torch.ops.torchvision.nms (ultralytics#860)

Don't load the entire torchvision library just for nms when the function is already in the torch library.

utils/general.py

@@ -17,7 +17,6 @@
 import numpy as np
 import torch
 import torch.nn as nn
-import torchvision
 import yaml
 from scipy.cluster.vq import kmeans
 from scipy.signal import butter, filtfilt
@@ -651,7 +650,7 @@ def non_max_suppression(prediction, conf_thres=0.1, iou_thres=0.6, merge=False,
         # Batched NMS
         c = x[:, 5:6] * (0 if agnostic else max_wh)  # classes
         boxes, scores = x[:, :4] + c, x[:, 4]  # boxes (offset by class), scores
-        i = torchvision.ops.boxes.nms(boxes, scores, iou_thres)
+        i = torch.ops.torchvision.nms(boxes, scores, iou_thres)
         if i.shape[0] > max_det:  # limit detections
             i = i[:max_det]
         if merge and (1 < n < 3E3):  # Merge NMS (boxes merged using weighted mean)