Why changing the value of numpy affects original tensor?

1

How does this work? Why would this assignment affect the original tensor?

aa = torch.tensor([1.,2.,3.])
bb = aa.numpy()
bb[0] = 99.
print(aa[0])   # <--- 99
2

Here’s a reference
https://pytorch.org/docs/stable/generated/torch.Tensor.numpy.html#torch.Tensor.numpy

aa and bb share the memory.

3

Python uses shallow copying, what you want is a hard copy so changing bb doesn’t affect aa. You’ll want to use .clone() before moving to numpy.

aa = torch.tensor([1.,2.,3.])
bb = aa.clone().numpy() #clone before numpy
bb[0] = 99.
print(aa[0])   # <--- 1
1 Like
4

That is very clear! Thank you so much!!