* fix benchmark and communicator config

* fix bugs of the_one_ps

* multi program and fix bug in optimizer

* multi program in the_one_ps

* public commcontext

* ps optimizer multi programs

* cvm & datanorm backend

* fix dim

* fix unittest

* fix

* the one ps merge

* remove comm

* add DownpourLiteWorker

* all

* fix

* fix

* device worker downpour lite

* fix

* fix bug in global shuffle

* save inference model

* fix & add log

* fix

* remove log

* fix

* fix save summary

* fix

* fix pscore

* fix

* fix

* fix

* fix

* fix

* remove logs

* fix

* fix

* fix

* fix

* fix

* add some comments

* fix
Co-authored-by: Nesythan <esythan@126.com>

* add raw program, test=develop

* update

* add clip/check

* add amp & clip grad in dygraph

* add logging

* support dp & mp

* add sharding

* add adaptivelsgd

* Todo fix the code to avoid the conflict.

* Support Heter Parameter Server

* fix api document

* move paddle.fleet to paddle.distributed.fleet

add lamb to fleet meta optimizer

* add paddle.fleet.AsyncOptimizer
Co-authored-by: Ndongdaxiang <dongdaxiang@baidu.com>

Add dgc to fleet meta optimizer, rm dgc from optimizer all

* add localsgd meta optimizer

* add pipeline optimizer

* add gradient Merge optimizer to meta, test=develop

refactor fleet api under paddle.fleet
update DistributedStrategy

* add paddle.fleet.DistributedStrategy for 2.0

This reverts commit 66fce9e8.

Fleet Parameter Server API Integrated

This is part of big move of v2 codes to legacy sub dir.

ISSUE=4586495

git-svn-id: https://svn.baidu.com/idl/trunk/paddle@1408 1ad973e4-5ce8-4261-8a94-b56d1f490c56