Files

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Python

import logging
import os
from types import SimpleNamespace
from typing import List, Optional, Tuple
import torch
import torch.nn as nn
import torch.nn.functional as F
from huggingface_hub import hf_hub_download
from safetensors import safe_open
from transformers import CLIPTokenizer
import comfy.model_management
import comfy.sample
import comfy.utils
class DecoderBlock(nn.Module):
def __init__(self, embed_dim: int, num_heads: int):
super().__init__()
self.norm1 = nn.LayerNorm(embed_dim)
self.self_attn = nn.MultiheadAttention(
embed_dim=embed_dim,
num_heads=num_heads,
batch_first=True,
)
self.norm2 = nn.LayerNorm(embed_dim)
self.cross_attn = nn.MultiheadAttention(
embed_dim=embed_dim,
num_heads=num_heads,
batch_first=True,
)
self.norm3 = nn.LayerNorm(embed_dim)
self.mlp = nn.Sequential(
nn.Linear(embed_dim, embed_dim * 4),
nn.GELU(),
nn.Identity(),
nn.Linear(embed_dim * 4, embed_dim),
)
def forward(
self,
x: torch.Tensor,
memory: torch.Tensor,
self_attn_mask: Optional[torch.Tensor] = None,
):
# self attention with mask
residual = x
x = self.norm1(x)
attn_output, _ = self.self_attn(
query=x,
key=x,
value=x,
attn_mask=self_attn_mask,
need_weights=False,
is_causal=True,
)
x = residual + attn_output
# cross attention
residual = x
x = self.norm2(x)
attn_output, _ = self.cross_attn(
query=x, key=memory, value=memory, need_weights=False
)
x = residual + attn_output
# FFN
residual = x
x = self.norm3(x)
x = residual + self.mlp(x)
return x
class Captioner(nn.Module):
def __init__(self, config, vision_embed_dim: int, vocab_size: int):
super().__init__()
self.embed_dim = vision_embed_dim
self.hidden_dim = config.hidden_dim
self.max_length = config.max_length
self.vocab_size = vocab_size
# projection from ViT dimension to decoder dimension
self.projection = nn.Linear(self.embed_dim, self.hidden_dim)
self.memory_pos_embedding = nn.Parameter(torch.zeros(1, 257, self.hidden_dim))
# decoder layers
self.layers = nn.ModuleList(
[
DecoderBlock(config.hidden_dim, config.num_heads)
for _ in range(config.num_blocks)
]
)
causal_mask = nn.Transformer.generate_square_subsequent_mask(self.max_length)
self.register_buffer("causal_mask", causal_mask, persistent=False)
class CLIPtionModel(nn.Module):
def __init__(self, config, clip, clip_vision):
super().__init__()
if not hasattr(clip, "cond_stage_model"):
raise ValueError("CLIP is missing from model checkpoint")
if not hasattr(clip.cond_stage_model, "clip_l"):
raise ValueError("Must use model which includes CLIP-L")
# store CLIP model references
self.clip_text = clip
self.clip_vision = clip_vision
self.tokenizer = clip.tokenizer.clip_l.tokenizer
self.text_model = clip.cond_stage_model.clip_l.transformer.text_model
self.vision_model = clip_vision.model.vision_model
# clip.cond_stage_model.clip_l.transformer.text_projection is empty
# so load a copy from the CLIPtion safetensors file instead
self.text_projection = nn.Linear(768, 768, bias=False)
# create caption decoder
self.captioner = Captioner(config, 1024, self.tokenizer.vocab_size)
# use CLIP's token embeddings for output projection
clip_embed_weight = self.text_model.embeddings.token_embedding.weight
self.output_projection = nn.Linear(
self.captioner.hidden_dim, self.tokenizer.vocab_size, bias=False
)
self.output_projection.weight = nn.Parameter(clip_embed_weight.clone())
def generate(
self,
images: torch.Tensor,
seed: int = 42,
temperature: float = 0.7,
best_of: int = 1,
ramble: bool = False,
) -> List[str]:
device = comfy.model_management.get_torch_device()
image_features, image_embeds = self._images_to_embeds(images, device)
captions = []
for image_idx in range(image_features.size(0)):
