area = (boxes[:, 3] - boxes[:, 1]) * (boxes[:, 2] - boxes[:, 0]) IndexError: too many indices for tensor of dimension 1

This error occurs when trying to access multiple columns of a tensor with a single index.

For example, if we have a tensor of size (10, 4) where each row represents a box with 4 values (x1, y1, x2, y2), and we want to compute the area of each box, we need to access two columns of the tensor for each box.

If we try to access multiple columns with a single index, we get the "IndexError: too many indices for tensor of dimension 1" error.

To fix this error, we need to make sure that we are accessing the correct columns of the tensor. In the case of computing the area of boxes, we need to access the columns for x1, y1, x2, and y2 separately, like this:

area = (boxes[:, 2] - boxes[:, 0]) * (boxes[:, 3] - boxes[:, 1])

This will compute the area of each box and return a tensor of size (10,).