add teacher student sigmoid loss

Fix mnist dataset error

Revert "Remove workspace_handle in conv_cudnn (#15186)"

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This reverts commit 064512aa.

fix gpu buils issue on windows test=develop

fix typo and refine

merge to local

* remove workspace_handle in conv2d_cudnn
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* remove workspace_handle
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* fix bug
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* make test_conv2d_op SERIAL
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* save memory in conv_cudnn
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* enhance thread safety
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* enhance temporary allocator
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* Add excess fraction
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* follow comments
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* fix bug and code refine
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* fix memory size check
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* rename reuse_tmp_allocation_excess_fraction
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Refine/seqpool/feed with infer zerocopytensor

* Enable basic MKL-DNN INT8 Conv OP
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* Modify test case
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* Clean unittest code
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* Fix test
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* Modify test
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* Enable MKL-DNN INT8 Conv with Relu Fusion OP
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* Enable INT8 Conv with residual fusion OP
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* Modify code.
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* Modify basic INT8 Conv
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* Modify Conv.
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* fix style
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* Fix style
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* Fix test
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* Modify code.
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* Fix test
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remove the dismatch enclosure to avoid warning message test=develop

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* clip softmax for fp16

* updates

* fuse xent support fp16 test=develop

* wip

* wip

* add simple row reduce

* wip fp16 accurate softmax

* add accurate softmax kernel for fp16 test=develop

* update test=develop

* fix cpu build test=develop

* update api.spec test=develop

* follow comments test=develop

* fix build test=develop

* fix trt build test=develop

* fix inference build test=develop

* fix merge test=develop

* update test=develop

* try fix build test=develop

* fix build test=develop

* rename real_exp test=develop

* fortest

* remove hacky kernels test=develop

* clean up test=develop

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Set correct TBB library name in debug build 

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reduce threads number to avoid analyzer_rnn1_tester hang in CI

fix demo ci bug

Enforce dim check in data feeder

fix dist sparse l2 decay

Set correct TBB library name in debug build and remove warning related to rpath dependency from symlink.
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Fix ngraph cmake warning 

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Fuse/seqpool concat 2

1. trt_demo bug
2. trigger exit when exists a bug

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