class BERTEncoder(nn.Module): def __init__(self, hidden_size, dropout, device): super(BERTEncoder, self).__init__() self.device = device # Load config and pre-trained model pre_trained_model = BertModel.from_pretrained( args['bert_model'], cache_dir=PYTORCH_PRETRAINED_BERT_CACHE / 'distributed_{}'.format(-1)) bert_config = pre_trained_model.config # modify config if you want bert_config.num_hidden_layers = args['num_bert_layers'] self.bert = BertModel(bert_config) # load desired layers from pre-trained model self.bert.load_state_dict(pre_trained_model.state_dict(), strict=False) self.proj = nn.Linear(bert_config.hidden_size, hidden_size) self.dropout = dropout self.dropout_layer = nn.Dropout(dropout) def forward(self, all_input_ids, all_input_mask, all_segment_ids, all_sub_word_masks): sequence_output, pooled_output = self.bert( all_input_ids, attention_mask=all_input_mask, token_type_ids=all_segment_ids) output = self.proj(sequence_output) hidden = self.proj(pooled_output) return output, hidden
class BertForMultiTaskClassification(BertPreTrainedModel): """ PyTorch BERT class for multitask learning. This model allows you to load in some pretrained tasks in addition to creating new ones. Examples -------- To instantiate a completely new instance of BertForMultiTaskClassification and load the weights into this architecture you can use the `from_pretrained` method of the base class by specifying the name of the weights to load, e.g.:: model = BertForMultiTaskClassification.from_pretrained( 'bert-base-uncased', new_task_dict=new_task_dict ) # DO SOME TRAINING model.save(SOME_FOLDER, SOME_MODEL_ID) To instantiate an instance of BertForMultiTaskClassification that has layers for pretrained tasks and new tasks, you would do the following:: model = BertForMultiTaskClassification.from_pretrained( 'bert-base-uncased', pretrained_task_dict=pretrained_task_dict, new_task_dict=new_task_dict ) model.load(SOME_FOLDER, SOME_MODEL_DICT) # DO SOME TRAINING Parameters ---------- config: json file Defines the BERT model architecture. Note: you will most likely be instantiating the class with the `from_pretrained` method so you don't need to come up with your own config. pretrained_task_dict: dict dictionary mapping each pretrained task to the number of labels it has new_task_dict: dict dictionary mapping each new task to the number of labels it has dropout: float dropout percentage for Dropout layer """ def __init__(self, config, pretrained_task_dict=None, new_task_dict=None, dropout=1e-1): super(BertForMultiTaskClassification, self).__init__(config) self.bert = BertModel(config) self.dropout = torch.nn.Dropout(dropout) if pretrained_task_dict is not None: pretrained_layers = {} for key, task_size in pretrained_task_dict.items(): pretrained_layers[key] = nn.Linear(config.hidden_size, task_size) self.pretrained_classifiers = nn.ModuleDict(pretrained_layers) if new_task_dict is not None: new_layers = {} for key, task_size in new_task_dict.items(): new_layers[key] = nn.Linear(config.hidden_size, task_size) self.new_classifiers = nn.ModuleDict(new_layers) def forward(self, tokenized_input): """ Defines forward pass for Bert model Parameters ---------- tokenized_input: torch tensor of integers integers represent tokens for each word Returns ---------- A dictionary mapping each task to its logits """ outputs = self.bert(tokenized_input) pooled_output = self.dropout(outputs[1]) logit_dict = {} if hasattr(self, 'pretrained_classifiers'): for key, classifier in self.pretrained_classifiers.items(): logit_dict[key] = classifier(pooled_output) if hasattr(self, 'new_classifiers'): for key, classifier in self.new_classifiers.items(): logit_dict[key] = classifier(pooled_output) return logit_dict def freeze_bert(self): """Freeze all core Bert layers""" for param in self.bert.parameters(): param.requires_grad = False def freeze_pretrained_classifiers_and_bert(self): """Freeze pretrained classifier layers and core Bert layers""" self.freeze_bert() if hasattr(self, 'pretrained_classifiers'): for param in self.pretrained_classifiers.parameters(): param.requires_grad = False else: print('There are no pretrained_classifier layers to be frozen.') def