features = image_features[image_idx : image_idx + 1]
image_embed = image_embeds[image_idx : image_idx + 1]
# generate candidates in parallel using single copy of features
tokens = self._batch_generate(
features,
temperature,
best_of,
seed + image_idx,
ramble=ramble,
)
if best_of == 1:
text = self.tokenizer.decode(
tokens[0],
skip_special_tokens=True,
clean_up_tokenization_spaces=True,
)
captions.append(text)
continue
# calculate CLIP similarity for each candidate
candidates = []
for token_seq in tokens:
text = self.tokenizer.decode(
token_seq,
skip_special_tokens=True,
clean_up_tokenization_spaces=True,
)
text_embeds = self._text_to_embed(text, device)
clip_sim = torch.sum(image_embed * text_embeds, dim=-1)[0]
candidates.append((clip_sim.item(), text))
# pick highest scoring candidate
candidates.sort(key=lambda x: x[0], reverse=False)
for score, text in candidates:
logging.debug(f"({score:.3f}) {text}")
captions.append(candidates[-1][1])
return captions
def generate_beam(
self,
images: torch.Tensor,
beam_width: int = 4,
ramble: bool = False,
) -> List[str]:
device = comfy.model_management.get_torch_device()
image_features, image_embeds = self._images_to_embeds(images, device)
captions = []
for image_idx in range(image_features.size(0)):
features = image_features[image_idx].unsqueeze(0)
candidates = self._beam_search(
features,
image_embeds[image_idx : image_idx + 1],
device,
beam_width=beam_width,
ramble=ramble,
)
# pick highest scoring candidate
candidates.sort(key=lambda x: x[0], reverse=False)
for score, text in candidates:
logging.debug(f"({score:.3f}) {text}")
captions.append(candidates[-1][1])
return captions
def get_tokenizer(self) -> CLIPTokenizer:
return self.tokenizer
def _batch_generate(
self,
image_features: torch.Tensor,
temperature: float,
batch_size: int,
seed: Optional[int] = None,
ramble: bool = False,
) -> torch.Tensor:
tokenizer = self.tokenizer
output_projection = self.output_projection
token_embedding_ = self.text_model.embeddings.token_embedding
pos_embedding_ = self.text_model.embeddings.position_embedding
# project and add positional embeddings to image features
memory = self.captioner.projection(image_features)
memory = memory + self.captioner.memory_pos_embedding
memory = memory.repeat(batch_size, 1, 1)
# initialize sequences with EOS tokens and BOS at start
sequences = torch.full(
(batch_size, self.captioner.max_length),
tokenizer.eos_token_id,
dtype=torch.long,
device=image_features.device,
)
sequences[:, 0] = tokenizer.bos_token_id
current_length = 1
# set up random generator
generator = torch.Generator(device=image_features.device)
if seed is not None:
generator.manual_seed(seed)
# generate tokens until hitting max length or all sequences have EOS
for current_length in range(1, self.captioner.max_length - 1):
# embed current sequences
token_embeddings = token_embedding_(sequences[:, :current_length])
positions = torch.arange(current_length, device=sequences.device)
pos_embeddings = pos_embedding_(positions)
x = token_embeddings + pos_embeddings
# pass through decoder layers
mask = self.captioner.causal_mask[:current_length, :current_length]
for layer in self.captioner.layers:
x = layer(x, memory, self_attn_mask=mask)
# get next token probabilities
logits = output_projection(x[:, -1:])
logits = logits / temperature
# force EOS for sequences that hit EOS, prevent EOS for rambling sequences
prev_is_eos = sequences[:, current_length - 1] == tokenizer.eos_token_id
vocab_mask = torch.zeros_like(logits)
vocab_mask[prev_is_eos, :, :] = float("-inf")
vocab_mask[prev_is_eos, :, tokenizer.eos_token_id] = 0
if ramble:
vocab_mask[~prev_is_eos, :, tokenizer.eos_token_id] = float("-inf")
logits = logits + vocab_mask
probs = F.softmax(logits, dim=-1)
