import torch
import torch.nn as nn

class DiceLoss(nn.Module):
    """Dice Loss for segmentation"""
    def __init__(self, smooth=1.0):
        super().__init__()
        self.smooth = smooth

    def forward(self, inputs, targets):
        inputs = torch.sigmoid(inputs).view(-1)
        targets = targets.view(-1).float()
        intersection = (inputs * targets).sum()
        dice = (2. * intersection + self.smooth) / (inputs.sum() + targets.sum() + self.smooth)
        return 1 - dice