from logging import warn import torch from transformers.models.pegasus.modeling_pegasus import * from transformers.models.pegasus.modeling_pegasus import _expand_mask import torch.nn as nn from torch.nn import BCEWithLogitsLoss import sys AUTO_MAP = { "AutoModel": "modeling_lsg_pegasus.LSGPegasusModel", "AutoModelForCausalLM": "modeling_lsg_pegasus.LSGPegasusForCausalLM", "AutoModelForSeq2SeqLM": "modeling_lsg_pegasus.LSGPegasusForConditionalGeneration" } class LSGPegasusConfig(PegasusConfig): """ This class overrides :class:`~transformers.RobertaConfig`. Please check the superclass for the appropriate documentation alongside usage examples. """ base_model_prefix = "lsg" model_type = "pegasus" keys_to_ignore_at_inference = ["past_key_values"] attribute_map = {"num_attention_heads": "encoder_attention_heads", "hidden_size": "d_model"} def __init__( self, adaptive=True, base_model_prefix="lsg", block_size=128, lsh_num_pre_rounds=1, mask_first_token=False, num_global_tokens=1, pass_global_tokens_to_decoder=True, pool_with_global=True, sparse_block_size=128, sparsity_factor=2, sparsity_type="norm", **kwargs ): """Constructs LSGConfig.""" super().__init__(**kwargs) self.adaptive = adaptive self.auto_map = AUTO_MAP self.base_model_prefix = base_model_prefix self.block_size = block_size self.lsh_num_pre_rounds = lsh_num_pre_rounds self.mask_first_token = mask_first_token self.num_global_tokens = num_global_tokens self.pass_global_tokens_to_decoder = pass_global_tokens_to_decoder self.pool_with_global = pool_with_global self.sparse_block_size = sparse_block_size self.sparsity_factor = sparsity_factor self.sparsity_type = sparsity_type if sparsity_type not in [None, "none", "norm", "lsh", "pooling", "stride", "block_stride"]: logger.warning( "[WARNING CONFIG]: sparsity_mode not in [None, 'none', 'norm', 'lsh', 'pooling', 'stride', 'block_stride'], setting sparsity_type=None, computation will skip sparse attention") self.sparsity_type = None if self.sparsity_type in ["stride", "block_stride"]: if self.sparsity_factor > self.encoder_attention_heads: logger.warning( "[WARNING CONFIG]: sparsity_factor > encoder_attention_heads is not recommended for stride/block_stride sparsity" ) if self.num_global_tokens < 1: logger.warning( "[WARNING CONFIG]: num_global_tokens < 1 is not compatible, setting num_global_tokens=1" ) self.num_global_tokens = 1 elif self.num_global_tokens > 512: logger.warning( "[WARNING CONFIG]: num_global_tokens > 512 is not compatible, setting num_global_tokens=512" ) self.num_global_tokens = 512 if self.sparsity_factor > 0: assert self.block_size % self.sparsity_factor == 0, "[ERROR CONFIG]: block_size must be divisible by sparsity_factor" assert self.block_size//self.sparsity_factor >= 1, "[ERROR CONFIG]: make sure block_size >= sparsity_factor" class BaseSelfAttention(nn.Module): def __init__( self, embed_dim, num_heads, dropout=0.0, is_decoder=False, bias=True, ): super().__init__() self.embed_dim = embed_dim self.num_heads = num_heads self.dropout = dropout self.head_dim = embed_dim // num_heads if (self.head_dim * num_heads) != self.embed_dim: raise ValueError( f"embed_dim must be divisible by num_heads (got `embed_dim`: {self.embed_dim}" f" and `num_heads`: {num_heads})." ) self.scaling = self.head_dim ** -0.5 self.is_decoder = is_decoder self.k_proj = nn.Linear(embed_dim, embed_dim, bias=bias) self.v_proj = nn.Linear(embed_dim, embed_dim, bias=bias) self.q_proj = nn.Linear(embed_dim, embed_dim, bias=bias) self.out_proj = nn.Linear(embed_dim, embed_dim, bias=bias) def transpose_for_scores(self, x): new_x_shape = x.size()[:-1] + ( self.num_heads, self.head_dim, ) x = x.view(*new_x_shape) return x.permute(0, 2, 1, 3) def reshape_output(self, context_layer): context_layer = context_layer.permute(0, 2, 1, 3).contiguous() new_context_layer_shape = context_layer.size()[:-2] + (self.embed_dim,) return context_layer.view(*new_context_layer_shape) def project_QKV(self, hidden_states): query_layer = self.transpose_for_scores(self.q_proj(hidden_states)) key_layer = self.transpose_for_scores(self.k_proj(hidden_states)) value_layer = self.transpose_for_scores(self.v_proj(hidden_states)) return query_layer, key_layer, value_layer class BaseAttentionProduct(nn.Module): def __init__(self, config): """ Compute attention: softmax(Q @ K.T) @ V """ super().__init__() self.dropout = nn.Dropout(config.attention_dropout) def forward(self, query_layer, key_layer, value_layer, attention_mask=None): d = query_layer.shape[-1] # Take the dot product between "query" and "key" to get the raw attention scores. attention_scores = query_layer @ key_layer.transpose(-1, -2) / math.sqrt(d) del query_layer del key_layer if attention_mask is not None: # Apply the attention mask is (precomputed for all layers in RobertaModel forward() function) attention_scores = attention_scores + attention_mask del attention_mask # Normalize the attention scores to probabilities. attention_probs = nn.Softmax(dim=-1)(attention_scores) # This is actually dropping out entire tokens to attend to, which might # seem a bit unusual, but is taken from the original Transformer paper. context_layer = self.dropout(attention_probs) @ value_layer return context_layer class LSGAttentionProduct(nn.Module): def __init__(self, config, block_size=None, sparse_block_size=None, sparsity_factor=4): """ Compute block or overlapping blocks attention products """ super().__init__() self.block_size = block_size self.sparse_block_size = sparse_block_size self.sparsity_factor = sparsity_factor if self.block_size is None: self.block_size = config.block_size if self.sparse_block_size is None: self.sparse_block_size = config.sparse_block_size # Shape of blocks self.local_shapes = (self.block_size*3, self.block_size) if self.sparse_block_size and self.sparsity_factor > 0: self.sparse_shapes = (self.sparse_block_size*3, self.block_size//self.sparsity_factor) self.attention = BaseAttentionProduct(config) def build_lsg_inputs(self, hidden_states, sparse_hidden_states, global_hidden_states, is_attn_mask=False): # Build local tokens local_hidden_states = self.reshape_to_local_block(hidden_states, is_attn_mask) del hidden_states # Build sparse tokens if sparse_hidden_states is not None: sparse_hidden_states = self.reshape_to_sparse_block(sparse_hidden_states, is_attn_mask) return self.cat_global_sparse_local_tokens(global_hidden_states, sparse_hidden_states, local_hidden_states) def forward( self, query_layer, key_layer, value_layer, attention_mask=None, sparse_key=None, sparse_value=None, sparse_mask=None, global_key=None, global_value=None, global_mask=None ): # Input batch, heads, length, hidden_size n, h, t, d = query_layer.size() n_blocks = t // self.block_size assert t % self.block_size == 0 key_layer = self.build_lsg_inputs( key_layer, sparse_key, global_key ) del sparse_key del global_key value_layer = self.build_lsg_inputs( value_layer, sparse_value, global_value ) del sparse_value del global_value attention_mask = self.build_lsg_inputs( attention_mask, sparse_mask, global_mask.transpose(-1, -2), is_attn_mask=True ).transpose(-1, -2) del sparse_mask del global_mask # expect (..., t, d) shape # Compute attention context_layer = self.attention( query_layer=self.chunk(query_layer, n_blocks), key_layer=key_layer, value_layer=value_layer, attention_mask=attention_mask ) return context_layer.reshape(n, h, -1, d) def reshape_to_local_block(self, hidden_states, is_attn_mask=False): size, step = self.local_shapes s = (size - step) // 2 # Pad before block reshaping if is_attn_mask: pad_value = -10000 hidden_states = hidden_states.transpose(-1, -2) else: pad_value = 0 hidden_states = torch.nn.functional.pad( hidden_states.transpose(-1, -2), pad=(s, s), value=pad_value ).transpose(-1, -2) # Make blocks hidden_states = hidden_states.unfold(-2, size=size, step=step).transpose(-1, -2) return hidden_states def reshape_to_sparse_block(self, hidden_states, is_attn_mask=False): size, step = self.sparse_shapes # In case of odd case odd_offset = (step % 2) # n, h, t, d*2 + 1 size = size*2 s = (size - step) // 2 + odd_offset # Pad before block reshaping if is_attn_mask: pad_value = -10000 hidden_states = hidden_states.transpose(-1, -2) else: pad_value = 0 hidden_states = torch.nn.functional.pad( hidden_states.transpose(-1, -2), pad=(s, s), value=pad_value ).transpose(-1, -2) # Make blocks hidden_states = hidden_states.unfold(-2, size=size, step=step).transpose(-1, -2) # Fix