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* add doc for MergeSelectedRows
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* checkout selected_rows
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This reverts commit 3d750f9c.

* Add test items for mkldnn conv2d

* Fix the regression issue and pass the unit test for conv2d and conv3d

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* wip

* wip

* wip

* wip for test

* add fp16 tests test=develop

* fix cpu build test=develop

* fix test=develop

* fix py3 tests test=develop

* fix lr_scheduler dtype test=develop

* fix test=dvelop

* test fix ci compile test=develop

* fix build and merge test=develop

* fallback momentumop change to general test=develop

* Enable mul operator for a ngraph
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* Enable activation ops test
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* Remove unused line
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* - Added transpose MKLDNN Op
- Few basic UT works
- Added 1D transpose
- implementing generic mem desc for MKLDNN transpose
- Modified trnaspose op to support  more dimensional data eg. 5,6..10
- Added is_test attribute to transpose op

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* - Added support for MKLDNN::memory::format::any for Transpose MKLDNN op

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* - Additional transpose mkldnn op correction to mkldnn layout

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* Cosmetic fixes

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* - Removed const_cast to obey coding standard

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* follow comments. test=develop

* Fix typo

* fix compile error. test=develop

* merge develop branch. test=develop

* Remove set_equal

* Polish code

* Delete unused functions

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* polish code. test=develop

* follow comment

* polish code.

* fix windows compile error. test=develop

* fix op handle.

* rerun ci. test=develop

* rerun ci. test=develop

* rerun macci. test=develop

* polish code. test=develop

* rewrite sort code. test=develop

* remove unused code. test=develop

* fix tests. test=develop

* fix conflict. test=develop

* follow comment. test=develop

* merge develop branch. test=develop

* fix tests. test=develop

* remove ToTypeIndex. test=develop

* rerun ci. test=develop

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* Enable ngraph tests for a ngraph engine
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* Move the test structure to other place
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* Add USE_NGRAPH flag, simple structure
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* Add psroi_pool operator.

* add l2 unit test
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* code refine
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add API.spec
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* fix nccl dist test acc test=develop

* fix test=develop

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* random failed. rerun ci. test=develop

* windows failed. rerun ci. test=develop

* add more log for dist test for ci test=develop

* increase deadline test=develop

Revert "Merge pull request #14798 from PaddlePaddle/revert-14786-revert-14782-revert-14398-imperative"

This reverts commit b1d3a1c8, reversing
changes made to f1fb64b1.

fix cmake
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add unittest model containing while_op
remove unnecessary codes
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* enable test_gradient_clip in mac
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* refine test_gradient_clip
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* add nccl2 dist tests test=develop

* fix dist_base test=develop

* fix tests test=develop

* fix test on mac test=develop