* 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 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

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

API(lstm_unit, lstmp, sequence_mask, sequence_enumerate, sequence_conv) error message enhancement (#27572)

* API(Compute) error message enhancement on line 44, 50, 53.

* lstm_unit error message enhancement.
lstmp error message enhancement.
sequence_conv error message enhencement.
sequence_enumerate error message enhencement.
sequence_mask error message enhencement.

* Update lstm_unit_op.cc

* Update lstm_unit_op.h

* error msg enhancement.

* Update sequence_conv_op.cc

* Update lstm_unit_op.cc

* Update sequence_conv_op.cc

* Update sequence_enumerate_op.cc

* Update sequence_enumerate_op.cu

* Update sequence_enumerate_op.h

* Update sequence_pool_op.h

* error message enhencement.

* error message enhancement.

* Optimize the error message for OPs.

* Optimize the error message for OPs in details.

* fix bilateral bug

Polish the error message of fc, fused_fc_elementwise_layernorm and fused_embedding_seq_pool. (#27692)

* Polish the error message of fc_op.

* Polish the error message of fused_fc_elementwise_layer_norm op.

* Polish an error message in fused_embedding_seq_pool_op.

* - condidate fix to issue #25537

test=develop

* - UT for transpose NHWC

test=develop

test=develop