next_tokens = torch.multinomial(probs.squeeze(1), 1, generator=generator)
# add tokens to sequences
sequences[:, current_length] = next_tokens.squeeze(-1)
# stop if all sequences generated an EOS token
if not ramble and (next_tokens == tokenizer.eos_token_id).all():
break
return sequences
def _beam_search(
self,
image_features: torch.Tensor,
image_embed: torch.Tensor,
device: torch.device,
beam_width: int = 5,
ramble: bool = False,
):
tokenizer = self.tokenizer
captioner = self.captioner
token_embedding = self.text_model.embeddings.token_embedding
pos_embedding = self.text_model.embeddings.position_embedding
vocab_size = tokenizer.vocab_size
# project image features
memory = captioner.projection(image_features)
memory = memory + captioner.memory_pos_embedding
# start with beam_width copies of BOS token
current_tokens = torch.full(
(beam_width, 1), tokenizer.bos_token_id, dtype=torch.long, device=device
)
# track sequence scores
scores = torch.zeros(beam_width, device=device)
for step in range(captioner.max_length - 2):
# embed current tokens
token_embeddings = token_embedding(current_tokens)
positions = torch.arange(current_tokens.size(1), device=device)
pos_embeddings = pos_embedding(positions)
x = token_embeddings + pos_embeddings
# run decoder layers
seq_len = x.size(1)
mask = captioner.causal_mask[:seq_len, :seq_len]
for layer in captioner.layers:
x = layer(x, memory.repeat(beam_width, 1, 1), self_attn_mask=mask)
# get next token logits and log probabilities
logits = self.output_projection(x[:, -1:])
if ramble:
logits[:, :, tokenizer.eos_token_id] = -float("inf")
log_probs = F.log_softmax(logits, dim=-1)
if step == 0:
# pick top-k tokens for first step
scores = log_probs.squeeze(1)[0]
scores, indices = scores.topk(beam_width)
current_tokens = torch.cat(
[current_tokens[0:1].repeat(beam_width, 1), indices.unsqueeze(1)],
dim=1,
)
else:
# calculate scores for next tokens [beam_width x vocab_size]
next_scores = scores.unsqueeze(1) + log_probs.squeeze(1)
# force sequences to continue EOS after first one
prev_is_eos = current_tokens[:, -1] == tokenizer.eos_token_id
vocab_mask = torch.zeros_like(next_scores)
vocab_mask[prev_is_eos] = float("-inf")
vocab_mask[prev_is_eos, tokenizer.eos_token_id] = 0
next_scores = next_scores + vocab_mask
# pick top beam_width sequences
next_scores = next_scores.view(-1)
scores, indices = next_scores.topk(beam_width)
beam_indices = indices // vocab_size # which sequence each came from
token_indices = indices % vocab_size # which token to append
current_tokens = torch.cat(
[current_tokens[beam_indices], token_indices.unsqueeze(1)], dim=1
)
# check if all beams ended with EOS
if (current_tokens[:, -1] == tokenizer.eos_token_id).all():
break
# add final EOS token
current_tokens = torch.cat(
[
current_tokens,
torch.full((beam_width, 1), tokenizer.eos_token_id, device=device),
],
dim=1,
)
# rank final candidates by CLIP similarity
candidates = []
for idx in range(beam_width):
text = tokenizer.decode(
current_tokens[idx],
skip_special_tokens=True,
clean_up_tokenization_spaces=True,
)
text_embeds = self._text_to_embed(text, device)
clip_sim = torch.sum(image_embed * text_embeds, dim=-1)[0]
candidates.append((clip_sim.item(), text))
return candidates
def _images_to_embeds(self, images: torch.Tensor, device: torch.device) -> Tuple[torch.Tensor, torch.Tensor]:
if images.size(-1) == 1:
images = images.repeat(1, 1, 1, 3)
elif images.size(-1) == 4:
images = images[..., :3]
outputs = self.clip_vision.encode_image(images)
features = outputs.last_hidden_state.to(device, dtype=torch.float16)
if features.size(2) != 1024:
raise ValueError(
f"Expected image features to have 1024 dimensions but got {features.size(2)}. Please ensure you are using CLIP L."
