'float' object has no attribute 'backward'的问题

 import torch
import math
x0 = torch.tensor(2.00,requires_grad=True)
w0 = torch.tensor(-1.00,requires_grad=True)
x1 = torch.tensor(-2.00,requires_grad=True)
w1 = torch.tensor(-3.00,requires_grad=True)
w2 = torch.tensor(-3.00,requires_grad=True)
y0 = w0 * x0
y1 = x1 * w1
z0 = y0 + y1
z1 = z0 + w2
z2 = z1 * -1
z3 = math.exp(z2)
z4 = z3 + 1
z5 = 1/z4
print(y0)
print(y1)
print(z0)
print(z1)
print(z2)
print(z3)
print(z4)
print(z5)
z5.backward()
print(w0.grad)
print(x0.grad)
print(w1.grad)
print(x1.grad)
print(w2.grad)
print(y0.grad)
print(y1.grad)
print(z0.grad)
print(z1.grad)
print(z2.grad)
print(z3.grad)
print(z4.grad)
print(z5.grad)

有大佬知道应该怎么改吗？

在函数update中self.moving_right: self.center += self.ai_settings.ship_speed_factor 和后面一句用法错误，因为在run_game函数中传入的参数ai_settings已经是一个类属性了，即在Settings类中定义的浮点数，在update函数中调用时就不能再用ai_settings.ship_speed_factor，改成self.center += self.ai_settings，后面一句作同样修改。这样改：