* test=develop, update error message

Add the cpu version of segment sum mean max min op

* argsort op acceleration on GPU when the input size is equal to the length of the ‘axis’ dimension

* add double grad compute for batch norm,test=develop

* fix unittest, test=develop

* remove unuse tensor,test=develop

* add format,test=develop

* update, test=develop

* fix bug sequececonv_eltadd_relu_fuse_pass, output error when sequence_conv's padding_start > 0

* fix seqconv_eltadd_relu_fuse_pass unitest error

* support use add instead of sum to do gradient accumulation

* add inplace addto pass

* add grad_add op and inplace addto pass

* remove debug code

* code refine

* fix bug when sereral sum ops inserts at same op_idx

* fix Flags type

* add addto attribute for conv3d

* fix ut

* code clean

* fix type

Fix bug: shapes of Topk outputs are wrong when the parameter k is Tensor 

* Finished ChannelWiseQuantDequantAbsMaxOp and Passed unittests.

* Finished channel-wise quantize strategy in imperative quantization.

* Added Cuda code of ChannelWiseQuantDequantMaxAbsOP
Add Cuda code of ChannelWiseQuantDequantMaxAbsOp

* Add quant_axis for channel_wise quant.

* fixed a bug in unnitests, which will not trigger axis = 1 case and cannot meet the coverage rate requirement.

* Added some assert infomation and fixed some coding style mistakes.

* refine error msg in var_handle.h, test=develop

* refine all_reduce_op_handle

* fix some error msg

* refine variable_visitor

* refine threaded_ssa_graph_executor

* refine inplace related files

* refine executor related files

* refine fetch_op_handle.cc

* fix bug

* follow comments

* fix adam

* rmsprop support double

* fix worker endpoints

* fix gloo wrapper for hdfs

* GPU fleetrun support gloo

* parameterserver fleetrun support gloo

* fix get server endpoint

* Support python3.8

test=notest

* pass compatibility

* add compatibility registry

* add unittests for different padding

* add assert

* drop errmsg

* fix cudnn dyload error

https://github.com/PaddlePaddle/Paddle/pull/27332

* fix op print error info problem. test=develop

* fix build error

* fix format

* fix error msg info

* fix format

and optimize the c++ implmentation of empty op as PR#26659 reviews,
and add bool for shape op.

paddle/fluid/operators/distributed_ops OP报错信息优化

* Fix install pr requirements.txt

* test=document_fix

enhance reduce op which can reduce tensor with arbitrary rank 

* fix floordiv

* add adaptivelsgd

* Todo fix the code to avoid the conflict.