TypeError: must be real number, not Tensor，这是什么问题呀

[sh2120170809]

Traceback (most recent call last):
File "train.py", line 108, in
main()
File "train.py", line 105, in main
strategy)
File "/face_landmark/lib/core/base_trainer/net_work.py", line 196, in custom_loop
train_dist_dataset,epoch)
File "/face_landmark/lib/core/base_trainer/net_work.py", line 169, in distributed_train_epoch
images_per_sec))
TypeError: must be real number, not Tensor