case where block_size == sparsify_factor if odd_offset: hidden_states = hidden_states[..., :-1, :, :] # Indexes for selection u = (size - self.block_size * 3 // self.sparsity_factor) // 2 + odd_offset s = self.sparse_block_size u_ = u + odd_offset return torch.cat([hidden_states[..., u-s:u, :], hidden_states[..., -u_:-u_+s, :]], dim=-2) def cat_global_sparse_local_tokens(self, x_global, x_sparse=None, x_local=None, dim=-2): n, h, b, t, d = x_local.size() x_global = x_global.unsqueeze(-3).expand(-1, -1, b, -1, -1) if x_sparse is not None: return torch.cat([x_global, x_sparse, x_local], dim=dim) return torch.cat([x_global, x_local], dim=dim) def chunk(self, x, n_blocks): t, d = x.size()[-2:] return x.reshape(*x.size()[:-2], n_blocks, -1, d) class LSGPegasusEncoderAttention(BaseSelfAttention): ''' Compute local attention with overlapping blocs Use global attention for tokens with highest norm ''' def __init__( self, config, embed_dim, num_heads, dropout ): super().__init__(embed_dim, num_heads, dropout) self.block_size = config.block_size self.sparse_block_size = config.sparse_block_size self.num_global_tokens = config.num_global_tokens self.sparsity_factor = config.sparsity_factor self.attention = LSGAttentionProduct( config, block_size=config.block_size, sparse_block_size=config.sparse_block_size, sparsity_factor=self.sparsity_factor, ) self.full_attention = BaseAttentionProduct(config) sparse_functions = { "norm": self.get_sparse_tokens_with_norm, "pooling": self.get_sparse_tokens_with_pooling, "lsh": self.get_sparse_tokens_with_lsh, "stride": self.get_sparse_tokens_with_stride, "block_stride": self.get_sparse_tokens_with_block_stride, } self.sparsity_type = config.sparsity_type self.get_sparse_elements = sparse_functions.get(self.sparsity_type, lambda x, y, z: (None, None, None)) if config.sparsity_type == "lsh": self.lsh_num_pre_rounds = config.lsh_num_pre_rounds def get_sparse_tokens_with_norm(self, keys, values, mask): if self.sparsity_factor == 1: return keys, values, mask.expand(-1, keys.size()[1], -1, -1) with torch.no_grad(): block_size = min(self.block_size, self.sparse_block_size) key_norm = keys.detach().norm(dim=-1, keepdim=True) key_norm = key_norm * ~mask.transpose(-1, -2).bool() key_norm = self.chunk(key_norm, block_size) n, h, b, t, d = key_norm.size() idx = key_norm.argsort(dim=-2) del key_norm idx += (torch.arange(b, device=keys.device)*t).reshape(1, 1, b, 1, 1) split = (t - block_size // self.sparsity_factor, block_size // self.sparsity_factor) sparse_idx = idx.split(split, -2)[-1].reshape(n, h, -1, 1) d = keys.size()[-1] keys = keys.gather(dim=-2, index=sparse_idx.expand(-1, -1, -1, d)) values = values.gather(dim=-2, index=sparse_idx.expand(-1, -1, -1, d)) mask = mask.expand(-1, h, -1, -1).transpose(-1, -2).gather(dim=-2, index=sparse_idx).transpose(-1, -2) return keys, values, mask def get_sparse_tokens_with_pooling(self, keys, values, mask): if self.sparsity_factor == 1: return keys, values, mask.expand(-1, keys.size()[1], -1, -1) keys = self.chunk(keys, self.sparsity_factor) values = self.chunk(values, self.sparsity_factor) n, h, b, t, d = keys.size() mask = mask.reshape(n, 1, b, 1, t) mask = ~mask.transpose(-1, -2).bool() keys = keys * mask values = values * mask mask = mask.sum(dim=-2) keys = keys.sum(dim=-2) / (mask + 1e-6) values = values.sum(dim=-2) / (mask + 1e-6) mask = - (1. - mask.clamp(0, 1)) * 1e4 return keys.reshape(n, h, -1, d), values.reshape(n, h, -1, d), mask.expand(-1, h, -1, -1).transpose(-1, -2) def get_sparse_tokens_with_stride(self, keys, values, mask): if self.sparsity_factor == 1: return keys, values, mask.expand(-1, keys.size()[1], -1, -1) n, h, t, d = keys.size() sparse_idx = torch.arange(t // self.sparsity_factor, device=keys.device) * self.sparsity_factor sparse_idx = sparse_idx.reshape(1, 1, -1, 1) + (torch.arange(h, device=keys.device) % self.sparsity_factor).reshape(1, h, 1, 1) sparse_idx = sparse_idx.expand(n, h, -1, 1) keys = keys.gather(dim=-2, index=sparse_idx.expand(-1, -1, -1, d)) values = values.gather(dim=-2, index=sparse_idx.expand(-1, -1, -1, d)) mask = mask.expand(-1, h, -1, -1).transpose(-1, -2).gather(dim=-2, index=sparse_idx).transpose(-1, -2) return