01_backward.py

```python import torch

x = torch.tensor(2.0, requires_grad = True)

a = torch.add(x, 1) b = torch.add(x, 2) y = torch.mul(a, b)

y.backward() print(x.grad)

print("requires_grad: ", x.requires_grad, a.requires_grad, b.requires_grad, y.requires_grad) print("is_leaf: ", x.is_leaf, a.is_leaf, b.is_leaf, y.is_leaf) print("grad: ", x.grad, a.grad, b.grad, y.grad)```