torch.narrow

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 or Tensor) – index of the element to start the narrowed dimension from. Can be negative, which means indexing from the end of dim. If Tensor, it must be an 0-dim integral Tensor (bools not allowed)

• length (int) – length of the narrowed dimension, must be weakly positive

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]])
>>> torch.narrow(x, -1, torch.tensor(-1), 1)
tensor([[3],
        [6],
        [9]])