From: @ginfung
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From: @ling_qiao_min
Reviewed-by: 
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1. description of num_shard in datasets.py
2. add param validation for sampler
3. add description for add_child in sampler.py

fix c++ ut compilation failed of Asan bug

From: @lixiachen
Reviewed-by: 
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From: @mengyuanli
Reviewed-by: @hangangqiang,@zhanghaibo5
Signed-off-by: @hangangqiang

From: @yuchaojie
Reviewed-by: @c_34,@liangchenghui
Signed-off-by: @c_34

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

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

From: @wangzhe128
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From: @wuxuejian
Reviewed-by: @kisnwang,@guoqi1024,@c_34
Signed-off-by: @c_34

From: @YeFeng_24
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From: @ch-l
Reviewed-by: @zhoufeng54,@kisnwang
Signed-off-by: @kisnwang

From: @zhangyunshu
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From: @ouwenchang
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From: @qujianwei
Reviewed-by: @linqingke,@liangchenghui
Signed-off-by: @liangchenghui

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

From: @sunsuodong
Reviewed-by: @zhang_xue_tong
Signed-off-by:

From: @zhouyaqiang0
Reviewed-by: @c_34,@linqingke
Signed-off-by: @linqingke

From: @pandoublefeng
Reviewed-by: @c_34,@linqingke
Signed-off-by: @c_34

From: @zhengjun10
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From: @cjh9368
Reviewed-by: @zhanghaibo5
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From: @changzherui
Reviewed-by: @zh_qh,@zhoufeng54
Signed-off-by: @zh_qh

Renamed illegal variables and functions.

reconverted the nae of function in Lite java files.

modified

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

From: @ling_qiao_min
Reviewed-by: @zhang_xue_tong,@hangangqiang
Signed-off-by: @zhang_xue_tong

From: @pengyongrong
Reviewed-by: 
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Cast the float16-input to float32 before ReduceSum, and cast back to float16 after ReduceSum.
If the op after this ReduceSum is a casting from float16 to float32, then it can be eliminated.