import torch import torch.nn as nn from torch.utils.checkpoint import checkpoint from transformers import T5Tokenizer, T5EncoderModel, CLIPTokenizer, CLIPTextModel, AutoProcessor, CLIPVisionModelWithProjection import open_clip from ldm.util import count_params def _expand_mask(mask, dtype, tgt_len=None): """ Expands attention_mask from `[bsz, seq_len]` to `[bsz, 1, tgt_seq_len, src_seq_len]`. """ bsz, src_len = mask.size() tgt_len = tgt_len if tgt_len is not None else src_len expanded_mask = mask[:, None, None, :].expand(bsz, 1, tgt_len, src_len).to(dtype) inverted_mask = 1.0 - expanded_mask return inverted_mask.masked_fill(inverted_mask.to(torch.bool), torch.finfo(dtype).min) def _build_causal_attention_mask(bsz, seq_len, dtype): # lazily create causal attention mask, with full attention between the vision tokens # pytorch uses additive attention mask; fill with -inf mask = torch.empty(bsz, seq_len, seq_len, dtype=dtype) mask.fill_(torch.tensor(torch.finfo(dtype).min)) mask.triu_(1) # zero out the lower diagonal mask = mask.unsqueeze(1) # expand mask return mask class AbstractEncoder(nn.Module): def __init__(self): super().__init__() def encode(self, *args, **kwargs): raise NotImplementedError class IdentityEncoder(AbstractEncoder): def encode(self, x): return x class ClassEmbedder(nn.Module): def __init__(self, embed_dim, n_classes=1000, key='class', ucg_rate=0.1): super().__init__() self.key = key self.embedding = nn.Embedding(n_classes, embed_dim) self.n_classes = n_classes self.ucg_rate = ucg_rate def forward(self, batch, key=None, disable_dropout=False): if key is None: key = self.key # this is for use in crossattn c = batch[key][:, None] if self.ucg_rate > 0. and not disable_dropout: mask = 1. - torch.bernoulli(torch.ones_like(c) * self.ucg_rate) c = mask * c + (1-mask) * torch.ones_like(c)*(self.n_classes-1) c = c.long() c = self.embedding(c) return c def get_unconditional_conditioning(self, bs, device="cuda"): uc_class = self.n_classes - 1 # 1000 classes --> 0 ... 999, one extra class for ucg (class 1000) uc = torch.ones((bs,), device=device) * uc_class uc = {self.key: uc} return uc def disabled_train(self, mode=True): """Overwrite model.train with this function to make sure train/eval mode does not change anymore.""" return self class FrozenT5Embedder(AbstractEncoder): """Uses the T5 transformer encoder for text""" def __init__(self, version="google/t5-v1_1-large", device="cuda", max_length=77, freeze=True): # others are google/t5-v1_1-xl and google/t5-v1_1-xxl super().__init__() self.tokenizer = T5Tokenizer.from_pretrained(version) self.transformer = T5EncoderModel.from_pretrained(version) self.device = device self.max_length = max_length # TODO: typical value? if freeze: self.freeze() def freeze(self): self.transformer = self.transformer.eval() #self.train = disabled_train for param in self.parameters(): param.requires_grad = False def forward(self, text): batch_encoding = self.tokenizer(text, truncation=True, max_length=self.max_length, return_length=True, return_overflowing_tokens=False, padding="max_length", return_tensors="pt") tokens = batch_encoding["input_ids"].to(self.device) outputs = self.transformer(input_ids=tokens) z = outputs.last_hidden_state return z def encode(self, text): return self(text) class FrozenCLIPEmbedder(AbstractEncoder): """Uses the CLIP transformer encoder for text (from huggingface)""" LAYERS = [ "last", "pooled", "hidden" ] def __init__(self, version="openai/clip-vit-large-patch14", device="cuda", max_length=77, freeze=True, layer="last", layer_idx=None): # clip-vit-base-patch32 super().