I have a misaligned point cloud and rotation matrix and I want to use backprop to tune the rotation matrix in 2d plane.
The problem is in the forward all I can get from the rotation matrix is index in the 2d plane which is duplicated like.
>>> x
[500.99, 500.5, 411.2, 411.02, 411]

But the desired output for this case should be
[500, 411]

While the ground truth maybe
[505, 501, 460, 420]

I can’t compare the float x and ground truth using mse directly because the dimension is not equal.
Both the x and ground truth are index of a 512 dimension vector but the gradient disappear as soon as I use x.long() so I can’t use them as index either.
How to properly calculate loss of this problem?
Thanks