* add double grad for tile, test=develop

* add double grad for expand_v2 op, test=develop

* add double grad for expand, test=develop

* - introducing oneDNN 1.6

test=develop

* - Removed redundant code

test=develop

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

update error info for selected_rows_functor

add lars to fleet meta optimizer

* set default value to strategy in distributed_optimizer test=develop

optimize the error message for math dir

* 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

* add correlation api to contrib

fix the error message for the unpooling.cc

* 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

* add lstm cudnn of padding data and refine cudnn codes

update the check for the dtype check for the argmin, argmax

* - Added fix to mobilenet

* - compilation fix

* - Fix to conv2d grad oneDNN with groups

test=develop

support heter-xpu-ps

test=develop

* fix dropout bug in backward when input is 1d tensor, test=develop

* add test case and refine error message, test=develop

* refine error message, test=develop

test=develop

* fix eigen in push sparse; fix hadoop command
test=develop

* add log in load_combine_op
test=develop

* fix the argmin,argmax op for the paddlepaddle 2.0， add checkPoint for the argmax/argmin

* fix fluid.embedding

* add check for bernoulli and register bool for unsqueeze

* follow comments

* add embedding 2.0

* add embedding support input int32