def test_cython_bbox_iou_against_coco_api_bbox_iou(self):
        """Check that our cython implementation of bounding box IoU overlap
        matches the COCO API implementation.
        """
        def _do_test(b1, b2):
            # Compute IoU overlap with the cython implementation
            cython_iou = box_utils.bbox_overlaps(b1, b2)
            # Compute IoU overlap with the COCO API implementation
            # (requires converting boxes from xyxy to xywh format)
            xywh_b1 = box_utils.xyxy_to_xywh(b1)
            xywh_b2 = box_utils.xyxy_to_xywh(b2)
            not_crowd = [int(False)] * b2.shape[0]
            coco_ious = COCOmask.iou(xywh_b1, xywh_b2, not_crowd)
            # IoUs should be similar
            np.testing.assert_array_almost_equal(
                cython_iou, coco_ious, decimal=5
            )

        # Test small boxes
        b1 = random_boxes([10, 10, 20, 20], 5, 10)
        b2 = random_boxes([10, 10, 20, 20], 5, 10)
        _do_test(b1, b2)

        # Test bigger boxes
        b1 = random_boxes([10, 10, 110, 20], 20, 10)
        b2 = random_boxes([10, 10, 110, 20], 20, 10)
        _do_test(b1, b2)
Check that our cython implementation of bounding box IoU overlap
        matches the COCO API implementation.
        
detectron/tests/test_bbox_transform.py