearScalingRotaryEmbedding(T5RotaryEmbedding): + def __init__(self, dim, max_position_embeddings=512, base=10000, device=None, scaling_factor=1.0): + self.scaling_factor = scaling_factor + super().__init__(dim, max_position_embeddings, base, device) + + def _set_cos_sin_cache(self, seq_len, device, dtype): + self.max_seq_len_cached = seq_len + t = torch.arange(self.max_seq_len_cached, device=device, dtype=self.inv_freq.dtype) + t = t / self.scaling_factor + + freqs = torch.einsum("i,j->ij", t, self.inv_freq) + # Different from paper, but it uses a different permutation in order to obtain the same calculation + emb = torch.cat((freqs, freqs), dim=-1) + self.register_buffer("cos_cached", emb.cos().to(dtype), persistent=False) + self.register_buffer("sin_cached", emb.sin().to(dtype), persistent=False) + + +class T5DynamicNTKScalingRotaryEmbedding(T5RotaryEmbedding): + + def __init__(self, dim, max_position_embeddings=512, base=10000, device=None, scaling_factor=1.0): + self.scaling_factor = scaling_factor + super().__init__(dim, max_position_embeddings, base, device) + + def _set_cos_sin_cache(self, seq_len, device, dtype): + self.max_seq_len_cached = seq_len + + if seq_len > self.max_position_embeddings: + base = self.base * ( + (self.scaling_factor * seq_len / self.max_position_embeddings) - (self.scaling_factor - 1) + ) ** (self.dim / (self.dim - 2)) + inv_freq = 1.0 / (base ** (torch.arange(0, self.dim, 2).float().to(device) / self.dim)) + self.register_buffer("inv_freq", inv_freq, persistent=False) + + t = torch.arange(self.max_seq_len_cached, device=device, dtype=self.inv_freq.dtype) + + freqs = torch.einsum("i,j->ij", t, self.inv_freq) + emb = torch.cat((freqs, freqs), dim=-1) + self.register_buffer("cos_cached", emb.cos().to(dtype), persistent=False) + self.register_buffer("sin_cached", emb.sin().to(dtype), persistent=False) + + +def rotate_half(x): + x1 = x[..., : x.shape[-1] // 2] + x2 = x[..., x.shape[-1] // 2 :] + return torch.cat((-x2, x1), dim=-1) +def apply_rotary_pos_emb(q, k, cos, sin, position_ids, unsqueeze_dim=1): + """Applies Rotary Position Embedding to the query and key tensors. + + Args: + q (`torch.Tensor`): The query tensor. + k (`torch.Tensor`): The key tensor. + cos (`torch.Tensor`): The cosine part of the rotary embedding. + sin (`torch.Tensor`): The sine part of the rotary embedding. + position_ids (`torch.Tensor`): + The position indices of the tokens corresponding to the query and key tensors. For example, this can be + used to pass offsetted position ids when working with a KV-cache. + unsqueeze_dim (`int`, *optional*, defaults to 1): + The 'unsqueeze_dim' argument specifies the dimension along which to unsqueeze cos[position_ids] and + sin[position_ids] so that they can be properly broadcasted to the dimensions of q and k. For example, note + that cos[position_ids] and sin[position_ids] have the shape [batch_size, seq_len, head_dim]. Then, if q and + k have the shape [batch_size, heads, seq_len, head_dim], then setting unsqueeze_dim=1 makes + cos[position_ids] and sin[position_ids] broadcastable to the shapes of q and k. Similarly, if q and k have + the shape [batch_size, seq_len, heads, head_dim], then set unsqueeze_dim=2. + Returns: + `tuple(torch.Tensor)` comprising of the query and key tensors rotated using the Rotary Position Embedding. + """ + + q_cos = cos[position_ids].unsqueeze(unsqueeze_dim) + q_sin = sin[position_ids].unsqueeze(unsqueeze_dim) + q_embed = (q * q_cos) + (rotate_half(q) * q_sin) + if k.shape[-2] != q.shape[-2]: + k_position_ids = torch.arange(k.shape[-2], device=k.device).unsqueeze(0) + k_cos = cos[k_position_ids].unsqueeze(unsqueeze_dim) + k_sin = sin[k_position_ids].unsqueeze(unsqueeze_dim) + k_embed = (k * k_cos) + (rotate_half(k) * k_sin) + else: + k_embed = (k * q_cos) + (rotate_half(k) * q_sin) + return q_embed, k_embed + + + +class T5Attention(nn.Module): + def __init__(self, config: T5Config, has_relative_attention_bias=False, is_causal=False): + super().