unfreeze_pretrained_classifiers(self): """Unfreeze pretrained classifier layers""" if hasattr(self, 'pretrained_classifiers'): for param in self.pretrained_classifiers.parameters(): param.requires_grad = True else: print('There are no pretrained_classifier layers to be unfrozen.') def unfreeze_pretrained_classifiers_and_bert(self): """Unfreeze pretrained classifiers and core Bert layers""" for param in self.bert.parameters(): param.requires_grad = True self.unfreeze_pretrained_classifiers() def save(self, folder, model_id): """ Saves the model state dicts to a specific folder. Each part of the model is saved separately to allow for new classifiers to be added later. Note: if the model has `pretrained_classifiers` and `new_classifers`, they will be combined into the `pretrained_classifiers_dict`. Parameters ---------- folder: str or Path place to store state dictionaries model_id: int unique id for this model Side Effects ------------ saves three files: - folder / f'bert_dict_{model_id}.pth' - folder / f'dropout_dict_{model_id}.pth' - folder / f'pretrained_classifiers_dict_{model_id}.pth' """ if hasattr(self, 'pretrained_classifiers'): # PyTorch's update method isn't working because it doesn't think ModuleDict is a Mapping classifiers_to_save = copy.deepcopy(self.pretrained_classifiers) if hasattr(self, 'new_classifiers'): for key, module in self.new_classifiers.items(): classifiers_to_save[key] = module else: classifiers_to_save = copy.deepcopy(self.new_classifiers) folder = Path(folder) folder.mkdir(parents=True, exist_ok=True) torch.save(self.bert.state_dict(), folder / f'bert_dict_{model_id}.pth') torch.save(self.dropout.state_dict(), folder / f'dropout_dict_{model_id}.pth') torch.save(classifiers_to_save.state_dict(), folder / f'pretrained_classifiers_dict_{model_id}.pth') def load(self, folder, model_id): """ Loads the model state dicts from a specific folder. Parameters ---------- folder: str or Path place where state dictionaries are stored model_id: int unique id for this model Side Effects ------------ loads from three files: - folder / f'bert_dict_{model_id}.pth' - folder / f'dropout_dict_{model_id}.pth' - folder / f'pretrained_classifiers_dict_{model_id}.pth' """ folder = Path(folder) if torch.cuda.is_available(): self.bert.load_state_dict( torch.load(folder / f'bert_dict_{model_id}.pth')) self.dropout.load_state_dict( torch.load(folder / f'dropout_dict_{model_id}.pth')) self.pretrained_classifiers.load_state_dict( torch.load(folder / f'pretrained_classifiers_dict_{model_id}.pth')) else: self.bert.load_state_dict( torch.load(folder / f'bert_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) self.dropout.load_state_dict( torch.load(folder / f'dropout_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) self.pretrained_classifiers.load_state_dict( torch.load(folder / f'pretrained_classifiers_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) def export(self, folder, model_id, model_name=None): """ Exports the entire model state dict to a specific folder. Note: if the model has `pretrained_classifiers` and `new_classifers`, they will be combined into the `pretrained_classifiers` attribute before being saved. Parameters ---------- folder: str or Path place to store state dictionaries model_id: int unique id for this model model_name: str (defaults to None) Name to store model under, if None, will default to `multi_task_bert_{model_id}.pth` Side Effects ------------ saves one file: - folder / model_name """ hold_new_classifiers = copy.deepcopy(self.new_classifiers) hold_pretrained_classifiers = None if not hasattr(self, 'pretrained_classifiers'): self.pretrained_classifiers = copy.deepcopy(self.new_classifiers) else: hold_pretrained_classifiers = copy.deepcopy( self.pretrained_classifiers) # PyTorch's update method isn't working because it doesn't think ModuleDict is a Mapping for key, module in self.new_classifiers.items(): self.pretrained_classifiers[key] = module del self.new_classifiers if model_name is None: model_name = f'multi_task_bert_{model_id}.pth' folder = Path(folder) folder.mkdir(parents=True, exist_ok=True) torch.save(self.state_dict(), folder / model_name) if hold_pretrained_classifiers is not None: self.pretrained_classifiers = hold_pretrained_classifiers else: del self.pretrained_classifiers self.new_classifiers = hold_new_classifiers def import_model(self, folder, file): """ Imports the entire model state dict from a specific folder. Note: to export a model based on the import_model from this method, use the export method Parameters ---------- folder: str or Path place to store state dictionaries file: str filename for the exported model object """ folder = Path(folder) self.load_state_dict(torch.load(folder / file))
