* add distributed dir and doc

* remove start_processes & move DataParallel

* add get rank and world size

* add cn docs

* add index to distributed_cn

* add white list api

* add api white list

* add cn to api name

* polish details

* add rst suffix

* add py function

* add functional_one_hot doc

* fix some bug

* fix some bug

* fix some bug

* fix some asc bug

* fix code bug

* fix text

* add example code

* fix bug

* fix bug

* fix bug

* fix some bug

* add InputSpec zh doc

* fix sample code

* modify declarative into to_static

* sync with 2.0 api

Add dynamic/static learning rate doc for the api2.0

* update the demo code and the doc of varbase.backward.

* remove the dependence of  BackwardStrategy

Co-authored-by: Nwangchaochaohu <wangchao66@baidu.com>

* api2.0, Add Bilinear doc(eng,cn), test=develop

* fix some description, test=develop

* fix some description, test=develop

* fix some description, test=develop

* fix some describtion, test=develop
Co-authored-by: NChen Weihang <chenweihang@baidu.com>

 update the doc for the topK

* add unique doc

* Test SmoothL1Loss

* fix SmoothL1Loss doc

* fix some error

* fix to_tensor and add name=None,test=develop

* Add chinese and english documents of paddle.prod

test=develop

* add cn doc of trace API

* add cn doc of functional ctc_loss and CTCLoss class.

* modified the format of doc.

* add en doc of ctc_loss and CTCLoss

* modified paddle.to_variable to paddle.to_tensor

 add doc of isnan, isinf, isfinite

* Add the argmax, argmin api doc for the api 2.0, test=develop

* add uniform op doc

* fix uniform en format

* delete useless code

* test distribution doc

* add paddle.rst

* fix paddle.rst

* Add distribution_cn

* Fixed doc in cn

* fix cn doc

* test paddle_cn

* Distributin, temp fix of Normal and Uniform

* fix code doc

* test_broadcast

* optimize doc

* return to the original index_cn.rst

* hidden _to_variable func

* refine sign tanh api, test=develop

* Add Tanh, test=develop

* fix en, test=develop

* test=develop, add addmm doc

* add addmm doc

* test=develop, add addmm doc

* test=develop, add pad doc

* restore addmm

* test=develop, add pad

* test=develop, fix pad interface

* test=develop, add pad eng doc link

* test=develop, add other pads

* test=develop, remove pad default

* test=develop, fix const pad1d code

* test=develop, fix var

* test=develop, fix pad typo

* test=develop, rename tovar to totensor

* test=develop, fix code

* test=develop, fix typo

* test=develop, fix cos_sim interface

* test=develop, fix typo

* refine bceloss doc

* fix doc

* fix name

* fix api 2.0 directory migration

* add dir file and change x to input

* add doc of loss function binary_cross_entropy.

* delete static demo code.

* add 2/3d adaptive_pooling

* fix format

* fix format

* add en doc rst

* fix format

* fix doc

* fix doc

* refine example code

* unify example code

* Udpate the doc format for the paddle, test=develop

* rename the inputs and update code example, test=develop

* update doc