Source code for torch_uncertainty.metrics.classification.categorical_nll
from typing import Any, Literal
import torch
import torch.nn.functional as F
from torch import Tensor
from torchmetrics import Metric
from torchmetrics.utilities.data import dim_zero_cat
[docs]class CategoricalNLL(Metric):
is_differentiable = False
higher_is_better = False
full_state_update = False
def __init__(
self,
reduction: Literal["mean", "sum", "none", None] = "mean",
**kwargs: Any,
) -> None:
"""The Negative Log Likelihood Metric.
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:
- :attr:`probs`: :math:`(B, C)`
- :attr:`target`: :math:`(B)`
where :math:`B` is the batch size and :math:`C` is the number of
classes.
Warning:
Make sure that the probabilities in :attr:`probs` are normalized to sum
to one.
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: Tensor, target: Tensor) -> None:
"""Update state with prediction probabilities and targets.
Args:
probs (Tensor): Probabilities from the model.
target (Tensor): Ground truth labels.
"""
if self.reduction is None or self.reduction == "none":
self.values.append(
F.nll_loss(torch.log(probs), target, reduction="none")
)
else:
self.values += F.nll_loss(torch.log(probs), target, reduction="sum")
self.total += target.size(0)
[docs] def compute(self) -> Tensor:
"""Computes NLL 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