From: @zhaozhenlong
Reviewed-by: @zhang_xue_tong,@zhanghaibo5
Signed-off-by: @zhang_xue_tong

From: @ehaleva
Reviewed-by: 
Signed-off-by:

From: @liubuyu
Reviewed-by: @zhoufeng54,@jjfeing
Signed-off-by: @jjfeing

From: @zoloft
Reviewed-by: @hangangqiang,@wangchengyuan
Signed-off-by: @hangangqiang

From: @yao_yf
Reviewed-by: @yangzhenzhang,@stsuteng
Signed-off-by: @stsuteng

From: @xiefangqi
Reviewed-by: @ms_yan,@liucunwei,@jonyguo
Signed-off-by: @liucunwei

modified:   model_zoo/official/nlp/bert/postprocess.py
        modified:   model_zoo/official/nlp/gru/postprocess.py
        modified:   model_zoo/official/nlp/lstm/preprocess.py
        modified:   model_zoo/official/nlp/textcnn/postprocess.py

From: @hanhuifeng2020
Reviewed-by: @gaoxiong1,@dylangeng
Signed-off-by: @dylangeng

From: @wenfangpei
Reviewed-by: @gaoxiong1,@ckey_dou
Signed-off-by: @ckey_dou

From: @wenfangpei
Reviewed-by: @gaoxiong1,@ckey_dou,@gaoxiong1,@ckey_dou
Signed-off-by: @ckey_dou,@ckey_dou

From: @tronzhang
Reviewed-by: @gaoxiong1,@ckey_dou
Signed-off-by: @ckey_dou

Use a disjoint-set to maintain the clusters before building anf-graph, to speed up the process of building graph.
Dump the change of nodes to file if the graphkernel flag "dump_as_text" is set.

The algorithm of CheckCircle is unchanged.
Reuse the FuseNodesToSubGraph interface.

From: @zhujingxuan
Reviewed-by: @wangchengyuan,@zhanghaibo5
Signed-off-by: @wangchengyuan

From: @zhujingxuan
Reviewed-by: @wangchengyuan,@zhanghaibo5
Signed-off-by: @wangchengyuan

From: @anzhengqi
Reviewed-by: @c_34,@jonyguo
Signed-off-by: @c_34

From: @anzhengqi
Reviewed-by: @oacjiewen,@jonyguo
Signed-off-by: @jonyguo

From: @yangzhenzhang
Reviewed-by: @kisnwang,@stsuteng
Signed-off-by: @stsuteng

From: @jachua
Reviewed-by: @liangchenghui,@guoqi1024
Signed-off-by: @liangchenghui

From: @anzhengqi
Reviewed-by: @c_34,@jonyguo
Signed-off-by: @c_34

From: @xiefangqi
Reviewed-by: @heleiwang,@jonyguo
Signed-off-by: @jonyguo

From: @xiefangqi
Reviewed-by: @heleiwang,@jonyguo
Signed-off-by: @jonyguo

From: @jojobugfree
Reviewed-by: @jjfeing,@zhoufeng54
Signed-off-by: @zhoufeng54

From: @lianliguang
Reviewed-by: @jjfeing,@zhoufeng54
Signed-off-by: @zhoufeng54

From: @yeyunpeng2020
Reviewed-by: @zhanghaibo5,@ddwsky
Signed-off-by: @zhanghaibo5

From: @zuochuanyong
Reviewed-by: @zhaizhiqiang,@guoqi1024,@zhoufeng54
Signed-off-by: @zhaizhiqiang

From: @jojobugfree
Reviewed-by: @kisnwang,@jjfeing
Signed-off-by: @jjfeing

From: @wenfangpei
Reviewed-by: @ckey_dou,@gaoxiong1
Signed-off-by: @ckey_dou

From: @lingyunli63
Reviewed-by: @ckey_dou,@gaoxiong1
Signed-off-by: @gaoxiong1

From: @dayschan
Reviewed-by: @gaoxiong1,@ckey_dou,@gaoxiong1
Signed-off-by: @gaoxiong1

From: @ZhengQihao3f3f3f
Reviewed-by: 
Signed-off-by:

From: @sishuikang
Reviewed-by: @zhanghaibo5
Signed-off-by: @zhanghaibo5

From: @ms_yan
Reviewed-by: @jonyguo,@heleiwang
Signed-off-by: @jonyguo

From: @zpac
Reviewed-by: 
Signed-off-by: