Created by: wuyefeilin

dice_loss的计算，分母这样计算的话为定值等于2HW,是否有问题

label = one_hot(label, depth=input.shape[-1])
    reduce_dim = list(range(1, len(input.shape)))
    inse = reduce_sum(input * label, dim=reduce_dim)
    dice_denominator = reduce_sum(
        input, dim=reduce_dim) + reduce_sum(
            label, dim=reduce_dim)
    dice_score = 1 - inse * 2 / (dice_denominator + epsilon)
    return reduce_mean(dice_score)