nn.MSELoss()得到的是平均到像素的loss
nn.MSELoss(size_average=False)得到整個batch所有像素loss和
MSELoss(size_average=False).div(batch_size)得到平均圖像loss
a=torch.Tensor([[1,1],[1,1]]) b=torch.Tensor([[0,0],[0,0]]) f = nn.MSELoss() f(a,b) >>>tensor(1.) f = nn.MSELoss(size_average=False) f(a,b) >>>tensor(4.)