__init__() assert layer in self.LAYERS self.tokenizer = CLIPTokenizer.from_pretrained(version) self.transformer = CLIPTextModel.from_pretrained(version) self.device = device self.max_length = max_length if freeze: self.freeze() self.layer = layer self.layer_idx = layer_idx if layer == "hidden": assert layer_idx is not None assert 0 <= abs(layer_idx) <= 12 def freeze(self): self.transformer = self.transformer.eval() # self.train = disabled_train for param in self.parameters(): param.requires_grad = False def forward(self, text): batch_encoding = self.tokenizer(text, truncation=True, max_length=self.max_length, return_length=True, return_overflowing_tokens=False, padding="max_length", return_tensors="pt") tokens = batch_encoding["input_ids"].to(self.device) outputs = self.transformer(input_ids=tokens, output_hidden_states=self.layer=="hidden") if self.layer == "last": z = outputs.last_hidden_state elif self.layer == "pooled": z = outputs.pooler_output[:, None, :] else: z = outputs.hidden_states[self.layer_idx] return z def encode(self, text): return self(text) class FrozenOpenCLIPEmbedder(AbstractEncoder): """ Uses the OpenCLIP transformer encoder for text """ LAYERS = [ # "pooled", "last", "penultimate" ] def __init__(self, arch="ViT-H-14", version="laion2b_s32b_b79k", device="cuda", max_length=77, freeze=True, layer="last"): super().__init__() assert layer in self.LAYERS model, _, _ = open_clip.create_model_and_transforms(arch, device=torch.device('cpu'), pretrained=version) del model.visual self.model = model self.device = device self.max_length = max_length if freeze: self.freeze() self.layer = layer if self.layer == "last": self.layer_idx = 0 elif self.layer == "penultimate": self.layer_idx = 1 else: raise NotImplementedError() def freeze(self): self.model = self.model.eval() for param in self.parameters(): param.requires_grad = False def forward(self, text): tokens = open_clip.tokenize(text) z = self.encode_with_transformer(tokens.to(self.device)) return z def encode_with_transformer(self, text): x = self.model.token_embedding(text) # [batch_size, n_ctx, d_model] x = x + self.model.positional_embedding x = x.permute(1, 0, 2) # NLD -> LND x = self.text_transformer_forward(x, attn_mask=self.model.attn_mask) x = x.permute(1, 0, 2) # LND -> NLD x = self.model.ln_final(x) return x def text_transformer_forward(self, x: torch.Tensor, attn_mask=None): for i, r in enumerate(self.model.transformer.resblocks): if i == len(self.model.transformer.resblocks) - self.layer_idx: break if self.model.transformer.grad_checkpointing and not torch.jit.is_scripting(): x = checkpoint(r, x, attn_mask) else: x = r(x, attn_mask=attn_mask) return x def encode(self, text): return self(text) class FrozenCLIPT5Encoder(AbstractEncoder): def __init__(self, clip_version="openai/clip-vit-large-patch14", t5_version="google/t5-v1_1-xl", device="cuda", clip_max_length=77, t5_max_length=77): super().__init__() self.clip_encoder = FrozenCLIPEmbedder(clip_version, device, max_length=clip_max_length) self.t5_encoder = FrozenT5Embedder(t5_version, device, max_length=t5_max_length) print(f"{self.clip_encoder.__class__.__name__} has {count_params(self.clip_encoder)*1.e-6:.2f} M parameters, " f"{self.t5_encoder.__class__.__name__} comes with {count_params(self.t5_encoder)*1.e-6:.2f} M params.") def encode(self, text): return self(text) def forward(self, text): clip_z = self.clip_encoder.encode(text) t5_z = self.t5_encoder.encode(text) return [clip_z, t5_z] class FrozenCLIPEmbedderT3(AbstractEncoder): """Uses the CLIP transformer encoder for text (from Hugging Face)""" def __init__(self, version="openai/clip-vit-large-patch14", device="cuda", max_length=77, freeze=True, use_vision=False): super().