JaccardIndex

ignite.metrics.JaccardIndex(cm, ignore_index=None)

Calculates the Jaccard Index using ConfusionMatrix metric. Implementation is based on IoU().

$$\text{J}(A, B) = \frac{ \lvert A \cap B \rvert }{ \lvert A \cup B \rvert }$$

Parameters:

• cm (ConfusionMatrix) – instance of confusion matrix metric

• ignore_index (int | None) – index to ignore, e.g. background index

Returns:

MetricsLambda

Return type:

MetricsLambda

Examples

train_evaluator = ...

cm = ConfusionMatrix(num_classes=num_classes)
JaccardIndex(cm, ignore_index=0).attach(train_evaluator, 'JaccardIndex')

state = train_evaluator.run(train_dataset)
# state.metrics['JaccardIndex'] -> tensor of shape (num_classes - 1, )