* fix selected_rows bug
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* refine cos_sim
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* add fp16 backward support
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* add sum_op fp16 test

* disable test_dist_save_load
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* add check_grad for sum

* add unit test for softmax_grad fp16
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* add scale_op unit test

* add mul_grad_op unit test for fp16

* add cross_entropy_grad and eman_grad unit test for fp16
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* fix cross_entropy unit test

* add pool2d fp16 unit test

* refine conv2d fp16 unit test
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* refine activation unit test
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* fix ci
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* follow zhihong's comment, copy from https://github.com/PaddlePaddle/Paddle/pull/12796
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- Added rough profiling

- Profiled maxpool itself

- First draft of max seqpool optimization (is_test added)

- Added unit tests to seqpool

- Cosmetic fixes

- Fix to UT of Seq pool

Disabled grad checking for sequence max pool when is_test is set to True

-Cosmetic fix to comment

test=develop

- Fix to GPU build

test=develop

- yet another GPU fix for sequence max pool

- Fix to comment

test=develop

- Change to API of sequence_pool

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- Yet another API spec change

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* speedup split_op
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* speedup split_op
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* rename ConcatGrad to Split

* refine concat and split
test=develop

* fix compile error