From: @zyx5256
Reviewed-by: @wuxuejian,@liangchenghui
Signed-off-by: @liangchenghui

From: @huangbo77
Reviewed-by: @wuxuejian,@liangchenghui
Signed-off-by: @wuxuejian

From: @jiangzg001
Reviewed-by: @c_34,@wuxuejian
Signed-off-by: @c_34

From: @jiaoy1224
Reviewed-by: @gaoxiong1,@gaoxiong1,@ckey_dou
Signed-off-by: @ckey_dou

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

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

From: @tom__chen
Reviewed-by: @robingrosman,@mikef
Signed-off-by:

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

From: @tina_mengting_zhang
Reviewed-by: @john_tzanakakis,@tom__chen
Signed-off-by: @john_tzanakakis

From: @tina_mengting_zhang
Reviewed-by: @john_tzanakakis,@mikef
Signed-off-by: @john_tzanakakis

From: @john_tzanakakis
Reviewed-by: @robingrosman,@nsyca
Signed-off-by: @robingrosman

From: @anzhengqi
Reviewed-by: @wuxuejian,@ms_yan,@jonyguo
Signed-off-by: @jonyguo

From: @zh_qh
Reviewed-by: @hwhewei,@ginfung
Signed-off-by: @ginfung

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