320 lines
11 KiB
Python

"""Minimal implementation of CLIPVisionModel intended to be only used
within a vision language model."""
from typing import Iterable, Optional, Tuple
import torch
import torch.nn as nn
from PIL import Image
from transformers import CLIPVisionConfig
from transformers.models.clip.modeling_clip import CLIPAttention
from vllm.config import ModelConfig
from vllm.inputs import LLMInputs
from vllm.model_executor.layers.activation import get_act_fn
from vllm.model_executor.layers.linear import (ColumnParallelLinear,
RowParallelLinear)
from vllm.model_executor.layers.quantization import QuantizationConfig
from vllm.model_executor.model_loader.weight_utils import default_weight_loader
from vllm.multimodal.image import (cached_get_tokenizer,
repeat_and_pad_image_tokens)
from vllm.sequence import SequenceData
def get_clip_patch_grid_length(*, image_size: int, patch_size: int) -> int:
assert image_size % patch_size == 0
return image_size // patch_size
def get_clip_num_patches(*, image_size: int, patch_size: int) -> int:
grid_length = get_clip_patch_grid_length(image_size=image_size,
patch_size=patch_size)
return grid_length * grid_length
def get_clip_image_feature_size(hf_config: CLIPVisionConfig) -> int:
return get_clip_num_patches(image_size=hf_config.image_size,
patch_size=hf_config.patch_size) + 1
def get_max_clip_image_tokens(hf_config: CLIPVisionConfig) -> int:
return get_clip_image_feature_size(hf_config)
def dummy_seq_data_for_clip(
hf_config: CLIPVisionConfig,
seq_len: int,
*,
image_token_id: int,
image_feature_size_override: Optional[int] = None,
):
if image_feature_size_override is None:
image_feature_size = get_clip_image_feature_size(hf_config)
else:
image_feature_size = image_feature_size_override
token_ids = [image_token_id] * image_feature_size
token_ids += [0] * (seq_len - image_feature_size)
return SequenceData(token_ids)
def dummy_image_for_clip(
hf_config: CLIPVisionConfig,
*,
image_width_override: Optional[int] = None,
image_height_override: Optional[int] = None,
):
width = height = hf_config.image_size
if image_width_override is not None:
width = image_width_override
if image_height_override is not None:
height = image_height_override
image = Image.new("RGB", (width, height), color=0)
return {"image": image}
def input_processor_for_clip(
model_config: ModelConfig,
hf_config: CLIPVisionConfig,
llm_inputs: LLMInputs,
*,
image_token_id: int,
image_feature_size_override: Optional[int] = None,
):
multi_modal_data = llm_inputs.get("multi_modal_data")
if multi_modal_data is None or "image" not in multi_modal_data:
return llm_inputs
tokenizer = cached_get_tokenizer(model_config.tokenizer)
if image_feature_size_override is None:
image_data = multi_modal_data["image"]
if isinstance(image_data, Image.Image):
image_feature_size = get_clip_image_feature_size(hf_config)
elif isinstance(image_data, torch.Tensor):
image_feature_size = image_data.shape[0]
else:
raise TypeError(f"Invalid image type: {type(image_data)}")
else:
image_feature_size = image_feature_size_override
new_prompt, new_token_ids = repeat_and_pad_image_tokens(
tokenizer,
llm_inputs.get("prompt"),
llm_inputs["prompt_token_ids"],
image_token_id=image_token_id,
repeat_count=image_feature_size,
)
# NOTE: Create a defensive copy of the original inputs
return LLMInputs(prompt_token_ids=new_token_ids,
prompt=new_prompt,
multi_modal_data=multi_modal_data)
# Adapted from https://github.com/huggingface/transformers/blob/v4.39.0/src/transformers/models/clip/modeling_clip.py#L164 # noqa
class CLIPVisionEmbeddings(nn.Module):
def __init__(self, config: CLIPVisionConfig):
super().__init__()
self.config = config
self.embed_dim = config.hidden_size
self.image_size = config.image_size
self.patch_size = config.patch_size
self.class_embedding = nn.Parameter(torch.randn(self.embed_dim))
self.patch_embedding = nn.Conv2d(
in_channels=config.num_channels,
out_channels=self.embed_dim,
kernel_size=self.patch_size,
stride=self.patch_size,
bias=False,
)
self.num_patches = get_clip_num_patches(image_size=self.image_size,
patch_size=self.patch_size)
self.num_positions = self.num_patches + 1
self.position_embedding = nn.Embedding(self.num_positions,
self.embed_dim)
self.register_buffer("position_ids",
torch.arange(self.num_positions).expand((1, -1)),
persistent=False)
def forward(self, pixel_values: torch.Tensor) -> torch.Tensor:
batch_size = pixel_values.shape[0]
target_dtype = self.patch_embedding.weight.dtype
patch_embeds = self.patch_embedding(pixel_values.to(
dtype=target_dtype)) # shape = [*, width, grid, grid]
