art.estimators.encoding

Encoder API.

Mixin Base Class Encoder

class art.estimators.encoding.EncoderMixin

Mixin abstract base class defining functionality for encoders.

abstract property encoding_length

Returns the length of the encoding size output.

Returns

The length of the encoding size output.

TensorFlow Encoder

class art.estimators.encoding.TensorFlowEncoder(input_ph: tf.Placeholder, model: tf.Tensor, loss: Optional[tf.Tensor] = None, sess: Optional[tf.compat.v1.Session] = None, channels_first: bool = False, clip_values: Optional[CLIP_VALUES_TYPE] = None, preprocessing_defences: Optional[Union[Preprocessor, List[Preprocessor]]] = None, postprocessing_defences: Optional[Union[Postprocessor, List[Postprocessor]]] = None, preprocessing: PREPROCESSING_TYPE = (0, 1), feed_dict: Optional[Dict[Any, Any]] = None)

This class implements an encoder model using the TensorFlow framework.

__init__(input_ph: tf.Placeholder, model: tf.Tensor, loss: Optional[tf.Tensor] = None, sess: Optional[tf.compat.v1.Session] = None, channels_first: bool = False, clip_values: Optional[CLIP_VALUES_TYPE] = None, preprocessing_defences: Optional[Union[Preprocessor, List[Preprocessor]]] = None, postprocessing_defences: Optional[Union[Postprocessor, List[Postprocessor]]] = None, preprocessing: PREPROCESSING_TYPE = (0, 1), feed_dict: Optional[Dict[Any, Any]] = None)

Initialization specific to encoder estimator implementation in TensorFlow.

Parameters
  • input_ph – The input placeholder.

  • model – TensorFlow model, neural network or other.

  • loss – The loss function for which to compute gradients. This parameter is necessary when training the model and when computing gradients w.r.t. the loss function.

  • sess – Computation session.

  • channels_first (bool) – Set channels first or last.

  • clip_values – Tuple of the form (min, max) of floats or np.ndarray representing the minimum and maximum values allowed for features. If floats are provided, these will be used as the range of all features. If arrays are provided, each value will be considered the bound for a feature, thus the shape of clip values needs to match the total number of features.

  • preprocessing_defences – Preprocessing defence(s) to be applied by the classifier.

  • postprocessing_defences – Postprocessing defence(s) to be applied by the classifier.

  • preprocessing – Tuple of the form (subtrahend, divisor) of floats or np.ndarray of values to be used for data preprocessing. The first value will be subtracted from the input. The input will then be divided by the second one.

  • feed_dict – A feed dictionary for the session run evaluating the classifier. This dictionary includes all additionally required placeholders except the placeholders defined in this class.

property channel_index
Returns

Index of the axis containing the color channels in the samples x.

property channels_first
Returns

Boolean to indicate index of the color channels in the sample x.

property clip_values

Return the clip values of the input samples.

Returns

Clip values (min, max).

property encoding_length

Returns the length of the encoding size output.

Returns

The length of the encoding size output.

fit(x: np.ndarray, y: np.ndarray, batch_size: int = 128, nb_epochs: int = 10, **kwargs) → None

Do nothing.

fit_generator(generator: DataGenerator, nb_epochs: int = 20, **kwargs) → None

Fit the estimator using a generator yielding training batches. Implementations can provide framework-specific versions of this function to speed-up computation.

Parameters
  • generator – Batch generator providing (x, y) for each epoch.

  • nb_epochs (int) – Number of training epochs.

get_activations(x: np.ndarray, layer: Union[int, str], batch_size: int, framework: bool = False) → np.ndarray

Do nothing.

get_params() → Dict[str, Any]

Get all parameters and their values of this estimator.

Returns

A dictionary of string parameter names to their value.

property input_shape

Return the shape of one input sample.

Returns

Shape of one input sample.

property layer_names

Return the names of the hidden layers in the model, if applicable.

Returns

The names of the hidden layers in the model, input and output layers are ignored.

Warning

layer_names tries to infer the internal structure of the model. This feature comes with no guarantees on the correctness of the result. The intended order of the layers tries to match their order in the model, but this is not guaranteed either.

property learning_phase

The learning phase set by the user. Possible values are True for training or False for prediction and None if it has not been set by the library. In the latter case, the library does not do any explicit learning phase manipulation and the current value of the backend framework is used. If a value has been set by the user for this property, it will impact all following computations for model fitting, prediction and gradients.

Returns

Learning phase.

loss(x: np.ndarray, y: np.ndarray, **kwargs) → np.ndarray

Compute the loss of the neural network for samples x.

Parameters
  • x – Samples of shape (nb_samples, nb_features) or (nb_samples, nb_pixels_1, nb_pixels_2, nb_channels) or (nb_samples, nb_channels, nb_pixels_1, nb_pixels_2).

  • y – Target values (class labels) one-hot-encoded of shape (nb_samples, nb_classes) or indices of shape (nb_samples,).

Returns

Loss values.

Return type

Format as expected by the model

loss_gradient(x: np.ndarray, y: np.ndarray, **kwargs) → np.ndarray

No gradients to compute for this method; do nothing.

property model

Return the model.

Returns

The model.

predict(x: np.ndarray, batch_size: int = 128, **kwargs)

Perform prediction for a batch of inputs.

Parameters
  • x – Test set.

  • batch_size (int) – Batch size.

Returns

Array of encoding predictions of shape (num_inputs, encoding_length).

property sess

Get current TensorFlow session.

Returns

The current TensorFlow session.

set_learning_phase(train: bool) → None

Do nothing.

set_params(**kwargs) → None

Take a dictionary of parameters and apply checks before setting them as attributes.

Parameters

kwargs – A dictionary of attributes.