MiniMind2-V / model_vlm.py
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import os
import torch
import warnings
from .model_minimind import *
from typing import Optional, Tuple, List
from torch import nn
from transformers import CLIPProcessor, CLIPModel
from typing import List
warnings.filterwarnings('ignore')
class VLMConfig(MiniMindConfig):
model_type = "minimind-v"
def __init__(
self,
image_special_token: str = '@' * 196,
image_ids: List = [34] * 196,
**kwargs,
):
self.image_special_token = image_special_token
self.image_ids = image_ids
super().__init__(**kwargs)
class VisionProj(nn.Module):
def __init__(self, ve_hidden_size=768, hidden_size=512):
super().__init__()
self.ve_hidden_size = ve_hidden_size
self.hidden_size = hidden_size
self.vision_proj = nn.Sequential(
nn.Linear(self.ve_hidden_size, self.hidden_size)
)
def forward(self, image_encoders):
vision_proj = self.vision_proj(image_encoders)
return vision_proj
# 继承自语言模型
class MiniMindVLM(MiniMindForCausalLM):
config_class = VLMConfig
def __init__(self, params: VLMConfig = None, vision_model_path="./model/vision_model/clip-vit-base-patch16"):
super().__init__(params)
if not params: params = VLMConfig()
self.params = params
self.vision_encoder, self.processor = self.__class__.get_vision_model(vision_model_path)
self.vision_proj = VisionProj(hidden_size=params.hidden_size)
@staticmethod
def get_vision_model(model_path: str):
from transformers import logging as hf_logging
hf_logging.set_verbosity_error()
if not os.path.exists(model_path):
return None, None
model = CLIPModel.from_pretrained(model_path)
processor = CLIPProcessor.from_pretrained(model_path)
# 冻结 vision_encoder 的所有参数
for param in model.parameters():
param.requires_grad = False
return model.eval(), processor
@staticmethod
def image2tensor(image, processor):
if image.mode in ['RGBA', 'LA']: image = image.convert('RGB')
inputs = processor(images=image, return_tensors="pt")['pixel_values']
return inputs
@staticmethod
def get_image_embeddings(image_tensors, vision_model):
with torch.no_grad():
outputs = vision_model.vision_model(pixel_values=image_tensors)
img_embedding = outputs.last_hidden_state[:, 1:, :].squeeze()
return img_embedding
def count_vision_proj(self, tokens, h, vision_tensors=None, seqlen=512):
def find_indices(tokens, image_ids):
image_ids_tensor = torch.tensor(image_ids).to(tokens.device)
len_image_ids = len(image_ids)
if len_image_ids > tokens.size(1):
return None
tokens_view = tokens.unfold(1, len_image_ids, 1)
matches = (tokens_view == image_ids_tensor).all(dim=2)
return {
batch_idx: [(idx.item(), idx.item() + len_image_ids - 1) for idx in
matches[batch_idx].nonzero(as_tuple=True)[0]]
for batch_idx in range(tokens.size(0)) if matches[batch_idx].any()
} or None
image_indices = find_indices(tokens, self.params.image_ids)
if vision_tensors is not None and image_indices:
vision_proj = self.vision_proj(vision_tensors)
if len(vision_proj.shape) == 3:
vision_proj = vision_proj.unsqueeze(0)
new_h = []
for i in range(h.size(0)):
if i in image_indices:
h_i = h[i]
img_idx = 0
for start_idx, end_idx in image_indices[i]:
if img_idx < vision_proj.size(1):
h_i = torch.cat((h_i[:start_idx], vision_proj[i][img_idx], h_i[end_idx + 1:]), dim=0)[
:seqlen]
img_idx += 1
new_h.append(h_i)
else:
new_h.append(h[i])
return torch.stack(new_h, dim=0)
return h
def forward(self,
input_ids: Optional[torch.Tensor] = None,
attention_mask: Optional[torch.Tensor] = None,
past_key_values: Optional[List[Tuple[torch.Tensor, torch.Tensor]]] = None,
use_cache: bool = False,
logits_to_keep: Union[int, torch.Tensor] = 0,
pixel_values: Optional[torch.FloatTensor] = None,
**args):
batch_size, seq_length = input_ids.shape
if hasattr(past_key_values, 'layers'): past_key_values = None
past_key_values = past_key_values or [None] * len(self.model.layers)
start_pos = past_key_values[0][0].shape[1] if past_key_values[0] is not None else 0
hidden_states = self.model.dropout(self.model.embed_tokens(input_ids))
if pixel_values is not None and start_pos == 0:
if len(pixel_values.shape) == 6:
pixel_values = pixel_values.squeeze(2)
bs, num, c, im_h, im_w = pixel_values.shape
stack_dim = 1 if bs > 1 else 0
vision_tensors = torch.stack([
MiniMindVLM.get_image_embeddings(pixel_values[:, i, :, :, :], self.vision_encoder)
for i in range(num)
], dim=stack_dim)
hidden_states = self.count_vision_proj(tokens=input_ids, h=hidden_states, vision_tensors=vision_tensors,
seqlen=input_ids.shape[1])
position_embeddings = (
self.model.freqs_cos[start_pos:start_pos + seq_length],
self.model.freqs_sin[start_pos:start_pos + seq_length]
)
presents = []
for layer_idx, (layer, past_key_value) in enumerate(zip(self.model.layers, past_key_values)):
hidden_states, present = layer(
hidden_states,
position_embeddings,
past_key_value=past_key_value,
use_cache=use_cache,
attention_mask=attention_mask
)
presents.append(present)
hidden_states = self.model.norm(hidden_states)
aux_loss = sum(
layer.mlp.aux_loss
for layer in self.model.layers
if isinstance(layer.mlp, MOEFeedForward)
)
slice_indices = slice(-logits_to_keep, None) if isinstance(logits_to_keep, int) else logits_to_keep
logits = self.lm_head(hidden_states[:, slice_indices, :])
output = CausalLMOutputWithPast(logits=logits, past_key_values=presents, hidden_states=hidden_states)
output.aux_loss = aux_loss
return output