* add multitask

* add multitask, test=develop

* fix code style, test=develop

* add partail push dense, test=develop

* fix has_kay in py3, test=develop

* fix, test=develop

* fix, test=develop

* fix, test=develop

* fix norm api doc, test=develop

* fix error message, test=develop

* fix api norm, test=develop

* add adagrad, test=develop

* fix bug, test=develop

* fix bug, test=develop

* add spetral_norm, test=develop

* fix adagrad, test=develop

* merge , test=develop

* add lookup_table_v2_op_xpu, test=kunlun

* add lookup_table_v2_op_xpu, test=kunlun

* change some Tips ,test=kunlun

* use exhaustive_search for float16

* tune algo only when dtype is float16

* add dropout,log_loss, test=kunlun
* fix dropout, test=kunlun
* polish error message, test=kunlun
* change boost::get to BOOST_GET_CONST, test=kunlun
* fix copyright, test=kunlun

* support mean,softmax_with_cross_entropy on Baidu Kunlun,test=kunlun

* fix unittests error,test=kunlun

* delete boost::get,test=kunlun

* add xpu sgd & momentum

* add sumary feature

* refine printting tensor

* add sci_mode

* add sample code

* fix indent error

* fix _format_item

* polish code

* support item indent

* add ut

* set place for ut

* fix py2 issue

* fix ut

* add conv for xpu, test=kunlun

* polish error_message, test=kunlun

* polish error_message, test=kunlun

* fix copyrigth, test=kunlun

* add xpu slice op
test=xpu

* add slice xpu op
test=xpu

* code style
test=kunlun

* style
test=kunlun

* format
test=kunlun

* op error info

* style

* code format

* add gather_op xpu, test=develop, test=kunlun

* fix ut, test=develop, test=kunlun

* fix the ut,test=develop, test=kunlun

* refine fleetrun.ps_launch

* update fleet run for multi device support

* ps_graph support ps-gpu

* fix heter save

* add heter save unittest

* fix unittest & simple code

* update fleetrun

* fix fleetrun

* fix launch barrier

* fix role maker

* add paddlecloud rolemaker unittest

* rename heter_worker_device_guard

* add info log for trt input dynamic shape check

* fix error msg error

test=develop

* add load_op_xpu for Baidu Kunlun, test=kunlun

* add is_compiled_with_xpu for unit test, test=kunlun

* add is_compiled_with_xpu for unit test, test=kunlun

* use IndexList to improve performance, test=develop

* remove EIGEN_HAS_INDEX_LIST, test=develop

* use IndexList only when EIGEN_HAS_INDEX_LIST is true

* add flattern weight of lstm

* error message optimization in softmax_with_cross_entropy_op

* fix some unsuited comment

* Add double grad in Squeeze and Unsqueeze

* Add double grad in Squeeze and Unsqueeze

Add xpu kernel for KUNLUN core:

* accuracy op
* sign op
* scale op
* sum op

Add default atol in xpu unittest.

* Add test attribute in channelwise_quant op, test=develop

* add matmul doublegrad op

* fix compile errors

* modify code according to review

* delete float16

* fix pool3d bug, test=develop

* fix unitest, test=develop

* fix test and fix pool2d bug, test=develop