)
embeds = outputs.image_embeds.to(device, dtype=torch.float16)
embeds /= embeds.norm(dim=-1, keepdim=True)
return features, embeds
def _text_to_embed(self, text: str, device: torch.device) -> torch.Tensor:
# load CLIP model and disable final projection since that's missing from comfy checkpoints
self.clip_text.load_model()
self.clip_text.cond_stage_model.reset_clip_options()
self.clip_text.cond_stage_model.set_clip_options({"projected_pooled": False})
# calculate text embedding
tokens = self.clip_text.tokenize(text)
clip_l = self.clip_text.cond_stage_model.clip_l
_, pooled = clip_l.encode_token_weights(tokens["l"])
text_embeds = self.text_projection(pooled.to(device, dtype=torch.float16))
text_embeds = text_embeds / text_embeds.norm(dim=-1, keepdim=True)
return text_embeds
class CLIPtionLoader:
CATEGORY = "pharmapsychotic"
FUNCTION = "load"
RETURN_TYPES = ("CLIPTION",)
@classmethod
def INPUT_TYPES(s):
return {
"required": {
"clip": (
"CLIP",
{"tooltip": "The CLIP model used for encoding the text."},
),
"clip_vision": ("CLIP_VISION",),
}
}
def load(self, clip, clip_vision):
state_dict = {}
file = "CLIPtion_20241219_fp16.safetensors"
base_path = os.path.dirname(os.path.abspath(__file__))
if os.path.exists(os.path.join(base_path, file)):
model_path = os.path.join(base_path, file)
else:
repo_id = "pharmapsychotic/CLIPtion"
revision = "15ee8cb77a902616478a033332011ff640e72277"
model_path = hf_hub_download(
repo_id=repo_id, filename=file, revision=revision
)
with safe_open(model_path, framework="pt", device="cpu") as f:
for key in f.keys():
state_dict[key] = f.get_tensor(key)
tp_dict = {"weight": state_dict.pop("text_projection.weight")}
config = SimpleNamespace(
**{"hidden_dim": 768, "num_heads": 8, "num_blocks": 6, "max_length": 77}
)
model = CLIPtionModel(config, clip, clip_vision)
model.captioner.load_state_dict(state_dict)
model.text_projection.load_state_dict(tp_dict)
model.eval()
model.to(comfy.model_management.get_torch_device(), dtype=torch.float16)
return (model,)
class CLIPtionGenerate:
CATEGORY = "pharmapsychotic"
FUNCTION = "caption"
OUTPUT_IS_LIST = (True,)
RETURN_TYPES = ("STRING",)
@classmethod
def INPUT_TYPES(s):
return {
"required": {
"model": ("CLIPTION", {"tooltip": "The CLIPtion model."}),
"image": ("IMAGE",),
"seed": (
"INT",
{
"default": 0,
"min": 0,
"max": 0xFFFFFFFFFFFFFFFF,
"tooltip": "The random seed used for creating the caption.",
},
),
},
"optional": {
"temperature": (
"FLOAT",
{"default": 0.7, "tooltip": "Temperature for sampling."},
),
"best_of": (
"INT",
{
"default": 1,
"min": 1,
"max": 64,
"tooltip": "Number of options to evaluate.",
},
),
"ramble": ("BOOLEAN", {"default": False}),
},
}
def caption(
self,
model: CLIPtionModel,
image: torch.Tensor,
seed: int,
temperature: float = 0.7,
best_of: int = 1,
ramble: bool = False,
):
with torch.inference_mode():
captions = model.generate(image, seed, temperature, best_of, ramble)
return (captions,)
class CLIPtionBeamSearch:
CATEGORY = "pharmapsychotic"
FUNCTION = "caption"
OUTPUT_IS_LIST = (True,)
RETURN_TYPES = ("STRING",)
@classmethod
def INPUT_TYPES(s):
return {
"required": {
"model": ("CLIPTION", {"tooltip": "The CLIPtion model."}),
"image": ("IMAGE",),
"beam_width": (
"INT",
{
"default": 4,
"min": 1,
"max": 64,
"tooltip": "Number of beams to maintain during search.",
},
),
},
"optional": {
"ramble": ("BOOLEAN", {"default": False}),
},
}
def caption(
self,
model: CLIPtionModel,
image: torch.Tensor,
beam_width: int = 4,
ramble: bool = False,
):
with torch.inference_mode():
captions = model.generate_beam(image, beam_width, ramble)
return (captions,)
NODE_CLASS_MAPPINGS = {
"CLIPtionBeamSearch": CLIPtionBeamSearch,
"CLIPtionGenerate": CLIPtionGenerate,
"CLIPtionLoader": CLIPtionLoader,
}
NODE_DISPLAY_NAME_MAPPINGS = {
"CLIPtionBeamSearch": "CLIPtion Beam Search",
"CLIPtionGenerate": "CLIPtion Generate",
"CLIPtionLoader": "CLIPtion Loader",
}