Computational graph's working during updating parameters

Hello everyone!
Work with part of the code below:

#data initialization
x = torch.randn(10, 10)
y = torch.randn(10, 1)

# param initialization
w = torch.randn(10, 1, requires_grad=True)

print('W before updating is leaf == ', w.is_leaf)

n_epoch = 1
for epoch in range(n_epoch):
  loss = ((x @ w) ** 2).sum()
  w = w - w.grad * 0.01
  print('W after updating is leaf == ', w.is_leaf)

Let’s, that I wanna do updating parameters without context manager torch.no_grad().

w = w - w.grad * 0.01

Does it cause to building new computational graph? Because this operation is using requires_grad=True variable?
Moreover, why w after updating become non-leaf variable?

I apologize in advance for the stupid question! Thank you!