Pytorch advanced indexing with list of lists as indices

Here is some python code to reproduce my issue:

import torchn, m = 9, 4x = torch.arange(0, n * m).reshape(n, m)print(x.shape)print(x)# torch.Size([9, 4])# tensor([[ 0,  1,  2,  3],#         [ 4,  5,  6,  7],#         [ 8,  9, 10, 11],#         [12, 13, 14, 15],#         [16, 17, 18, 19],#         [20, 21, 22, 23],#         [24, 25, 26, 27],#         [28, 29, 30, 31],#         [32, 33, 34, 35]])list_of_indices = [    [],    [2, 3],    [1],    [],    [],    [],    [0, 1, 2, 3],    [],    [0, 3],]print(list_of_indices)for i, indices in enumerate(list_of_indices):    x[i, indices] = -1print(x)# tensor([[ 0,  1,  2,  3],#         [ 4,  5, -1, -1],#         [ 8, -1, 10, 11],#         [12, 13, 14, 15],#         [16, 17, 18, 19],#         [20, 21, 22, 23],#         [-1, -1, -1, -1],#         [28, 29, 30, 31],#         [-1, 33, 34, -1]])

I have a list of list of indices. I want to set the indices in x to a specific value (here -1) using the indices in list_of_indices. In this list, each sublist correspond to a row of x, containing the indices to set to -1 for this row. This can be easily done using a for-loop, but I feel like pytorch would allow to do that much more efficiently.

I tried the following:

x[torch.arange(len(list_of_indices)), list_of_indices] = -1

but it resulted in

IndexError: shape mismatch: indexing tensors could not be broadcast together with shapes [9], [9, 0]

I tried to find people having the same problem, but the number of questions about indexing tensors is so large that I might have missed it.