patch_embeds = patch_embeds.flatten(2).transpose(1, 2)
class_embeds = self.class_embedding.expand(batch_size, 1, -1)
embeddings = torch.cat([class_embeds, patch_embeds], dim=1)
embeddings = embeddings + self.position_embedding(self.position_ids)
return embeddings
class CLIPMLP(nn.Module):
def __init__(self,
config: CLIPVisionConfig,
quant_config: Optional[QuantizationConfig] = None):
super().__init__()
self.config = config
self.activation_fn = get_act_fn(config.hidden_act)
self.fc1 = ColumnParallelLinear(config.hidden_size,
config.intermediate_size,
bias=True,
quant_config=quant_config)
self.fc2 = RowParallelLinear(config.intermediate_size,
config.hidden_size,
bias=True,
quant_config=quant_config)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
hidden_states, _ = self.fc1(hidden_states)
hidden_states = self.activation_fn(hidden_states)
hidden_states, _ = self.fc2(hidden_states)
return hidden_states
class CLIPEncoderLayer(nn.Module):
def __init__(self,
config: CLIPVisionConfig,
quant_config: Optional[QuantizationConfig] = None):
super().__init__()
self.self_attn = CLIPAttention(config)
self.layer_norm1 = nn.LayerNorm(config.hidden_size,
eps=config.layer_norm_eps)
self.mlp = CLIPMLP(config, quant_config=quant_config)
self.layer_norm2 = nn.LayerNorm(config.hidden_size,
eps=config.layer_norm_eps)
def forward(self, hidden_states: torch.Tensor) -> torch.Tensor:
residual = hidden_states
hidden_states = self.layer_norm1(hidden_states)
hidden_states, _ = self.self_attn(hidden_states=hidden_states)
hidden_states = residual + hidden_states
residual = hidden_states
hidden_states = self.layer_norm2(hidden_states)
hidden_states = self.mlp(hidden_states)
hidden_states = residual + hidden_states
return hidden_states
class CLIPEncoder(nn.Module):
"""
Transformer encoder consisting of `config.num_hidden_layers` self
attention layers. Each layer is a [`CLIPEncoderLayer`].
Args:
config: CLIPConfig
"""
def __init__(self,
config: CLIPVisionConfig,
quant_config: Optional[QuantizationConfig] = None,
num_hidden_layers_override: Optional[int] = None):
super().__init__()
self.config = config
if num_hidden_layers_override is None:
num_hidden_layers = config.num_hidden_layers
else:
num_hidden_layers = num_hidden_layers_override
self.layers = nn.ModuleList([
CLIPEncoderLayer(config=config, quant_config=quant_config)
for _ in range(num_hidden_layers)
])
def forward(self, inputs_embeds: torch.Tensor):
hidden_states = inputs_embeds
for encoder_layer in self.layers:
hidden_states = encoder_layer(hidden_states)
return hidden_states
class CLIPVisionTransformer(nn.Module):
def __init__(self,
config: CLIPVisionConfig,
quant_config: Optional[QuantizationConfig] = None,
num_hidden_layers_override: Optional[int] = None):
super().__init__()
self.config = config
embed_dim = config.hidden_size
self.embeddings = CLIPVisionEmbeddings(config)
# NOTE: This typo of "layrnorm" is not fixed on purpose to match
# the original transformers code and name of the model weights.
self.pre_layrnorm = nn.LayerNorm(embed_dim, eps=config.layer_norm_eps)
self.encoder = CLIPEncoder(
config=config,
quant_config=quant_config,
num_hidden_layers_override=num_hidden_layers_override)
def forward(
self,
pixel_values: torch.Tensor,
) -> torch.Tensor:
hidden_states = self.embeddings(pixel_values)
hidden_states = self.pre_layrnorm(hidden_states)
hidden_states = self.encoder(inputs_embeds=hidden_states)
return hidden_states
class CLIPVisionModel(nn.Module):
config_class = CLIPVisionConfig
main_input_name = "pixel_values"
def __init__(self,
config: CLIPVisionConfig,
quant_config: Optional[QuantizationConfig] = None,
num_hidden_layers_override: Optional[int] = None):
super().__init__()
self.vision_model = CLIPVisionTransformer(
config=config,
quant_config=quant_config,
num_hidden_layers_override=num_hidden_layers_override)
def forward(self, pixel_values: Optional[torch.Tensor] = None):
return self.vision_model(pixel_values=pixel_values)
@property
def device(self):
return next(self.parameters()).device
def load_weights(self, weights: Iterable[Tuple[str, torch.Tensor]]):
params_dict = dict(self.named_parameters())
layer_count = len(self.vision_model.encoder.layers)
for name, loaded_weight in weights:
# post_layernorm is not needed in CLIPVisionModel
if "vision_model.post_layernorm" in name:
continue
# omit layers when num_hidden_layers_override is set
if "vision_model.encoder.layers." in name:
layer_idx = int(name.split(".")[3])
if layer_idx >= layer_count:
continue
param = params_dict[name]
weight_loader = getattr(param, "weight_loader",
default_weight_loader)
weight_loader(param, loaded_weight)