| '''
|
| * Copyright (c) 2022, salesforce.com, inc.
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| * All rights reserved.
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| * SPDX-License-Identifier: BSD-3-Clause
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| * For full license text, see LICENSE.txt file in the repo root or https://opensource.org/licenses/BSD-3-Clause
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| * By Junnan Li
|
| '''
|
| import warnings
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| warnings.filterwarnings("ignore")
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|
|
| from extras.BLIP.models.vit import VisionTransformer, interpolate_pos_embed
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| from extras.BLIP.models.med import BertConfig, BertModel, BertLMHeadModel
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| from transformers import BertTokenizer
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|
|
| import torch
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| from torch import nn
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| import torch.nn.functional as F
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|
|
| import os
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| from urllib.parse import urlparse
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| from timm.models.hub import download_cached_file
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|
|
| class BLIP_Base(nn.Module):
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| def __init__(self,
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| med_config = 'configs/med_config.json',
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| image_size = 224,
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| vit = 'base',
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| vit_grad_ckpt = False,
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| vit_ckpt_layer = 0,
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| ):
|
| """
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| Args:
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| med_config (str): path for the mixture of encoder-decoder model's configuration file
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| image_size (int): input image size
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| vit (str): model size of vision transformer
|
| """
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| super().__init__()
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|
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| self.visual_encoder, vision_width = create_vit(vit,image_size, vit_grad_ckpt, vit_ckpt_layer)
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| self.tokenizer = init_tokenizer()
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| med_config = BertConfig.from_json_file(med_config)
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| med_config.encoder_width = vision_width
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| self.text_encoder = BertModel(config=med_config, add_pooling_layer=False)
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|
|
|
|
| def forward(self, image, caption, mode):
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|
|
| assert mode in ['image', 'text', 'multimodal'], "mode parameter must be image, text, or multimodal"
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| text = self.tokenizer(caption, return_tensors="pt").to(image.device)
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|
|
| if mode=='image':
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|
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| image_embeds = self.visual_encoder(image)
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| return image_embeds
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|
|
| elif mode=='text':
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|
|
| text_output = self.text_encoder(text.input_ids, attention_mask = text.attention_mask,
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| return_dict = True, mode = 'text')
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| return text_output.last_hidden_state
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|
|
| elif mode=='multimodal':
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|
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| image_embeds = self.visual_encoder(image)
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| image_atts = torch.ones(image_embeds.size()[:-1],dtype=torch.long).to(image.device)
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|
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| text.input_ids[:,0] = self.tokenizer.enc_token_id
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| output = self.text_encoder(text.input_ids,
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| attention_mask = text.attention_mask,
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| encoder_hidden_states = image_embeds,
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| encoder_attention_mask = image_atts,
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| return_dict = True,
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| )
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| return output.last_hidden_state
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|
|
|
|
|
|
| class BLIP_Decoder(nn.Module):
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| def __init__(self,
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| med_config = 'configs/med_config.json',
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| image_size = 384,
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| vit = 'base',
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| vit_grad_ckpt = False,
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| vit_ckpt_layer = 0,
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| prompt = 'a picture of ',
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| ):
|
| """
|
| 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)
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| self.tokenizer = init_tokenizer()
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| med_config = BertConfig.from_json_file(med_config)
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| med_config.encoder_width = vision_width
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| self.text_decoder = BertLMHeadModel(config=med_config)
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|
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| self.prompt = prompt
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| self.prompt_length = len(self.tokenizer(self.prompt).input_ids)-1
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|
|
|
|
| def forward(self, image, caption):
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|
|
| image_embeds = self.visual_encoder(image)
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| image_atts = torch.ones(image_embeds.size()[:-1],dtype=torch.long).to(image.device)
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|
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| text = self.tokenizer(caption, padding='longest', truncation=True, max_length=40, return_tensors="pt").to(image.device)
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|
|
| text.input_ids[:,0] = self.tokenizer.bos_token_id
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|
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| decoder_targets = text.input_ids.masked_fill(text.input_ids == self.tokenizer.pad_token_id, -100)
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| decoder_targets[:,:self.prompt_length] = -100
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|
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| decoder_output = self.text_decoder(text.input_ids,
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| attention_mask = text.attention_mask,
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| encoder_hidden_states = image_embeds,
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| encoder_attention_mask = image_atts,
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| labels = decoder_targets,
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| return_dict = True,
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| )
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| loss_lm = decoder_output.loss
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|
