Attribution Methods¶
trulens.nn.attribution
¶
Attribution methods quantitatively measure the contribution of each of a function's individual inputs to its output. Gradientbased attribution methods compute the gradient of a model with respect to its inputs to describe how important each input is towards the output prediction. These methods can be applied to assist in explaining deep networks.
TruLens provides implementations of several such techniques, found in this package.
Classes¶
AttributionResult
dataclass
¶
_attribution method output container.
AttributionMethod
¶
Bases: ABC
Interface used by all attribution methods.
An attribution method takes a neural network model and provides the ability to assign values to the variables of the network that specify the importance of each variable towards particular predictions.
Attributes¶
Functions¶
__init__
abstractmethod
¶
__init__(
model: ModelWrapper,
rebatch_size: int = None,
*args,
**kwargs
)
Abstract constructor.
PARAMETER  DESCRIPTION 

model 
ModelWrapper Model for which attributions are calculated.
TYPE:

rebatch_size 
int (optional) Will rebatch instances to this size if given. This may be required for GPU usage if using a DoI which produces multiple instances per userprovided instance. Many valued DoIs will expand the tensors sent to each layer to original_batch_size * doi_size. The rebatch size will break up original_batch_size * doi_size into rebatch_size chunks to send to model.
TYPE:

attributions
¶
attributions(
*model_args: ArgsLike, **model_kwargs: KwargsLike
) > Union[
TensorLike,
ArgsLike[TensorLike],
ArgsLike[ArgsLike[TensorLike]],
]
Returns attributions for the given input. Attributions are in the same shape as the layer that attributions are being generated for.
The numeric scale of the attributions will depend on the specific implementations of the Distribution of Interest and Quantity of Interest. However it is generally related to the scale of gradients on the Quantity of Interest.
For example, Integrated Gradients uses the linear interpolation Distribution of Interest which subsumes the completeness axiom which ensures the sum of all attributions of a record equals the output determined by the Quantity of Interest on the same record.
The Point Distribution of Interest will be determined by the gradient at a single point, thus being a good measure of model sensitivity.
PARAMETER  DESCRIPTION 

model_args 
ArgsLike, model_kwargs: KwargsLike
The args and kwargs given to the call method of a model. This
should represent the records to obtain attributions for, assumed
to be a batched input. if
TYPE:

Returns  np.ndarray when single attribution_cut input, single qoi output  or ArgsLike[np.ndarray] when single input, multiple output (or vice versa)  or ArgsLike[ArgsLike[np.ndarray]] when multiple output (outer), multiple input (inner)
An array of attributions, matching the shape and type of `from_cut`
of the slice. Each entry in the returned array represents the degree
to which the corresponding feature affected the model's outcome on
the corresponding point.
If attributing to a component with multiple inputs, a list for each
will be returned.
If the quantity of interest features multiple outputs, a list for
each will be returned.
InternalInfluence
¶
Bases: AttributionMethod
Internal attributions parameterized by a slice, quantity of interest, and distribution of interest.
The slice specifies the layers at which the internals of the model are to be exposed; it is represented by two cuts, which specify the layer the attributions are assigned to and the layer from which the quantity of interest is derived. The Quantity of Interest (QoI) is a function of the output specified by the slice that determines the network output behavior that the attributions are to describe. The Distribution of Interest (DoI) specifies the records over which the attributions are aggregated.
More information can be found in the following paper:
InfluenceDirected Explanations for Deep Convolutional Networks
This should be cited using:
@INPROCEEDINGS{
leino18influence,
author={
Klas Leino and
Shayak Sen and
Anupam Datta and
Matt Fredrikson and
Linyi Li},
title={
InfluenceDirected Explanations
for Deep Convolutional Networks},
booktitle={IEEE International Test Conference (ITC)},
year={2018},
}
Functions¶
__init__
¶
__init__(
model: ModelWrapper,
cuts: SliceLike,
qoi: QoiLike,
doi: DoiLike,
multiply_activation: bool = True,
return_grads: bool = False,
return_doi: bool = False,
*args,
**kwargs
)
PARAMETER  DESCRIPTION 

