pytorch中torch.narrow()函数

提示：扫一扫查出行
【扫一扫了解最新限行尾号】
复制提示

torch. narrow ( input , dim , start , length ) → Tensor

Returns a new tensor that is a narrowed version of input tensor. The dimension dim is input from start to start +length . The returned tensor and input tensor share the same underlying storage.

Parameters

input ( Tensor ) – the tensor to narrow
dim ( int ) – the dimension along which to narrow
start ( int ) – the starting dimension
length ( int ) – the distance to the ending dimension

Example:

>>> x = torch.tensor([[1, 2, 3], [4, 5, 6], [7, 8, 9]])

>>> torch.narrow(x, 0, 0, 2)

tensor([[ 1,  2,  3],

        [ 4,  5,  6]])

>>> torch.narrow(x, 1, 1, 2)

tensor([[ 2,  3],

        [ 5,  6],

        [ 8,  9]])

根据定义得知，这个函数是返回tensor的第dim维切片start: start+length的数, 针对例子，

x.size() = (3, 3)

torch.narrow(x, 0, 0, 2) == x[0:0+2, :]

torch.narrow(x, 1, 2, 1) == x[:, 2:2+1]