about training

[leizhu1989]

hello author,when I am training the shanghai_dataset model ,I meet this problem,what is maybe the reason of it? The error likes this:
Traceback (most recent call last):
File "train_lr.py", line 232, in
main()
File "train_lr.py", line 67, in main
i_tb,model_path = train(train_loader, net, optimizer, epoch, i_tb)
File "train_lr.py", line 96, in train
pred_map,pred_cls, pred_seg = net(img, gt_map, roi, gt_roi, gt_seg)
File "/home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torch/nn/modules/module.py", line 541, in call
result = self.forward(*input, **kwargs)
File "/home/zhulei/PCC-Net/models/CC.py", line 34, in forward
density_map, density_cls_score,pred_seg = self.CCN(img,roi)
File "/home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torch/nn/modules/module.py", line 541, in call
result = self.forward(*input, **kwargs)
File "/home/zhulei/PCC-Net/models/ori_big.py", line 80, in forward
x_bbx = self.roi_pool(x_hlp, roi)
File "/home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torch/nn/modules/module.py", line 541, in call
result = self.forward(*input, **kwargs)
File "/home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torchvision/ops/roi_pool.py", line 75, in forward
return roi_pool(input, rois, self.output_size, self.spatial_scale)
File "/home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torchvision/ops/roi_pool.py", line 62, in roi_pool
return _RoIPoolFunction.apply(input, rois, output_size, spatial_scale)
File "/home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torchvision/ops/roi_pool.py", line 19, in forward
_C = _lazy_import()
File "/home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torchvision/extension.py", line 12, in _lazy_import
from torchvision import _C as C
ImportError: /home/zhulei/anaconda3/envs/maskrcnn_benchmark/lib/python3.6/site-packages/torchvision/_C.so: undefined symbol: _ZN3c107Warning4warnENS_14SourceLocationENSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE