Spaces:
Runtime error
Runtime error
File size: 8,971 Bytes
7fc7f3d |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 |
from modelsn.med import BertConfig, BertModel, BertLMHeadModel
from modelsn.blip import create_vit, init_tokenizer, load_checkpoint
import torch
from torch import nn
import torch.nn.functional as F
from transformers import BertTokenizer
import numpy as np
class BLIP_VQA(nn.Module):
def __init__(self,
med_config = 'configs/med_config.json',
image_size = 480,
vit = 'base',
vit_grad_ckpt = False,
vit_ckpt_layer = 0,
):
"""
Args:
med_config (str): path for the mixture of encoder-decoder model's configuration file
image_size (int): input image size
vit (str): model size of vision transformer
"""
super().__init__()
self.visual_encoder, vision_width = create_vit(vit, image_size, vit_grad_ckpt, vit_ckpt_layer, drop_path_rate=0.1)
self.tokenizer = init_tokenizer()
encoder_config = BertConfig.from_json_file(med_config)
encoder_config.encoder_width = vision_width
self.text_encoder = BertModel(config=encoder_config, add_pooling_layer=False)
decoder_config = BertConfig.from_json_file(med_config)
self.text_decoder = BertLMHeadModel(config=decoder_config)
def forward(self, image, question, answer=None, n=None, weights=None, train=True, inference='rank', k_test=128):
image_embeds = self.visual_encoder(image)
image_atts = torch.ones(image_embeds.size()[:-1],dtype=torch.long).to(image.device)
question = self.tokenizer(question, padding='longest', truncation=True, max_length=35,
return_tensors="pt").to(image.device)
question.input_ids[:,0] = self.tokenizer.enc_token_id
if train:
'''
n: number of answers for each question
weights: weight for each answer
'''
answer = self.tokenizer(answer, padding='longest', return_tensors="pt").to(image.device)
answer.input_ids[:,0] = self.tokenizer.bos_token_id
answer_targets = answer.input_ids.masked_fill(answer.input_ids == self.tokenizer.pad_token_id, -100)
question_output = self.text_encoder(question.input_ids,
attention_mask = question.attention_mask,
encoder_hidden_states = image_embeds,
encoder_attention_mask = image_atts,
return_dict = True)
question_states = []
question_atts = []
for b, n in enumerate(n):
question_states += [question_output.last_hidden_state[b]]*n
question_atts += [question.attention_mask[b]]*n
question_states = torch.stack(question_states,0)
question_atts = torch.stack(question_atts,0)
answer_output = self.text_decoder(answer.input_ids,
attention_mask = answer.attention_mask,
encoder_hidden_states = question_states,
encoder_attention_mask = question_atts,
labels = answer_targets,
return_dict = True,
reduction = 'none',
)
loss = weights * answer_output.loss
loss = loss.sum()/image.size(0)
return loss
else:
question_output = self.text_encoder(question.input_ids,
attention_mask = question.attention_mask,
encoder_hidden_states = image_embeds,
encoder_attention_mask = image_atts,
return_dict = True)
if inference=='generate':
num_beams = 3
question_states = question_output.last_hidden_state.repeat_interleave(num_beams,dim=0)
question_atts = torch.ones(question_states.size()[:-1],dtype=torch.long).to(question_states.device)
model_kwargs = {"encoder_hidden_states": question_states, "encoder_attention_mask":question_atts}
bos_ids = torch.full((image.size(0),1),fill_value=self.tokenizer.bos_token_id,device=image.device)
outputs = self.text_decoder.generate(input_ids=bos_ids,
max_length=10,
min_length=1,
num_beams=num_beams,
eos_token_id=self.tokenizer.sep_token_id,
pad_token_id=self.tokenizer.pad_token_id,
**model_kwargs)
answers = []
for output in outputs:
answer = self.tokenizer.decode(output, skip_special_tokens=True)
answers.append(answer)
return answers
elif inference=='rank':
max_ids = self.rank_answer(question_output.last_hidden_state, question.attention_mask,
answer.input_ids, answer.attention_mask, k_test)
return max_ids
def rank_answer(self, question_states, question_atts, answer_ids, answer_atts, k):
num_ques = question_states.size(0)
start_ids = answer_ids[0,0].repeat(num_ques,1) # bos token
start_output = self.text_decoder(start_ids,
encoder_hidden_states = question_states,
encoder_attention_mask = question_atts,
return_dict = True,
reduction = 'none')
logits = start_output.logits[:,0,:] # first token's logit
# topk_probs: top-k probability
# topk_ids: [num_question, k]
answer_first_token = answer_ids[:,1]
prob_first_token = F.softmax(logits,dim=1).index_select(dim=1, index=answer_first_token)
topk_probs, topk_ids = prob_first_token.topk(k,dim=1)
# answer input: [num_question*k, answer_len]
input_ids = []
input_atts = []
for b, topk_id in enumerate(topk_ids):
input_ids.append(answer_ids.index_select(dim=0, index=topk_id))
input_atts.append(answer_atts.index_select(dim=0, index=topk_id))
input_ids = torch.cat(input_ids,dim=0)
input_atts = torch.cat(input_atts,dim=0)
targets_ids = input_ids.masked_fill(input_ids == self.tokenizer.pad_token_id, -100)
# repeat encoder's output for top-k answers
question_states = tile(question_states, 0, k)
question_atts = tile(question_atts, 0, k)
output = self.text_decoder(input_ids,
attention_mask = input_atts,
encoder_hidden_states = question_states,
encoder_attention_mask = question_atts,
labels = targets_ids,
return_dict = True,
reduction = 'none')
log_probs_sum = -output.loss
log_probs_sum = log_probs_sum.view(num_ques,k)
max_topk_ids = log_probs_sum.argmax(dim=1)
max_ids = topk_ids[max_topk_ids>=0,max_topk_ids]
return max_ids
def blip_vqa(pretrained='',**kwargs):
model = BLIP_VQA(**kwargs)
if pretrained:
model,msg = load_checkpoint(model,pretrained)
# assert(len(msg.missing_keys)==0)
return model
def tile(x, dim, n_tile):
init_dim = x.size(dim)
repeat_idx = [1] * x.dim()
repeat_idx[dim] = n_tile
x = x.repeat(*(repeat_idx))
order_index = torch.LongTensor(np.concatenate([init_dim * np.arange(n_tile) + i for i in range(init_dim)]))
return torch.index_select(x, dim, order_index.to(x.device))
|