I have a PyTorch tensor b with the shape: torch.Size([10, 10, 51]). I want to select one element between the 10 possible elements in the dimension d=1 (middle one) using a numpy array: a = np.array([0,1,2,3,4,5,6,7,8,9]). this is just a random example.
I wanted to do:
b[:,a,:] but that isn't working
Your solution is likely torch.index_select (docs)
You'll have to turn a into a tensor first, though.
a_torch = torch.from_numpy(a)
answer = torch.index_select(b, 1, a_torch)
An indexing of b on the second axis using a should do:
>>> b = torch.rand(10, 10, 51)
>>> a = np.array([0,1,2,3,4,5,6,7,8,9])
>>> b[:, a].shape
torch.Size([10, 10, 51])
[10, 10, 51], while I want one such as [10, 51] @Ivan
I have found the solution on the PyTorch forum: (https://discuss.pytorch.org/t/how-to-select-specific-vector-in-3d-tensor-beautifully/37724)
x = torch.tensor([[[1, 2, 3],
[4, 5, 6],
[7, 8, 9]],
[[11, 12, 13],
[14, 15, 16],
[17, 18, 19]]])
idx = torch.tensor([1, 2])
x[torch.arange(x.size(0)), idx]
(10, 51)?btensor and what tensor you're expecting to get out.