Solved by richard in post #8 
              
              
                I’m not 100% sure I understand what your example is, but I think this is what you want. Given the following: 
[image] 
You want to be able to “index” x with i. I think the following code should get you the desired behavior: 
torch.cat([x[coord[0], coord[1]] for coord in i])

This iterates through th…