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Source code for torch_uncertainty.metrics.classification.entropy

from typing import Any, Literal

import torch
from torchmetrics import Metric
from torchmetrics.utilities.data import dim_zero_cat


[docs]class Entropy(Metric): is_differentiable: bool = False higher_is_better: bool | None = None full_state_update: bool = False def __init__( self, reduction: Literal["mean", "sum", "none", None] = "mean", **kwargs: Any, ) -> None: """The Shannon Entropy Metric to estimate the confidence of a single model or the mean confidence across estimators. Args: reduction (str, optional): Determines how to reduce over the :math:`B`/batch dimension: - ``'mean'`` [default]: Averages score across samples - ``'sum'``: Sum score across samples - ``'none'`` or ``None``: Returns score per sample kwargs: Additional keyword arguments, see `Advanced metric settings <https://torchmetrics.readthedocs.io/en/stable/pages/overview.html#metric-kwargs>`_. Inputs: - ``probs``: :math:`(B, C)` or :math:`(B, N, C)` where :math:`B` is the batch size, :math:`C` is the number of classes and :math:`N` is the number of estimators. Note: A higher entropy means a lower confidence. Raises: ValueError: If :attr:`reduction` is not one of ``'mean'``, ``'sum'``, ``'none'`` or ``None``. """ super().__init__(**kwargs) allowed_reduction = ("sum", "mean", "none", None) if reduction not in allowed_reduction: raise ValueError( "Expected argument `reduction` to be one of ", f"{allowed_reduction} but got {reduction}", ) self.reduction = reduction if self.reduction in ["mean", "sum"]: self.add_state("values", default=torch.tensor(0.0), dist_reduce_fx="sum") else: self.add_state("values", default=[], dist_reduce_fx="cat") self.add_state("total", default=torch.tensor(0), dist_reduce_fx="sum")
[docs] def update(self, probs: torch.Tensor) -> None: """Update the current entropy with a new tensor of probabilities. Args: probs (torch.Tensor): Probabilities from the model. """ batch_size = probs.size(0) entropy = torch.special.entr(probs).sum(dim=-1) if len(probs.shape) == 3: entropy = entropy.mean(dim=1) if self.reduction is None or self.reduction == "none": self.values.append(entropy) else: self.values += entropy.sum() self.total += batch_size
[docs] def compute(self) -> torch.Tensor: """Computes Entropy based on inputs passed in to ``update`` previously. """ values = dim_zero_cat(self.values) if self.reduction == "sum": return values.sum(dim=-1) if self.reduction == "mean": return values.sum(dim=-1) / self.total # reduction is None or "none" return values