there is a bug in vtransformer, lidar points is changed in this line

[brucejiangsaic]

bevfusion/mmdet3d/models/vtransforms/base.py

Line 249 in db75150

cur_coords -= cur_lidar_aug_matrix[:3, 3]

cur_coords = points[b][:, :3]
cur_coords use memory of points, and conducted a inplace-subtract
I run code in torch1.12. lidar points was changed here and would not match GT

[JingweiZhang12]

Yeah, I also found it. However, in float16 mode, the decorator @auto_fp16 in MMCV will deep copy the points and bypass this potential bug, so the points is not modified in-place. In float32 mode, this bug occurs.
Solution: the points here could be replaced by copy.deepcopy(points)