DoU / upstream /models /dou.py
Yanmou's picture
Release DoU evaluation checkpoint and model card
df66507 verified
Raw History Blame Contribute Delete
10.8 kB
import torch
import os
import torch.nn as nn
from clip import clip
from clip.simple_tokenizer import SimpleTokenizer as _Tokenizer
_tokenizer = _Tokenizer()
def cuda(tensor, is_cuda):
if is_cuda:
return tensor.cuda()
else:
return tensor
class Hook:
def __init__(self, name, module):
self.name = name
self.hook = module.register_forward_hook(self.hook_fn)
def hook_fn(self, module, input, output):
self.input = input
self.output = output
def close(self):
self.hook.remove()
# Load the CLIP model
def load_clip_to_cpu(cfg):
backbone_name = cfg.model_name
url = clip._MODELS[backbone_name]
model_path = clip._download(url, os.path.expanduser("~/.cache/clip"))
try:
# Loading JIT archive
model = torch.jit.load(model_path, map_location="cpu").eval()
state_dict = None
except RuntimeError:
state_dict = torch.load(model_path, map_location="cpu")
model = clip.build_model(state_dict or model.state_dict())
return model
# Text encoder that maps prompt tokens into feature vectors
class TextEncoder(nn.Module):
def __init__(self, clip_model):
super().__init__()
self.transformer = clip_model.transformer
self.positional_embedding = clip_model.positional_embedding
self.ln_final = clip_model.ln_final
self.text_projection = clip_model.text_projection
self.dtype = clip_model.dtype
def forward(self, prompts, tokenized_prompts):
"""
:param prompts: Tensor representation of text prompts
:param tokenized_prompts: Tokenized text prompts
:return: Text features
"""
# Add prompts and positional embeddings
x = prompts + self.positional_embedding.type(self.dtype)
x = x.permute(1, 0, 2) # NLD -> LND
x = self.transformer(x)
x = x.permute(1, 0, 2) # LND -> NLD
x = self.ln_final(x).type(self.dtype)
# x.shape = [batch_size, n_ctx, transformer.width]
# Take features from the EOT embedding (EOT token is the highest number in each sequence)
x = x[torch.arange(x.shape[0]), tokenized_prompts.argmax(dim=-1)] @ self.text_projection
return x
# Learn and generate context-aware prompts
class PromptLearner(nn.Module):
def __init__(self, cfg, classnames, clip_model):
super().__init__()
n_cls = len(classnames)
n_ctx = cfg.n_ctx
ctx_init = cfg.ctx_init
dtype = clip_model.dtype
ctx_dim = clip_model.ln_final.weight.shape[0]
clip_imsize = clip_model.visual.input_resolution
cfg_imsize = cfg.img_size
assert cfg_imsize == clip_imsize, f"cfg_imsize ({cfg_imsize}) must equal to clip_imsize ({clip_imsize})"
if ctx_init:
# Use CLIP tokenize to determine the actual number of tokens
# instead of counting spaces manually
ctx_init = ctx_init.replace("_", " ")
with torch.no_grad():
tok = clip.tokenize(ctx_init) # [1, L]
eot = tok.argmax(dim=-1).item() # Index of the final EOT token
n_ctx = eot - 1 # Remove [SOS] and keep only context tokens
emb = clip_model.token_embedding(tok).to(torch.float32) # Use FP32 for parameters, not fp16
# Extract the token vectors corresponding to the context
# remove [SOS] and keep n_ctx tokens
ctx_vectors = emb[0, 1:1 + n_ctx, :].contiguous() # [n_ctx, D]
prompt_prefix = ctx_init
else:
# Random initialization: parameters must be FP32
if cfg.csc:
print("Initializing class-specific contexts")
ctx_vectors = torch.empty(n_cls, n_ctx, ctx_dim, dtype=torch.float32)
else:
print("Initializing a generic context")
ctx_vectors = torch.empty(n_ctx, ctx_dim, dtype=torch.float32)
nn.init.normal_(ctx_vectors, std=0.02)
prompt_prefix = " ".join(["X"] * n_ctx)
print(f'Initial context: "{prompt_prefix}"')
print(f"Number of context words (tokens): {n_ctx}")
self.ctx = nn.Parameter(ctx_vectors) # To be optimized
classnames = [name.replace("_", " ") for name in classnames]
name_lens = [len(_tokenizer.encode(name)) for name in classnames]
prompts = [prompt_prefix + " " + name + "." for name in classnames]
tokenized_prompts = torch.cat([clip.tokenize(p) for p in prompts])
with torch.no_grad():
embedding = clip_model.token_embedding(tokenized_prompts).type(dtype)
# These token vectors will be saved in save_model(),
# but they should be ignored in load_model() because we want to use
# those computed using the current class names
self.register_buffer("token_prefix", embedding[:, :1, :]) # SOS