__init__() self.tokenizer = CLIPTokenizer.from_pretrained(version) self.transformer = CLIPTextModel.from_pretrained(version) if use_vision: self.vit = CLIPVisionModelWithProjection.from_pretrained(version) self.processor = AutoProcessor.from_pretrained(version) self.device = device self.max_length = max_length if freeze: self.freeze() def embedding_forward( self, input_ids=None, position_ids=None, inputs_embeds=None, embedding_manager=None, ): seq_length = input_ids.shape[-1] if input_ids is not None else inputs_embeds.shape[-2] if position_ids is None: position_ids = self.position_ids[:, :seq_length] if inputs_embeds is None: inputs_embeds = self.token_embedding(input_ids) if embedding_manager is not None: inputs_embeds = embedding_manager(input_ids, inputs_embeds) position_embeddings = self.position_embedding(position_ids) embeddings = inputs_embeds + position_embeddings return embeddings self.transformer.text_model.embeddings.forward = embedding_forward.__get__(self.transformer.text_model.embeddings) def encoder_forward( self, inputs_embeds, attention_mask=None, causal_attention_mask=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 encoder_states = () if output_hidden_states else None all_attentions = () if output_attentions else None hidden_states = inputs_embeds for idx, encoder_layer in enumerate(self.layers): if output_hidden_states: encoder_states = encoder_states + (hidden_states,) layer_outputs = encoder_layer( hidden_states, attention_mask, causal_attention_mask, output_attentions=output_attentions, ) hidden_states = layer_outputs[0] if output_attentions: all_attentions = all_attentions + (layer_outputs[1],) if output_hidden_states: encoder_states = encoder_states + (hidden_states,) return hidden_states self.transformer.text_model.encoder.forward = encoder_forward.__get__(self.transformer.text_model.encoder) def text_encoder_forward( self, input_ids=None, attention_mask=None, position_ids=None, output_attentions=None, output_hidden_states=None, return_dict=None, embedding_manager=None, ): output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions output_hidden_states = ( output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states ) return_dict = return_dict if return_dict is not None else self.config.use_return_dict if input_ids is None: raise ValueError("You have to specify either input_ids") input_shape = input_ids.size() input_ids = input_ids.view(-1, input_shape[-1]) hidden_states = self.embeddings(input_ids=input_ids, position_ids=position_ids, embedding_manager=embedding_manager) bsz, seq_len = input_shape # CLIP's text model uses causal mask, prepare it here. # https://github.com/openai/CLIP/blob/cfcffb90e69f37bf2ff1e988237a0fbe41f33c04/clip/model.py#L324 causal_attention_mask = _build_causal_attention_mask(bsz, seq_len, hidden_states.dtype).to( hidden_states.device ) # 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, hidden_states.dtype) last_hidden_state = self.encoder( inputs_embeds=hidden_states, attention_mask=attention_mask, causal_attention_mask=causal_attention_mask, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, ) last_hidden_state = self.final_layer_norm(last_hidden_state) return last_hidden_state self.transformer.text_model.forward = text_encoder_forward.__get__(self.transformer.text_model) def transformer_forward( self, input_ids=None, attention_mask=None, position_ids=None, output_attentions=None, output_hidden_states=None, return_dict=None, embedding_manager=None, ): return self.text_model( input_ids=input_ids, attention_mask=attention_mask, position_ids=position_ids, output_attentions=output_attentions, output_hidden_states=output_hidden_states, return_dict=return_dict, embedding_manager=embedding_manager ) self.transformer.forward = transformer_forward.__get__(self.transformer) def freeze(self): self.transformer = self.transformer.eval() for param in self.parameters(): param.requires_grad = False def forward(self, text, **kwargs): batch_encoding = self.tokenizer(text, truncation=True, max_length=self.max_length, return_length=True, return_overflowing_tokens=False, padding="max_length", return_tensors="pt") tokens = batch_encoding["input_ids"].to(self.device) z = self.transformer(input_ids=tokens, **kwargs) return z def encode(self, text, **kwargs): return self(text, **kwargs)