* add amp support for model SE_ResNet50_vd

* optimize code, add model ResNet50 and SE_ResNet50_vd to list

* merge develop

* add the support of amp for the fleet train
* remove the attribute for the amp

* update lrscheduler

* minor fix

* add pre-commit

* minor fix

* Add __len__ to squad dataset

* minor fix

* update lrscheduler

* minor fix

* add pre-commit

Co-authored-by: Nfangzeyang <fangzeyang@baidu.com>

* update api 1.8

* fix paddlerec readme

* fix

* fix

* fix 2.0

* fix 2.0

* fix 2.0

* fix 2.0

* fix 2.0

* fix

* add pure fp16 training.

* update the usage of cast_parameters_to_fp16.

* use fp32 to initilize parameter values and then cast to fp16.

* enable multi_precision when training with fp16.

* add static loss scaling.

* add the rescale_grad function in the pure fp16 training.

* use cast to complete the pure fp16 training.

* use sum loss for fp16 trainging and mean loss for fp32 training.

* refine codes according reviewers' suggestions

* Calculate and print the average time for video models.

* Calculate and print the average time for dygraph of slowfast.

* Print ips for nextvlad, slowfast, tsm and tsn.

add mso significant commit, because of creep API change, no more steps toward to be a time killer and all of it is crap (#4953)

average reader cost; test=develop

* add reader cost, and change speed to ips; test=develop

* fix inf bug; test=develop

* Create inception_v3.py

* Update __init__.py

* Create InceptionV3.sh

* fix load in metric learning

* fix load in metric learning

* fix typo

* fix typo

* fix video bug and slowfast benchmark bug

* refine bmn doc

* update api 1.8

* fix paddlerec readme

* fix readme

* update 2.0 api

* fix, test=develop

* update videotag, add fine-tune code and doc

* refine datalist

* refine eval.py

* Revert "add fuse_bn_add_act_ops args (#4864)"

* add fuse_bn_add_act_ops args