self.register_buffer("token_suffix", embedding[:, 1 + n_ctx:, :]) # CLS, EOS
self.n_cls = n_cls
self.n_ctx = n_ctx
self.tokenized_prompts = tokenized_prompts # torch.Tensor
self.name_lens = name_lens
self.class_token_position = cfg.class_token_position
def forward(self):
ctx = self.ctx
if ctx.dim() == 2:
ctx = ctx.unsqueeze(0).expand(self.n_cls, -1, -1)
ctx = ctx.to(self.token_prefix.dtype)
prefix = self.token_prefix
suffix = self.token_suffix
if self.class_token_position == "end":
prompts = torch.cat(
[
prefix, # (n_cls, 1, dim)
ctx, # (n_cls, n_ctx, dim)
suffix, # (n_cls, *, dim)
],
dim=1,
)
elif self.class_token_position == "middle":
half_n_ctx = self.n_ctx // 2
prompts = []
for i in range(self.n_cls):
name_len = self.name_lens[i]
prefix_i = prefix[i: i + 1, :, :]
class_i = suffix[i: i + 1, :name_len, :]
suffix_i = suffix[i: i + 1, name_len:, :]
ctx_i_half1 = ctx[i: i + 1, :half_n_ctx, :]
ctx_i_half2 = ctx[i: i + 1, half_n_ctx:, :]
prompt = torch.cat(
[
prefix_i, # (1, 1, dim)
ctx_i_half1, # (1, n_ctx//2, dim)
class_i, # (1, name_len, dim)
ctx_i_half2, # (1, n_ctx//2, dim)
suffix_i, # (1, *, dim)
],
dim=1,
)
prompts.append(prompt)
prompts = torch.cat(prompts, dim=0)
elif self.class_token_position == "front":
prompts = []
for i in range(self.n_cls):
name_len = self.name_lens[i]
prefix_i = prefix[i: i + 1, :, :]
class_i = suffix[i: i + 1, :name_len, :]
suffix_i = suffix[i: i + 1, name_len:, :]
ctx_i = ctx[i: i + 1, :, :]
prompt = torch.cat(
[
prefix_i, # (1, 1, dim)
class_i, # (1, name_len, dim)
ctx_i, # (1, n_ctx, dim)
suffix_i, # (1, *, dim)
],
dim=1,
)
prompts.append(prompt)
prompts = torch.cat(prompts, dim=0)
else:
raise ValueError
return prompts
# Combine the image encoder and the text encoder
class DoUNet(nn.Module):
def __init__(self, cfg, clip_model, proj_dim=1024):
super().__init__()
classnames = cfg.classnames
self.clip = clip_model
self.image_encoder = clip_model.visual
self.prompt_learner = PromptLearner(cfg, classnames, clip_model)
self.tokenized_prompts = self.prompt_learner.tokenized_prompts
self.text_encoder = TextEncoder(clip_model)
self.logit_scale = clip_model.logit_scale
self.dtype = clip_model.dtype
# Register hooks to capture intermediate layer outputs
hook_candidates = [(name, module) for name, module in self.clip.visual.named_modules() if "ln_2" in name]
hook_candidates.sort(key=lambda x: x[0]) # Ensure stable layer ordering
self.hooks = [Hook(name, module) for name, module in hook_candidates]
H = len(self.hooks)
self.alpha = nn.Parameter(torch.randn(1, H, proj_dim)) # [1, H, D]
self.layer_mu = nn.ModuleList([
nn.Linear(proj_dim, proj_dim) for _ in range(H)
])
self.layer_logvar = nn.ModuleList([
nn.Linear(proj_dim, proj_dim) for _ in range(H)
])
def reparameterize(self, mu, logvar):
std = torch.exp(0.5 * logvar) # logvar = log(σ^2)
eps = torch.randn_like(std) # Same shape/device/dtype as std
return mu + std * eps
def forward(self, image, depth=None, return_features=False):
with torch.no_grad():
_ = self.clip.encode_image(image)
cls_list = [h.output[0, :, :].to(torch.float32) for h in self.hooks]
g = torch.stack(cls_list, dim=1).float()
mu_layers = []
logvar_layers = []
z_layers = []
for idx, feat in enumerate(torch.unbind(g, dim=1)):
mu_i = self.layer_mu[idx](feat)
logvar_i = self.layer_logvar[idx](feat)
z_i = self.reparameterize(mu_i, logvar_i)
mu_layers.append(mu_i)
logvar_layers.append(logvar_i)
z_layers.append(z_i)
mu = torch.stack(mu_layers, dim=1)
logvar = torch.stack(logvar_layers, dim=1)
z_stack = torch.stack(z_layers, dim=1)
for h in self.hooks:
h.output = None # Optional: clear cache
w = torch.softmax(self.alpha, dim=1).to(z_stack.dtype)
if w.size(0) != z_stack.size(0):
w = w.expand(z_stack.size(0), -1, -1)
z = (w * z_stack).sum(dim=1)
z = z.to(self.dtype)
image_features = z @ self.clip.visual.proj
prompts = self.prompt_learner()
tokenized_prompts = self.tokenized_prompts
text_features = self.text_encoder(prompts, tokenized_prompts)
image_features = image_features / image_features.norm(dim=-1, keepdim=True)
text_features = text_features / text_features.norm(dim=-1, keepdim=True)
logit_scale = self.logit_scale.exp()
logits = logit_scale * image_features @ text_features.t()
if return_features:
return logits, (mu, logvar), image_features, text_features, z_stack
else:
return logits