* test=develop

* Make layers.reshape/expand/slice in dygraph support var inputs.
Make transpose support size 0.
test=develop

* Update layers.expand and layers.slice to support var inputs.
test=develop

* enhance pad.* error message, test=develop

 fix compare and logical ops cond/out parameter doc bug，correct the dtype message 

* enhance error message test=develop

* fix CI test of 3 op test=develop

* fix bug caused by the diff of long type in py2 and py3, test=develop

* fix error message of l2_normalize, matmul, mean, etc. 
* add the test case for those ops

* OP clip, merge_lod_tensor, convert/elementwise error message enhancement. test=develop

API/OP (center_loss, fluid.one_hot, prroi_pool, roi_pool, ctc_greed_decoder) error message enhancement (#23794)

* error message enchanced, test=develop

* error message enchanced for APIs, test=develop

* error message enhanced for roi_pool, test=develop

* update added code, test=develop

* update fluid/input.py, test=develop

* update fluid/input.py ,test=develop

* fix code style, test=develop

* fix lower converage, test=develop

* error message enhanced for roi pool, test=develop

* fix bug in reduce op test=develop

* fix bug in reduce op test=develop

* enhance error message test=develop

* enhance error message test=develop

* change to INOUT_CHECK  test=develop

Fix the scale fp16 dtype support for scale op, and delete the test case for fp16 case

* add approximation for gelu, test=develop

* add functional conv

* add test and doc for function convs, test=develop

* update ConvTransposeOp's InferShape and error message, test=develop

* add hsigmoid, row_conv in paddle.nn(functional and layer), test=develop

* fix hyperlinks in docstring

* enhance error message, test=develop

* optimize compare and logical ops error info
* add out and cond dtype test

* error message enhance for clip_by_norm. test=develop

* fix clip_by_norm. test=develop

* fix clip error message. test=develop

1. update error info of the ops (abs, acos, asin, atan, ceil, cos, exp, floor, log, pow, reciprocal, round, rsqrt, sin, sqrt, square, tanh)
2. add the unittests of the above refered ops (test error info)

API(has_inf, has_nan, cumsum, fsp_matrix, increment) error message enhancement, test=develop (#23769)

* API(argsort, argmax, argmin, cast, diag) add error message，and the same time add the test cases for those apis.

Those ops include，scale， sum， sums，unique_with_counts，unique，
wherre， add error message and test case

* error enhance,test=develop

* update,test=develop

* update type, test=develop

* replace inout_check, test=develop

Ops(relu6/selu/soft_relu/softshrink/stanh/swish/thresholded_relu/hard_shrink/hard_sigmoid/hard_swish/hsigmoid/maxout) error message enhancement (#23718)

OP(retinanet_detection_output, retinanet_target_assign, sigmoid_focal_loss, deformable_roi_pooling) error message enhancement. test=develop (#23726)

* test=develop modify some op for dyg rcnn

* refine example code in en doc, test=develop, test=document_fix

* update shape to make it meaningful, test=develop, test=document_fix

error message enhancement for py_func op. 

* solve the conflict of ops with the same name. test=develop

* rename op paddle.fluid.matmul to paddle.matmul
* modify original API fluid.layers.matmul,and add new API paddle.matmul

* Add the matmul, elementwise_euqal, elementwise_sum ops to API2.0
* Fix the import meesage in common_ops_import
* Update the test cast for mm

This reverts commit abe3e690.
test=develop

* solve the conflict of ops with the same name. test=develop