Explain LoD and a few other concepts

fix demo_ci bug in vis_demo.cc

* fix layers.uniform_random

* fix uniform_random
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* remove var type set
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* fix similar error
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* optimize depthwise conv by register memory
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* profiler infor merge thread statistic information

* update profiler

* fix bug

* add merge thread msg to report

* optimize report

* statistic the time of ops in each thread but not all

* optimize report format

* optimize profile report

* optimize profile report
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Merge selected_rows for clip_by_norm op

Revert "[MKLDNN] Pass: Fuse Conv + Bias"

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[MKLDNN] Pass: Fuse Conv + Bias

* Fix truncated normal.

* test=develop

Sfraczek/conv bn fuse pass

add trt api lib to paddle_fluid lib

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Unit test to Fused_embedding_fc_lstm op

Fix flowers data read in python3

Make cmake support compile in MacOSX 10.14

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Revert "optimize pyreader"

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* set the right shape of selected_rows
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* enhance check

* fix activation_op

* remove cast

* use ShareDimInfo replace SetDim and ShareLod

* use ShareDimAndLod
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* follow comment

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* check whether the input has lod
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* Split ShareDimAndLod

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* checkout clip.py
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fix lod tensor

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* Fix bug in reduce_op caused by PR #13534
* Fix output shape and enhance unit test.
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revert with_fast_math to ON

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optimize pyreader

* "avoid copy back to cpu"

* "add infinity support"

* "fix ci"

* "add cpu macro"

* rerun ci; test=develop

* "fix api"
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