Optimize the concat and split cuda implementation for cases when the number of inputs/outputs is less than 5. (#17979)

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* fix save/load in Fleet
* add UT framework of Fleet

* Fix the GetExpectedKernelType of add_position_encoding_op.
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* Fix the doc of lstm_unit outputs in nn.py.
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* test=develop
The scatter op has a calc bug when the indices has same index, the scatter op use overwrite mode to calculate the same index, fix this bug by using the accumulate mode to calculate the same index.At the same time, the gather op has the same bug when the op calc the grad. And we use the lib of open-blas and eigen to optimize the time cost in accumulate mode.

* test=develop
Fix some code format problem, and the same time add the test case in gather and scatter op

Repair error prompt: Users are prompted to check whether the model or parameter files are damaged when loading parameters are wrong.

Fix bug in sequence_unpad op, when allocate the output memory do not match actual memory, check memory failed. Fix this bug by allocating the output memeory in correct code position.

* add deformable psroi pooling

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modify format

* fix bug

* test=develop run ci

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add API.spec

* add test_layers.py

* run ci again

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run ci again

* run ci again

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run ci again

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run ci again

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run ci again

* add space between two lines

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add space between two lines

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add space between lines

* test=develop
modify comment in nn.py

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add space between two lines

* test=develop
add space between two lines

* update API.spec

* run ci again

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run ci again

* rerun ci

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rerun ci

* change input shape

* run ci

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run ci

* modify format of nn.py

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update API.spec

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fix API doc

* modify API comment

* modift API comment

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update API.spec

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modify comment

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modift comment

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modift comment

* test=develop
update API.spec

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modify comment

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add inference in nn.py

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update API.spec

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resolve confict

* test=develop
update API.spec

* add unfold op
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* fix divide bug in python3 when calculating output width and height
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* add name=None in python api, move redundant code into inline function

* try to trigger ci for this code
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* - removed is_reusing_

* - Added TID to keys for reusing apart from softmax PD

* - compilation fix

* - Yet another compilation fix

* - Batch Norm and Conv adapted

* - Fix to softmax MT

* - Fixes to MT code of MKL-DNN

* - Lint fixes

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* update anakin-engine interfaces for content-dnn

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* support only-gpu mode of Anakin

modify eltwise parse

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* modification for thread-safe

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* Integrated template instance

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* increase template parameters

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* support MLU predictor

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* update anakin cmake files

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* update TargetWrapper::set_device

* update the initialization of anakin subgraph

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* use the default constructor of base class

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fix merge conflict of 'Remove attribute in Allocator::Allocate' and elementwise_add_mkldnn_op (#17949)

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* remove attribute in Allocator::Allocate, test=develop

* fix travis ci error, test=develop

* Enable seq_pool op to accept len 0 input

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* Update sequence_pool's api

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* Add more unittest cases for seq_pool op

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* Remove legacy comments

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* Don't use template in op maker

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* add reshape support tensor; test=develop

* fix reshape bug; test=develop

* change reshape attribute default value; test=develop

* fix reshape input name; test=develop

* fix reshape unitest; test=develop

* check dim tensor shape; test=develop

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fix bug: the lod_tensor_to_array op will aplly a new var but not release when dong inference (#17856)

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* Enable ngraph layer_norm operator

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* Disable/Enable cuda, new unit-test test=develop

* Fix use_cudnn test=develop

* Fixed test_layer test, new funciton is added test=develop

* set use_cudnn by default test=develop

* delay infershape test=develop

* fall back subblock to paddle test=develop

* fix edge cases test=develop

* remove output duplicates test=develop

* handle reshape2_grad infershape test=develop

* expand support tensor attribute; test=develop

* fix bug ; test=develop

* fix uni test bug; test=develop

* fix copy bug; test=develop

* refine expand_times default value; test=develop

* support some input tensor remain on cpu; test=develop

* fix input = none; test=develop

* fix unfound bug; test=develop

* fix proto None case; test=develop

* fix bug; test=develop

* fix proto null bug; test=develop

* remove conv check; test=develop

* fix test bug; test=develop

* move fill constant; test=develop

* no change in proto; test=develop

* fix bug; test=develop

* change attr detph name; test=develop

* remove remain cpu; test=develop

* fix bug; test=develop

* merge develop; test=develop

* fix one_hot bug; test=develop

* fix bug; test=develop

* fix bug; test=develop

* fix bug; test=develop

* fix python api bug; test=develop

Refactor the code to be OpenMP friendly

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* revise conv layer cudnn algo choose test=develop

* update for code style test=develop

* update for code style test=develop

* Enable elementwise_div operator test=develop

* Fix update date test=develop

* fix the bug of mobilenet-ssd INT8 inference without overloading GetHash
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* remove the out_grad->format() in TransposeMKLDNNGradOpKernel
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* unit commits, test=develop

* update API.spec, test=develop

* fix bug for ctr_reader test=develop

* fix svm data test=develop

fix svm data test=develop

* Enhance fused_elementwise_activation op.
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* Move the api fused_elementwise_activation to contrib.
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* Add including files.
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* Add the support of sigmoid in fused_elementwise_activetion op.

* Update API.spec.
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Optimize recurrent_op using Prepare and RunPreparedContext, avoiding create operators in every iter. (#17689)

test=develop