Merge pull request !17839 from zyli2020/fix_issue_defect

Merge pull request !12151 from fanrb/unet

2.Optimize slice grad kernel

3.Add Unet GPU Model

Merge pull request !17987 from limingqi107/actor_runtime

From: @yanghaitao1
Reviewed-by: @ouwenchang,@yelihua
Signed-off-by: @yelihua

Merge pull request !17819 from ZPaC/master-add-gpu-all-gather-fusion

From: @VectorSL
Reviewed-by: @limingqi107,@wilfchen
Signed-off-by: @wilfchen

From: @limingqi107
Reviewed-by: @cristoval,@wilfchen
Signed-off-by: @wilfchen

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

From: @wilfchen
Reviewed-by: @limingqi107,@cristoval
Signed-off-by: @cristoval

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

From: @limingqi107
Reviewed-by: @cristoval,@wilfchen
Signed-off-by: @wilfchen

From: @zyli2020
Reviewed-by: @limingqi107,@cristoval
Signed-off-by: @cristoval

From: @VectorSL
Reviewed-by: @wilfchen,@wilfchen
Signed-off-by:

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

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

lenet memory leak fix

From: @limingqi107
Reviewed-by: @cristoval,@wilfchen
Signed-off-by: @cristoval

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

From: @limingqi107
Reviewed-by: @wilfchen,@cristoval
Signed-off-by: @cristoval

From: @john_tzanakakis
Reviewed-by: @yelihua,@pandoublefeng
Signed-off-by: @pandoublefeng