test=develop

* human readable memory warns test=develop

* update test=develop

* refine test=develop

* fix build test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

* Support softmax return in softmax_with_cross_entropy

* Add test for return_softmax=False

test=develop

Density prior box operator for image detection model.

test=develop

* Add int type support for stack_op

* Improve gather op to support index with shape N x 1

test=develop

* Fix stack_op kernel's registry

test=develop

test=develop

test=develop

test=develop

test=develop

* add lod tensor array concat

* add lod tensor array concat

* test=develop

* add lod tensor array concat
test=develop

* Fix API.spec
test=develop

* add lod tensor array concat
test=develop

* revise some bug of lod tensor array concat
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* add unittest for tensor array concat
test=develop

* change to tensor array to tensor
test=develop

* revise bug
test=develop

* revise a bug
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* revise a bug
test=develop

* revise a bug of python3
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* add_infer_var_type
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* InferVarTypeHelper-> VarTypeInferenceHelper
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* PassInputTypeAndDTypeOnOutput
 test=develop

* follow comment
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test=develop

* exhaustive search for cuDNN conv.
* Refine code and add unit testing.
* Fix model load in fluid/inference and unit testing in conv2d
* Follow comments.
* Fix compiling test=develop

test=develop

* fix input<tensor>
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* fix split_ids
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* ElementwiseMul should not support SelectedRows

* fix scale op
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* change GetTensorFromVar() method to GetTensorOrSelectedRowsFromVar()

* fix operator

* refine MultiOutput

* fix MultiOutput
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* disable test_dist_save_load
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* fix elementwise_op
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* add get_sparse_as_op
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* add info for check
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* rename get_sparse_as_op with extract_rows_as_op.
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* elementwise doesn't support selected_rows

* fix regularizer

* remove extract_rows_as
test=develop

* fix ci
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* add test for sum_op

* fix regularizer
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*  test=develop

* fix pserver weight decay multi inputs test=develop

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test=develop

Fix code to support cpplint syntax check

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