Pytorch beginner : tensor.new method

Question

everyone, I have a small question.

What is the purpose of the method tensor.new(..) in Pytorch, I didn't find anything in the documentation. It looks like it creates a new Tensor (like the name suggests), but why we don't just use torch.Tensor constructors instead of using this new method that requires an existing tensor.

Thank you in advance.

Answer 1

As the documentation of tensor.new() says:

Constructs a new tensor of the same data type as self tensor.

Also note:

For CUDA tensors, this method will create new tensor on the same device as this tensor.

Answer 2

It seems that in the newer versions of PyTorch there are many of various new_* methods that are intended to replace this "legacy" new method.

So if you have some tensor t = torch.randn((3, 4)) then you can construct a new one with the same type and device using one of these methods, depending on your goals:

t = torch.randn((3, 4))
a = t.new_tensor([1, 2, 3])  # same type, device, new data
b = t.new_empty((3, 4))      # same type, device, non-initialized
c = t.new_zeros((2, 3))      # same type, device, filled with zeros
... 

for x in (t, a, b, c):
    print(x.type(), x.device, x.size())
# torch.FloatTensor cpu torch.Size([3, 4])
# torch.FloatTensor cpu torch.Size([3])
# torch.FloatTensor cpu torch.Size([3, 4])
# torch.FloatTensor cpu torch.Size([2, 3])