Multilabelrecallatfixedprecision

multilabelrecallatfixedprecision

Metric MultilabelRecallAtFixedPrecision from torchmetrics (torchmetrics.classification.MultilabelRecallAtFixedPrecision)

When to invoke this skill

The user has predictions + ground truth and asks to evaluate with MultilabelRecallAtFixedPrecision, or mentions torchmetrics.classification.MultilabelRecallAtFixedPrecision directly, or wants the standard torchmetrics implementation.

Reference signature

from torchmetrics.classification import MultilabelRecallAtFixedPrecision

# MultilabelRecallAtFixedPrecision(num_labels: int, min_precision: float, thresholds: Union[int, list[float], torch.Tensor, NoneType] = None, ignore_index: Optional[int] = None, validate_args: bool = True, **kwargs: Any) -> None

Library docstring

Compute the highest possible recall value given the minimum precision thresholds provided.

This is done by first calculating the precision-recall curve for different thresholds and the find the recall for
a given precision level.

As input to ``forward`` and ``update`` the metric accepts the following input:

- ``preds`` (:class:`~torch.Tensor`): A float tensor of shape ``(N, C, ...)``. Preds should be a tensor
  containing probabilities or logits for each observation. If preds has values outside [0,1] range we consider
  the input to be logits and will auto apply sigmoid per element.
- ``target`` (:class:`~torch.Tensor`): An int tensor of shape ``(N, ...)``. Target should be a tensor containing
  ground truth labels, and therefore only contain {0,1} values (except if `ignore_index` is specified). The value
  1 always encodes the positive class.

.. tip::
   Additional dimension ``...`` will be flattened into the batch dimension.

As output to ``forward`` and ``compute`` the metric returns a tuple of either 2 tensors or 2 lists containing:

- ``recall`` (:class:`~torch.Tensor`): A 1d tensor of size ``(n_classes, )`` with the maximum recall for the
  given precision level per class
- ``threshold`` (:class:`~torch.Tensor`): A 1d tensor of size ``(n_classes, )`` with the corresponding threshold
  level per class

.. note::
   The implementation both supports calculating the metric in a non-binned but accurate version and a binned version
   that is less accurate but more memory efficient. Setting the `thresholds` argument to ```None``` will activate
   the non-binned  version that uses memory of size :math:`\mathcal{O}(n_{samples})` whereas setting the
   `thresholds` argument to either an integer, list or a 1d tensor will use a binned version that uses memory of
   size :math:`\mathcal{O}(n_{thresholds} \times n_{labels})` (constant memory).

Args:
    num_labels: Integer specifying the number of labels
    min_precision: float value specifying minimum precision threshold.
    thresholds:
        Can be one of:

        - If set to ``None``, will use a non-binned approach where thresholds are dynamically calculated from
          all the data. Most accurate but a

Quick recipe

import torchmetrics.classification as _m
score = _m.MultilabelRecallAtFixedPrecision(y_true, y_pred)

Don'ts

• Don't reimplement when the library version handles edge cases (NaN, ties, empty inputs) better than a hand-rolled formula.
• Always check the library version's argument order — sklearn is (y_true, y_pred) while torchmetrics is (preds, target).