why set layer0~4 to be eval() model twice?

[Hexuanfang]

https://github.com/HKUST-Aerial-Robotics/Stereo-RCNN/blob/4d6dd65049f52c1a5f2b6ad716a7e0da5cb02cb3/lib/model/stereo_rcnn/resnet.py#L339 hi, thanks for your reading ahead, i got a confusion that why set self.RCNN_layer0.eval() self.RCNN_layer1.eval() and what's the difference between line 316-317 and line 339-340? looking forward to your reply!