Version: 2.x

rasa.core.policies.ted_policy

TEDPolicy Objects

class TEDPolicy(Policy)

Transformer Embedding Dialogue (TED) Policy.

The model architecture is described in detail in https://arxiv.org/abs/1910.00486. In summary, the architecture comprises of the following steps:

- concatenate user input (user intent and entities), previous system actions,
slots and active forms for each time step into an input vector to
pre-transformer embedding layer;
- feed it to transformer;
- apply a dense layer to the output of the transformer to get embeddings of a
dialogue for each time step;
- apply a dense layer to create embeddings for system actions for each time
step;
- calculate the similarity between the dialogue embedding and embedded system
actions. This step is based on the StarSpace
(https://arxiv.org/abs/1709.03856) idea.

__init__

| __init__(featurizer: Optional[TrackerFeaturizer] = None, priority: int = DEFAULT_POLICY_PRIORITY, max_history: Optional[int] = None, model: Optional[RasaModel] = None, fake_features: Optional[Dict[Text, List["Features"]]] = None, entity_tag_specs: Optional[List[EntityTagSpec]] = None, should_finetune: bool = False, **kwargs: Any, ,) -> None

Declares instance variables with default values.

model_class

| @staticmethod
| model_class() -> Type["TED"]

Gets the class of the model architecture to be used by the policy.

Returns:

Required class.

run_training

| run_training(model_data: RasaModelData, label_ids: Optional[np.ndarray] = None) -> None

Feeds the featurized training data to the model.

Arguments:

  • model_data - Featurized training data.
  • label_ids - Label ids corresponding to the data points in model_data. These may or may not be used by the function depending on how the policy is trained.

train

| train(training_trackers: List[TrackerWithCachedStates], domain: Domain, interpreter: NaturalLanguageInterpreter, **kwargs: Any, ,) -> None

Trains the policy on given training trackers.

Arguments:

  • training_trackers - List of training trackers to be used for training the model.
  • domain - Domain of the assistant.
  • interpreter - NLU Interpreter to be used for featurizing the states.
  • **kwargs - Any other argument.

predict_action_probabilities

| predict_action_probabilities(tracker: DialogueStateTracker, domain: Domain, interpreter: NaturalLanguageInterpreter, **kwargs: Any, ,) -> PolicyPrediction

Predicts the next action the bot should take after seeing the tracker.

Arguments:

  • tracker - the :class:rasa.core.trackers.DialogueStateTracker
  • domain - the :class:rasa.shared.core.domain.Domain
  • interpreter - Interpreter which may be used by the policies to create additional features.

Returns:

The policy's prediction (e.g. the probabilities for the actions).

persist

| persist(path: Union[Text, Path]) -> None

Persists the policy to a storage.

persist_model_utilities

| persist_model_utilities(model_path: Path) -> None

Persists model's utility attributes like model weights, etc.

Arguments:

  • model_path - Path where model is to be persisted

load

| @classmethod
| load(cls, path: Union[Text, Path], should_finetune: bool = False, epoch_override: int = defaults[EPOCHS], **kwargs: Any, ,) -> "TEDPolicy"

Loads a policy from the storage.

Arguments:

  • path - Path on disk where policy is persisted.
  • should_finetune - Whether to load the policy for finetuning.
  • epoch_override - Override the number of epochs in persisted configuration for further finetuning.
  • **kwargs - Any other arguments

Returns:

Loaded policy

Raises:

PolicyModelNotFound if the model is not found in the supplied path.

TED Objects

class TED(TransformerRasaModel)

TED model architecture from https://arxiv.org/abs/1910.00486.

__init__

| __init__(data_signature: Dict[Text, Dict[Text, List[FeatureSignature]]], config: Dict[Text, Any], max_history_featurizer_is_used: bool, label_data: RasaModelData, entity_tag_specs: Optional[List[EntityTagSpec]]) -> None

Intializes the TED model.

Arguments:

  • data_signature - the data signature of the input data
  • config - the model configuration
  • max_history_featurizer_is_used - if 'True' only the last dialogue turn will be used
  • label_data - the label data
  • entity_tag_specs - the entity tag specifications

batch_loss

| batch_loss(batch_in: Union[Tuple[tf.Tensor], Tuple[np.ndarray]]) -> tf.Tensor

Calculates the loss for the given batch.

Arguments:

  • batch_in - The batch.

Returns:

The loss of the given batch.

prepare_for_predict

| prepare_for_predict() -> None

Prepares the model for prediction.

batch_predict

| batch_predict(batch_in: Union[Tuple[tf.Tensor], Tuple[np.ndarray]]) -> Dict[Text, Union[tf.Tensor, Dict[Text, tf.Tensor]]]

Predicts the output of the given batch.

Arguments:

  • batch_in - The batch.

Returns:

The output to predict.