__init__() + self.config=config + self.is_decoder = config.is_decoder + self.has_relative_attention_bias = False + 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.rope_theta = config.rope_theta + self.is_causal = is_causal + + + # 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) + + + self.pruned_heads = set() + self.gradient_checkpointing = False + self._init_rope() + + def _init_rope(self): + if self.config.rope_scaling is None: + self.rotary_emb = T5RotaryEmbedding( + self.key_value_proj_dim, + max_position_embeddings=self.config.max_position_embeddings, + base=self.rope_theta, + ) + else: + scaling_type = self.config.rope_scaling["type"] + scaling_factor = self.config.rope_scaling["factor"] + if scaling_type == "linear": + self.rotary_emb = T5LinearScalingRotaryEmbedding( + self.attention_head_size, + max_position_embeddings=self.max_position_embeddings, + scaling_factor=scaling_factor, + base=self.rope_theta, + ) + elif scaling_type == "dynamic": + self.rotary_emb = T5DynamicNTKScalingRotaryEmbedding( + self.attention_head_size, + max_position_embeddings=self.max_position_embeddings, + scaling_factor=scaling_factor, + base=self.rope_theta, + ) + else: + raise ValueError(f"Unknown RoPE scaling type {scaling_type}") + + 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): + """Compute binned relative position bias""" + if device is None: + device = self.relative_attention_bias.weight.device + context_position = torch.arange(query_length, dtype=torch.long, device=device)[:, None] + 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, + ): + """ + 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, key_length) (non-causal) or (batch_size, key_length, key_length) + # past_key_value[0] is (batch_size, n_heads, q_len - 1, dim_per_head) + batch_size, seq_length = hidden_states.shape[:2] + + real_seq_length = seq_length + + if past_key_value is not None: + if len(past_key_value) != 2: + raise ValueError( + f"past_key_value should have 2 past states: keys and values. Got { len(past_key_value)} past states" + ) + real_seq_length += past_key_value[0].shape[2] if query_length is None else query_length + + key_length = real_seq_length if key_value_states is None else key_value_states.shape[1] + + def shape(states): + """projection""" + return states.view(batch_size, -1, self.n_heads, self.key_value_proj_dim).transpose(1, 2) + + def unshape(states): + """reshape""" + return states.transpose(1, 2).contiguous().view(batch_size, -1, self.inner_dim) + + def project(hidden_states, proj_layer, key_value_states, past_key_value): + """projects hidden states correctly to key/query states""" + if key_value_states is None: + # self-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(hidden_states)) + elif past_key_value is None: + # cross-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(key_value_states)) + + if past_key_value is not None: + if key_value_states is None: + # self-attn + # (batch_size, n_heads, key_length, dim_per_head) + hidden_states = torch.cat([past_key_value, hidden_states], dim=2) + elif past_key_value.shape[2] != key_value_states.shape[1]: + # checking that the `sequence_length` of the `past_key_value` is the same as + # the provided `key_value_states` to support prefix tuning + # cross-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(key_value_states)) + else: + # cross-attn + hidden_states = past_key_value + return hidden_states + + # get query states + query_states = shape(self.q(hidden_states)) # (batch_size, n_heads, seq_length, dim_per_head) + + # get key/value states + key_states = project( + hidden_states, self.k, key_value_states, past_key_value[0] if past_key_value is not None else None + ) + value_states = project( + hidden_states, self.v, key_value_states, past_key_value[1] if past_key_value is not None else None + ) + kv_seq_len = key_states.shape[-2] + cos, sin = self.rotary_emb(value_states, seq_len=max(kv_seq_len, seq_length)) + query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin, position_bias) + # compute scores + scores = torch.matmul( + query_states, key_states.transpose(3, 2) + ) # equivalent of torch.einsum("bnqd,bnkd->bnqk", query_states, key_states), compatible with onnx op>9 + # print(scores.shape) + # print(value_states.shape) + + if mask is not None: + # Apply the attention mask is (precomputed for all layers in BertModel forward() function) + scores += mask + + + attn_weights = nn.functional.softmax(scores.float(), dim=-1).type_as( + scores + ) # (batch_size, n_heads, seq_length, key_length) + attn_weights = nn.functional.dropout( + attn_weights, p=self.dropout, training=self.training + ) # (batch_size, n_heads, seq_length, key_length) + + # Mask heads if we want to + if layer_head_mask is not None: + attn_weights = attn_weights * layer_head_mask + + attn_output = unshape(torch.matmul(attn_weights, value_states)) # (batch_size, seq_length, dim) + attn_output = self.o(attn_output) + + present_key_value_state = (key_states, value_states) if (self.is_decoder and use_cache) else None + outputs = (attn_output,) + (present_key_value_state,) + (position_bias,) + + if output_attentions: + outputs = outputs + (attn_weights,) + return outputs + +class T5FlashAttention2(T5Attention): + def __init__(self, *args, **kwargs): + super().__init__(*args, **kwargs) + self._flash_attn_uses_top_left_mask = not is_flash_attn_greater_or_equal_2_10() + + def _init_rope(self): + if self.config.rope_scaling is None: + self.rotary_emb = T5RotaryEmbedding( + self.key_value_proj_dim, + max_position_embeddings=self.config.max_position_embeddings, + base=self.rope_theta, + ) + else: + scaling_type = self.config.rope_scaling["type"] + scaling_factor = self.config.rope_scaling["factor"] + if scaling_type == "linear": + self.rotary_emb = T5LinearScalingRotaryEmbedding( + self.attention_head_size, + max_position_embeddings=self.max_position_embeddings, + scaling_factor=scaling_factor, + base=self.rope_theta, + ) + elif scaling_type == "dynamic": + self.rotary_emb = T5DynamicNTKScalingRotaryEmbedding( + self.attention_head_size, + max_position_embeddings=self.max_position_embeddings, + scaling_factor=scaling_factor, + base=self.rope_theta, + ) + else: + raise ValueError(f"Unknown RoPE scaling type {scaling_type}") + + 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): + """Compute binned relative position bias""" + if device is None: + device = self.relative_attention_bias.weight.device + context_position = torch.arange(query_length, dtype=torch.long, device=device)[:, None] + 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, + ): + """ + 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, key_length) (non-causal) or (batch_size, key_length, key_length) + # past_key_value[0] is (batch_size, n_heads, q_len - 1, dim_per_head) + batch_size, seq_length = hidden_states.shape[:2] + + real_seq_length = seq_length + + if past_key_value is not None: + if len(past_key_value) != 2: + raise ValueError( + f"past_key_value should have 2 past states: keys and values. Got { len(past_key_value)} past states" + ) + real_seq_length += past_key_value[0].shape[2] if query_length is None else query_length + + key_length = real_seq_length if key_value_states is None else key_value_states.shape[1] + + def shape(states): + """projection""" + return states.view(batch_size, -1, self.n_heads, self.key_value_proj_dim).transpose(1, 2) + + def unshape(states): + """reshape""" + return states.contiguous().view(batch_size, -1, self.inner_dim) + + def project(hidden_states, proj_layer, key_value_states, past_key_value): + """projects hidden states correctly to key/query states""" + if key_value_states is None: + # self-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(hidden_states)) + elif past_key_value is None: + # cross-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(key_value_states)) + + if past_key_value is not None: + if key_value_states is None: + # self-attn + # (batch_size, n_heads, key_length, dim_per_head) + hidden_states = torch.cat([past_key_value, hidden_states], dim=2) + elif past_key_value.shape[2] != key_value_states.shape[1]: + # checking that the `sequence_length` of the `past_key_value` is the same as + # the provided `key_value_states` to support prefix tuning + # cross-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(key_value_states)) + else: + # cross-attn + hidden_states = past_key_value + return hidden_states + + # get query states + query_states = shape(self.q(hidden_states)) # (batch_size, n_heads, seq_length, dim_per_head) + + # get key/value states + key_states = project( + hidden_states, self.k, key_value_states, past_key_value[0] if past_key_value is not None else None + ) + value_states = project( + hidden_states, self.v, key_value_states, past_key_value[1] if past_key_value is not None else None + ) + kv_seq_len = key_states.shape[-2] + + cos, sin = self.rotary_emb(value_states, seq_len=max(kv_seq_len, seq_length)) + query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin, position_bias) + # compute scores + attn_output = self._flash_attention_forward( + query_states.transpose(1, 2), + key_states.transpose(1, 2), + value_states.transpose(1, 2), + mask, seq_length, dropout=self.dropout + ) + # scores = torch.matmul( + # query_states, key_states.transpose(3, 2) + # ) # equivalent of torch.einsum("bnqd,bnkd->bnqk", query_states, key_states), compatible with onnx op>9 + # print(scores.shape) + # print(value_states.shape) + + # if mask is not None: + # # Apply the attention mask is (precomputed for all layers in BertModel forward() function) + # scores += mask + + + # attn_weights = nn.functional.softmax(scores.float(), dim=-1).type_as( + # scores + # ) # (batch_size, n_heads, seq_length, key_length) + # attn_weights = nn.functional.dropout( + # attn_weights, p=self.dropout, training=self.training + # ) # (batch_size, n_heads, seq_length, key_length) + + # Mask heads if we want to + # if layer_head_mask is not None: + # attn_weights = attn_weights * layer_head_mask + + #attn_output = unshape(torch.matmul(attn_weights, value_states)) # (batch_size, seq_length, dim) + attn_output = self.o(unshape(attn_output)) + + present_key_value_state = (key_states, value_states) if (self.is_decoder and use_cache) else None + outputs = (attn_output,) + (present_key_value_state,) + (position_bias,) + + if output_attentions: + outputs = outputs + (attn_output,) + return outputs + + def _flash_attention_forward( + self, query_states, key_states, value_states, attention_mask, query_length, dropout=0.0, softmax_scale=None + ): + if not self._flash_attn_uses_top_left_mask: + causal = self.is_causal + else: + # TODO: Remove the `query_length != 1` check once Flash Attention for RoCm is bumped to 2.1. For details, please see the comment in LlamaFlashAttention2 __init__. + causal = self.is_causal and query_length != 1 + + # Contains at least one padding token in the sequence + if attention_mask is not None: + batch_size = query_states.shape[0] + query_states, key_states, value_states, indices_q, cu_seq_lens, max_seq_lens = self._upad_input( + query_states, key_states, value_states, attention_mask, query_length + ) + + cu_seqlens_q, cu_seqlens_k = cu_seq_lens + max_seqlen_in_batch_q, max_seqlen_in_batch_k = max_seq_lens + + attn_output_unpad = flash_attn_varlen_func( + query_states, + key_states, + value_states, + cu_seqlens_q=cu_seqlens_q, + cu_seqlens_k=cu_seqlens_k, + max_seqlen_q=max_seqlen_in_batch_q, + max_seqlen_k=max_seqlen_in_batch_k, + dropout_p=dropout, + softmax_scale=softmax_scale, + causal=causal, + ) + + attn_output = pad_input(attn_output_unpad, indices_q, batch_size, query_length) + else: + attn_output = flash_attn_func( + query_states, key_states, value_states, dropout, softmax_scale=softmax_scale, causal=causal + ) + + return attn_output + + # Copied from transformers.models.llama.modeling_llama.LlamaFlashAttention2._upad_input + def _upad_input(self, query_layer, key_layer, value_layer, attention_mask, query_length): + indices_k, cu_seqlens_k, max_seqlen_in_batch_k = _get_unpad_data(attention_mask) + batch_size, kv_seq_len, num_key_value_heads, head_dim = key_layer.shape + + key_layer = index_first_axis( + key_layer.reshape(batch_size * kv_seq_len, num_key_value_heads, head_dim), indices_k + ) + value_layer = index_first_axis( + value_layer.reshape(batch_size * kv_seq_len, num_key_value_heads, head_dim), indices_k + ) + if query_length == kv_seq_len: + query_layer = index_first_axis( + query_layer.reshape(batch_size * kv_seq_len, self.n_heads, head_dim), indices_k + ) + cu_seqlens_q = cu_seqlens_k + max_seqlen_in_batch_q = max_seqlen_in_batch_k + indices_q = indices_k + elif query_length == 1: + max_seqlen_in_batch_q = 1 + cu_seqlens_q = torch.arange( + batch_size + 