import torch

class diceloss(torch.nn.Module):

    def init(self):
        super(diceloss, self).init()

    def forward(self, pred, target):
        smooth = 1
        iflat = pred.contiguous().view(-1)
        tflat = target.contiguous().view(-1)
        intersection = (iflat * tflat).sum()
        A_sum = torch.sum(iflat * iflat)
        B_sum = torch.sum(tflat * tflat)
        return 1 - ((2. * intersection + smooth) / (A_sum + B_sum + smooth))