torch.unsqueeze — PyTorch 2.7 documentation (original) (raw)

torch.unsqueeze(input, dim) → Tensor¶

Returns a new tensor with a dimension of size one inserted at the specified position.

The returned tensor shares the same underlying data with this tensor.

A dim value within the range [-input.dim() - 1, input.dim() + 1)can be used. Negative dim will correspond to unsqueeze()applied at dim = dim + input.dim() + 1.

Parameters

• input (Tensor) – the input tensor.
• dim (int) – the index at which to insert the singleton dimension

Example:

x = torch.tensor([1, 2, 3, 4]) torch.unsqueeze(x, 0) tensor([[ 1, 2, 3, 4]]) torch.unsqueeze(x, 1) tensor([[ 1], [ 2], [ 3], [ 4]])