1, dtype=torch.int32, device=query_layer.device + ) # There is a memcpy here, that is very bad. + indices_q = cu_seqlens_q[:-1] + query_layer = query_layer.squeeze(1) + else: + # The -q_len: slice assumes left padding. + attention_mask = attention_mask[:, -query_length:] + query_layer, indices_q, cu_seqlens_q, max_seqlen_in_batch_q = unpad_input(query_layer, attention_mask) + + return ( + query_layer, + key_layer, + value_layer, + indices_q, + (cu_seqlens_q, cu_seqlens_k), + (max_seqlen_in_batch_q, max_seqlen_in_batch_k), + ) + +class T5SdpaAttention(T5Attention): + def _init_rope(self): + if self.config.rope_scaling is None: + self.rotary_emb = T5RotaryEmbedding( + self.key_value_proj_dim, + max_position_embeddings=self.config.max_position_embeddings, + base=self.rope_theta, + ) + else: + scaling_type = self.config.rope_scaling["type"] + scaling_factor = self.config.rope_scaling["factor"] + if scaling_type == "linear": + self.rotary_emb = T5LinearScalingRotaryEmbedding( + self.attention_head_size, + max_position_embeddings=self.max_position_embeddings, + scaling_factor=scaling_factor, + base=self.rope_theta, + ) + elif scaling_type == "dynamic": + self.rotary_emb = T5DynamicNTKScalingRotaryEmbedding( + self.attention_head_size, + max_position_embeddings=self.max_position_embeddings, + scaling_factor=scaling_factor, + base=self.rope_theta, + ) + else: + raise ValueError(f"Unknown RoPE scaling type {scaling_type}") + + 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): + """Compute binned relative position bias""" + if device is None: + device = self.relative_attention_bias.weight.device + context_position = torch.arange(query_length, dtype=torch.long, device=device)[:, None] + 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, + ): + """ + 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, key_length) (non-causal) or (batch_size, key_length, key_length) + # past_key_value[0] is (batch_size, n_heads, q_len - 1, dim_per_head) + batch_size, seq_length = hidden_states.shape[:2] + + real_seq_length = seq_length + + if past_key_value is not None: + if len(past_key_value) != 2: + raise ValueError( + f"past_key_value should have 2 past states: keys and values. Got { len(past_key_value)} past states" + ) + real_seq_length += past_key_value[0].shape[2] if query_length is None else query_length + + key_length = real_seq_length if key_value_states is None else key_value_states.shape[1] + + def shape(states): + """projection""" + return states.view(batch_size, -1, self.n_heads, self.key_value_proj_dim).transpose(1, 2) + + def unshape(states): + """reshape""" + return states.transpose(1, 2).contiguous().view(batch_size, -1, self.inner_dim) + + def project(hidden_states, proj_layer, key_value_states, past_key_value): + """projects hidden states correctly to key/query states""" + if key_value_states is None: + # self-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(hidden_states)) + elif past_key_value is None: + # cross-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(key_value_states)) + + if past_key_value is not None: + if key_value_states is None: + # self-attn + # (batch_size, n_heads, key_length, dim_per_head) + hidden_states = torch.cat([past_key_value, hidden_states], dim=2) + elif past_key_value.shape[2] != key_value_states.shape[1]: + # checking that the `sequence_length` of the `past_key_value` is the same as + # the provided `key_value_states` to support prefix tuning + # cross-attn + # (batch_size, n_heads, seq_length, dim_per_head) + hidden_states = shape(proj_layer(key_value_states)) + else: + # cross-attn + hidden_states = past_key_value + return hidden_states + + # get query states + query_states = shape(self.q(hidden_states)) # (batch_size, n_heads, seq_length, dim_per_head) + + # get key/value states + key_states = project( + hidden_states, self.k, key_value_states, past_key_value[0] if past_key_value is not None else None + ) + value_states = project( + hidden_states, self.v, key_value_states, past_key_value[1] if past_key_value is not None else None + ) + kv_seq_len = key_states.shape[-2] + + cos, sin = self.rotary_emb(value_states, seq_len=max(kv_seq_len, seq_length)) + query_states, key_states = apply_rotary_pos_emb(query_states, key_states, cos, sin, position_bias) + # compute scores + + attn_output = torch.nn.functional.scaled_dot_product_attention( + query_states, + key_states, + value_states, + attn_mask=mask, + dropout_p=self.dropout if self.training else 0.0, + is_causal=self.is_causal and mask is None and seq_length > 1, + ) + # scores = torch.matmul( + # query_states, key_states.transpose(3, 2) + # ) # equivalent of torch.einsum("bnqd,bnkd->bnqk", query_states, key_states), compatible with onnx op>9 + # print(scores.shape) + # print(value_states.shape) + + # if mask is not None: + # # Apply the attention mask is (precomputed for all layers in BertModel forward() function) + # scores += mask + + + # attn_weights = nn.functional.softmax(scores.float(), dim=-1).type_as( + # scores + # ) # (batch_size, n_heads, seq_length, key_length) + # attn_weights = nn.functional.dropout( + # attn_weights, p=self.dropout, training=self.training + # ) # (batch_size, n_heads, seq_length, key_length) + + # Mask heads if we want to + # if layer_head_mask is not None: + # attn_weights = attn_weights * layer_head_mask + + #attn_output = unshape(torch.matmul(attn_weights, value_states)) # (batch_size, seq_length, dim) + attn_output = self.o(unshape(attn_output)) + + present_key_value_state = (key_states, value_states) if (self.is_decoder and use_cache) else None + outputs = (attn_output,) + (present_key_value_state,) + (position_bias,) + + if output_attentions: + outputs = outputs + (attn_output,) + return outputs + + + + # Copied from transformers.models.llama.modeling_llama.LlamaFlashAttention2._upad_input + + +T5_ATTENTION_CLASSES = { + "eager": T5Attention, + "flash_attention_2": T5FlashAttention2, + 'sdpa': T5SdpaAttention +} + +class T5LayerSelfAttention(nn.Module): + def __init__(self, config, has_relative_attention_bias=False): + super().__init__() + self.SelfAttention = T5_ATTENTION_CLASSES[config._attn_implementation](config, has_relative_attention_bias=has_relative_attention_bias, is_causal=config.is_decoder) + 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, + ): + 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, + ) + 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): + super().__init__() + self.EncDecAttention = T5_ATTENTION_CLASSES[config._attn_implementation](config, has_relative_attention_bias=False) + 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, + ): + 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, + ) + 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): + 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)) + if self.is_decoder: + self.layer.append(T5LayerCrossAttention(config)) + + 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, + ): + if past_key_value is not None: + if not self.is_decoder: + logger.warning("`past_key_values` is passed to the encoder. Please make sure this is intended.") + expected_num_past_key_values = 2 if encoder_hidden_states is None else 4 + + if len(past_key_value) != expected_num_past_key_values: + raise ValueError( + f"There should be {expected_num_past_key_values} past states. " + f"{'2 (key / value) for cross attention. ' if expected_num_past_key_values == 4 else ''}" + f"Got {len(past_key_value)} past key / value states" + ) + + self_attn_past_key_value = past_key_value[:2] + cross_attn_past_key_value = past_key_value[2:] + else: + self_attn_past_key_value, cross_attn_past_key_value = None, 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=self_attn_past_key_value, + use_cache=use_cache, + output_attentions=output_attentions, + ) + hidden_states, present_key_value_state = 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: + # the actual query length is unknown for cross attention + # if using past key value states. Need to inject it here + if present_key_value_state is not None: + query_length = present_key_value_state[0].shape[2] + else: + query_length = None + + cross_attention_outputs = self.layer[1]( + hidden_states, + key_value_states=encoder_hidden_states, + attention_mask=encoder_attention_mask, + position_bias=position_bias, + layer_head_mask=cross_attn_layer_head_mask, + past_key_value=cross_attn_past_key_value, + query_length=query_length, + use_cache=use_cache, + output_attentions=output_attentions, + ) + hidden_states = cross_attention_outputs[0] + + # 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) + + # Combine self attn and cross attn key value states + if present_key_value_state is not None: + present_key_value_state = present_key_value_state + cross_attention_outputs[1] + + # 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 + (present_key_value_state,) + attention_outputs + else: + outputs = outputs + attention_outputs + + return outputs # hidden-states, present_key_value_states, (self-attention position bias), (self-attention weights), (cross-attention position bias), (cross-attention weights) + + +class T5ClassificationHead(nn.Module): + """Head for sentence-level classification tasks.""" + + def __init__(self, config: T5Config): + super().__init__() + self.dense = nn.Linear(config.d_model, config.d_model) + self.dropout = nn.Dropout(p=config.classifier_dropout) + self.out_proj = nn.Linear(config.d_model, config.num_labels) + + def forward(self, hidden_states: torch.Tensor) -> torch.Tensor: + hidden_states = self.dropout(hidden_states) + hidden_states = self.dense(hidden_states) + hidden_states = torch.tanh(hidden_states) + hidden_states = self.dropout(hidden_states) + hidden_states = self.out_proj(hidden_states) + return hidden_states + + +class 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 + _no_split_modules = ["T5Block"] + _keep_in_fp32_modules = ["wo"] + _supports_flash_attn_2 = True + _supports_sdpa = True + + @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.weight.data.normal_(mean=0.0, std=factor * ((self.config.d_model) ** -0.5)) + if hasattr(module.dense, "bias") and module.dense.bias is not None: + module.dense.bias.data.zero_() + module.out_proj.weight.data.normal_(mean=0.0, std=factor * ((self.config.d_model) ** -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)) 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 + self._use_flash_attention_2 = config._attn_implementation == "flash_attention_2" + self._use_sdpa = config._attn_implementation == "sdpa" + + @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, + ): + # 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 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 + + # required mask seq length can be calculated via length of past + mask_seq_length = past_key_values[0][0].shape[2] + seq_length if past_key_values is not None else seq_length + + 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 with `None` if past does not exist + if past_key_values is None: + past_key_values = [None] * len(self.block) + + + if self._use_flash_attention_2: + extended_attention_mask = attention_mask if (attention_mask is not None and 0 in attention_mask) else None + elif self._use_sdpa: + if self.is_decoder: + extended_attention_mask = _prepare_4d_causal_attention_mask_for_sdpa( + attention_mask, + input_shape, + inputs_embeds, + mask_seq_length - seq_length, + ) + else: + extended_attention_mask = _prepare_4d_attention_mask_for_sdpa(attention_mask, inputs_embeds.dtype) + else: + if attention_mask is None: + attention_mask = torch.ones(batch_size, mask_seq_length, device=inputs_embeds.device) + extended_attention_mask = self.get_extended_attention_mask(attention_mask, input_shape) + + 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 not None: + + if self._use_flash_attention_2: + if encoder_attention_mask is not None: + encoder_extended_attention_mask = encoder_attention_mask if 0 in encoder_attention_mask else None + elif self._use_sdpa: + encoder_extended_attention_mask = _prepare_4d_attention_mask_for_sdpa( + encoder_attention_mask, + inputs_embeds.dtype, + tgt_len=input_shape[-1], + ) + else: + encoder_extended_attention_mask = self.invert_attention_mask(encoder_attention_mask) + else: + if not self._use_sdpa and not self._use_flash_attention_2: + 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 + else: + encoder_extended_attention_mask = None + + 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 + + # 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) + present_key_value_states = () if