keys, values, mask def get_sparse_tokens_with_block_stride(self, keys, values, mask): if self.sparsity_factor == 1: return keys, values, mask.expand(-1, keys.size()[1], -1, -1) n, h, t, d = keys.size() t, b = self.block_size, t // self.block_size sparse_idx = torch.arange(t // self.sparsity_factor, device=keys.device) sparse_idx = sparse_idx.reshape(1, 1, 1, -1, 1) + torch.arange(h, device=keys.device).reshape(1, h, 1, 1, 1) * (t // self.sparsity_factor) sparse_idx = (sparse_idx % t) sparse_idx = sparse_idx + torch.arange(b, device=keys.device).reshape(1, 1, -1, 1, 1) * t sparse_idx = sparse_idx.reshape(1, h, -1, 1).expand(n, h, -1, 1) keys = keys.gather(dim=-2, index=sparse_idx.expand(-1, -1, -1, d)) values = values.gather(dim=-2, index=sparse_idx.expand(-1, -1, -1, d)) mask = mask.expand(-1, h, -1, -1).transpose(-1, -2).gather(dim=-2, index=sparse_idx).transpose(-1, -2) return keys, values, mask def get_sparse_tokens_with_lsh(self, keys, values, mask): if self.sparsity_factor == 1: return keys, values, mask.expand(-1, keys.size()[1], -1, -1) block_size = min(self.block_size, self.sparse_block_size) keys = self.chunk(keys, block_size) values = self.chunk(values, block_size) n, h, b, t, d = keys.size() mask = mask.reshape(n, 1, b, 1, t) mask = ~mask.transpose(-1, -2).bool() keys = keys * mask values = values * mask mask = mask.expand(-1, h, -1, -1, -1).float() extra_factor = 1 for _ in range(self.lsh_num_pre_rounds): keys, values, mask = self.lsh_round(keys, values, mask, t*extra_factor) keys, values, mask = self.lsh_round(keys, values, mask, t//self.sparsity_factor) keys /= mask + 1e-8 values /= mask + 1e-8 mask = -10000 * (1. - mask.clamp(0, 1)) return keys.reshape(n, h, -1, d), values.reshape(n, h, -1, d), mask.transpose(-1, -2).reshape(n, h, 1, -1) def lsh_round(self, keys, values, mask, output_size): with torch.no_grad(): n_hashes = output_size // 2 n, h, b, t, d = keys.size() binary_mask = mask.clamp(0, 1) indexes = (torch.nn.functional.normalize(keys, dim=-1) * binary_mask) @ torch.randn(1, h, 1, d, n_hashes, device=keys.device) indexes = torch.cat([indexes, -indexes], dim=-1).argmax(dim=-1, keepdim=True) n, h, b, t, d = keys.size() x_ = torch.zeros(n, h, b, output_size, d, device=keys.device) mask_ = torch.zeros(n, h, b, output_size, 1, device=keys.device) keys = torch.scatter_add(x_, dim=-2, index=indexes.expand(-1, -1, -1, -1, d), src=keys) values = torch.scatter_add(x_, dim=-2, index=indexes.expand(-1, -1, -1, -1, d), src=values) mask = torch.scatter_add(mask_, dim=-2, index=indexes, src=mask) return keys[..., :output_size, :], values[..., :output_size, :], mask[..., :output_size, :] def forward( self, hidden_states, attention_mask=None, layer_head_mask=None, output_attentions=False ): query_layer, key_layer, value_layer = self.project_QKV(hidden_states) outputs = self.not_causal_forward( query_layer, key_layer, value_layer, attention_mask=attention_mask[:, :, :1, :], head_mask=layer_head_mask, output_attentions=output_attentions ) return self.out_proj(outputs), None, None def not_causal_forward( self, query_layer, key_layer, value_layer, attention_mask=None, head_mask=None, output_attentions=False, ): n, h, t, d = query_layer.size() # Cat global mask attention_mask = torch.nn.functional.pad(attention_mask, (self.num_global_tokens, 0), value=0) # Use normal attention if local attention covers every tokens if t <= 2 * self.block_size + self.num_global_tokens: context_layer = self.full_attention( query_layer=query_layer, key_layer=key_layer, value_layer=value_layer, attention_mask=attention_mask ) if head_mask is not None: context_layer = context_layer * head_mask[:, :, :1, :1] return self.reshape_output(context_layer) # Split input into global tokens and other tokens split = (self.num_global_tokens, t - self.num_global_tokens) global_query, query_layer = query_layer.split(split, dim=-2) # Get global_attention bos = self.full_attention( query_layer=global_query, key_layer=key_layer, value_layer=value_layer, attention_mask=attention_mask ) # Split K Q M on global and non global global_key, key_layer = key_layer.split(split, dim=-2) global_value, value_layer = value_layer.split(split, dim=-2) global_mask, attention_mask = attention_mask.split(split, dim=-1) n, h, t, d = key_layer.size() # Get sparse idx sparse_key, sparse_value, sparse_mask = (None, None, None) if self.sparse_block_size and self.sparsity_factor > 0: sparse_key, sparse_value, sparse_mask = self.get_sparse_elements(key_layer, value_layer, attention_mask) # Expand masks on heads attention_mask = attention_mask.expand(-1, h, -1, -1) global_mask = global_mask.expand(-1, h, -1, -1) # Compute dot product attention context_layer = self.attention( query_layer, key_layer, value_layer, attention_mask, sparse_key=sparse_key, sparse_value=sparse_value, sparse_mask=sparse_mask, global_key=global_key, global_value=global_value, global_mask=global_mask ) # Merge global and local-sparse tokens context_layer = torch.cat([bos, context_layer], dim=-2) if head_mask is not None: context_layer = context_layer * head_mask[:, :, :1, :1] context_layer = self.reshape_output(context_layer) return context_layer def chunk(self, x, chunk_size): n, h, t, d = x.size() return x.reshape(n, h, -1, chunk_size, d) # Copied from transformers.models.marian.modeling_marian.MarianSinusoidalPositionalEmbedding with Marian->Pegasus class LSGPegasusSinusoidalPositionalEmbedding(nn.Embedding): """This module produces sinusoidal positional embeddings of any length.""" def __init__(self, num_positions: int, embedding_dim: int, padding_idx: Optional[int] = None): super().__init__(num_positions, embedding_dim) self.weight = self._init_weight(self.weight) @staticmethod def _init_weight(out: nn.Parameter): """ Identical to the XLM create_sinusoidal_embeddings except features are not interleaved. The cos features are in the 2nd half of the vector. [dim // 2:] """ n_pos, dim = out.shape position_enc = np.array( [[pos / np.power(10000, 2 * (j // 2) / dim) for j in range(dim)] for pos in range(n_pos)] ) out.requires_grad = False # set early to avoid an error in pytorch-1.8+ sentinel = dim // 2 if dim % 2 == 0 else (dim // 2) + 1 out[:, 0:sentinel] = torch.FloatTensor(np.sin(position_enc[:, 0::2])) out[:, sentinel:] = torch.FloatTensor(np.cos(position_enc[:, 1::2])) out.detach_() return out @torch.no_grad() def forward(self, input_ids_shape: torch.Size, past_key_values_length: int = 0): """`input_ids_shape` is expected to be [bsz x seqlen].""" bsz, seq_len = input_ids_shape[:2] positions = torch.arange( past_key_values_length, past_key_values_length + seq_len, dtype=torch.long, device=self.weight.device ) return super().forward(positions) # Copied from transformers.models.mbart.modeling_mbart.MBartEncoderLayer with MBart->Pegasus class LSGPegasusEncoderLayer(PegasusEncoderLayer): def __init__(self, config: LSGPegasusConfig): super().__init__(config) self.self_attn = LSGPegasusEncoderAttention( config=config, embed_dim=self.embed_dim, num_heads=config.encoder_attention_heads, dropout=config.attention_dropout, ) # Copied from transformers.models.mbart.modeling_mbart.MBartDecoderLayer with MBart->Pegasus class LSGPegasusDecoderLayer(PegasusDecoderLayer): def __init__(self, config: LSGPegasusConfig): super().__init__(config) class LSGPegasusPreTrainedModel(PegasusPreTrainedModel): config_class = LSGPegasusConfig def _set_gradient_checkpointing(self, module, value=False): if isinstance(module, (PegasusDecoder, PegasusEncoder, LSGPegasusDecoder, LSGPegasusEncoder)): module.gradient_checkpointing = value class LSGPegasusEncoder(LSGPegasusPreTrainedModel, PegasusEncoder): """ Transformer encoder consisting of *config.encoder_layers* self attention layers. Each layer is a :class:`PegasusEncoderLayer`. Args: config: PegasusConfig embed_tokens (nn.Embedding): output embedding """ def __init__(self, config: LSGPegasusConfig, embed_tokens: Optional[nn.Embedding] = None): LSGPegasusPreTrainedModel.