Expected all tensors to be on the same device, but found at least two devices, cuda:0 and cpu!

[get-Resource]

File "E:\SourceCode\GitHub_item\yolov7-polygon-detection\utils\general.py", line 1142, in polygon_bbox_iou
iou -= (rho2 / c2 + v * alpha) # CIoU
RuntimeError: Expected all tensors to be on the same device, but found at least two devices, cuda:0 and cpu!

update:

                iou = iou.to(device)
                alpha = v / (v - iou + (1 + eps))