Jaccard¶
Jaccard index for binary multi-outputs.
The Jaccard index, or Jaccard similarity coefficient, defined as the size of the intersection divided by the size of the union of two label sets, is used to compare the set of predicted labels for a sample with the corresponding set of labels in y_true.
The Jaccard index may be a poor metric if there are no positives for some samples or labels. The Jaccard index is undefined if there are no true or predicted labels, this implementation will return a score of 0.0 if this is the case.
Parameters¶
-
cm (river.metrics.confusion.MultiLabelConfusionMatrix) – defaults to
NoneThis parameter allows sharing the same confusion matrix between multiple metrics. Sharing a confusion matrix reduces the amount of storage and computation time.
Attributes¶
-
bigger_is_better
Indicate if a high value is better than a low one or not.
-
requires_labels
-
sample_correction
Examples¶
>>> from river import metrics
>>> y_true = [
... {0: False, 1: True, 2: True},
... {0: True, 1: True, 2: False},
... ]
>>> y_pred = [
... {0: True, 1: True, 2: True},
... {0: True, 1: False, 2: False},
... ]
>>> jac = metrics.Jaccard()
>>> for yt, yp in zip(y_true, y_pred):
... jac = jac.update(yt, yp)
>>> jac
Jaccard: 0.583333
Methods¶
clone
Return a fresh estimator with the same parameters.
The clone has the same parameters but has not been updated with any data. This works by looking at the parameters from the class signature. Each parameter is either - recursively cloned if it's a River classes. - deep-copied via copy.deepcopy if not. If the calling object is stochastic (i.e. it accepts a seed parameter) and has not been seeded, then the clone will not be idempotent. Indeed, this method's purpose if simply to return a new instance with the same input parameters.
get
Return the current value of the metric.
revert
Revert the metric.
Parameters
- y_true (Dict[Union[str, int], Union[bool, str, int]])
- y_pred (Union[Dict[Union[str, int], Union[bool, str, int]], Dict[Union[str, int], Dict[Union[bool, str, int], float]]])
- sample_weight (numbers.Number) – defaults to
1.0 - correction – defaults to
None
update
Update the metric.
Parameters
- y_true (Dict[Union[str, int], Union[bool, str, int]])
- y_pred (Union[Dict[Union[str, int], Union[bool, str, int]], Dict[Union[str, int], Dict[Union[bool, str, int], float]]])
- sample_weight (numbers.Number) – defaults to
1.0
works_with
Indicates whether or not a metric can work with a given model.
Parameters
- model (river.base.estimator.Estimator)