__init__(self, config) self.dropout = config.dropout self.layerdrop = config.encoder_layerdrop embed_dim = config.d_model self.padding_idx = config.pad_token_id self.max_source_positions = config.max_position_embeddings self.embed_scale = math.sqrt(embed_dim) if config.scale_embedding else 1.0 if embed_tokens is not None: self.embed_tokens = embed_tokens else: self.embed_tokens = nn.Embedding(config.vocab_size, embed_dim, self.padding_idx) self.embed_positions = LSGPegasusSinusoidalPositionalEmbedding( config.max_position_embeddings, embed_dim, self.padding_idx, ) self.layers = nn.ModuleList([LSGPegasusEncoderLayer(config) for _ in range(config.encoder_layers)]) self.layer_norm = nn.LayerNorm(config.d_model) # New params assert hasattr(config, "num_global_tokens") self.num_global_tokens = config.num_global_tokens self.pad_idx = config.pad_token_id assert hasattr(config, "block_size") and hasattr(config, "adaptive") self.block_size = config.block_size self.adaptive = config.adaptive self.mask_first_token = config.mask_first_token self.pool_with_global = config.pool_with_global self.pass_global_tokens_to_decoder = config.pass_global_tokens_to_decoder self.global_embeddings = nn.Embedding(512, embedding_dim=config.d_model) self.gradient_checkpointing = False # Initialize weights and apply final processing #self.post_init() self.init_weights() def resize_position_embeddings(self, new_num_position_embeddings: int): """ Resizes position embeddings matrix of the model if :obj:`new_num_position_embeddings != config.max_position_embeddings`. Arguments: new_num_position_embeddings (:obj:`int`): The number of new position embeddings. If position embeddings are learned, increasing the size will add newly initialized vectors at the end, whereas reducing the size will remove vectors from the end. If position embeddings are not learned (*e.g.* sinusoidal position embeddings), increasing the size will add correct vectors at the end following the position encoding algorithm, whereas reducing the size will remove vectors from the end. """ logger.info(f"Setting `config.max_position_embeddings={new_num_position_embeddings}`...") self.config.max_position_embeddings = new_num_position_embeddings self.embed_positions = LSGPegasusSinusoidalPositionalEmbedding( self.config.max_position_embeddings, self.config.d_model, self.padding_idx, ) self.embed_positions.to(self.device) def forward(self, input_ids=None, attention_mask=None, head_mask=None, inputs_embeds=None, output_attentions=None, output_hidden_states=None, return_dict=None ): inputs_ = input_ids if input_ids is not None else inputs_embeds n, t = inputs_.size()[:2] if attention_mask is None: attention_mask = torch.ones(n, t, device=inputs_.device) if self.mask_first_token: attention_mask[:,0] = 0 b = self.block_size * 2 pad = t % self.block_size # Check if t is multiple of block_size and pad if self.adaptive and t > b and pad > 0: pad_length = self.block_size - pad if input_ids is not None: input_ids = torch.nn.functional.pad(input_ids, (0, pad_length), value=self.pad_idx) else: inputs_embeds = torch.nn.functional.pad(inputs_embeds.transpose(-1, -2), (0, pad_length), value=0.).transpose(-1, -2) attention_mask = torch.nn.functional.pad(attention_mask, (0, pad_length), value=0) n, t_ = attention_mask.size() encoder_outputs = self.forward_with_adaptive( input_ids=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, ) context = encoder_outputs[0] diff = t - t_ if self.pass_global_tokens_to_decoder: offset = self.num_global_tokens else: if self.pool_with_global: context[:, self.num_global_tokens] = context[:, 0] context = context[..., self.num_global_tokens:, :] offset = 0 # Adapt sequence to initial shape if diff < 0: context = context[:, :t + offset] if return_dict: encoder_outputs.last_hidden_state = context else: encoder_outputs = (context, ) + encoder_outputs[1:] return encoder_outputs def forward_with_adaptive( self, input_ids=None, attention_mask=None, head_mask=None, inputs_embeds=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions output_hidden_states = ( output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states ) return_dict = return_dict if return_dict is not None else self.config.use_return_dict # retrieve input_ids and inputs_embeds if input_ids is not None and inputs_embeds is not None: raise ValueError("You cannot specify both input_ids and inputs_embeds at the same time") elif input_ids is not None: input_shape = input_ids.size() input_ids = input_ids.view(-1, input_shape[-1]) elif inputs_embeds is not None: input_shape = inputs_embeds.size()[:-1] else: raise ValueError("You have to specify either input_ids or