foolbox.models
¶
Provides classes to wrap existing models in different framworks so that they provide a unified API to the attacks.
Models¶
Model 
Base class to provide attacks with a unified interface to models. 
DifferentiableModel 
Base class for differentiable models that provide gradients. 
TensorFlowModel 
Creates a Model instance from existing TensorFlow tensors. 
TensorFlowEagerModel 
Creates a Model instance from a TensorFlow model using eager execution. 
PyTorchModel 
Creates a Model instance from a PyTorch module. 
KerasModel 
Creates a Model instance from a Keras model. 
TheanoModel 
Creates a Model instance from existing Theano tensors. 
LasagneModel 
Creates a Model instance from a Lasagne network. 
MXNetModel 
Creates a Model instance from existing MXNet symbols and weights. 
MXNetGluonModel 
Creates a Model instance from an existing MXNet Gluon Block. 
Wrappers¶
ModelWrapper 
Base class for models that wrap other models. 
DifferentiableModelWrapper 
Base class for models that wrap other models and provide gradient methods. 
ModelWithoutGradients 
Turns a model into a model without gradients. 
ModelWithEstimatedGradients 
Turns a model into a model with gradients estimated by the given gradient estimator. 
CompositeModel 
Combines predictions of a (blackbox) model with the gradient of a (substitute) model. 
Detailed description¶

class
foolbox.models.
Model
(bounds, channel_axis, preprocessing=(0, 1))[source]¶ Base class to provide attacks with a unified interface to models.
The
Model
class represents a model and provides a unified interface to its predictions. Subclasses must implement batch_predictions and num_classes.Model
instances can be used as context managers and subclasses can require this to allocate and release resources.Parameters:  bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

class
foolbox.models.
DifferentiableModel
(bounds, channel_axis, preprocessing=(0, 1))[source]¶ Base class for differentiable models that provide gradients.
The
DifferentiableModel
class can be used as a base class for models that provide gradients. Subclasses must implement predictions_and_gradient.A model should be considered differentiable based on whether it provides a
predictions_and_gradient()
method and agradient()
method, not based on whether it subclassesDifferentiableModel
.A differentiable model does not necessarily provide reasonable values for the gradients, the gradient can be wrong. It only guarantees that the relevant methods can be called.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also

gradient
(image, label)[source]¶ Calculates the gradient of the crossentropy loss w.r.t. the image.
The default implementation calls predictions_and_gradient. Subclasses can provide more efficient implementations that only calculate the gradient.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also


class
foolbox.models.
TensorFlowModel
(images, logits, bounds, channel_axis=3, preprocessing=(0, 1))[source]¶ Creates a
Model
instance from existing TensorFlow tensors.Parameters:  images : tensorflow.Tensor
The input to the model, usually a tensorflow.placeholder.
 logits : tensorflow.Tensor
The predictions of the model, before the softmax.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

classmethod
from_keras
(model, bounds, input_shape=None, channel_axis=3, preprocessing=(0, 1))[source]¶ Alternative constructor for a TensorFlowModel that accepts a tf.keras.Model instance.
Parameters:  model : tensorflow.keras.Model
A tensorflow.keras.Model that accepts a single input tensor and returns a single output tensor representing logits.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 input_shape : tuple
The shape of a single input, e.g. (28, 28, 1) for MNIST. If None, tries to get the the shape from the model’s input_shape attribute.
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

gradient
(image, label)[source]¶ Calculates the gradient of the crossentropy loss w.r.t. the image.
The default implementation calls predictions_and_gradient. Subclasses can provide more efficient implementations that only calculate the gradient.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

class
foolbox.models.
TensorFlowEagerModel
(model, bounds, num_classes=None, channel_axis=3, preprocessing=(0, 1))[source]¶ Creates a
Model
instance from a TensorFlow model using eager execution.Parameters:  model : a TensorFlow eager model
The TensorFlow eager model that should be attacked. It will be called with input tensors and should return logits.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 num_classes : int
If None, will try to infer it from the model’s output shape.
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also
gradient()

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also
gradient()

class
foolbox.models.
PyTorchModel
(model, bounds, num_classes, channel_axis=1, device=None, preprocessing=(0, 1))[source]¶ Creates a
Model
instance from a PyTorch module.Parameters:  model : torch.nn.Module
The PyTorch model that should be attacked.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 num_classes : int
Number of classes for which the model will output predictions.
 channel_axis : int
The index of the axis that represents color channels.
 device : string
A string specifying the device to do computation on. If None, will default to “cuda:0” if torch.cuda.is_available() or “cpu” if not.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also
gradient()

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also
gradient()

class
foolbox.models.
KerasModel
(model, bounds, channel_axis=3, preprocessing=(0, 1), predicts='probabilities')[source]¶ Creates a
Model
instance from a Keras model.Parameters:  model : keras.models.Model
The Keras model that should be attacked.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.
 predicts : str
Specifies whether the Keras model predicts logits or probabilities. Logits are preferred, but probabilities are the default.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also
gradient()

