torchoutil.nn.functional.indices module¶

get_inverse_perm( indices: Tensor, dim: int = -1, ) → Tensor[source]¶

Return inverse permutation indices. The output will be a tensor of shape (…, N).

Args:: indices: Original permutation indices as tensor of shape (…, N). dim: Dimension of indices. defaults to -1.

Example 1¶

>>> x = torch.as_tensor([2, 4, 8, 10])
>>> indices = torch.randperm(len(x))
>>> x = x[indices]
>>> # x is now shuffled, to get back the original order we need the indices
>>> inv_indices = get_inverse_perm(indices)
>>> x_reordered = x[inv_indices]
>>> x_reordered
... tensor([2, 4, 8, 10])

get_perm_indices( x1: Tensor, x2: Tensor, ) → LongTensor[source]¶

Find permutation between two vectors t1 and t2 which contains values from 0 to N-1.

Example 1::¶

>>> x1 = torch.as_tensor([0, 1, 2, 4, 3, 6, 5, 7])
>>> x2 = torch.as_tensor([0, 2, 1, 4, 3, 5, 6, 7])
>>> indices = get_perm_indices(x1, x2)
>>> torch.equal(x1, x2[indices])
True

Insert value(s) in vector at specified indices.

Example 1::¶

>>> x = torch.as_tensor([1, 1, 2, 2, 2, 3])
>>> indices = torch.as_tensor([2, 5])
>>> values = 4
>>> insert_values(x, indices, values)
tensor([1, 1, 4, 2, 2, 2, 4, 3])

This function ensure that every value i cannot be the element at index i. The output will be a tensor of shape (size,).

Args:: size: The number of indices. Cannot be < 2. seed: The seed or torch.Generator used to generate permutation. device: The PyTorch device of the output indices tensor.

Example 1¶

>>> torch.randperm(5)
tensor([1, 4, 2, 5, 0])  # 2 is the element of index 2 !
>>> randperm_diff(5)
tensor([2, 0, 4, 1, 3])

remove_at_indices( x: Tensor, indices: Tensor | List | bool | int | float | complex, ) → Tensor1D[source]¶: Remove value(s) in vector at specified indices.