[Fix] Fix memory overflow in the rotated box IoU calculation (#2134)

* fix iou3d bug

* replace clamp_min with clamp

mmdet3d/structures/bbox_3d/base_box3d.py

@@ -463,11 +463,17 @@ def overlaps(cls, boxes1, boxes2, mode='iou'):
  # height overlap
  overlaps_h = cls.height_overlaps(boxes1, boxes2)
 
+ # Restrict the min values of W and H to avoid memory overflow in
+ # ``box_iou_rotated``.
+ boxes1_bev, boxes2_bev = boxes1.bev, boxes2.bev
+ boxes1_bev[:, 2:4] = boxes1_bev[:, 2:4].clamp(min=1e-4)
+ boxes2_bev[:, 2:4] = boxes2.bev[:, 2:4].clamp(min=1e-4)
+
  # bev overlap
- iou2d = box_iou_rotated(boxes1.bev, boxes2.bev)
- areas1 = (boxes1.bev[:, 2] * boxes1.bev[:, 3]).unsqueeze(1).expand(
+ iou2d = box_iou_rotated(boxes1_bev, boxes2_bev)
+ areas1 = (boxes1_bev[:, 2] * boxes1_bev[:, 3]).unsqueeze(1).expand(
  rows, cols)
- areas2 = (boxes2.bev[:, 2] * boxes2.bev[:, 3]).unsqueeze(0).expand(
+ areas2 = (boxes2_bev[:, 2] * boxes2_bev[:, 3]).unsqueeze(0).expand(
  rows, cols)
  overlaps_bev = iou2d * (areas1 + areas2) / (1 + iou2d)