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| return loss_lm
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|
|
| def generate(self, image, sample=False, num_beams=3, max_length=30, min_length=10, top_p=0.9, repetition_penalty=1.0):
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| image_embeds = self.visual_encoder(image)
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|
|
| if not sample:
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| image_embeds = image_embeds.repeat_interleave(num_beams,dim=0)
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|
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| image_atts = torch.ones(image_embeds.size()[:-1],dtype=torch.long).to(image.device)
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| model_kwargs = {"encoder_hidden_states": image_embeds, "encoder_attention_mask":image_atts}
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|
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| prompt = [self.prompt] * image.size(0)
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| input_ids = self.tokenizer(prompt, return_tensors="pt").input_ids.to(image.device)
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| input_ids[:,0] = self.tokenizer.bos_token_id
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| input_ids = input_ids[:, :-1]
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|
|
| if sample:
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|
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| outputs = self.text_decoder.generate(input_ids=input_ids,
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| max_length=max_length,
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| min_length=min_length,
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| do_sample=True,
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| top_p=top_p,
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| num_return_sequences=1,
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| eos_token_id=self.tokenizer.sep_token_id,
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| pad_token_id=self.tokenizer.pad_token_id,
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| repetition_penalty=1.1,
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| **model_kwargs)
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| else:
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|
|
| outputs = self.text_decoder.generate(input_ids=input_ids,
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| max_length=max_length,
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| min_length=min_length,
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| num_beams=num_beams,
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| eos_token_id=self.tokenizer.sep_token_id,
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| pad_token_id=self.tokenizer.pad_token_id,
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| repetition_penalty=repetition_penalty,
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| **model_kwargs)
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|
|
| captions = []
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| for output in outputs:
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| caption = self.tokenizer.decode(output, skip_special_tokens=True)
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| captions.append(caption[len(self.prompt):])
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| return captions
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|
|
|
|
| def blip_decoder(pretrained='',**kwargs):
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| model = BLIP_Decoder(**kwargs)
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| if pretrained:
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| model,msg = load_checkpoint(model,pretrained)
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| assert(len(msg.missing_keys)==0)
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| return model
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|
|
| def blip_feature_extractor(pretrained='',**kwargs):
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| model = BLIP_Base(**kwargs)
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| if pretrained:
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| model,msg = load_checkpoint(model,pretrained)
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| assert(len(msg.missing_keys)==0)
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| return model
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|
|
| def init_tokenizer():
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| tokenizer_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), "bert_tokenizer")
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| tokenizer = BertTokenizer.from_pretrained(tokenizer_path)
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| tokenizer.add_special_tokens({'bos_token':'[DEC]'})
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| tokenizer.add_special_tokens({'additional_special_tokens':['[ENC]']})
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| tokenizer.enc_token_id = tokenizer.additional_special_tokens_ids[0]
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| return tokenizer
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|
|
|
|
| def create_vit(vit, image_size, use_grad_checkpointing=False, ckpt_layer=0, drop_path_rate=0):
|
|
|
| assert vit in ['base', 'large'], "vit parameter must be base or large"
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| if vit=='base':
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| vision_width = 768
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| visual_encoder = VisionTransformer(img_size=image_size, patch_size=16, embed_dim=vision_width, depth=12,
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| num_heads=12, use_grad_checkpointing=use_grad_checkpointing, ckpt_layer=ckpt_layer,
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| drop_path_rate=0 or drop_path_rate
|
| )
|
| elif vit=='large':
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| vision_width = 1024
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| visual_encoder = VisionTransformer(img_size=image_size, patch_size=16, embed_dim=vision_width, depth=24,
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| num_heads=16, use_grad_checkpointing=use_grad_checkpointing, ckpt_layer=ckpt_layer,
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| drop_path_rate=0.1 or drop_path_rate
|
| )
|
| return visual_encoder, vision_width
|
|
|
| def is_url(url_or_filename):
|
| parsed = urlparse(url_or_filename)
|
| return parsed.scheme in ("http", "https")
|
|
|
| def load_checkpoint(model,url_or_filename):
|
| if is_url(url_or_filename):
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| cached_file = download_cached_file(url_or_filename, check_hash=False, progress=True)
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| checkpoint = torch.load(cached_file, map_location='cpu')
|
| elif os.path.isfile(url_or_filename):
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| checkpoint = torch.load(url_or_filename, map_location='cpu')
|
| else:
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| raise RuntimeError('checkpoint url or path is invalid')
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|
|
| state_dict = checkpoint['model']
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|
|
| state_dict['visual_encoder.pos_embed'] = interpolate_pos_embed(state_dict['visual_encoder.pos_embed'],model.visual_encoder)
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| if 'visual_encoder_m.pos_embed' in model.state_dict().keys():
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| state_dict['visual_encoder_m.pos_embed'] = interpolate_pos_embed(state_dict['visual_encoder_m.pos_embed'],
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| model.visual_encoder_m)
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| for key in model.state_dict().keys():
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| if key in state_dict.keys():
|
| if state_dict[key].shape!=model.state_dict()[key].shape:
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| del state_dict[key]
|
|
|
| msg = model.load_state_dict(state_dict,strict=False)
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| print('load checkpoint from %s'%url_or_filename)
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| return model,msg
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|
|
|
|