use_cache else None + 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 + if position_bias is None: + position_bias = torch.arange( + 0, seq_length, dtype=torch.long, + ) + position_bias = position_bias.unsqueeze(0) + + encoder_decoder_position_bias = None + + hidden_states = self.dropout(inputs_embeds) + + for i, (layer_module, past_key_value) in enumerate(zip(self.block, past_key_values)): + 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 attention_mask is not None: + attention_mask = attention_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, + extended_attention_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, + ) + else: + layer_outputs = layer_module( + hidden_states, + attention_mask=extended_attention_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_value, + use_cache=use_cache, + output_attentions=output_attentions, + ) + + # 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, present_key_value_state = 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] + # append next layer key value states + if use_cache: + present_key_value_states = present_key_value_states + (present_key_value_state,) + + 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,) + + if not return_dict: + return tuple( + v + for v in [ + hidden_states, + present_key_value_states, + all_hidden_states, + all_attentions, + all_cross_attentions, + ] + if v is not None + ) + return BaseModelOutputWithPastAndCrossAttentions( + last_hidden_state=hidden_states, + past_key_values=present_key_value_states, + hidden_states=all_hidden_states, + attentions=all_attentions, + cross_attentions=all_cross_attentions, + ) + + +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. +""" + +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, + ) -> 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, + ) + + 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): + _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, shared=None): + super().__init__(config) + self.model_dim = config.d_model + if shared is None: + self.shared = nn.Embedding(config.vocab_size, config.d_model) + else: + self.shared = shared + + 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(self.shared.embedding_dim, self.shared.num_embeddings, 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 + + def set_teacher(self, teacher): + self.teacher = teacher + + def set_lm_head(self, head): + self.lm_head = head + + @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, + ) -> 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, + ) + + 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_inputs_for_generation( + self, + input_ids, + past_key_values=None, + attention_mask=None, + head_mask=None, + decoder_head_mask=None, + decoder_attention_mask=None, + cross_attn_head_mask=None, + use_cache=None, + encoder_outputs=None, + **kwargs, + ): + # cut decoder_input_ids if past_key_values is used + if past_key_values is not None: + past_length = past_key_values[0][0].shape[2] + + # Some generation methods already pass only the last input ID + if input_ids.shape[1] > past_length: + remove_prefix_length = past_length + else: + # Default to old behavior: keep only final ID + remove_prefix_length = input_ids.shape[1] - 1 + + input_ids = input_ids[:, remove_prefix_length:] + + return { + "decoder_input_ids": input_ids, + "past_key_values": past_key_values, + "encoder_outputs": encoder_outputs, + "attention_mask": attention_mask, + "head_mask": head_mask, + "decoder_head_mask": decoder_head_mask, + "decoder_attention_mask": decoder_attention_mask, + "cross_attn_head_mask": cross_attn_head_mask, + "use_cache": use_cache, + } + + 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 + + +@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() + loss = loss_fct(logits.view(-1, self.config.num_labels), labels.view(-1)) + elif self.config.problem_type == "multi_label_classification": + loss_fct = BCEWithLogitsLoss() + loss = loss_fct(logits, labels) + if not return_dict: + output = (logits,) + outputs[1:] + return ((loss,) + output) if loss is not None else output + + return 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, + ) \ No newline at end of file