Merge pull request !2316 from JunhanHu/alter_node_cpp

addr review cmts

revert

ci

private class

ci

fix ci

address ci

address review cmts

fix style err

Merge pull request !2273 from lichen/fix_embeding_look_up

Merge pull request !2211 from h.farahat/pair_truncate

Merge pull request !2281 from zyli2020/add_sigmoid

Merge pull request !1993 from luoyang/pylint

Merge pull request !2239 from liyong126/csv_to_mindrecord

Merge pull request !2275 from Xiaoda/4-fix-the-embeddinglookup-errors

Merge pull request !2292 from limingqi107/master

Merge pull request !2276 from fary86/fix_eliminate_get_ref

Merge pull request !2194 from 王东旭/master

Merge pull request !2252 from ms_yan/config_load

Merge pull request !2197 from zhaoting/ResNet50_st

Merge pull request !2220 from leopz/fix_dump

Merge pull request !2251 from YuJianfeng/proximal

Merge pull request !2150 from chenweifeng/tanh-fp16

Merge pull request !2236 from 李鸿章/callback

Merge pull request !2148 from wangqiuliang/fix-hook-bprop-issue

Merge pull request !2199 from Simson/push-to-opensource

Merge pull request !2179 from YuJianfeng/all_reduce_index

Merge pull request !2163 from Xiaoda/3-changing-embeddinglookup-internal

Merge pull request !2229 from zyli2020/add_ftrl_op

Merge pull request !2226 from zyli2020/add_adam_op

Merge pull request !2235 from zyli2020/add_sigmoid_cross_entropy_with_logits_grad

Merge pull request !2234 from zyli2020/add_sigmoid_cross_entropy_with_logits

Merge pull request !2256 from JesseKLee/sampler

Merge pull request !2198 from h.farahat/mask_op

Merge pull request !2142 from Tinazhang/reorg-visualize

Merge pull request !2092 from qianlong21st/june_third

Merge pull request !2210 from limingqi107/max_device_memory_optimize