debug loss of YOLOv2

models/yolov2/loss.py

@@ -77,7 +77,7 @@ class Criterion(object):
         
         # cls loss
         pred_cls_pos = pred_cls[pos_masks]
-        gt_classes_pos = gt_classes[pos_masks] * ious.clamp(0.)
+        gt_classes_pos = gt_classes[pos_masks] * ious.unsqueeze(-1).clamp(0.)
         loss_cls = self.loss_classes(pred_cls_pos, gt_classes_pos)
         loss_cls = loss_cls.sum() / num_fgs