Merge pull request !818 from wandongdong/master

Merge pull request !819 from Etone.Chan/master

Merge pull request !806 from VectorSL/gpu-fix-bn

Merge pull request !799 from dinghao/dirty_flag

Merge pull request !732 from zhangbuxue/dock_AcoshGrad_AvgPool_AvgPoolGrad_for_vm

Merge pull request !734 from jiangjinsheng/nn_ops_example

Merge pull request !728 from yao_yf/strategy_checkpoint_extend

Merge pull request !810 from zyli2020/develop

Merge pull request !805 from fanglei/checklegalvalue

Merge pull request !791 from 梅晓蔚/master

Merge pull request !776 from guozhijian/enhance_add_zhwiki_and_CLUERNER2020_to_mindrecord

Merge pull request !801 from fary86/fix_checking_bug_of_prelu

Merge pull request !808 from zhoufeng/cmake-gvar-order

Merge pull request !800 from lianliguang/master

Merge pull request !793 from yanghaitao/yht_err_msg_num_rows_zero

Merge pull request !705 from chujinjin/add_pynative_cache

Merge pull request !788 from caojian05/mindspore_master_dev

Merge pull request !751 from zjun/remove_enable_hccl

Merge pull request !784 from 梅晓蔚/master

Merge pull request !746 from lirongzhen1/bp_reducescatter

Merge pull request !785 from wukesong/maxpool_alexnet

Merge pull request !694 from rick_sanchez/master

Merge pull request !700 from penn/validate_bprop_rules

Merge pull request !761 from Simson/push-to-opensource

Merge pull request !743 from guozhijian/add_perf_test_for_mindrecord

Merge pull request !665 from caojian05/mindspore_master_dev

Merge pull request !778 from fary86/fix_bug_of_ApplyRMSProp

Merge pull request !750 from liubuyu/master