[Enhance] Remove mmcv.iou3d from mmdetecion3d

[filaPro]

Motivation

Remove mmcv.iou3d from mmdetection3d.

• iou3d_boxes_overlap_bev_forward -> box_iou_rotated.box_iou_rotated
• iou_3d.nms_bev -> nms.nms_rotated
• iou_3d.nms_normal_bev -> nms.nms

Modification

For now only iou3d_boxes_overlap_bev_forward -> box_iou_rotated.box_iou_rotated is done. Nms can be replaced in this PR in the future or in the other PR.

BC-breaking (Optional)

May be only due to some float tolerance.

[codecov]

Codecov Report

Merging #1403 (3f38b02) into dev (4b73f74) will decrease coverage by 0.03%.
The diff coverage is 29.54%.

@@            Coverage Diff             @@
##              dev    #1403      +/-   ##
==========================================
- Coverage   51.20%   51.17%   -0.04%     
==========================================
  Files         212      212              
  Lines       18280    18284       +4     
  Branches     2978     2980       +2     
==========================================
- Hits         9361     9356       -5     
- Misses       8362     8371       +9     
  Partials      557      557              

Flag	Coverage Δ
unittests	51.17% <29.54%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmdet3d/core/post_processing/box3d_nms.py	28.76% <22.22%> (-1.54%)	⬇️
mmdet3d/models/dense_heads/point_rpn_head.py	27.02% <25.00%> (-0.31%)	⬇️
...odels/roi_heads/bbox_heads/point_rcnn_bbox_head.py	30.49% <25.00%> (-0.18%)	⬇️
mmdet3d/core/bbox/structures/base_box3d.py	71.57% <33.33%> (-0.15%)	⬇️
mmdet3d/core/post_processing/merge_augs.py	8.00% <33.33%> (-1.81%)	⬇️
mmdet3d/models/dense_heads/parta2_rpn_head.py	15.15% <33.33%> (-1.52%)	⬇️
...3d/models/roi_heads/bbox_heads/parta2_bbox_head.py	68.35% <33.33%> (-0.14%)	⬇️
mmdet3d/models/dense_heads/centerpoint_head.py	44.73% <50.00%> (ø)
mmdet3d/core/post_processing/__init__.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 4b73f74...3f38b02. Read the comment docs.

[filaPro]

I've also checked that

• iou_3d.nms_bev is same with nms.nms_rotated;
• iou_3d.nms_normal_bev is same with nms.nms.

So, I plan to add this replacements to the current PR.

[Tai-Wang]

There are two issues related to compatibility:

• We need to upgrade the lower bound of mmcv version if merging this PR?
• Does mmcv support the previous version of nms? I do not check the PRs in mmcv, but maybe we need to keep the deprecated version for several releases and add compatibility docs in mmcv/mmdet3d.

[filaPro]

Actually this PR is not connected to any PRs to mmcv for now. We simply replace some current cuda ops from mmcv with some equal cuda ops. So this PR implies no compatibility issues of this kind.

But, if it will be merged, than we can update unused iou3d in mmcv.

[Tai-Wang]

Actually this PR is not connected to any PRs to mmcv for now. We simply replace some current cuda ops from mmcv with some equal cuda ops. So this PR implies no compatibility issues of this kind.

But, if it will be merged, than we can update unused iou3d in mmcv.

Great, so the main idea is to merge nms ops in mmcv and use the unified one in mmdet3d? Then I think this PR is ready.

[ZwwWayne]

Hi @filaPro ,
Thanks for your kind contribution. We plan to merge this PR, could you rebase this branch to dev so that we can merge it into dev?

[CLAassistant]

All committers have signed the CLA.

[filaPro]

Rebase somehow broke CLA agreement of the author of one of previous commits. Can we ignore it?

Hm, everything is ok now.