Increasing the values for specific indices in a tensor

1

I want to increase specific indices in a tensor by 10%.
I have a tensor

x = torch.randint(-2,2,[4,3])

tensor([[-2,  0,  1],
        [-2,  1, -2],
        [ 0,  0, -1],
        [ 0, -1,  1]])

and the following indices

indices = torch.tensor([[0,0,1],[2,1,1]])

I want to increase the values by 10% on the indices above, so that I get the following tensor

tensor([[-2,  0,  1.1],
        [-2,  1.1, -2],
        [ 0,  0, -1],
        [ 0, -1,  1]])

How can I achieve that?

2

Hi,

I guess you can do something like this no?
x[indices[0], indices[1]] *= 1.1

3

HI @albanD thank you for the response.
I tried your solution but I lose the full matrix, ang get only the selected vector

x[indices[0], indices[1]]

>> tensor([ 1, -2, -1])

Also, multiplying by negative numbers by 1.1 will reduce them and instead of increasing them
so I guess I need a calculation similar to

x + x.abs() * 0.1

I just don’t know how to apply it only on the specific indices.

4

Ho in that case you can do:

vals = x[indices[0], indices[1]]
updated_vals = vals + vals.abs() * 1.1
x[indices[0], indices[1]] = vals
5

Thank you @albanD, just what I was looking for