inputs_embeds") if inputs_embeds is None: inputs_embeds = self.embed_tokens(input_ids) * self.embed_scale embed_pos = self.embed_positions(input_shape) hidden_states = inputs_embeds + embed_pos # Add global tokens n, t, d = hidden_states.size() global_idx = torch.arange(self.num_global_tokens, device=hidden_states.device).reshape(1, -1) hidden_states = torch.cat([self.global_embeddings(global_idx).expand(n, -1, -1), hidden_states], dim=-2) hidden_states = nn.functional.dropout(hidden_states, p=self.dropout, training=self.training) # expand attention_mask if attention_mask is not None: # [bsz, seq_len] -> [bsz, 1, tgt_seq_len, src_seq_len] attention_mask = _expand_mask(attention_mask, inputs_embeds.dtype) encoder_states = () if output_hidden_states else None all_attentions = () if output_attentions else None # check if head_mask has a correct number of layers specified if desired if head_mask is not None: assert head_mask.size()[0] == ( len(self.layers) ), f"The head_mask should be specified for {len(self.layers)} layers, but it is for {head_mask.size()[0]}." for idx, encoder_layer in enumerate(self.layers): if output_hidden_states: encoder_states = encoder_states + (hidden_states,) # add LayerDrop (see https://arxiv.org/abs/1909.11556 for description) dropout_probability = random.uniform(0, 1) if self.training and (dropout_probability < self.layerdrop): # skip the layer layer_outputs = (None, None) else: if self.gradient_checkpointing and self.training: def create_custom_forward(module): def custom_forward(*inputs): return module(*inputs, output_attentions) return custom_forward layer_outputs = torch.utils.checkpoint.checkpoint( create_custom_forward(encoder_layer), hidden_states, attention_mask, (head_mask[idx] if head_mask is not None else None), ) else: layer_outputs = encoder_layer( hidden_states, attention_mask, layer_head_mask=(head_mask[idx] if head_mask is not None else None), output_attentions=output_attentions, ) hidden_states = layer_outputs[0] if output_attentions: all_attentions = all_attentions + (layer_outputs[1],) hidden_states = self.layer_norm(hidden_states) if output_hidden_states: encoder_states = encoder_states + (hidden_states,) if not return_dict: return tuple(v for v in [hidden_states, encoder_states, all_attentions] if v is not None) return BaseModelOutput( last_hidden_state=hidden_states, hidden_states=encoder_states, attentions=all_attentions ) class LSGPegasusDecoder(LSGPegasusPreTrainedModel, PegasusDecoder): """ Transformer decoder consisting of *config.decoder_layers* layers. Each layer is a :class:`PegasusDecoderLayer` Args: config: PegasusConfig embed_tokens (nn.Embedding): output embedding """ def __init__(self, config: LSGPegasusConfig, embed_tokens: Optional[nn.Embedding] = None): LSGPegasusPreTrainedModel.__init__(self, config) self.dropout = config.dropout self.layerdrop = config.decoder_layerdrop self.padding_idx = config.pad_token_id self.max_target_positions = config.max_position_embeddings self.embed_scale = math.sqrt(config.d_model) if config.scale_embedding else 1.0 self.adaptive = config.adaptive if embed_tokens is not None: self.embed_tokens = embed_tokens else: self.embed_tokens = nn.Embedding(config.vocab_size, config.d_model, self.padding_idx) self.embed_positions = LSGPegasusSinusoidalPositionalEmbedding( config.max_position_embeddings, config.d_model, self.padding_idx, ) self.layers = nn.ModuleList([LSGPegasusDecoderLayer(config) for _ in range(config.decoder_layers)]) self.layer_norm = nn.LayerNorm(config.d_model) self.gradient_checkpointing = False # Initialize weights and apply final processing self.post_init() class LSGPegasusModel(LSGPegasusPreTrainedModel, PegasusModel): def __init__(self, config: LSGPegasusConfig): LSGPegasusPreTrainedModel.