* 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

* Rename uniform and gaussian APIs

* rename uniform_random API as uniform

* Fixed unittest

* fixed unittest AttributeError

* Fixed unittest

* Add uniform function rather than alias

* remove templatedoc

* solve conflict and fix doc code

* fix doc code

* Update `paddle.clamp`

rename to `paddle.clip`
add fast path for dygraph mode
remove `out`
rename `input` -> `x`
update doc sample

* Fix leftover `Variable` wording

* Indent doc with spaces

* Remove `:alias` in docs

* Update `enable_imperative` -> `disable_static`

* Remove `imperative`

also trigger CI

* Update tests for better coverage

* Rebase to fix `cosine_similarity`

* Fix `cosine_similarity` some more

* Add new API: paddle.prod

test=develop

* fix the doc of dot

(1) Add api paddle.reshape(x, shape, name); 

(2) Use Tensor replaces Variable. test=develop

* rename input

* add unittest, test=develop

* use paddle.data instead of fluid.data, test=develop

* add pad func

* add pad

* test=develop, add pad op and apis

* restore pad2d

* test=develop, fix paddl declare

* fix pad interface

* test=develop, fix pad

* test=develop, add all pad api and cos_sim

* test=develop, remove padding default value

* test=develop, rename var to tensor

* test=develop, add more tests

* test=develop, rename tovar to totensor

* test=develop, fix init

* test=develop, add more test

* test=develop, add more tests

* 1.Fix api sum:(1) input->sum; (2)dim->axis; (3)keep_dim->keepdim.

* 2. fix bug when len(axis) == len(x.shape). 

align expand_as op to expand.

* Update `paddle.add`

remove `alpha`
update doc sample code
remove `:alias` etc

* Remove `imperative` reference from docstring

* adaptive expand op to 2.0 (align to torch.expand) , test=develop

* expose and unify the Tensor concepts to the user

* expose tensor to user

* add copy place for Tensor

* add copy place for Tensor

* add note

* add macro PADDLE_WITH_CUDA

* remove RUN_TYPE=DIST

* fix some error

* add tile_op, test=develop

* fix the doc of inverse, dot, cholesky