* add nccl related info

* refine code

* refine doc

* add nccl related info

* refine code

* link default

* link-fault

* link-default-3

* Quickstart (#544)

* upload enhowto

* upload cluster quick start en

* review commit

* recover original multi_node.rst index

* fix index of cluster_howto

* fix index

* fix bugs

* upload save_load_variables_en (#549)

* upload save_load_variables_en

* Textual Review

* upload train_on_baidu_cloud_en (#550)

* upload train_on_baidu_cloud_en

* First round review check

* review on webpage, fix minors

* upload indexen (#551)

* upload indexen

* Textual Review

* upload metricsen (#552)

* upload metricsen

* First round review

* minor fix to round 1 review

* Update metricsen.rst

* Change file name and re-review

* lod_tensor_en (#554)

* lod_tensor_en

* Textual Content Check

* Review and fix on webpage

* numpt_array_en (#555)

* numpt_array_en

* Textual Content Check

* fix wrong file location and name

* review on webpage

* simple_model (#557)

* simple_model

* Contextual Review

* review on webpage

* single_node (#558)

* single_node

* Textual Fix

* review on webpage

* test_while_training (#559)

* test_while_training

* Textual Review

Textual Fix

* py_reader_en (#564)

* py_reader_en

* Textual Check

* user guides index of all (#595)

* visualdl en +cn  official readme (#598)

* FluidModel Fix (#611)

- delete the Models index in root index
- update models/index_en.rst

This reverts commit 2b012ad6.

* update link of models

* update en_version

* 0123-routine-docbug-fix

* Update metrics.rst

* update_to_develop

* fix

* update_to_1.2.1

* update_to_1.2.1

* polish_win_install (#562)

* polish_win_install

* follow_comments

* update_to_1.2.1

* update_inference_link

* delete cuda 7.5 line in table

* add&update develop table

* integration_2tables

* cn api fix bugs

* Update fluid_cn.rst

* Update lod_tensor.rst

- Modify some inaccurate descriptions
- Add the complete code example

* Update lod_tensor.rst

[cherry-pick] Update cn_api from develop to release/1.2

* fix the ref for api_guides

* update_book

* fix for python3 support (#488)

* fix for python3 support
test=develop

* test=develop

* backward.rst

* Update backward.rst

* Update programming_guide.md (#493)

* update layers_nn

* Update layers_cn.rst

* Update layers_cn.rst

* update api_cn except layers

* update fluid_cn.rst

* Update metrics_cn.rst

* update_ciwhl

* update_2nd

* fix_3rd

* fix_deadlinks (#476)

* [infer][rl_note]develop=1.2 (#480)

* update_infer_toctree

* add_fluid

* Update release_note.rst

* update_install_doc

* update layers_cn_by_wh

* Fix some typo 1211 (#483)

* fix some typo

* Update nets_cn.rst

* update_version

* refine info of whl (#485)

* refine info of whl

* fix link for release-whls

* remove fast install info (#486)

* refine info of whl

* fix link for release-whls

* remove fast install info

* update layers_nn

* Update layers_cn.rst

* Update layers_cn.rst

* update api_cn except layers

* update fluid_cn.rst

* Update metrics_cn.rst

* update_ciwhl

* update_2nd

* fix_3rd

* fix_deadlinks (#476)

* [infer][rl_note]develop=1.2 (#480)

* update_infer_toctree

* add_fluid

* Update release_note.rst

* add_api_cn (#437)

* add gpu benchmark page (#436)

* add gpu benchmark

* fix comments

* add chinese link in gen_doc.py (#439)

* modified gen_doc.py

* Update gen_doc.py

* update gen_doc.py

* Update mobile doc (#440)

* update_en_structure

* update_Paddle_commitid

* delete_DS

* update_mobile_doc

* Update book commit (#438)

* update_en_structure

* update_Paddle_commitid

* delete_DS

* update_book_commit_id

* update_api_rst

* Adjust structure of advanced usage (#442)

* adjust_structure_of_advanced_usage

* Update paddle_gpu_benchmark.md

* adjust_toctree_hidden

* fix_api_guide

* Update index.rst

* fix deadlinkes (#443)

* add_toctree (#445)

* adjust_beginners_structure (#446)

* adjust_beginners_structure

* Update index.rst

* update install_doc for python3 (#418)

* update install_doc for python3

* update python3.5+ info,test=develop

* fix review, test=develop

* fix_pic (#447)

* delete en2zn link

* update lod_tensor

* 1207

 1.english api reference links removed
2. formatted

* update transpiler

* update profilse_cn

* Update docker-image instroduce, test=develop (#459)

* fix_bug (#460)

* [cp2dev]Add avx info 1.1 (#279) (#451)

* Add avx info 1.1 (#279)

* refine avx info representation

* refine avx info representation

* refine avx info representation

* updatetoavx

* fix_AVX

* update_en_api (#461)

* update api guides for cn (#462)

* Update commit_id of Paddle (#463)

* update_en_api

* update_again

* Fix bug (#465)

* update_en_api

* update_again

* bug_fix

* fix_2nd

* add_release_note

* add_api_cn (#437)

* add gpu benchmark page (#436)

* add gpu benchmark

* fix comments

* add chinese link in gen_doc.py (#439)

* modified gen_doc.py

* Update gen_doc.py

* update gen_doc.py

* Update mobile doc (#440)

* update_en_structure

* update_Paddle_commitid

* delete_DS

* update_mobile_doc

* Update book commit (#438)

* update_en_structure

* update_Paddle_commitid

* delete_DS

* update_book_commit_id

* update_api_rst

* Adjust structure of advanced usage (#442)

* adjust_structure_of_advanced_usage

* Update paddle_gpu_benchmark.md

* adjust_toctree_hidden

* fix_api_guide

* Update index.rst

* fix deadlinkes (#443)

* add_toctree (#445)

* adjust_beginners_structure (#446)

* adjust_beginners_structure

* Update index.rst

* update install_doc for python3 (#418)

* update install_doc for python3

* update python3.5+ info,test=develop

* fix review, test=develop

* fix_pic (#447)

* delete en2zn link

* update lod_tensor

* 1207

 1.english api reference links removed
2. formatted

* update transpiler

* update profilse_cn

* Update docker-image instroduce, test=develop (#459)

* fix_bug (#460)

* [cp2dev]Add avx info 1.1 (#279) (#451)

* Add avx info 1.1 (#279)

* refine avx info representation

* refine avx info representation

* refine avx info representation

* updatetoavx

* fix_AVX

* update_en_api (#461)

* update api guides for cn (#462)

* Update commit_id of Paddle (#463)

* update_en_api

* update_again

* Fix bug (#465)

* update_en_api

* update_again

* bug_fix

* fix_2nd