Implement CLIP extensions (training + inference)

configs/stable-diffusion/v1-finetune-4gpu.yaml

@@ -67,6 +67,10 @@ model:
 
     cond_stage_config:
       target: ldm.modules.encoders.modules.FrozenCLIPEmbedder
+      params:
+        penultimate: True
+        extended_mode: True
+        max_chunks: 3
 
 data:
   target: main.DataModuleFromConfig

ldm/modules/encoders/modules.py

@@ -5,6 +5,7 @@ import clip
 from einops import rearrange, repeat
 from transformers import CLIPTokenizer, CLIPTextModel
 import kornia
+import numpy as np
 
 from ldm.modules.x_transformer import Encoder, TransformerWrapper  # TODO: can we directly rely on lucidrains code and simply add this as a reuirement? --> test
 
@@ -136,13 +137,15 @@ class SpatialRescaler(nn.Module):
 
 class FrozenCLIPEmbedder(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, penultimate=True):
+    def __init__(self, version="openai/clip-vit-large-patch14", device="cuda", max_length=77, penultimate=True, max_chunks=3, extended_mode=True):
         super().__init__()
         self.tokenizer = CLIPTokenizer.from_pretrained(version)
         self.transformer = CLIPTextModel.from_pretrained(version)
         self.device = device
         self.max_length = max_length
-        self.penultimate = penultimate # return embeddings from 2nd to last layer, see https://arxiv.org/pdf/2205.11487.pdf
+        self.penultimate = penultimate  # return embeddings from 2nd to last layer, see https://arxiv.org/pdf/2205.11487.pdf
+        self.extended_mode = extended_mode
+        self.max_chunks = max_chunks
         self.freeze()
 
     def freeze(self):
@@ -150,20 +153,59 @@ class FrozenCLIPEmbedder(AbstractEncoder):
         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)
+    def transform(self, tokens):
         outputs = self.transformer(input_ids=tokens, output_hidden_states=True)
 
         if self.penultimate:
-            z = outputs.hidden_states[-2] # simple enough
+            z = outputs.hidden_states[-2]  # simple enough
             z = self.transformer.text_model.final_layer_norm(z)
         else:
             z = outputs.last_hidden_state
 
         return z
 
+    def forward(self, text):
+        if self.extended_mode:
+            max_standard_tokens = self.max_length - 2
+
+            batch_encoding = self.tokenizer(text, truncation=True, max_length=(self.max_length * self.max_chunks) - (self.max_chunks * 2), return_length=True, return_overflowing_tokens=False, padding=False,
+                                            add_special_tokens=False)
+            
+            # get the max length aligned to chunk size.
+            max_len = np.ceil(max([len(x) for x in batch_encoding["input_ids"]]) / max_standard_tokens).astype(int).item() * max_standard_tokens
+            if max_len > max_standard_tokens:
+                z = None
+
+                for index, x in enumerate(batch_encoding["input_ids"]):
+                    if len(x) < max_len:
+                        # pad all tokens to the longest sentence/sequence, maybe find a torch method that can do this?
+                        batch_encoding["input_ids"][index] = [*x, *np.full((max_len - len(x)), self.tokenizer.eos_token_id)]
+
+                batch_t = torch.tensor(batch_encoding["input_ids"])
+                # process the tensors in vertically sliced chunks
+                chunks = [batch_t[:, i:i + max_standard_tokens] for i in range(0, max_len, max_standard_tokens)]
+                for chunk in chunks:
+                    chunk = torch.cat((torch.full((chunk.shape[0], 1), self.tokenizer.bos_token_id), chunk, torch.full((chunk.shape[0], 1), self.tokenizer.eos_token_id)), 1)
+
+                    if z is None:
+                        z = self.transform(chunk.to(self.device))
+                    else:
+                        z = torch.cat((z, self.transform(chunk.to(self.device))), dim=-2)
+
+                return z
+            else:
+                chunk = batch_encoding['input_ids']
+                for i, x in enumerate(chunk):
+                    chunk[i] = [self.tokenizer.bos_token_id, *x, *np.full((self.max_length - len(x) - 1), self.tokenizer.eos_token_id)]
+                return self.transform(torch.asarray(chunk).to(self.device))
+
+        else:
+            # default behavior
+            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)
+
+            return self.transform(tokens)
+
     def encode(self, text):
         return self(text)
 

scripts/txt2img_gradio.py

@@ -145,6 +145,17 @@ model = load_model_from_config(config, "models/ldm/stable-diffusion-v1/model.ckp
 device = torch.device("cuda") if torch.cuda.is_available() else torch.device("cpu")
 model = model.half().to(device)
 
+def reshape_c_uc(c, uc):
+    # I have no idea how to generate an empty tensor that's valid for the model,
+    # so I'm gonna just pass in an empty prompt and hope it works!
+    padding = model.get_learned_conditioning(["" for _ in range(c.shape[0])])
+    while c.shape[1] != uc.shape[1]:
+        if c.shape[1] > uc.shape[1]:
+            uc = torch.cat([uc, padding], dim=1)
+        else:
+            c = torch.cat([c, padding], dim=1)
+    return c, uc
+
 def dream(prompt: str, ddim_steps: int, sampler: str, fixed_code: bool, ddim_eta: float, n_iter: int, n_samples: int, cfg_scale: float, seed: int, height: int, width: int):
     torch.cuda.empty_cache()
 
@@ -202,6 +213,8 @@ def dream(prompt: str, ddim_steps: int, sampler: str, fixed_code: bool, ddim_eta
                             prompts = list(prompts)
                         c = model.get_learned_conditioning(prompts)
                         shape = [opt.C, opt.H // opt.f, opt.W // opt.f]
+                        if uc is not None:
+                            c, uc = reshape_c_uc(c, uc)
                         if sampler == 'k_lms':
                             sigmas = model_wrap.get_sigmas(ddim_steps)
                             model_wrap_cfg = CFGDenoiser(model_wrap)