Tensor ellipsis (three points) slice

Checking these three points means ellipsis

type(...)
<class 'ellipsis'>

It means automatically judging the dimension in the process of slicing , Basically, according to the total size- Number of commas , Therefore, two ellipsis will not appear in the slicing operation , For example ：

a = torch.randn(3,4,5,6,7,requires_grad=True)
a.shape
>>>torch.Size([3, 4, 5, 6, 7])
a[...,0].shape
>>>torch.Size([3, 4, 5, 6])
a[0,...,0].shape
>>>torch.Size([4, 5, 6])
a[0,1,...,0,0].shape
torch.Size([5])
>>>a[0,...].shape
torch.Size([4, 5, 6, 7])