Remove out parameter from functions in PyTorch to simplify the functions and the documentation

[hyperkai]

🚀 The feature, motivation and pitch

In PyTorch, there is out parameter in many functions like matmul(), rand(), arrange().

For example, I find the pros of matmul() with out parameter is that the result is displayed with one line of code different from matmul() without out parameter which are two lines of code using IPython, Jupyter Notebook, Google Colab, etc as shown below:

import torch

tensor1 = torch.tensor([0, 1, 2])
tensor2 = torch.tensor([3, 4, 5])
new_tensor = torch.tensor(0)

# One line of code
torch.matmul(input=tensor1, other=tensor2, out=new_tensor) # tensor(14)

# Two lines of code
new_tensor = torch.matmul(input=tensor1, other=tensor2)
new_tensor # tensor(14)

About out parameter of functions in PyTorch:

Pros:

1. Less lines of code.

Cons:

1. People will write either of 2 ways(with or without out parameter) so it breaks the consistency of how people write code so such a code is less readable, less efficient and less productive which is seriously bad.
2. It makes PyTorch documentation complicated (I mean It is not simple because of out parameter.).

So, I think out parameter has more disadvantages than advantages so out parameter should be removed to simplify the functions and the documentation.

Alternatives

No response

Additional context

No response

[ezyang]

For BC reasons we are not going to do this