Merge pull request !383 from zhaozhenlong/cell/psnr

Merge pull request !286 from wangqiuliang/resolve-pynative-operator-issue

Merge pull request !378 from h.farahat/multi_itr

-- Iterator list is keeping  all created iterators wihtout cleaning them up
-- alter tree modifies the original.

Merge pull request !377 from h.farahat/end_iterator

Merge pull request !183 from JunhanHu/cpp_sampler

Merge pull request !397 from chenjianping/building-on-windows-3

Merge pull request !296 from StrawNoBerry/ExcludeFV

Merge pull request !396 from zhangbuxue/fix_example_of_controldepend_for_cpu_and_gpu

Merge pull request !398 from penn/fix_example_doc_of_insert_grad_of

Merge pull request !391 from Simson/push-to-opensource

Merge pull request !386 from changzherui/modify-ut

Merge pull request !388 from Maoweiyong/fix-gpu-op-register

Merge pull request !343 from amongo/FixGradUsingInterfaceExtend

Merge pull request !314 from VectorSL/assign

Merge pull request !392 from caifubi/use-graphid-as-key-in-ascend-kernel-runtime

Merge pull request !217 from zhangbuxue/support_pow_operator

!332 Fixing problems including class slice example in ME cannot run, adding an example for class SigmoidCrossEntropyWIthLogits in ME etc.
Merge pull request !332 from zhangzheng/master

Merge pull request !379 from JichenZhao/groupnorm

Merge pull request !382 from yangzhenzhang/sigmoidloss

Fixing problem issues including class slice example cannot run, adding an example for class SigmoidCrossEntropyWithLogits etc.

add test case for grad concat

fix usage in test framework

fix testcase

format code

Merge pull request !389 from leonwanghui/dockerfile

Signed-off-by: Nleonwanghui <wanghui71leon@gmail.com>

Merge pull request !342 from zjun/fix_log_level

Merge pull request !376 from wenchunjiang/getnext_pass