* This PR improve performance of prior_box op about 1.25x faster on CPU.

* Test Env:SKX 8180 with fake data on 28 threads(bs=1).
* The below table shows the ~25% improvement which generated by [eval_tp_fake_data.py](https://github.com/PaddlePaddle/Paddle/issues/15618#issuecomment-464613976).

| Type |Event | Calls |   Total     |  Min.    |   Max.      |  Ave.      |  Ratio.|
| ---------------- | ------------------ | ---- | ------- | -------- | -------- | ------------ | -------- |
| w/ optimization  | thread0::prior_box | 6000 | 921.201 | 0.110572 | 0.383402 | **0.153533** | 0.084585 |
| w/o optimization | thread0::prior_box | 6000 | 1151.85 | 0.102276 | 0.426702 | **0.191976** | 0.103337 |

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* Fix the style issue.

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Refactor MKL-DNN Sum to use reference version on fallback

* add alloc_continuous_space_op
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* Polish code
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* follow comment
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fix nightly build

fix build issue for cudaEvent_t

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accelerate memory optimize process

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Imperative training network to the end

Pass graph to parallel executor instead of program

fix build issue on windows for sample prop op

* refile profiler
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* follow comment
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* Refine doc of uniform_random and fix dtype
* Update defaule value in the arguments

add per kernel config and remove const_cast.

* - Implemented draft of primitive desc keeping in Tensor

test=develop

- TransposeMKLDNNHandler::AcquireSrcMemory was reimplemented

- Added nchw and nc formats setting for sake of compatiblity

Fixed unit tests

- Worakaround to problem with 5D data in conv

- Added 3D and 1D MKL-DNN formats for name handles for tensor

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- Fix to UTs

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- Conv fp32 op was updated

Cosmetic fixes

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- tensor mkldnn cosmetics

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- Moved most of mkl-dnn specific code from Tensor to mkl-dnn utils

* - Lint fixes

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* - setting prim dec in Tensor , sets also layout to kMKLDNN

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* - Moved creation of prim desc totally out of Tensor

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* - Cosmetic fixes adter review

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fix pool3d doc. test=develop

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fix bug for sampled softmax

fix cpu broadcast

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Change *(smart_ptr.get()) -> *smart_ptr

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* [Don't merge now]update_readme_to_1.3

* fix sth

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* update reademe_cn

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* fix en

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add sample_logits  and sampled_softmax_with_cross_entropy op

fix adaptive pool doc.test=develop

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