__init__(self, config) padding_idx, vocab_size = config.pad_token_id, config.vocab_size self.shared = nn.Embedding(vocab_size, config.d_model, padding_idx) self.pass_global_tokens_to_decoder = config.pass_global_tokens_to_decoder self.num_global_tokens = config.num_global_tokens self.encoder = LSGPegasusEncoder(config, self.shared) self.decoder = LSGPegasusDecoder(config, self.shared) # Initialize weights and apply final processing self.post_init() def forward( self, input_ids=None, attention_mask=None, decoder_input_ids=None, decoder_attention_mask=None, head_mask=None, decoder_head_mask=None, cross_attn_head_mask=None, encoder_outputs=None, past_key_values=None, inputs_embeds=None, decoder_inputs_embeds=None, use_cache=None, output_attentions=None, output_hidden_states=None, return_dict=None, ): r""" Returns: Example:: >>> from transformers import PegasusTokenizer, PegasusModel >>> tokenizer = PegasusTokenizer.from_pretrained("google/pegasus-large") >>> model = PegasusModel.from_pretrained("google/pegasus-large") >>> 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 >>> outputs = model(input_ids=input_ids, decoder_input_ids=decoder_input_ids) >>> last_hidden_states = outputs.last_hidden_state """ output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions output_hidden_states = ( output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states ) use_cache = use_cache if use_cache is not None else self.config.use_cache return_dict = return_dict if return_dict is not None else self.config.use_return_dict if encoder_outputs is None: encoder_outputs = self.encoder( input_ids=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, ) # If the user passed a tuple for encoder_outputs, we wrap it in a BaseModelOutput when return_dict=True 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, ) # Pad mask if we keep globals if self.pass_global_tokens_to_decoder and attention_mask is not None: attention_mask = torch.nn.functional.pad(attention_mask, pad=(self.num_global_tokens, 0), value=1) # decoder outputs consists of (dec_features, past_key_value, dec_hidden, dec_attn) decoder_outputs = self.decoder( input_ids=decoder_input_ids, attention_mask=decoder_attention_mask, encoder_hidden_states=encoder_outputs[0], encoder_attention_mask=attention_mask, head_mask=decoder_head_mask, cross_attn_head_mask=cross_attn_head_mask, past_key_values=past_key_values, inputs_embeds=decoder_inputs_embeds, use_cache=use_cache, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) if not return_dict: return decoder_outputs + encoder_outputs return 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, ) class LSGPegasusForConditionalGeneration(LSGPegasusPreTrainedModel, PegasusForConditionalGeneration): base_model_prefix = "model" _keys_to_ignore_on_load_missing = [ r"final_logits_bias", r"encoder\.version", r"decoder\.version", r"lm_head\.weight", r"embed_positions\.weight", ] def __init__(self, config: LSGPegasusConfig): LSGPegasusPreTrainedModel.__init__(self, config) self.model = LSGPegasusModel(config) self.register_buffer("final_logits_bias", torch.zeros((1, self.model.shared.num_embeddings))) self.lm_head = nn.Linear(config.d_model, self.model.shared.num_embeddings, bias=False) # Initialize weights and apply final processing self.post_init() # Copied from transformers.models.bart.modeling_bart.BartDecoderWrapper with Bart->Pegasus class LSGPegasusDecoderWrapper(LSGPegasusPreTrainedModel): """ This wrapper class is a helper class to correctly load pretrained checkpoints when the causal language model is used in combination with the :class:`~transformers.EncoderDecoderModel` framework. """ def __init__(self, config): super().__init__(config) self.decoder = LSGPegasusDecoder(config) def forward(self, *args, **kwargs): return self.decoder(*args, **kwargs) class LSGPegasusForCausalLM(LSGPegasusPreTrainedModel, PegasusForCausalLM): def __init__(self, config): LSGPegasusPreTrainedModel.__init__(self, config) config = copy.deepcopy(config) config.is_decoder = True config.is_encoder_decoder = False self.model = LSGPegasusDecoderWrapper(config) self.lm_head = nn.Linear(config.hidden_size, config.vocab_size, bias=False) # Initialize weights and apply final processing self.post_init() def str_to_class(classname): return getattr(sys.modules[__name__], classname) # Register model in Auto API try: LSGPegasusConfig.register_for_auto_class() for key, value in AUTO_MAP.items(): str_to_class(value.split(".")[-1]).register_for_auto_class(key) except: warn("AutoRegister isn't available, you'll have to manually copy modeling.py after .save_pretrained(...).") warn("Update to transformers >= 4.17.0 to fix.")