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also
gradient()

class
foolbox.models.
TheanoModel
(images, logits, bounds, num_classes, channel_axis=1, preprocessing=[0, 1])[source]¶ Creates a
Model
instance from existing Theano tensors.Parameters:  images : theano.tensor
The input to the model.
 logits : theano.tensor
The predictions of the model, before the softmax.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 num_classes : int
Number of classes for which the model will output predictions.
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

gradient
(image, label)[source]¶ Calculates the gradient of the crossentropy loss w.r.t. the image.
The default implementation calls predictions_and_gradient. Subclasses can provide more efficient implementations that only calculate the gradient.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

class
foolbox.models.
LasagneModel
(input_layer, logits_layer, bounds, channel_axis=1, preprocessing=(0, 1))[source]¶ Creates a
Model
instance from a Lasagne network.Parameters:  input_layer : lasagne.layers.Layer
The input to the model.
 logits_layer : lasagne.layers.Layer
The output of the model, before the softmax.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

gradient
(image, label)[source]¶ Calculates the gradient of the crossentropy loss w.r.t. the image.
The default implementation calls predictions_and_gradient. Subclasses can provide more efficient implementations that only calculate the gradient.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

class
foolbox.models.
MXNetModel
(data, logits, args, ctx, num_classes, bounds, channel_axis=1, aux_states=None, preprocessing=(0, 1))[source]¶ Creates a
Model
instance from existing MXNet symbols and weights.Parameters:  data : mxnet.symbol.Variable
The input to the model.
 logits : mxnet.symbol.Symbol
The predictions of the model, before the softmax.
 args : dictionary mapping str to mxnet.nd.array
The parameters of the model.
 ctx : mxnet.context.Context
The device, e.g. mxnet.cpu() or mxnet.gpu().
 num_classes : int
The number of classes.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 channel_axis : int
The index of the axis that represents color channels.
 aux_states : dictionary mapping str to mxnet.nd.array
The states of auxiliary parameters of the model.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also
gradient()

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also
gradient()

class
foolbox.models.
MXNetGluonModel
(block, bounds, num_classes, ctx=None, channel_axis=1, preprocessing=(0, 1))[source]¶ Creates a
Model
instance from an existing MXNet Gluon Block.Parameters:  block : mxnet.gluon.Block
The Gluon Block representing the model to be run.
 ctx : mxnet.context.Context
The device, e.g. mxnet.cpu() or mxnet.gpu().
 num_classes : int
The number of classes.
 bounds : tuple
Tuple of lower and upper bound for the pixel values, usually (0, 1) or (0, 255).
 channel_axis : int
The index of the axis that represents color channels.
 preprocessing: 2element tuple with floats or numpy arrays
Elementwises preprocessing of input; we first subtract the first element of preprocessing from the input and then divide the input by the second element.

backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also
gradient()

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also
gradient()

class
foolbox.models.
ModelWrapper
(model)[source]¶ Base class for models that wrap other models.
This base class can be used to implement model wrappers that turn models into new models, for example by preprocessing the input or modifying the gradient.
Parameters:  model :
Model
The model that is wrapped.

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.
 model :

class
foolbox.models.
DifferentiableModelWrapper
(model)[source]¶ Base class for models that wrap other models and provide gradient methods.
This base class can be used to implement model wrappers that turn models into new models, for example by preprocessing the input or modifying the gradient.
Parameters:  model :
Model
The model that is wrapped.
 model :

class
foolbox.models.
ModelWithoutGradients
(model)[source]¶ Turns a model into a model without gradients.

class
foolbox.models.
ModelWithEstimatedGradients
(model, gradient_estimator)[source]¶ Turns a model into a model with gradients estimated by the given gradient estimator.
Parameters:  model :
Model
The model that is wrapped.
 gradient_estimator : callable
Callable taking three arguments (pred_fn, image, label) and returning the estimated gradients. pred_fn will be the batch_predictions method of the wrapped model.
 model :

class
foolbox.models.
CompositeModel
(forward_model, backward_model)[source]¶ Combines predictions of a (blackbox) model with the gradient of a (substitute) model.
Parameters: 
backward
(gradient, image)[source]¶ Backpropagates the gradient of some loss w.r.t. the logits through the network and returns the gradient of that loss w.r.t to the input image.
Parameters:  gradient : numpy.ndarray
Gradient of some loss w.r.t. the logits.
 image : numpy.ndarray
Image with shape (height, width, channels).
Returns:  gradient : numpy.ndarray
The gradient w.r.t the image.
See also

batch_predictions
(images)[source]¶ Calculates predictions for a batch of images.
Parameters:  images : numpy.ndarray
Batch of images with shape (batch size, height, width, channels).
Returns:  `numpy.ndarray`
Predictions (logits, i.e. before the softmax) with shape (batch size, number of classes).
See also
predictions()

gradient
(image, label)[source]¶ Calculates the gradient of the crossentropy loss w.r.t. the image.
The default implementation calls predictions_and_gradient. Subclasses can provide more efficient implementations that only calculate the gradient.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also

num_classes
()[source]¶ Determines the number of classes.
Returns:  int
The number of classes for which the model creates predictions.

predictions_and_gradient
(image, label)[source]¶ Calculates predictions for an image and the gradient of the crossentropy loss w.r.t. the image.
Parameters:  image : numpy.ndarray
Image with shape (height, width, channels).
 label : int
Reference label used to calculate the gradient.
Returns:  predictions : numpy.ndarray
Vector of predictions (logits, i.e. before the softmax) with shape (number of classes,).
 gradient : numpy.ndarray
The gradient of the crossentropy loss w.r.t. the image. Will have the same shape as the image.
See also
