* moe ref

* ref commit; test=document_fix

* update; test=document_fix

* update test=document_fix

* add random routing op

add _random_routing api in utils

add random routing ut

* # This is a combination of 10 commits.
# The first commit's message is:
add expert count op

add ut for expert_count

# This is the 2nd commit message:

update UT only for cuda

# This is the 3rd commit message:

fix for rocm

# This is the 4th commit message:

update ut

# This is the 5th commit message:

add moe module

# This is the 6th commit message:

add expert count op

add ut for expert_count

# This is the 7th commit message:

update UT only for cuda

# This is the 8th commit message:

update ut

# This is the 9th commit message:

add moe module

# This is the 10th commit message:

make expert count private

* add assign pos op

* fix upper num name

* add api _assign pos

* add ut for assign pos op

* update date

* add op about moe gate

update utils

add limit by capacity op

add ut for limit_by_capacity

add ut for prune_gate_by_capacity

add ut for limit_by_capacity

add ut for prune_gate_by_capacity

* fix for win

* fix bugs in test_limit_by_capacity_op

* update ut

* update for test (timeout)

* fix ut

* update

* update(fix) ut for win

* moe apis in incubate

* # This is a combination of 10 commits.
# The first commit's message is:
add expert count op

add ut for expert_count

# This is the 2nd commit message:

update UT only for cuda

# This is the 3rd commit message:

fix for rocm

# This is the 4th commit message:

update ut

# This is the 5th commit message:

add moe module

# This is the 6th commit message:

add expert count op

add ut for expert_count

# This is the 7th commit message:

update UT only for cuda

# This is the 8th commit message:

update ut

# This is the 9th commit message:

add moe module

# This is the 10th commit message:

make expert count private

* add assign pos op

* fix upper num name

* add api _assign pos

* add ut for assign pos op

* update date

* fix for win

* update for test (timeout)

* fix ut

* update

* fix ut for number count

* add apis and utils

* add gate apis

* add moe and grad clip apis

* update moe apis

* add ops for moe gate

* fix

* update for base moe layer api

* add random routing op

add _random_routing api in utils

add random routing ut

* fix for dygraph

* update with ranodm routing

* update

* fix ut for limit by capacity

* update

* update limit by capacity for easily to switch to single thread mode

* update api docs
Co-authored-by: Nhlygit66666 <2570058140@qq.com>

* add random routing op

add _random_routing api in utils

add random routing ut

* # This is a combination of 10 commits.
# The first commit's message is:
add expert count op

add ut for expert_count

# This is the 2nd commit message:

update UT only for cuda

# This is the 3rd commit message:

fix for rocm

# This is the 4th commit message:

update ut

# This is the 5th commit message:

add moe module

# This is the 6th commit message:

add expert count op

add ut for expert_count

# This is the 7th commit message:

update UT only for cuda

# This is the 8th commit message:

update ut

# This is the 9th commit message:

add moe module

# This is the 10th commit message:

make expert count private

* add assign pos op

* fix upper num name

* add api _assign pos

* add ut for assign pos op

* update date

* add op about moe gate

update utils

add limit by capacity op

add ut for limit_by_capacity

add ut for prune_gate_by_capacity

add ut for limit_by_capacity

add ut for prune_gate_by_capacity

* fix for win

* fix bugs in test_limit_by_capacity_op

* update ut

* update for test (timeout)

* fix ut

* update

* update(fix) ut for win

* moe apis in incubate

* # This is a combination of 10 commits.
# The first commit's message is:
add expert count op

add ut for expert_count

# This is the 2nd commit message:

update UT only for cuda

# This is the 3rd commit message:

fix for rocm

# This is the 4th commit message:

update ut

# This is the 5th commit message:

add moe module

# This is the 6th commit message:

add expert count op

add ut for expert_count

# This is the 7th commit message:

update UT only for cuda

# This is the 8th commit message:

update ut

# This is the 9th commit message:

add moe module

# This is the 10th commit message:

make expert count private

* add assign pos op

* fix upper num name

* add api _assign pos

* add ut for assign pos op

* update date

* fix for win

* update for test (timeout)

* fix ut

* update

* fix ut for number count

* add apis and utils

* add gate apis

* add moe and grad clip apis

* update moe apis

* add ops for moe gate

* fix

* update for base moe layer api

* add random routing op

add _random_routing api in utils

add random routing ut

* fix for dygraph

* update with ranodm routing

* update

* fix ut for limit by capacity

* update
Co-authored-by: Nhlygit66666 <2570058140@qq.com>

* add Hub Module for easy to use pre-trained models.
*   support list, load, help fucntions.
*   support load models by github, gitee, local 
Co-authored-by: NLielinJiang <jianglielin@baidu.com>

* custom python backward

* polish up the code

* polish up the code

* polish up the code.

* Fix code format and comments.

* Delete redundant files.

* add unnittest.

* edit unnittest.

* edit unnittest.

* Remove redundant header files.

* Improve coverage and remove redundant code.

* support saving for backward.

* polish code according to comments.

* Add support type for PyLayer.

* Modify the DOC.

* polish Doc.

* polish Doc.

* polish Doc.

* polish Doc.

* polish Doc.

* polish Doc.

* polish code and make the code robust.

* Modify the code format.

* add custom init grad for backward function

* add custom init grad for backward function

* handle when the grad_tensor is none

* handle when the grad_tensor is none

* fix the args type error on windows platform

* modify the args order and doc

* format code

* add grad_tensor to xpu

* modify the grad_tensor type check

* add paddle.backward api to support multi tensors gradient compute

* add paddle.backward api to support multi tensors gradient compute

* add paddle.atuograd module and backward api

* change tensor.backward func args

* modify tensor backward api

* remove create_graph intputs args

* add doc and examplex code for backward api

* when have the same tensor, throw error

* modify test Init func args

* modify the execute.Init func args in test files

* add paddle.autograd package in setup.py.in

* modify error msg, remove _run_backward method in class Tensor

* add test cases for backward api

* 01:Modify the shell script according to the specification

* 01:Modify the shell script according to the specification

* add train demo to paddle_build.sh

test=develop
test=document_preview

* code cleaning

* test=develop

test=develop

* remove program desc files

test=develop

* add test_train to CI

test=develop
test=document_preview

* make run.sh excutable

test=develop
test=document_preview

* switch with_mkl to off

test=develop
test=document_preview

* switch with_mkl to off

test=develop

* switch with_mkl to on

test=develop

* move test_fluid_lib_train to ci_py35

test=develop

* fix bugs of MKLDNN building

* rm build_train_lib(), test=develop

* restore tensor.h, test=develop