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Classwise Wrapper

Module Interface

class torchmetrics.ClasswiseWrapper(metric, labels=None)[source]

Wrapper class for altering the output of classification metrics that returns multiple values to include label information.

Parameters
  • metric (Metric) – base metric that should be wrapped. It is assumed that the metric outputs a single tensor that is split along the first dimension.

  • labels (Optional[List[str]]) – list of strings indicating the different classes.

Example

>>> import torch
>>> _ = torch.manual_seed(42)
>>> from torchmetrics import Accuracy, ClasswiseWrapper
>>> metric = ClasswiseWrapper(Accuracy(num_classes=3, average=None))
>>> preds = torch.randn(10, 3).softmax(dim=-1)
>>> target = torch.randint(3, (10,))
>>> metric(preds, target)
{'accuracy_0': tensor(0.5000), 'accuracy_1': tensor(0.7500), 'accuracy_2': tensor(0.)}
Example (labels as list of strings):
>>> import torch
>>> from torchmetrics import Accuracy, ClasswiseWrapper
>>> metric = ClasswiseWrapper(
...    Accuracy(num_classes=3, average=None),
...    labels=["horse", "fish", "dog"]
... )
>>> preds = torch.randn(10, 3).softmax(dim=-1)
>>> target = torch.randint(3, (10,))
>>> metric(preds, target)
{'accuracy_horse': tensor(0.3333), 'accuracy_fish': tensor(0.6667), 'accuracy_dog': tensor(0.)}
Example (in metric collection):
>>> import torch
>>> from torchmetrics import Accuracy, ClasswiseWrapper, MetricCollection, Recall
>>> labels = ["horse", "fish", "dog"]
>>> metric = MetricCollection(
...     {'accuracy': ClasswiseWrapper(Accuracy(num_classes=3, average=None), labels),
...     'recall': ClasswiseWrapper(Recall(num_classes=3, average=None), labels)}
... )
>>> preds = torch.randn(10, 3).softmax(dim=-1)
>>> target = torch.randint(3, (10,))
>>> metric(preds, target)  
{'accuracy_horse': tensor(0.), 'accuracy_fish': tensor(0.3333), 'accuracy_dog': tensor(0.4000),
'recall_horse': tensor(0.), 'recall_fish': tensor(0.3333), 'recall_dog': tensor(0.4000)}

Initializes internal Module state, shared by both nn.Module and ScriptModule.

compute()[source]

Override this method to compute the final metric value from state variables synchronized across the distributed backend.

Return type

Dict[str, Tensor]

update(*args, **kwargs)[source]

Override this method to update the state variables of your metric class.

Return type

None