class BertResnetEnsembleForMultiTaskClassification(nn.Module): """ PyTorch ensemble class for multitask learning consisting of a text and image models This model is made up of multiple component models: - for text: Google's BERT model - for images: multiple ResNet50's (the exact number depends on how the image model tasks were split up) You may need to train the component image and text models first before combining them into an ensemble model to get good results. Note: For explicitness, `vanilla` refers to the `transformers` BERT or `PyTorch` ResNet50 weights while `pretrained` refers to previously trained Tonks weights. Examples -------- The ensemble model should be used with pretrained BERT and ResNet50 component models. To initialize a model in this way:: image_task_dict = { 'color_pattern': { 'color': color_train_df['labels'].nunique(), 'pattern': pattern_train_df['labels'].nunique() }, 'dress_sleeve': { 'dress_length': dl_train_df['labels'].nunique(), 'sleeve_length': sl_train_df['labels'].nunique() }, 'season': { 'season': season_train_df['labels'].nunique() } } model = BertResnetEnsembleForMultiTaskClassification( image_task_dict=image_task_dict ) resnet_model_id_dict = { 'color_pattern': 'SOME_RESNET_MODEL_ID1', 'dress_sleeve': 'SOME_RESNET_MODEL_ID2', 'season': 'SOME_RESNET_MODEL_ID3' } model.load_core_models( folder='SOME_FOLDER', bert_model_id='SOME_BERT_MODEL_ID', resnet_model_id_dict=resnet_model_id_dict ) # DO SOME TRAINING model.save(SOME_FOLDER, SOME_MODEL_ID) # OR model.export(SOME_FOLDER, SOME_MODEL_ID) Parameters ---------- image_task_dict: dict dictionary mapping each pretrained ResNet50 models to a dictionary of the tasks it was trained on dropout: float dropout percentage for Dropout layer """ def __init__(self, image_task_dict=None, dropout=1e-1): super(BertResnetEnsembleForMultiTaskClassification, self).__init__() # Define text architecture config = BertConfig() self.bert = BertModel(config) self.dropout = torch.nn.Dropout(dropout) self.image_task_dict = image_task_dict self.text_task_dict = self.create_text_dict(image_task_dict) # Define image architecture image_resnets = {} image_dense_layers = {} ensemble_layers = {} for key in self.image_task_dict.keys(): resnet = torch_models.resnet50(pretrained=False) resnet.fc = _Identity() image_resnets[key] = resnet image_dense_layers[key] = nn.Sequential( _dense_block(2048 * 2, 1024, 2e-3), _dense_block(1024, 512, 2e-3), _dense_block(512, 256, 2e-3)) # Define final ensemble before classifier layers # The input is size 768 from BERT and 256 from ResNet50 models # so the total size is 1024 ensemble_layers[key] = nn.Sequential( _dense_block(1024, 512, 2e-3), _dense_block(512, 512, 2e-3), _dense_block(512, 256, 2e-3), ) self.image_resnets = nn.ModuleDict(image_resnets) self.image_dense_layers = nn.ModuleDict(image_dense_layers) self.ensemble_layers = nn.ModuleDict(ensemble_layers) pretrained_layers = {} for key, task_size in self.text_task_dict.items(): pretrained_layers[key] = nn.Linear(256, task_size) self.classifiers = nn.ModuleDict(pretrained_layers) def forward(self, x): """ Defines forward pass for ensemble model Parameters ---------- x: dict dictionary of torch tensors with keys: - `bert_text`: integers mapping to BERT vocabulary - `full_img`: tensor of full image - `crop_img`: tensor of cropped image Returns ---------- A dictionary mapping each task to its logits """ bert_output = self.bert(x['bert_text']) pooled_output = self.dropout(bert_output[1]) logit_dict = {} for key in self.image_task_dict.keys(): full_img = self.image_resnets[key](x['full_img']) crop_img = self.image_resnets[key](x['crop_img']) full_crop_combined = torch.cat((full_img, crop_img), 1) dense_layer_output = self.image_dense_layers[key]( full_crop_combined) ensemble_input = torch.cat((pooled_output, dense_layer_output), 1) ensemble_layer_output = self.ensemble_layers[key](ensemble_input) for task in self.image_task_dict[key].keys(): classifier = self.classifiers[task] logit_dict[task] = classifier(ensemble_layer_output) return logit_dict def freeze_bert(self): """Freeze all core BERT layers""" for param in self.bert.parameters(): param.requires_grad = False def freeze_resnets(self): """Freeze all core ResNet models layers""" for key in self.image_resnets.keys(): for param in self.image_resnets[key].parameters(): param.requires_grad = False for param in self.image_dense_layers[key].parameters(): param.requires_grad = False def freeze_ensemble_layers(self): """Freeze all final ensemble layers""" for key in self.ensemble_layers.keys(): for param in self.ensemble_layers[key].parameters(): param.requires_grad = False def freeze_classifiers_and_core(self): """Freeze pretrained classifier layers and core BERT/ResNet layers""" self.freeze_bert() self.freeze_resnets() self.freeze_ensemble_layers() for param in self.classifiers.parameters(): param.requires_grad = False def unfreeze_classifiers(self): """Unfreeze pretrained classifier layers""" for param in self.classifiers.parameters(): param.requires_grad = True def unfreeze_classifiers_and_core(self): """Unfreeze pretrained classifiers and core BERT/ResNet layers""" for param in self.bert.parameters(): param.requires_grad = True for key in self.image_resnets.keys(): for param in self.image_resnets[key].parameters(): param.requires_grad = True for param in self.image_dense_layers[key].parameters(): param.requires_grad = True for param in self.ensemble_layers[key].parameters(): param.requires_grad = True self.unfreeze_classifiers() def save(self, folder, model_id): """ Saves the model state dicts to a specific folder. Each part of the model is saved separately, along with the image_task_dict, which is needed to reinstantiate the model. Parameters ---------- folder: str or Path place to store state dictionaries model_id: int unique id for this model Side Effects ------------ saves six files: - folder / f'bert_dict_{model_id}.pth' - folder / f'dropout_dict_{model_id}.pth' - folder / f'image_resnets_dict_{model_id}.pth' - folder / f'image_dense_layers_dict_{model_id}.pth' - folder / f'ensemble_layers_dict_{model_id}.pth' - folder / f'classifiers_dict_{model_id}.pth' """ folder = Path(folder) folder.mkdir(parents=True, exist_ok=True) # BERT model torch.save(self.bert.state_dict(), folder / f'bert_dict_{model_id}.pth') torch.save(self.dropout.state_dict(), folder / f'dropout_dict_{model_id}.pth') # ResNet model(s) torch.save(self.image_resnets.state_dict(), folder / f'image_resnets_dict_{model_id}.pth') torch.save(self.image_dense_layers.state_dict(), folder / f'image_dense_layers_dict_{model_id}.pth') # Ensemble layers torch.save(self.ensemble_layers.state_dict(), folder / f'ensemble_layers_dict_{model_id}.pth') # Classifier layers torch.save(self.classifiers.state_dict(), folder / f'classifiers_dict_{model_id}.pth') # image_task_dict joblib.dump(self.image_task_dict, folder / f'image_task_dict_{model_id}.pickle') def load(self, folder, model_id): """ Loads the model state dicts for ensemble model from a specific folder. This will load all the model components including the final ensemble and existing pretrained `classifiers`. Parameters ---------- folder: str or Path place where state dictionaries are stored model_id: int unique id for this model Side Effects ------------ loads from six files: - folder / f'bert_dict_{model_id}.pth' - folder / f'dropout_dict_{model_id}.pth' - folder / f'image_resnets_dict_{model_id}.pth' - folder / f'dense_layers_dict_{model_id}.pth' - folder / f'ensemble_layers_dict_{model_id}.pth' - folder / f'classifiers_dict_{model_id}.pth' """ folder = Path(folder) if torch.cuda.is_available(): self.bert.load_state_dict( torch.load(folder / f'bert_dict_{model_id}.pth')) self.dropout.load_state_dict( torch.load(folder / f'dropout_dict_{model_id}.pth')) self.image_resnets.load_state_dict( torch.load(folder / f'image_resnets_dict_{model_id}.pth')) self.dense_layers.load_state_dict( torch.load(folder / f'image_dense_layers_dict_{model_id}.pth')) self.ensemble_layers.load_state_dict( torch.load(folder / f'ensemble_layers_dict_{model_id}.pth')) self.classifiers.load_state_dict( torch.load(folder / f'classifiers_dict_{model_id}.pth')) else: self.bert.load_state_dict( torch.load(folder / f'bert_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) self.dropout.load_state_dict( torch.load(folder / f'dropout_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) self.resnet.load_state_dict( torch.load(folder / f'image_resnets_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) self.dense_layers.load_state_dict( torch.load(folder / f'image_dense_layers_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) self.final_ensemble.load_state_dict( torch.load(folder / f'ensemble_layers_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) self.classifiers.load_state_dict( torch.load(folder / f'classifiers_dict_{model_id}.pth', map_location=lambda storage, loc: storage)) def load_core_models(self, folder, bert_model_id, resnet_model_id_dict): """ Loads the weights from pretrained BERT and ResNet50 Tonks models Does not load weights from the final ensemble and classifier layers. use case is for loading SR_pretrained component BERT and image model weights into a new ensemble model. Parameters ---------- folder: str or Path place where state dictionaries are stored bert_model_id: int unique id for pretrained BERT text model resnet_model_id: int unique id for pretrained image model Side Effects ------------ loads from four files: - folder / f'bert_dict_{bert_model_id}.pth' - folder / f'dropout_dict_{bert_model_id}.pth' - folder / f'resnet_dict_{resnet_model_id}.pth' - folder / f'dense_layers_dict_{resnet_model_id}.pth' """ folder = Path(folder) if torch.cuda.is_available(): self.bert.load_state_dict( torch.load(folder / f'bert_dict_{bert_model_id}.pth')) self.dropout.load_state_dict( torch.load(folder / f'dropout_dict_{bert_model_id}.pth')) for key, model_id in resnet_model_id_dict.items(): self.image_resnets[key].load_state_dict( torch.load(folder / f'resnet_dict_{model_id}.pth')) self.image_dense_layers[key].load_state_dict( torch.load(folder / f'dense_layers_dict_{model_id}.pth')) else: self.bert.load_state_dict( torch.load(folder / f'bert_dict_{bert_model_id}.pth', map_location=lambda storage, loc: storage)) self.dropout.load_state_dict( torch.load(folder / f'dropout_dict_{bert_model_id}.pth', map_location=lambda storage, loc: storage)) for key, model_id in resnet_model_id_dict.items(): self.image_resnets[key].load_state_dict( torch.load(folder / f'resnet_dict_{model_id}.pth'), map_location=lambda storage, loc: storage) self.image_dense_layers[key].load_state_dict( torch.load(folder / f'dense_layers_dict_{model_id}.pth'), map_location=lambda storage, loc: storage) def export(self, folder, model_id, model_name=None): """ Exports the entire model state dict to a specific folder, along with the image_task_dict, which is needed to reinstantiate the model. Parameters ---------- folder: str or Path place to store state dictionaries model_id: int unique id for this model model_name: str (defaults to None) Name to store model under, if None, will default to `multi_task_ensemble_{model_id}.pth` Side Effects ------------ saves two files: - folder / f'multi_task_ensemble_{model_id}.pth' - folder / f'image_task_dict_{model_id}.pickle' """ folder = Path(folder) folder.mkdir(parents=True, exist_ok=True) if model_name is None: model_name = f'multi_task_ensemble_{model_id}.pth' torch.save(self.state_dict(), folder / model_name) joblib.dump(self.image_task_dict, folder / f'image_task_dict_{model_id}.pickle') @staticmethod def create_text_dict(image_task_dict): """Create a task dict for the text model from the image task dict""" text_task_dict = {} for joint_task in image_task_dict.keys(): for task, task_size in image_task_dict[joint_task].items(): if task in text_task_dict.keys(): raise TonksError( 'Task {} is in multiple models. Each task can only be in one image model.' .format(task)) text_task_dict[task] = task_size return text_task_dict