lightning/pytorch_lightning/metrics/classification/auc.py

91 lines
3.1 KiB
Python

# Copyright The PyTorch Lightning team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Any, Callable, Optional
import torch
from pytorch_lightning.metrics.functional.auc import _auc_compute, _auc_update
from pytorch_lightning.metrics.metric import Metric
from pytorch_lightning.utilities import rank_zero_warn
class AUC(Metric):
r"""
Computes Area Under the Curve (AUC) using the trapezoidal rule
Forward accepts two input tensors that should be 1D and have the same number
of elements
Args:
reorder: AUC expects its first input to be sorted. If this is not the case,
setting this argument to ``True`` will use a stable sorting algorithm to
sort the input in decending order
compute_on_step:
Forward only calls ``update()`` and return None if this is set to False.
dist_sync_on_step:
Synchronize metric state across processes at each ``forward()``
before returning the value at the step.
process_group:
Specify the process group on which synchronization is called. default: None (which selects the entire world)
dist_sync_fn:
Callback that performs the allgather operation on the metric state. When ``None``, DDP
will be used to perform the allgather
"""
def __init__(
self,
reorder: bool = False,
compute_on_step: bool = True,
dist_sync_on_step: bool = False,
process_group: Optional[Any] = None,
dist_sync_fn: Callable = None,
):
super().__init__(
compute_on_step=compute_on_step,
dist_sync_on_step=dist_sync_on_step,
process_group=process_group,
dist_sync_fn=dist_sync_fn,
)
self.reorder = reorder
self.add_state("x", default=[], dist_reduce_fx=None)
self.add_state("y", default=[], dist_reduce_fx=None)
rank_zero_warn(
'Metric `AUC` will save all targets and predictions in buffer.'
' For large datasets this may lead to large memory footprint.'
)
def update(self, x: torch.Tensor, y: torch.Tensor):
"""
Update state with predictions and targets.
Args:
x: Predictions from model (probabilities, or labels)
y: Ground truth labels
"""
x, y = _auc_update(x, y)
self.x.append(x)
self.y.append(y)
def compute(self) -> torch.Tensor:
"""
Computes AUC based on inputs passed in to ``update`` previously.
"""
x = torch.cat(self.x, dim=0)
y = torch.cat(self.y, dim=0)
return _auc_compute(x, y, reorder=self.reorder)