* add double grad for tile, test=develop

* add double grad for expand_v2 op, test=develop

* add double grad for expand, test=develop

* add some unittest cases ot verify jit.save, no_test

* add more unittests

* add test with example inputs

* polish implement details

* remove useless blank

* fix fetch random error

* parameter_server_optimizer support auto_strategy

 fix the CudaPinMemory bug for the equal op and add the test case for the equal op

Decrease the number of running iterations to reduce CI time.

CI system shows it decreased the unittest time from about 90 seconds to about 30 seconds

add lars to fleet meta optimizer

* refine launch and distributed repr string for print

* set default value to strategy in distributed_optimizer test=develop

* update requirements.txt

* add unittest_py directory and add new requirements.txt file,test=document_fix

* add unittest_py directory and add new requirements.txt file,test=document_fix

* Add naming rule if not specific InputSpec.name

* fix function name typo

* refine comment

* remove print statement

* fix frobenius_norm error, rm p=0 2-axis support. test=develop

* fix summary rnn

* fix kl_div bug when input shape is [1] and reduction is batchmean

* enhance collect_op for dygraph, test=develop

* enhance detection ops with lod, test=develop

* support none bbox left in generate_proposals, test=develop

* unfiy MultiLevelRoisNum, test=develop

* update core.ops, test=develop

* add op register for new input & output, test=develop

* test=develop, add ps auto

* add correlation api to contrib

* fix weight

* fix weight and fix doc

* fix embeeding padding idx

* add UT

* fix interval

* delate some wrong message test=develop, test=document_fix

* delate some wrong message

* fix unsqueeze in dygraph

* add test

* add test

* fix typo for interp_v2,test=develop

* align with torch, test=develop

* add area mode, test=develop

* fix bug, test=develop

* format notes, test=develop

* update for converage, test=develop

* fix bilinear, test=develop

* fix bicubic, test=develop

* fix typo, test=develop

* fix coverage, test=develop

* fix helper.input_dtype, test=develop

* polish notes, test=develop

* polish notes, test=develop

* polish notes, test=develop

* fix 2.0api, test=develop

* fix, test=develop

* fix the localsgd

* change configs to config & update examples

* fix deprecate decorator conflict

* add auto parallel L1 implementation
test=develop

fix the bug for dtype check for the argmin/argmax

test=develop

* fix dimensions error for mobilenetv1_KL_quant

fixes AssertionError: The size of weight scales vector (1000) does not match the number of output channels (1024) in the weights tensor fc7_weights.

add mul test

* remove comment

* add third case unit test

remove the dependence of matplotlib  in dataset of uci_housing