* refine paddle.stack

* support TensorArray

* add test

* fix coverage problem

* fix coverage problem

* fix sample code

* set_default_type only take effect on python floats or complex

* fix doc

* add check for bernoulli and register bool for unsqueeze

* follow comments

* set default dtype for distribution API

* Add unittest

* Add unittest

* fix import get_default_dtype problem

* delete change under fluid.layers.nn

* little change

* add set_default_type for tensor

* fix doc

* fix doc

add parameters check in static mode for diag op 

* Fix clip input check

* Fix default min/max value

* Allow both max and min to be None

* Register op change

* Revert OP signature change

As the title

* update doc, test=document_fix

* add attr(dtype)

* refine code

* fix the tanh

* fix the learning rate

add the top v2 for the paddlepaddle api 2.0

Co-authored-by: Nwujionghao <wujionghao@email.com>
As the title

* add unique_v2 op

* remove unique_v2 op

* update doc

* Refine typo of english document of paddle.prod

test=document_fix

* add div, floor_div, remainder

add the isnan, isfinite, isinf api for the paddle 2.0

* add the new api and op for the argmax, argmin

add paddle.tensor.linalg.diag API, diag_v2 OP and CUDA kernel.

* add matmul_v2

* fix docstring, test=document_fix

* fix the comment of scatter

* add bernoulli op

* fix cuda kernel and add unit test

* refine doc

* fix uniform

* fix the example codes, test=develop