pytorch documentation study notes (2)

3. CUDA semantics

 

 

2. Broadcasting semantics Broadcasting mechanism

The broadcast mechanism requires the first item to be aligned, and the first item can be broadcast after it is aligned (equal), or a certain first item is 1.

But if the two sizes are equal, the first item must be equal, even if one item is 1.

 

1. Autograd mechanics

x=torch.randn(5,5)
y=torch.randn(5,5)
z=torch.randn((5,5),requires_grad=True)
a = x+ y
a.requires_grad
Out[135]: False
b=a+z
b.requires_grad
Out[137]: True