The CallbackTrainer should be considered experimental code. Its API may change at any time, and it may disappear altogether.

class allennlp.models.model.Model, training_data: Iterable[], iterator:, optimizer: torch.optim.optimizer.Optimizer, num_epochs: int = 20, shuffle: bool = True, serialization_dir: Optional[str] = None, cuda_device: Union[int, List] = -1, callbacks: List[] = None)[source]


batch_loss(self, batch_group:List[Dict[str, Union[torch.Tensor, Dict[str, torch.Tensor]]]], for_training:bool) → torch.Tensor[source]

Does a forward pass on the given batches and returns the loss value in the result. If for_training is True also applies regularization penalty.

This is a method on the trainer so that it can be used both in training and validation (which are handled separately).

classmethod from_params(params:allennlp.common.params.Params, serialization_dir:str, recover:bool=False, cache_directory:str=None, cache_prefix:str=None) → 'CallbackTrainer'[source]

This is the automatic implementation of from_params. Any class that subclasses FromParams (or Registrable, which itself subclasses FromParams) gets this implementation for free. If you want your class to be instantiated from params in the “obvious” way – pop off parameters and hand them to your constructor with the same names – this provides that functionality.

If you need more complex logic in your from from_params method, you’ll have to implement your own method that overrides this one.


Generates one epoch worth of training data. Stores it in trainer instance variables so that callbacks can access it.

train(self) → Dict[str, Any][source]

Trains the supplied model with the supplied parameters. Fires off the events TRAINING_START and TRAINING END, and repeatedly calls self.train_one_epoch().

train_one_batch_group(self, batch_group:List[Dict[str, Union[torch.Tensor, Dict[str, torch.Tensor]]]]) → str[source]

Handles the training for a single batch group. Fires off the events BATCH_START, FORWARD, BACKWARD, and BATCH_END.

train_one_epoch(self) → None[source]

Trains the model for a single epoch. Fires off the events EPOCH_START and EPOCH_END, and repeatedly calls self.train_one_batch_group().