model 
Model for which attributions are calculated.
TYPE:

cuts 
The slice to use when computing the attributions. The slice
keeps track of the layer whose output attributions are
calculated and the layer for which the quantity of interest is
computed. Expects a If a single A cut (or the cuts within the tuple) can also be represented as
an
TYPE:

qoi 
Quantity of interest to attribute. Expects a If an
If a tuple or list of two integers is given, then the quantity of interest is taken to be the comparative quantity for the class given by the first integer against the class given by the second integer, i.e.,
If a callable is given, it is interpreted as a function representing the QoI, i.e.,
If the string,
TYPE:

doi 
Distribution of interest over inputs. Expects a If the string,
If the string,
TYPE:

multiply_activation 
Whether to multiply the gradient result by its corresponding activation, thus converting from "influence space" to "attribution space."
TYPE:

InputAttribution
¶
Bases: InternalInfluence
Attributions of input features on either internal or output quantities. This is essentially an alias for
InternalInfluence(
model,
(trulens.nn.slices.InputCut(), cut),
qoi,
doi,
multiply_activation)
Functions¶
__init__
¶
__init__(
model: ModelWrapper,
qoi_cut: CutLike = None,
qoi: QoiLike = "max",
doi_cut: CutLike = None,
doi: DoiLike = "point",
multiply_activation: bool = True,
*args,
**kwargs
)
PARAMETER  DESCRIPTION 

model 
Model for which attributions are calculated.

qoi_cut 
The cut determining the layer from which the QoI is derived.
Expects a If an If a
DEFAULT:

qoi 
quantities.QoI  int  tuple  str
Quantity of interest to attribute. Expects a If an If a tuple or list of two integers is given, then the quantity of interest is taken to be the comparative quantity for the class given by the first integer against the class given by the second integer, i.e., ```python quantities.ComparativeQoI(*qoi)
If the string,
DEFAULT:

doi_cut 
For models which have nondifferentiable preprocessing at the start of the model, specify the cut of the initial differentiable input form. For NLP models, for example, this could point to the embedding layer. If not provided, InputCut is assumed.
DEFAULT:

doi 
distributions.DoI  str
Distribution of interest over inputs. Expects a If the string, If the string,
DEFAULT:

multiply_activation 
bool, optional Whether to multiply the gradient result by its corresponding activation, thus converting from "influence space" to "attribution space."
DEFAULT:

IntegratedGradients
¶
Bases: InputAttribution
Implementation for the Integrated Gradients method from the following paper:
Axiomatic Attribution for Deep Networks
This should be cited using:
@INPROCEEDINGS{
sundararajan17axiomatic,
author={Mukund Sundararajan and Ankur Taly, and Qiqi Yan},
title={Axiomatic Attribution for Deep Networks},
booktitle={International Conference on Machine Learning (ICML)},
year={2017},
}
This is essentially an alias for
InternalInfluence(
model,
(trulens.nn.slices.InputCut(), trulens.nn.slices.OutputCut()),
'max',
trulens.nn.distributions.LinearDoi(baseline, resolution),
multiply_activation=True)
Functions¶
__init__
¶
__init__(
model: ModelWrapper,
baseline=None,
resolution: int = 50,
doi_cut=None,
qoi="max",
qoi_cut=None,
*args,
**kwargs
)
PARAMETER  DESCRIPTION 

model 
Model for which attributions are calculated.
TYPE:

baseline 
The baseline to interpolate from. Must be same shape as the
input. If
DEFAULT:

resolution 
Number of points to use in the approximation. A higher resolution is more computationally expensive, but gives a better approximation of the mathematical formula this attribution method represents.
TYPE:
