# Source code for catalyst.contrib.losses.iou

from typing import List
from functools import partial
import torch
from torch import nn
from catalyst.metrics.functional import iou
[docs]class IoULoss(nn.Module):
"""The intersection over union (Jaccard) loss.
IOULoss = 1 - iou score
iou score = intersection / union = tp / (tp + fp + fn)
"""
[docs] def __init__(
self,
class_dim: int = 1,
mode: str = "macro",
weights: List[float] = None,
eps: float = 1e-7,
):
"""
Args:
class_dim: indicates class dimention (K) for
``outputs`` and ``targets`` tensors (default = 1)
mode: class summation strategy. Must be one of ['micro', 'macro',
'weighted']. If mode='micro', classes are ignored, and metric
are calculated generally. If mode='macro', metric are
calculated per-class and than are averaged over all classes.
If mode='weighted', metric are calculated per-class and than
summed over all classes with weights.
weights: class weights(for mode="weighted")
eps: epsilon to avoid zero division
"""
super().__init__()
assert mode in ["micro", "macro", "weighted"]
self.loss_fn = partial(
iou, eps=eps, class_dim=class_dim, threshold=None, mode=mode, weights=weights
)
def forward(self, outputs: torch.Tensor, targets: torch.Tensor) -> torch.Tensor:
"""Calculates loss between ``logits`` and ``target`` tensors."""
iou_score = self.loss_fn(outputs, targets)
return 1 - iou_score
__all__ = ["IoULoss"]