Pytorch: Why is model.cuda() a class method instead of property ?

[kdexd]

import torch
from torch.autograd import Variable

a = Variable(torch.Tensor([1, 2]))
if torch.cuda.is_available():
    b = a.cuda()

b_data = b.data
b_grad = b.grad
b_grad_data = b.grad.data

If .data and .grad are class attributes, then .cuda() can be kept as property so that one a do b = a.cuda. I am making suggestion thinking that it would increase API consistency, as .cuda(), .data and .grad are torch.Tensor so cuda() can be changed to a property. By doing this, the GPU residing model can be accessed by model.cuda

[chenzhekl]

cuda is made a method since it is a relatively expensive operation, which involves copying data from CPU to GPU. While grad and data are cheap operations (O(1)), which only retrieve references to the corresponding Tensor. I think making cuda a method is reasonable.

[lg-zhang]

.cuda() copies CPU data to GPU. You probably don't want to keep the data in GPU all the time. That means, you only store data in GPU when it's really necessary.

[soumith]

as mentioned by both above comments, making .cuda a property is inappropriate. We return new objects when referencing .cuda() and a lot is happening.