optimizer = torch.optim.SGD(model.parameters(), lr=0.05)
loss_fn = nn.MSELoss()
inputs = torch.tensor(
    [
        [1.0, 0.5, -1.0, 2.0],
        [0.0, -1.5, 2.0, 1.0],
        [2.0, 1.0, 0.5, -0.5],
        [-1.0, 2.0, 1.5, 0.0],
    ]
)
target = torch.full((4, 1), 25.0)
max_norm = 0.25